Sample records for flame retention head

  1. Running heading: Water retention properties of the clay in clayey soils Water retention properties of the clay in soils developed

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    1 Running heading: Water retention properties of the clay in clayey soils Water retention properties of the clay in soils developed on clayey sediments: Significance of parent material and soil of clayey subsoils horizons according to the variation of clay characteristics. The horizons studied

  2. Direct numerical simulations of type Ia supernovae flames I: The landau-darrieus instability

    E-Print Network [OSTI]

    Bell, J.B.; Day, M.S.; Rendleman, C.A.; Woosley, S.E.; Zingale, M.

    2003-01-01T23:59:59.000Z

    Simulations of Type Ia Supernovae Flames I: The Landau-Subject headings: supernovae: general — white dwarfs —could occur in Type Ia supernovae (Niemeyer & Woosley 1997),

  3. Direct numerical simulations of type Ia supernovae flames II: The rayleigh-taylor instability

    E-Print Network [OSTI]

    Bell, J.B.; Day, M.S.; Rendleman, C.A.; Woosley, S.E.; Zingale, M.

    2004-01-01T23:59:59.000Z

    Weaver, T. A. 1994, in Supernovae, Les Houches, Session LIV,Simulations of Type Ia Supernovae Flames II: The Rayleigh-Subject headings: supernovae: general — white dwarfs —

  4. Flame front configuration of turbulent premixed flames

    SciTech Connect (OSTI)

    Furukawa, Junichi [Tokyo Metropolitan Technical Coll. (Japan). Dept. of Mechanical Engineering] [Tokyo Metropolitan Technical Coll. (Japan). Dept. of Mechanical Engineering; Maruta, Kaoru [Tohoku Univ., Sendai (Japan). Inst. of Fluid Science] [Tohoku Univ., Sendai (Japan). Inst. of Fluid Science; Hirano, Toshisuke [Univ. of Tokyo (Japan). Dept. of Chemical System Engineering] [Univ. of Tokyo (Japan). Dept. of Chemical System Engineering

    1998-02-01T23:59:59.000Z

    The present study is performed to explore dependence of the wrinkle scale of propane-air turbulent premixed flames on the characteristics of turbulence in the nonreacting flow, burner size, and mixture ratio. The wrinkle scales are examined and expressed in the frequency distribution of the radii of flame front curvatures. The average wrinkle scale depends not only on the characteristics of turbulence in the nonreacting flow but also on burner diameter and mixture ratio. The average wrinkle scale of a lean propane-air flame is larger than those of the near stoichiometric and rich flames. The smallest wrinkle scale of turbulent premixed flame is in the range of 0.75--1.0 mm, which is much larger than the Kolmogorov scale of turbulence in the nonreacting flow.

  5. Electrical probe diagnostics for the laminar flame quenching distance

    SciTech Connect (OSTI)

    Karrer, Maxime; Makarov, Maxime [Renault Technocentre, 78288 Guyancourt Cedex (France); Bellenoue, Marc; Labuda, Sergei; Sotton, Julien [Laboratoire de Combustion et de Detonique, CNRS, 86961 Futuroscope Chasseneuil (France)

    2010-02-15T23:59:59.000Z

    A simplified theory, previously developed for the general case of weakly ionized gas flow, is used to predict electrical probe response when the flame is quenched on the probe surface. This theory is based on the planar model of space charge sheaths around the measuring electrode. For the flame quenching case, by assuming that the sheath thickness is comparable with the thermal boundary layer thickness, probe current can be related to flame quenching distance. The theoretical assumptions made to obtain the analytical formulation of probe current were experimentally proved by using direct visualization and high-frequency PIV. The direct visualization method was also used to validate the results of flame quenching distance values obtained with electrical probe. The electrical probe diagnostics have been verified for both head-on and sidewall flame quenching regimes and for stoichiometric methane/air and propane/air mixtures in a pressure range of 0.05-0.6 MPa. (author)

  6. On the Flame Height Definition for Upward Flame Spread 

    E-Print Network [OSTI]

    Consalvi, Jean L; Pizzo, Yannick; Porterie, Bernard; Torero, Jose L

    2007-01-01T23:59:59.000Z

    Flame height is defined by the experimentalists as the average position of the luminous flame and, consequently is not directly linked with a quantitative value of a physical parameter. To determine flame heights from ...

  7. Three-dimensional numerical simulations of Rayleigh-Taylor unstable flames in type Ia supernovae

    E-Print Network [OSTI]

    Zingale, M.; Woosley, S.E.; Rendleman, C.A.; Day, M.S.; Bell, J.B.

    2005-01-01T23:59:59.000Z

    Unstable Flames in Type Ia Supernovae M. Zingale 1 , S. E.Subject headings: supernovae: general — white dwarfs —ame in Type Ia supernovae (SNe Ia) is well recognized (M¨

  8. Approaches to modeling thermonuclear flames

    E-Print Network [OSTI]

    J. C. Niemeyer; W. K. Bushe; G. R. Ruetsch

    Turbulence-flame interactions of thermonuclear fusion flames occurring in Type Ia Supernovae were studied by means of incompressible DNS with a highly simplified flame description. The flame is treated as a single diffusive scalar field with a nonlinear source term. It is characterized by its

  9. Dynamics and structure of stretched flames

    SciTech Connect (OSTI)

    Law, C.K. [Princeton Univ., NJ (United States)

    1993-12-01T23:59:59.000Z

    This program aims to gain fundamental understanding on the structure, geometry, and dynamics of laminar premixed flames, and relate these understanding to the practical issues of flame extinction and stabilization. The underlying fundamental interest here is the recent recognition that the response of premixed flames can be profoundly affected by flame stretch, as manifested by flow nonuniformity, flame curvature, and flame/flow unsteadiness. As such, many of the existing understanding on the behavior of premixed flames need to be qualitatively revised. The research program consists of three major thrusts: (1) detailed experimental and computational mapping of the structure of aerodynamically-strained planar flames, with emphasis on the effects of heat loss, nonequidiffusion, and finite residence time on the flame thickness, extent of incomplete reaction, and the state of extinction. (2) Analytical study of the geometry and dynamics of stretch-affected wrinkled flame sheets in simple configurations, as exemplified by the Bunsen flame and the spatially-periodic flame, with emphasis on the effects of nonlinear stretch, the phenomena of flame cusping, smoothing, and tip opening, and their implications on the structure and burning rate of turbulent flames. (3) Stabilization and blowoff of two-dimensional inverted premixed and stabilization and determining the criteria governing flame blowoff. The research is synergistically conducted through the use of laser-based diagnostics, computational simulation of the flame structure with detailed chemistry and transport, and mathematical analysis of the flame dynamics.

  10. Segmented vs conventional numerals: legibility and long term retention

    E-Print Network [OSTI]

    Hill, Steve Edgar

    1971-01-01T23:59:59.000Z

    SEGMENTED VS CONVENTIONAL NUMERALS: LEGIBILITY AND LONG TERM RETENTION A Thesis by STEVE EDGAR HILL Submitted to the Graduate College of Texas A8cM University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE... December 1971 Ma]or Subject: Industrial Engineering SEGMENTED VS CONVENTIONAL NUMERALS: LEGIBILITY AND LONG TERM RETENTION A Thesis STEVE EDGAR HILL Approved as to style and content by: Elias Chairman of Committee) r. A. W. ortham (Head...

  11. advanced flame quality: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    to modeling thermonuclear flames CiteSeer Summary: Turbulence-flame interactions of thermonuclear fusion flames occurring in Type Ia Supernovae were studied by means of...

  12. aircraft cargo flame: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    to modeling thermonuclear flames CiteSeer Summary: Turbulence-flame interactions of thermonuclear fusion flames occurring in Type Ia Supernovae were studied by means of...

  13. aerosol flame deposition: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    to modeling thermonuclear flames CiteSeer Summary: Turbulence-flame interactions of thermonuclear fusion flames occurring in Type Ia Supernovae were studied by means of...

  14. On the critical flame radius and minimum ignition energy for spherical flame initiation

    SciTech Connect (OSTI)

    Chen, Zheng; Burke, M. P.; Ju, Yiguang

    2011-01-01T23:59:59.000Z

    Spherical flame initiation from an ignition kernel is studied theoretically and numerically using different fuel/oxygen/helium/argon mixtures (fuel: hydrogen, methane, and propane). The emphasis is placed on investigating the critical flame radius controlling spherical flame initiation and its correlation with the minimum ignition energy. It is found that the critical flame radius is different from the flame thickness and the flame ball radius and that their relationship depends strongly on the Lewis number. Three different flame regimes in terms of the Lewis number are observed and a new criterion for the critical flame radius is introduced. For mixtures with Lewis number larger than a critical Lewis number above unity, the critical flame radius is smaller than the flame ball radius but larger than the flame thickness. As a result, the minimum ignition energy can be substantially over-predicted (under-predicted) based on the flame ball radius (the flame thickness). The results also show that the minimum ignition energy for successful spherical flame initiation is proportional to the cube of the critical flame radius. Furthermore, preferential diffusion of heat and mass (i.e. the Lewis number effect) is found to play an important role in both spherical flame initiation and flame kernel evolution after ignition. It is shown that the critical flame radius and the minimum ignition energy increase significantly with the Lewis number. Therefore, for transportation fuels with large Lewis numbers, blending of small molecule fuels or thermal and catalytic cracking will significantly reduce the minimum ignition energy.

  15. Drug Retention Times

    SciTech Connect (OSTI)

    Center for Human Reliability Studies

    2007-05-01T23:59:59.000Z

    The purpose of this monograph is to provide information on drug retention times in the human body. The information provided is based on plausible illegal drug use activities that might be engaged in by a recreational drug user

  16. Drug Retention Times

    SciTech Connect (OSTI)

    Center for Human Reliability Studies

    2007-05-01T23:59:59.000Z

    The purpose of this monograph is to provide information on drug retention times in the human body. The information provided is based on plausible illegal drug use activities that might be engaged in by a recreational drug user.

  17. Flame Spectral Analysis for Boiler Control 

    E-Print Network [OSTI]

    Metcalfe, C. I.; Cole, W. E.; Batra, S. K.

    1987-01-01T23:59:59.000Z

    FLAME SPECTRAL ANALYSIS FOR BOILER CONTROL CHRISTOPHER I. METCALFE WILLIAM E. COLE SUSHIL K. BATRA Tecogen, Inc. ( A Subsidiary of Thermo Electron Corporation) Waltham, Massachusetts ABSTRACT SPECTRAL FLAME ANALYSIS FOR BURNER CONTROL During...

  18. Transient Supersonic Methane-Air Flames

    E-Print Network [OSTI]

    Richards, John L.

    2012-07-16T23:59:59.000Z

    The purpose of this study was to investigate the thermochemical properties of a transient supersonic flame. Creation of the transient flame was controlled by pulsing air in 200 millisecond intervals into a combustor filled with flowing methane...

  19. Characterization of acoustically forced swirl flame dynamics

    E-Print Network [OSTI]

    Lieuwen, Timothy C.

    of the flame to acoustic excitation is required. This study presents an analysis of phase-locked OH PLIF images of acoustically excited swirl flames, to identify the key controlling physical processes and qualitatively discuss, and whose relative significance depends upon forcing frequency, amplitude of excitation, and flame

  20. Premixed-gas flames Paul D. Ronney

    E-Print Network [OSTI]

    Premixed-gas flames Paul D. Ronney Department of Aerospace and Mechanical Engineering University of Southern California, Los Angeles, CA 90089-1453 USA ronney@usc.edu Keywords: Microgravity; premixed-gas; cool flames; turbulence. Reference: Ronney, P. D., "Premixed-Gas Flames," in: Microgravity Combustion

  1. Detection of OH in a flame by degenerate four-wave mixing

    SciTech Connect (OSTI)

    Ewart, P.; O'Leary, S.V.

    1986-05-01T23:59:59.000Z

    The detection of OH in a laminar premixed air-methane flame by degenerate four-wave mixing (DFWM) is reported. The four-wave mixing spectrum was recorded in the region of the R/sub 1/, R/sub 2/ band heads of the (0, 0) /sup 2/..sigma..-/sup 2/Pi transition, showing clearly resolved rotational structure. Applications of the DFWM technique to combustion diagnostics are discussed. As an example, the distribution of sodium atoms in a sodium-seeded flame has been measured using a 90/sup 0/ geometry to enhance spatial resolution.

  2. Electric-field-induced flame speed modification

    SciTech Connect (OSTI)

    Marcum, S.D. [Department of Physics, Miami University, Oxford, OH 45056 (United States); Ganguly, B.N. [Air Force Research Laboratory, Wright-Patterson AFB, OH 45433 (United States)

    2005-10-01T23:59:59.000Z

    The effects of pulsed and continuous DC electric fields on the reaction zones of premixed propane-air flames have been investigated using several types of experimental measurements. All observed effects on the flame are dependent on the applied voltage polarity, indicating that negatively charged flame species do not play a role in the perturbation of the reaction zone. Experiments designed to characterize the electric-field-induced modifications of the shape and size of the inner cone, and the concomitant changes in the temperature profiles of flames with equivalence ratios between 0.8 and 1.7, are also reported. High-speed two-dimensional imaging of the flame response to a pulsed DC voltage shows that the unperturbed conical flame front (laminar flow) is driven into a wrinkled laminar flamelet (cellular) geometry on a time scale of the order of 5 ms. Temperature distributions derived from thin filament pyrometry (TFP) measurements in flames perturbed by continuous DC fields show similar large changes in the reaction zone geometry, with no change in maximum flame temperature. All measurements are consistent with the observed flame perturbations being a fluid mechanical response to the applied field brought about by forcing positive flame ions counter to the flow. The resulting electric pressure decreases Lewis numbers of the ionic species and drives the effective flame Lewis number below unity. The observed increases in flame speed and the flame fronts trend toward turbulence can be described in terms of the flame front wrinkling and concomitant increase in reaction sheet area. This effect is a potentially attractive means of controlling flame fluid mechanical characteristics. The observed effects require minimal input electrical power (<1 W for a 1 kW burner) due to the much better electric field coupling achieved in the present experiments compared to the previous studies.

  3. Flex-flame burner and combustion method

    DOE Patents [OSTI]

    Soupos, Vasilios (Chicago, IL); Zelepouga, Serguei (Hoffman Estates, IL); Rue, David M. (Chicago, IL); Abbasi, Hamid A. (Naperville, IL)

    2010-08-24T23:59:59.000Z

    A combustion method and apparatus which produce a hybrid flame for heating metals and metal alloys, which hybrid flame has the characteristic of having an oxidant-lean portion proximate the metal or metal alloy and having an oxidant-rich portion disposed above the oxidant lean portion. This hybrid flame is produced by introducing fuel and primary combustion oxidant into the furnace chamber containing the metal or metal alloy in a substoichiometric ratio to produce a fuel-rich flame and by introducing a secondary combustion oxidant into the furnace chamber above the fuel-rich flame in a manner whereby mixing of the secondary combustion oxidant with the fuel-rich flame is delayed for a portion of the length of the flame.

  4. Design, Modeling, and Validation of a Flame Reformer for LNT...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Design, Modeling, and Validation of a Flame Reformer for LNT External Bypass Regeneration Design, Modeling, and Validation of a Flame Reformer for LNT External Bypass Regeneration...

  5. Effect of Nitrogen Additives on Flame Retardant Action of Tributyl...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Nitrogen Additives on Flame Retardant Action of Tributyl Phosphate: Phosphorus – Nitrogen Synergism. Effect of Nitrogen Additives on Flame Retardant Action of Tributyl...

  6. Flame acceleration studies in the MINIFLAME facility

    SciTech Connect (OSTI)

    Tieszen, S.R.; Sherman, M.P.; Benedick, W.B.

    1989-07-01T23:59:59.000Z

    Flame acceleration and deflagration-to-detonation transition (DDT) studies have been conducted in a 19.4-cm high, 14.5-cm wide, and 2. 242-m long channel (MINIFLAME) that is a 1:12.6 scale model of the 136-m{sup 3} FLAME facility. Tests were conducted with two levels of hydrogen concentration -- 20% and 30%, with and without obstacles in the channel, and with three levels of transverse top venting -- 0%, 13%, and 50%. The flame acceleration results in MINIFLAME are qualitatively similar to those in FLAME; however, the small-scale results are more benign quantitatively. The results show that insufficient venting, 13% venting in this case, can promote flame acceleration due to turbulence produced by the flow through the vents in smooth channels. However, with obstacle-generated turbulence in the channel, 13% top venting was found to be beneficial. Flame acceleration resulting in DDT was shown to occur in as little as 35 liters of mixture. Comparison of the DDT data with obstacles in MINIFLAME and FLAME supports d/{lambda} scaling of DDT, where {lambda} is the detonation cell width of the mixture and d is the characteristic open diameter of the channel. In the MINIFLAME and FLAME tests, DDT occurred for d/{lambda} greater than approximately three. Comparison with other experiments shows that the value of d/{lambda} for DDT is not constant but depends on the obstacle type, spacing, and channel geometry. The comparison of MINIFLAME and FLAME experiments extends the use of d/{lambda} scaling to different geometries and larger scales than previous studies. Small-scale-model testing of flame acceleration and DDT with the same combustible mixture as the full-scale prototype underpredicts flame speeds, overpressures, and the possibility of DDT. 18 refs., 16 figs.

  7. Flame Interactions in Turbulent Premixed Twin V-flames

    E-Print Network [OSTI]

    Dunstan, T. D.; Swaminathan, N.; Bray, K. N. C.; Kingsbury, N. G.

    2013-01-16T23:59:59.000Z

    diminish with increasing turbulence intensity, and so it is unlikely that any significant influence remains within the regions of interest for the flames presented here. It should also be noted that no energy is added to the flow in the current implemen... . A flow-chart summary is given in Fig. 2, and an example of the procedure applied to two-dimensional test data is shown in Fig. 3. The AFE procedure used here comprises three principal stages: (1) the binarised c field data from two successive time...

  8. Active control for turbulent premixed flame simulations

    SciTech Connect (OSTI)

    Bell, John B.; Day, Marcus S.; Grcar, Joseph F.; Lijewski, Michael J.

    2004-03-26T23:59:59.000Z

    Many turbulent premixed flames of practical interest are statistically stationary. They occur in combustors that have anchoring mechanisms to prevent blow-off and flashback. The stabilization devices often introduce a level of geometric complexity that is prohibitive for detailed computational studies of turbulent flame dynamics. As a result, typical detailed simulations are performed in simplified model configurations such as decaying isotropic turbulence or inflowing turbulence. In these configurations, the turbulence seen by the flame either decays or, in the latter case, increases as the flame accelerates toward the turbulent inflow. This limits the duration of the eddy evolutions experienced by the flame at a given level of turbulent intensity, so that statistically valid observations cannot be made. In this paper, we apply a feedback control to computationally stabilize an otherwise unstable turbulent premixed flame in two dimensions. For the simulations, we specify turbulent in flow conditions and dynamically adjust the integrated fueling rate to control the mean location of the flame in the domain. We outline the numerical procedure, and illustrate the behavior of the control algorithm. We use the simulations to study the propagation and the local chemical variability of turbulent flame chemistry.

  9. Correlation of flame speed with stretch in turbulent premixed methane/air flames

    SciTech Connect (OSTI)

    Chen, J.H.; Im, Hong G.

    1997-11-01T23:59:59.000Z

    In the flamelet approach of turbulent premixed combustion, the flames are modeled as a wrinkled surface whose propagation speed, termed the {open_quotes}displacement speed,{close_quotes} is prescribed in terms of the local flow field and flame geometry. Theoretical studies suggest a linear relation between the flame speed and stretch for small values of stretch, S{sub L}/S{sub L}{sup 0} = 1 - MaKa, where S{sub L}{sup 0} is the laminar flame speed, Ka = {kappa}{delta}{sub F}/S{sub L}{sup 0} is the nondimensional stretch or the Karlovitz number, and Ma = L/{delta}{sub F} is the Markstein number. The nominal flame thickness, {delta}{sub F}, is determined as the ratio of the mass diffusivity of the unburnt mixture to the laminar flame speed. Thus, the turbulent flame model relies on an accurate estimate of the Markstein number in specific flame configurations. Experimental measurement of flame speed and stretch in turbulent flames, however, is extremely difficult. As a result, measurement of flame speeds under strained flow fields has been made in simpler geometries, in which the effect of flame curvature is often omitted. In this study we present results of direct numerical simulations of unsteady turbulent flames with detailed methane/air chemistry, thereby providing an alternative method of obtaining flame structure and propagation statistics. The objective is to determine the correlation between the displacement speed and stretch over a broad range of Karlovitz numbers. The observed response of the displacement speed is then interpreted in terms of local tangential strain rate and curvature effects. 13 refs., 3 figs.

  10. Modelling of turbulent stratified flames

    E-Print Network [OSTI]

    Darbyshire, Oliver Richard

    ) shows data with a negative correlation, (b) shows data with no correlation and (c) shows data with a positive correlation. . . . . . . . . 44 3.3 Flow chart of the SIMPLE algorithm. . . . . . . . . . . . . . . . . . . . . 50 3.4 Schematic of the V... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55 4.1 Comparison of predicted and measured velocities (m/s) and turbulence kinetic energy (m2/s2) for the cold flow ORACLES experiment. . . . . . 64 4.2 Comparison of cold flow results for the V-flame case. Mean axial velocity is shown on the left...

  11. Aromatics oxidation and soot formation in flames

    SciTech Connect (OSTI)

    Howard, J.B.; Pope, C.J.; Shandross, R.A.; Yadav, T. [Massachusetts Institute of Technology, Cambridge (United States)

    1993-12-01T23:59:59.000Z

    This project is concerned with the kinetics and mechanisms of aromatics oxidation and soot and fullerenes formation in flames. The scope includes detailed measurements of profiles of stable and radical species concentrations in low-pressure one-dimensional premixed flames. Intermediate species identifications and mole fractions, fluxes, and net reaction rates calculated from the measured profiles are used to test postulated reaction mechanisms. Particular objectives are to identify and to determine or confirm rate constants for the main benzene oxidation reactions in flames, and to characterize fullerenes and their formation mechanisms and kinetics.

  12. atomic-absorption flame photometry: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    to modeling thermonuclear flames CiteSeer Summary: Turbulence-flame interactions of thermonuclear fusion flames occurring in Type Ia Supernovae were studied by means of...

  13. Flame Spectral Analysis for Boiler Control

    E-Print Network [OSTI]

    Metcalfe, C. I.; Cole, W. E.; Batra, S. K.

    range from the flames and using these measurements to determine the burner operating conditions. Two prototype instruments have been installed on package boilers at a Con Edison powerplant and Polaroid facility, and their performance has been evaluated...

  14. Theory of DDT in unconfined flames

    E-Print Network [OSTI]

    Khokhlov, A M; Wheeler, J C; Wheeler, J Craig

    1996-01-01T23:59:59.000Z

    This paper outlines a theoretical approach for predicting the onset of detonation in unconfined turbulent flames which is relevant both to problems of terrestrial combustion and to thermonuclear burning in Type Ia supernovae. Two basic assumuptions are made: 1) the gradient mechanism is the inherent mechanism that leads to DDT in unconfined conditions, and 2) the sole mechanism for preparing the gradient in induction time is by turbulent mixing and local flame quenching. The criterion for DDT is derived in terms of the one-dimensional detonation wave thickness, the laminar flame speed, and the laminar flame thickness in the reactive gas. This approach gives a lower-bound criterion for DDT for conditions where shock preheating, wall effects, and interactions with obstacles are absent. Regions in parameter space where unconfined DDT can and cannot occur are determined. A subsequent paper will address these issues specifically in the astrophysical context.

  15. Theory of DDT in Unconfined Flames

    E-Print Network [OSTI]

    A. M. Khokhlov; E. S. Oran; J. Craig Wheeler

    1996-05-15T23:59:59.000Z

    This paper outlines a theoretical approach for predicting the onset of detonation in unconfined turbulent flames which is relevant both to problems of terrestrial combustion and to thermonuclear burning in Type Ia supernovae. Two basic assumuptions are made: 1) the gradient mechanism is the inherent mechanism that leads to DDT in unconfined conditions, and 2) the sole mechanism for preparing the gradient in induction time is by turbulent mixing and local flame quenching. The criterion for DDT is derived in terms of the one-dimensional detonation wave thickness, the laminar flame speed, and the laminar flame thickness in the reactive gas. This approach gives a lower-bound criterion for DDT for conditions where shock preheating, wall effects, and interactions with obstacles are absent. Regions in parameter space where unconfined DDT can and cannot occur are determined. A subsequent paper will address these issues specifically in the astrophysical context.

  16. Enol Intermediates Unexpectedly Found in Flames

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    at ALS Chemical Dynamics Beamline 9.0.2. In the apparatus, premixed reagent gases enter the flame chamber through the porous flat face of a burner that translates...

  17. Characterisation of an oxy-coal flame through digital imaging

    SciTech Connect (OSTI)

    Smart, John; Riley, Gerry [RWE npower plc, Windmill Hill Business Park, Whitehill Way, Swindon SN5 6PB (United Kingdom); Lu, Gang; Yan, Yong [Instrumentation, Control and Embedded Systems Research Group, School of Engineering and Digital Arts, University of Kent, Canterbury, Kent CT2 7NT (United Kingdom)

    2010-06-15T23:59:59.000Z

    This paper presents investigations into the impact of oxy-fuel combustion on flame characteristics through the application of digital imaging and image processing techniques. The characteristic parameters of the flame are derived from flame images that are captured using a vision-based flame monitoring system. Experiments were carried out on a 0.5 MW{sub th} coal combustion test facility. Different flue gas recycle ratios and furnace oxygen levels were created for two different coals. The characteristics of the flame and the correlation between the measured flame parameters and corresponding combustion conditions are described and discussed. The results show that the flame temperature decreases with the recycle ratio for both test coals, suggesting that the flame temperature is effectively controlled by the flue gas recycle ratio. The presence of high levels of CO{sub 2} at high flue gas recycle ratios may result in delayed combustion and thus has a detrimental effect on the flame stability. (author)

  18. NO concentration imaging in turbulent nonpremixed flames

    SciTech Connect (OSTI)

    Schefer, R.W. [Sandia National Laboratories, Livermore, CA (United States)

    1993-12-01T23:59:59.000Z

    The importance of NO as a pollutant species is well known. An understanding of the formation characteristics of NO in turbulent hydrocarbon flames is important to both the desired reduction of pollutant emissions and the validation of proposed models for turbulent reacting flows. Of particular interest is the relationship between NO formation and the local flame zone, in which the fuel is oxidized and primary heat release occurs. Planar imaging of NO provides the multipoint statistics needed to relate NO formation to the both the flame zone and the local turbulence characteristics. Planar imaging of NO has been demonstrated in turbulent flames where NO was seeded into the flow at high concentrations (2000 ppm) to determine the gas temperature distribution. The NO concentrations in these experiments were significantly higher than those expected in typical hydrocarbon-air flames, which require a much lower detectability limit for NO measurements. An imaging technique based on laser-induced fluorescence with sufficient sensitivity to study the NO formation mechanism in the stabilization region of turbulent lifted-jet methane flames.

  19. On the critical flame radius and minimum ignition energy for spherical flame initiation

    E-Print Network [OSTI]

    Ju, Yiguang

    , methane, and propane). The emphasis is placed on investigating the critical flame radius controlling to the cube of the critical flame radius. Furthermore, preferential diffusion of heat and mass (i.e. the Lewis igni- tion energy. Ã? 2010 The Combustion Institute. Published by Elsevier Inc. All rights reserved

  20. Ultraviolet imaging of hydrogen flames

    SciTech Connect (OSTI)

    Yates, G.J.; Wilke, M.; King, N.

    1988-01-01T23:59:59.000Z

    We have assembled an ultraviolet-sensitive intensified camera for observing hydrogen combustion by imaging the OH, A/sup 2/..sigma.. - X/sup 2//Pi/ bandhead emissions near 309 nm. The camera consists of a quartz and CaF achromat lense-coupled to an ultraviolet image intensifier which is in turn fiber-coupled to a focus projection scan (FPS) vidicon. The emission band is selected with interference filters which serve to discriminate against background. The camera provides optical gain of 100 to 1000 and is capable of being shuttered at nanosecond speeds and of being framed at over 600 frames per second. We present data from observations of test flames in air at standard RS-170 video rates with varying background conditions. Enhanced images using background subtraction are presented. Finally, we discuss the use of polarizaton effects to further discrimination against sky background. This work began as a feasibility study to investigate ultraviolet technology to detect hydrogen fires for the NASA space program. 6 refs., 7 figs, 2 tabs.

  1. Aromatics oxidation and soot formation in flames

    SciTech Connect (OSTI)

    Howard, J.B.; Pope, C.J.; Shandross, R.A.; Yadav, T.

    1993-04-01T23:59:59.000Z

    This project is concerned with the kinetics and mechanisms of aromatics oxidation and soot and fullerenes formation in flames. The scope includes detailed measurements of profiles of stable and radical species concentrations in low-pressure one-dimensional premixed flames. Intermediate species identifications and mole fractions, fluxes, and net reaction rates calculated from the measured profiles are used to test postulated reaction mechanisms. Particular objectives are to identify, and to confirm or determine rate constants for, the main benzene oxidation reactions in flames, and to characterize soot and fullerenes and their formation mechanisms and kinetics. Stable and radical species profiles in the aromatics oxidation study are measured using molecular beam sampling with on-line mass spectrometry. The rate of soot formation measured by conventional optical techniques is found to support the hypotheses that particle inception occurs through reactive coagulation of high molecular weight PAH in competition with destruction by OHattack, and that the subsequent growth of the soot mass occurs through addition reactions of PAH and C[sub 2]H[sub 2] with the soot particles. During the first year of this reporting period, fullerenes C[sub 60] and C[sub 70] in substantial quantities were found in the flames being studied. The fullerenes were recovered, purified and spectroscopically identified. The yields of C[sub 60] and C[sub 70] were then determined over ranges of conditions in low-pressure premixed flames of benzene and oxygen.

  2. Paper # A02 Topic: Laminar Flames US Combustion Meeting

    E-Print Network [OSTI]

    Seitzman, Jerry M.

    been focused on synthetic fuel gas (syngas) combustion. Syngas is derived from coal through of the flame speeds of syngas mixtures.3-5 For example, stretch corrected laminar flame speed measurements

  3. Intake retention functions and derived investigation levels for selected radioelements

    E-Print Network [OSTI]

    Buitron Sanchez, Susana

    1990-01-01T23:59:59.000Z

    of these metabolic processes as well as those that occur in all compartments that feed the systemic circulation. 16 INHALATION I INGESTION ST (1) SI (2) ULI (3) j j LYMPH NODES UPTAKE LLI (4) 1S 2S . . . . iS . " nS F f WOUND E SYSTEMIC EXCRETION 1-F..., Sr. (Chair of Committee) Milton . McLain (Member) Wesl E. Bolch (Member) Dan ightower (Member) ohn W. oston, Sr (Department Head) August 1990 ABSTRACT Intake Retention Functions and Derived Investigation Levels for Selected Radioelements...

  4. Investigating the Flame Microstructure in Type Ia Supernovae

    E-Print Network [OSTI]

    Roepke, F K; Niemeyer, J C

    2002-01-01T23:59:59.000Z

    We present a numerical model to study the behavior of thermonuclear flames in the discontinuity approximation. This model is applied to investigate the Landau-Darrieus instability under conditions found in Type Ia supernova explosions of Chandrasekhar mass white dwarfs. This is a first step to explore the flame microstructure in these events. The model reproduces Landau's linearized stability analysis in early stages of the flame evolution and the stabilization in a cellular flame structure in the nonlinear stage.

  5. Investigating the Flame Microstructure in Type Ia Supernovae

    E-Print Network [OSTI]

    F. K. Roepke; W. Hillebrandt; J. C. Niemeyer

    2002-04-02T23:59:59.000Z

    We present a numerical model to study the behavior of thermonuclear flames in the discontinuity approximation. This model is applied to investigate the Landau-Darrieus instability under conditions found in Type Ia supernova explosions of Chandrasekhar mass white dwarfs. This is a first step to explore the flame microstructure in these events. The model reproduces Landau's linearized stability analysis in early stages of the flame evolution and the stabilization in a cellular flame structure in the nonlinear stage.

  6. Pentan isomers compound flame front structure

    SciTech Connect (OSTI)

    Mansurov, Z.A.; Mironenko, A.W.; Bodikov, D.U.; Rachmetkaliev, K.N. [Kazakh Al-Farabi State National Univ., Almaty (Kazakhstan)

    1995-08-13T23:59:59.000Z

    The fuels (hexane, pentane, diethyl ether) and conditions investigated in this study are relevant to engine knock in spark- ignition engines. A review is provided of the field of low temperature hydrocarbon oxidation. Studies were made of radical and stable intermediate distribution in the front of cool flames: Maximum concentrations of H atoms and peroxy radicals were observed in the luminous zone of the cool flame front. Peroxy radicals appear before the luminous zone at 430 K due to diffusion. H atoms were found in cool flames of butane and hexane. H atoms diffuses from the luminous zone to the side of the fresh mixture, and they penetrate into the fresh mixture to a small depth. Extension of action sphear of peroxy radicals in the fresh mixture is much greater than that of H atoms due to their small activity and high concentrations.

  7. FLAME SURFACE DENSITIES IN PREMIXED COMBUSTION AT MEDIUM TO HIGH

    E-Print Network [OSTI]

    Gülder, �mer L.

    premixed combustion diagrams. Small-scale transport of heat and species may be more important and chemistryFLAME SURFACE DENSITIES IN PREMIXED COMBUSTION AT MEDIUM TO HIGH TURBULENCE INTENSITIES O¨ MER L in turbulent premixed propane= air flames were determined experimentally. The instantaneous flame fronts were

  8. Flame front tracking by laser induced fluorescence spectroscopy and advanced

    E-Print Network [OSTI]

    Hamarneh, Ghassan

    surface characteristics in turbulent premixed propane/air combustion," Combustion and Flame 120(4), 407 References and links 1. J. Warnatz, U. Maas, and R.W. Dibble, Combustion - physical and chemical fundamentals, "Characterization of flame front surfaces in turbulent premixed methane/air combustion," Combustion and Flame 101

  9. Computatonal and experimental study of laminar flames

    SciTech Connect (OSTI)

    Smooke, M.D.; Long, M.B. [Yale Univ., New Haven, CT (United States)

    1993-12-01T23:59:59.000Z

    This research has centered on an investigation of the effects of complex chemistry and detailed transport on the structure and extinction of hydrocarbon flames in counterflow, cylindrical and coflowing axisymmetric configurations. The authors have pursued both computational and experimental aspects of the research in parallel. The computational work has focused on the application of accurate and efficient numerical methods for the solution of the one and two-dimensional nonlinear boundary value problems describing the various reacting systems. Detailed experimental measurements were performed on axisymmetric coflow flames using two-dimensional imaging techniques. In particular, spontaneous Raman scattering and laser induced fluorescence were used to measure the temperature, major and minor species profiles.

  10. The effect of flame structure on soot formation and transport in turbulent nonpremixed flames using direct numerical simulation

    SciTech Connect (OSTI)

    Lignell, David O. [Department of Chemical Engineering, University of Utah, Salt Lake City, UT 84098 (United States); Reacting Flow Research Department, Combustion Research Facility, Sandia National Laboratories, Livermore, CA 94551 (United States); Chen, Jacqueline H. [Reacting Flow Research Department, Combustion Research Facility, Sandia National Laboratories, Livermore, CA 94551 (United States); Smith, Philip J. [Department of Chemical Engineering, University of Utah, Salt Lake City, UT 84098 (United States); Lu, Tianfeng; Law, Chung K. [Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, NJ 08540 (United States)

    2007-10-15T23:59:59.000Z

    Direct numerical simulations of a two-dimensional, nonpremixed, sooting ethylene flame are performed to examine the effects of soot-flame interactions and transport in an unsteady configuration. A 15-step, 19-species (with 10 quasi-steady species) chemical mechanism was used for gas chemistry, with a two-moment, four-step, semiempirical soot model. Flame curvature is shown to result in flames that move, relative to the fluid, either toward or away from rich soot formation regions, resulting in soot being essentially convected into or away from the flame. This relative motion of flame and soot results in a wide spread of soot in the mixture fraction coordinate. In regions where the center of curvature of the flame is in the fuel stream, the flame motion is toward the fuel and soot is located near the flame at high temperature and hence has higher reaction rates and radiative heat fluxes. Soot-flame breakthrough is also observed in these regions. Fluid convection and flame displacement velocity relative to fluid convection are of similar magnitudes while thermophoretic diffusion is 5-10 times lower. These results emphasize the importance of both unsteady and multidimensional effects on soot formation and transport in turbulent flames. (author)

  11. COMBUSTION AND FLAME 24, 27-34 (1975) 27 Flame Emission Studies of Ozone with Metal Alkyls

    E-Print Network [OSTI]

    Zare, Richard N.

    COMBUSTION AND FLAME 24, 27-34 (1975) 27 Flame Emission Studies of Ozone with Metal Alkyls: Zn (CH3 of combustion. Premixed [2, 3] anddiffusion [4] flames of metal alkyl compounds have been carried out to deter- tageous to study the combustion of polyatomic molecules under single-collision conditions, i

  12. Rayleigh-Taylor Unstable Flames -- Fast or Faster?

    E-Print Network [OSTI]

    Hicks, E P

    2015-01-01T23:59:59.000Z

    Rayleigh-Taylor (RT) unstable flames play a key role in the explosions of Type Ia supernovae. However, the dynamics of these flames is still not well-understood. RT unstable flames are affected by both the RT instability of the flame front and by RT-generated turbulence. The coexistence of these factors complicates the choice of flame speed subgrid models for full-star Type Ia simulations. Both processes can stretch and wrinkle the flame surface, increasing its area and, therefore, the burning rate. In past research, subgrid models have been based on either the RT instability or turbulence setting the flame speed. We evaluate both models, checking their assumptions and their ability to correctly predict the turbulent flame speed. Specifically, we analyze a large parameter study of 3D direct numerical simulations of RT unstable model flames. This study varies both the simulation domain width and the gravity in order to probe a wide range of flame behaviors. We show that RT unstable flames are different from tr...

  13. Power-law wrinkling turbulence-flame interaction model for astrophysical flames

    SciTech Connect (OSTI)

    Jackson, Aaron P. [Laboratories for Computational Physics and Fluid Dynamics, Naval Research Laboratory, Washington, DC (United States); Townsley, Dean M. [Department of Physics and Astronomy, The University of Alabama, Tuscaloosa, AL (United States); Calder, Alan C. [Department of Physics and Astronomy, The State University of New York - Stony Brook, Stony Brook, NY (United States)

    2014-04-01T23:59:59.000Z

    We extend a model for turbulence-flame interactions (TFI) to consider astrophysical flames with a particular focus on combustion in Type Ia supernovae. The inertial range of the turbulent cascade is nearly always under-resolved in simulations of astrophysical flows, requiring the use of a model in order to quantify the effects of subgrid-scale wrinkling of the flame surface. We provide implementation details to extend a well-tested TFI model to low-Prandtl number flames for use in the compressible hydrodynamics code FLASH. A local, instantaneous measure of the turbulent velocity is calibrated for FLASH and verification tests are performed. Particular care is taken to consider the relation between the subgrid rms turbulent velocity and the turbulent flame speed, especially for high-intensity turbulence where the turbulent flame speed is not expected to scale with the turbulent velocity. Finally, we explore the impact of different TFI models in full-star, three-dimensional simulations of Type Ia supernovae.

  14. Radiation Heat Transfer in Particle-Laden Gaseous Flame: Flame Acceleration and Triggering Detonation

    E-Print Network [OSTI]

    Liberman, M A; Kiverin, A D

    2015-01-01T23:59:59.000Z

    In this study we examine influence of the radiation heat transfer on the combustion regimes in the mixture, formed by suspension of fine inert particles in hydrogen gas. The gaseous phase is assumed to be transparent for the thermal radiation, while the radiant heat absorbed by the particles is then lost by conduction to the surrounding gas. The particles and gas ahead of the flame is assumed to be heated by radiation from the original flame. It is shown that the maximum temperature increase due to the radiation preheating becomes larger for a flame with lower velocity. For a flame with small enough velocity temperature of the radiation preheating may exceed the crossover temperature, so that the radiation heat transfer may become a dominant mechanism of the flame propagation. In the case of non-uniform distribution of particles, the temperature gradient formed due to the radiation preheating can initiate either deflagration or detonation ahead of the original flame via the Zel'dovich's gradient mechanism. Th...

  15. Environmentally Benign Flame Retardant Nanocoatings for Fabric

    E-Print Network [OSTI]

    Li, Yu-Chin

    2012-07-16T23:59:59.000Z

    nanocomposites in an effort to produce more flame-retardant coatings. Laponite and montmorillonite (MMT) clay were paired with branched poly(ethylenimine) to create thin film assemblies that can be tailored by changing pH and concentration of aqueous deposition...

  16. Environmentally Benign Flame Retardant Nanocoatings for Fabric 

    E-Print Network [OSTI]

    Li, Yu-Chin

    2012-07-16T23:59:59.000Z

    nanocomposites in an effort to produce more flame-retardant coatings. Laponite and montmorillonite (MMT) clay were paired with branched poly(ethylenimine) to create thin film assemblies that can be tailored by changing pH and concentration of aqueous deposition...

  17. AIAA 010189 Ignition and Flame Studies for

    E-Print Network [OSTI]

    Liu, Feng

    beyond the turbine blade material limit. Sirignano and Liu1,2 show by thermodynamic analysis-dimensional diffusion flame in a transonic flow with large pressure gradients typical of conditions in a turbine passage-to-weight ratio and to widen the range of engine operation. Since the flow in a turbine passage is accelerating

  18. Flame Propagation of Butanol Isomers/Air Mixtures

    SciTech Connect (OSTI)

    Veloo, Peter S.; Egolfopoulos, Fokion N.

    2011-01-01T23:59:59.000Z

    An experimental and computational study was conducted on the propagation of flames of saturated butanol isomers. The experiments were performed in the counterflow configuration under atmospheric pressure, unburned mixture temperature of 343 K, and for a wide range of equivalence ratios. The experiments were simulated using a recent kinetic model for the four isomers of butanol. Results indicate that n-butanol/air flames propagate somewhat faster than both sec-butanol/air and iso-butanol/air flames, and that tert-butanol/air flames propagate notably slower compared to the other three isomers. Reaction path analysis of tert-butanol/air flames revealed that iso-butene is a major intermediate, which subsequently reacts to form the resonantly stable iso-butenyl radical retarding thus the overall reactivity of tert-butanol/air flames relatively to the other three isomers. Through sensitivity analysis, it was determined that the mass burning rates of sec-butanol/air and iso-butanol/air flames are sensitive largely to hydrogen, carbon monoxide, and C{sub 1}–C{sub 2} hydrocarbon kinetics and not to fuel-specific reactions similarly to n-butanol/air flames. However, for tert-butanol/air flames notable sensitivity to fuel-specific reactions exists. While the numerical results predicted closely the experimental data for n-butanol/air and sec-butanol/air flames, they overpredicted and underpredicted the laminar flame speeds for iso-butanol/air and tert-butanol/air flames respectively. It was demonstrated further that the underprediction of the laminar flame speeds of tert-butanol/air flames by the model was most likely due to deficiencies of the C{sub 4}-alkene kinetics.

  19. [Mechanism and enhancement of flame stabilization]. [Annual report, 1993--1994

    SciTech Connect (OSTI)

    Not Available

    1993-11-01T23:59:59.000Z

    During this period, the following projects were completed: structural invariance of purely strained planar premixed flames, thermophoretic effects on seeding particles in LDV measurements, analysis of geometry of Bunsen flames, flame propagation in periodic flow fields, adiabatic flame stabilization, and chain-thermal theory of flame extinction.

  20. Flame quality monitor system for fixed firing rate oil burners

    DOE Patents [OSTI]

    Butcher, Thomas A. (Pt. Jefferson, NY); Cerniglia, Philip (Moriches, NY)

    1992-01-01T23:59:59.000Z

    A method and apparatus for determining and indicating the flame quality, or efficiency of the air-fuel ratio, in a fixed firing rate heating unit, such as an oil burning furnace, is provided. When the flame brightness falls outside a preset range, the flame quality, or excess air, has changed to the point that the unit should be serviced. The flame quality indicator output is in the form of lights mounted on the front of the unit. A green light indicates that the flame is about in the same condition as when the burner was last serviced. A red light indicates a flame which is either too rich or too lean, and that servicing of the burner is required. At the end of each firing cycle, the flame quality indicator goes into a hold mode which is in effect during the period that the burner remains off. A yellow or amber light indicates that the burner is in the hold mode. In this mode, the flame quality lights indicate the flame condition immediately before the burner turned off. Thus the unit can be viewed when it is off, and the flame condition at the end of the previous firing cycle can be observed.

  1. Bottom head assembly

    DOE Patents [OSTI]

    Fife, A.B.

    1998-09-01T23:59:59.000Z

    A bottom head dome assembly is described which includes, in one embodiment, a bottom head dome and a liner configured to be positioned proximate the bottom head dome. The bottom head dome has a plurality of openings extending there through. The liner also has a plurality of openings extending there through, and each liner opening aligns with a respective bottom head dome opening. A seal is formed, such as by welding, between the liner and the bottom head dome to resist entry of water between the liner and the bottom head dome at the edge of the liner. In the one embodiment, a plurality of stub tubes are secured to the liner. Each stub tube has a bore extending there through, and each stub tube bore is coaxially aligned with a respective liner opening. A seat portion is formed by each liner opening for receiving a portion of the respective stub tube. The assembly also includes a plurality of support shims positioned between the bottom head dome and the liner for supporting the liner. In one embodiment, each support shim includes a support stub having a bore there through, and each support stub bore aligns with a respective bottom head dome opening. 2 figs.

  2. Non-premixed acoustically perturbed swirling flame dynamics

    SciTech Connect (OSTI)

    Idahosa, Uyi; Saha, Abhishek; Xu, Chengying; Basu, Saptarshi [Department of Mechanical, Materials and Aerospace Engineering, University of Central Florida, Orlando, FL (United States)

    2010-09-15T23:59:59.000Z

    An investigation into the response of non-premixed swirling flames to acoustic perturbations at various frequencies (f{sub p}=0-315 Hz) and swirl intensities (S=0.09 and 0.34) is carried out. Perturbations are generated using a loudspeaker at the base of an atmospheric co-flow burner with resulting velocity oscillation amplitudes vertical stroke u'/U{sub avg} vertical stroke in the 0.03-0.30 range. The dependence of flame dynamics on the relative richness of the flame is investigated by studying various constant fuel flow rate flame configurations. Flame heat release rate is quantitatively measured using a photomultiplier with a 430 nm bandpass filter for observing CH* chemiluminescence which is simultaneously imaged with a phase-locked CCD camera. The flame response is observed to exhibit a low-pass filter characteristic with minimal flame response beyond pulsing frequencies of 200 Hz. Flames at lower fuel flow rates are observed to remain attached to the central fuel pipe at all acoustic pulsing frequencies. PIV imaging of the associated isothermal fields show the amplification in flame aspect ratio is caused by the narrowing of the inner recirculation zone (IRZ). Good correlation is observed between the estimated flame surface area and the heat release rate signature at higher swirl intensity flame configurations. A flame response index analogous to the Rayleigh criterion in non-forced flames is used to assess the potential for a strong flame response at specific perturbation configurations and is found to be a good predictor of highly responsive modes. Phase conditioned analysis of the flame dynamics yield additional criteria in highly responsive modes to include the effective amplitude of velocity oscillations induced by the acoustic pulsing. In addition, highly responsive modes were characterized by velocity to heat release rate phase differences in the {+-}{pi}/2 range. A final observed characteristic in highly responsive flames is a Strouhal number between 1 and 3.5 based on the burner co-flow annulus diameter (St = f{sub p}U{sub avg}/d{sub m}). Finally, wavelet analyses of heat release rate perturbations indicate highly responsive modes are characterized by sustained low frequency oscillations which accompany the high amplitude velocity perturbations at these modes. Higher intensity low frequency heat release rate oscillations are observed for lean flame/low pulsing frequency conditions. (author)

  3. Correlation of flame speed with stretch in turbulent premixed methane/air flames

    SciTech Connect (OSTI)

    Chen, J.H.; Im, H.G.

    1998-03-01T23:59:59.000Z

    Direct numerical simulations of two-dimensional unsteady premixed methane/air flames are performed to determine the correlation of flame speed with stretch over a wide range of curvatures and strain rates generated by intense two-dimensional turbulence. Lean and stoichiometric premixtures are considered with a detailed C{sub 1}-mechanism for methane oxidation. The computed correlation shows the existence of two distinct stable branches. It further shows that exceedingly large negative values of stretch can be obtained solely through curvature effects which give rise to an overall nonlinear correlation of the flame speed with stretch. Over a narrower stretch range, {minus}1 {le} Ka {le} 1, which includes 90% of the sample, the correlation is approximately linear, and hence, the asymptotic theory for stretch is practically applicable. Overall, one-third of the sample has negative stretch. In this linear range, the Markstein number associated with the positive branch is determined and is consistent with values obtained from comparable steady counterflow computations. In addition to this conventional positive branch, a negative branch is identified. This negative branch occurs when a flame cusp, with a center of curvature in the burnt gases, is subjected to intense compressive strain, resulting in a negative displacement speed. Negative flame speeds are also encountered for extensive tangential strain rates exceeding a Karlovitz number of unity, a value consistent with steady counterflow computations.

  4. Turbulent Nonpremixed Flames (TNF): Experimental Data Archives and Computational Submodels

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    In the 1990s an international collaboration formed around a series of workshops that became known collectively as the International Workshop on Measurement and Computation of Turbulent Non-Premixed Flames (TNF). An online library, hosted by Sandia National Laboratory (California) was established that provides data sets and submodels or "mechanisms" for the study of turbulence-chemistry interactions in turbulent nonpremixed and partially premixed combustion. Data are organized by flame types: simple jet flames, piloted jet flames, bluff body flames, and swirl flames. These data sets provide a means for collaborative comparisons of both measured and simulated/modeled research results and also assist scientists in determining priorities for further research. More than 20 data sets or databases are available from this website, along with various downloadable files of chemical mechanisms. The website also provides an extensive bibliography and the proceedings of the workshops themselves from 1996 through 2012. Information continues to be added to this collection.

  5. The advanced flame quality indicator system

    SciTech Connect (OSTI)

    Oman, R.; Rossi, M.J.; Calia, V.S.; Davis, F.L.; Rudin, A. [Insight Technologies, Inc., Bohemia, NY (United States)

    1997-09-01T23:59:59.000Z

    By combining oil tank monitoring, systems diagnostics and flame quality monitoring in an affordable system that communicates directly with dealers by telephone modem, Insight Technologies offers new revenue opportunities and the capability for a new order of customer relations to oil dealers. With co-sponsorship from New York State Energy Research and Development Authority, we have incorporated several valuable functions to a new product based on the original Flame Quality Indicator concept licensed from the US DOE`s Brookhaven National Laboratory. The new system is the Advanced Flame Quality Indicator, or AFQI. As before, the AFQI monitors and reports the intensity of the burner flame relative to a calibration established when the burner is set up at AFQI installation. Repairs or adjustments are summoned by late-night outgoing telephone calls when limits are exceeded in either direction, indicating an impending contamination or other malfunction. A independently, a pressure transducer for monitoring oil tank level and filter condition, safety lockout alarms and a temperature monitor; all reporting automatically at instructed intervals via an on-board modem to a central station PC computer (CSC). Firmware on each AFQI unit and Insight-supplied software on the CSC automatically interact to maintain a customer database for an oil dealer, an OEM, or a regional service contractor. In addition to ensuring continuously clean and efficient operation, the AFQI offers the oil industry a new set of immediate payoffs, among which are reduced outages and emergency service calls, shorter service calls from cleaner operation, larger oil delivery drops, the opportunity to stretch service intervals to as along as three years in some cases, new selling features to keep and attract customers, and greatly enhanced customer contact, quality and reliability.

  6. Soot Deposit Properties in Practical Flames

    SciTech Connect (OSTI)

    Preciado, Ignacio [University of Utah; Eddings, Eric G. [University of Utah; Sarofim, Adel F. [University of Utah; Dinwiddie, Ralph Barton [ORNL; Porter, Wallace D [ORNL; Lance, Michael J [ORNL

    2009-01-01T23:59:59.000Z

    Soot deposition from hydrocarbon flames was investigated in order to evaluate the evolution of the deposits during the transient process of heating an object that starts with a cold metal surface that is exposed to a flame. The study focused on the fire/metal surface interface and the critical issues associated with the specification of the thermal boundaries at this interface, which include the deposition of soot on the metal surface, the chemical and physical properties of the soot deposits and their subsequent effect on heat transfer to the metal surface. A laboratory-scale device (metallic plates attached to a water-cooled sampling probe) was designed for studying soot deposition in a laminar ethylene-air premixed flame. The metallic plates facilitate the evaluation of the deposition rates and deposit characteristics such as deposit thickness, bulk density, PAH content, deposit morphology, and thermal properties, under both water-cooled and uncooled conditions. Additionally, a non-intrusive Laser Flash Technique (in which the morphology of the deposit is not modified) was used to estimate experimental thermal conductivity values for soot deposits as a function of deposition temperature (water-cooled and uncooled experiments), location within the flame and chemical characteristics of the deposits. Important differences between water-cooled and uncooled surfaces were observed. Thermophoresis dominated the soot deposition process and enhanced higher deposition rates for the water-cooled experiments. Cooler surface temperatures resulted in the inclusion of increased amounts of condensable hydrocarbons in the soot deposit. The greater presence of condensable material promoted decreased deposit thicknesses, larger deposit densities, different deposit morphologies, and higher thermal conductivities.

  7. Clothes That Care -- Flame Resistant Protection.

    E-Print Network [OSTI]

    Kerbel, Claudia

    1980-01-01T23:59:59.000Z

    fabrics , how to care for FR clothing, how consumers can express opinions about flame-resistant gar ments and how consumers can avoid fires at home. Protection For . .. Certain groups are more likely to be involved in clothing fire accidents than... fr quently than in their proportional share of the population . People whose reflexes are slowed by drugs , alcohol , physical disability or mental illness are also susceptible to injury or death by fire be cause they cannot respond quickly...

  8. Simulation of spherically expanding turbulent premixed flames

    E-Print Network [OSTI]

    Ahmed, I.; Swaminathan, N.

    2013-09-16T23:59:59.000Z

    canonically im- portant configuration and its investigation is helpful to understand combustion in prac- tical devices such as the spark ignited internal combustion engine, modern stratified charge engines and accidental explosions of fuel vapour cloud... Simulation of spherically expanding turbulent premixed flames I. Ahmed, N. Swaminathan? Department of Engineering, Cambridge University, Cambridge, CB2 1PZ, UK. ?Corresponding author: Department of Engineering, Cambridge University, Trumpington...

  9. Analyzing and Tracking Burning Structures in Lean Premixed Hydrogen Flames

    E-Print Network [OSTI]

    Bremer, Peer-Timo

    2010-01-01T23:59:59.000Z

    structures in lean premixed hydrogen ?ames. Combustion andStructures in Lean Premixed Hydrogen Flames P. -T. Bremersimulations of lean hydrogen ?ames subject to different

  10. Soot precursor measurements in benzene and hexane diffusion flames

    SciTech Connect (OSTI)

    Kobayashi, Y.; Furuhata, T.; Amagai, K.; Arai, M. [Department of Mechanical System Engineering, Graduate School of Engineering, Gunma University, 1-5-1 Tenjin-cho, Kiryu-shi, Gunma 376-8515 (Japan)

    2008-08-15T23:59:59.000Z

    To clarify the mechanism of soot formation in diffusion flames of liquid fuels, measurements of soot and its precursors were carried out. Sooting diffusion flames formed by a small pool combustion equipment system were used for this purpose. Benzene and hexane were used as typical aromatic and paraffin fuels. A laser-induced fluorescence (LIF) method was used to obtain spatial distributions of polycyclic aromatic hydrocarbons (PAHs), which are considered as soot particles. Spatial distributions of soot in test flames were measured by a laser-induced incandescence (LII) method. Soot diameter was estimated from the temporal change of LII intensity. A region of transition from PAHs to soot was defined from the results of LIF and LII. Flame temperatures, PAH species, and soot diameters in this transition region were investigated for both benzene and hexane flames. The results show that though the flame structures of benzene and hexane were different, the temperature in the PAHs-soot transition region of the benzene flame was similar to that of the hexane flame. Furthermore, the relationship between the PAH concentrations measured by gas chromatography in both flames and the PAH distributions obtained from LIF are discussed. It was found that PAHs with smaller molecular mass, such as benzene and toluene, remained in both the PAHs-soot transition and sooting regions, and it is thought that molecules heavier than pyrene are the leading candidates for soot precursor formation. (author)

  11. adiabatic flame temperature: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    initial temperature 0 296 Knyazev, Vadim D. 6 Temperature field reconstruction of combustion flame based on high Engineering Websites Summary: radiant existence field on camera...

  12. FIELD TEST OF THE FLAME QUALITY INDICATOR

    SciTech Connect (OSTI)

    Andrew M. Rudin; Thomas Butcher; Henry Troost

    2003-02-04T23:59:59.000Z

    The flame quality indicator concept was developed at BNL specifically to monitor the brightness of the flame in a small oil burner and to provide a ''call for service'' notification when the brightness has changed from its setpoint, either high or low. In prior development work BNL has explored the response of this system to operational upsets such as excess air changes, fouled atomizer nozzles, poor fuel quality, etc. Insight Technologies, Inc. and Honeywell, Inc. have licensed this technology from the U.S. Department of Energy and have been cooperating to develop product offerings which meet industry needs with an optimal combination of function and price. Honeywell has recently completed the development of the Flame Quality Monitor (FQM or Honeywell QS7100F). This is a small module which connects via a serial cable to the burners primary operating control. Primary advantages of this approach are simplicity, cost, and ease of installation. Call-for-service conditions are output in the form of front panel indicator lights and contact closure which can trigger a range of external communication options. Under this project a field test was conducted of the FQM in cooperation with service organizations in Virginia, Pennsylvania, New Jersey, New York, and Connecticut. At total of 83 field sites were included. At each site the FQM was installed in parallel with another embodiment of this concept--the Insight AFQI. The AFQI incorporates a modem and provides the ability to provide detailed information on the trends in the flame quality over the course of the two year test period. The test site population was comprised of 79.5% boilers, 13.7% warm air furnaces, and 6.8% water heaters. Nearly all were of residential size--with firing rates ranging from 0.6 gallons of oil per hour to 1.25. During the course of the test program the monitoring equipment successfully identified problems including: plugged fuel lines, fouled nozzles, collapsed combustion chambers, and poor fuel pump cut-off. Service organizations can use these early indications to reduce problems and service costs. There were also some ''call-for-service'' indications for which problems were not identified. The test program also showed that monitoring of the flame can provide information on burner run times and this can be used to estimate current oversize factors and to determine actual fuel usage, enabling more efficient fuel delivery procedures.

  13. Non-Sooting, Low Flame Temperature Mixing-Controlled DI Diesel...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Sooting, Low Flame Temperature Mixing-Controlled DI Diesel Combustion Non-Sooting, Low Flame Temperature Mixing-Controlled DI Diesel Combustion 2003 DEER Conference Presentation:...

  14. Technetium Retention During LAW Vitrification

    Office of Environmental Management (EM)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625 1,006 492 742 33 1112011 Strategic2Uranium Transferon the PassingRouting TECFinish LineTaraTechnetium Retention

  15. Maneuvering impact boring head

    DOE Patents [OSTI]

    Zollinger, W. Thor (Idaho Falls, ID); Reutzel, Edward W. (Idaho Falls, ID)

    1998-01-01T23:59:59.000Z

    An impact boring head may comprise a main body having an internal cavity with a front end and a rear end. A striker having a head end and a tail end is slidably mounted in the internal cavity of the main body so that the striker can be reciprocated between a forward position and an aft position in response to hydraulic pressure. A compressible gas contained in the internal cavity between the head end of the striker and the front end of the internal cavity returns the striker to the aft position upon removal of the hydraulic pressure.

  16. Maneuvering impact boring head

    DOE Patents [OSTI]

    Zollinger, W.T.; Reutzel, E.W.

    1998-08-18T23:59:59.000Z

    An impact boring head may comprise a main body having an internal cavity with a front end and a rear end. A striker having a head end and a tail end is slidably mounted in the internal cavity of the main body so that the striker can be reciprocated between a forward position and an aft position in response to hydraulic pressure. A compressible gas contained in the internal cavity between the head end of the striker and the front end of the internal cavity returns the striker to the aft position upon removal of the hydraulic pressure. 8 figs.

  17. Lean and ultralean stretched propane-air counterflow flames

    SciTech Connect (OSTI)

    Cheng, Zhongxian; Pitz, Robert W. [Mechanical Engineering Department, Vanderbilt University, Box 1592, Station B, Nashville, TN 37235 (United States); Wehrmeyer, Joseph A. [Aerospace Testing Alliance, Building 1099, Avenue C, Arnold Air Force Base, TN 37389 (United States)

    2006-06-15T23:59:59.000Z

    Stretched laminar flame structures for a wide range of C{sub 3}H{sub 8}-air mixtures vs hot products are investigated by laser-based diagnostics and numerical simulation. The hot products are produced by a lean H{sub 2}-air premixed flame. The effect of stretch rate and equivalence ratio on four groups of C{sub 3}H{sub 8}-air flame structures is studied in detail by Raman scattering measurements and by numerical calculations of the major species concentration and temperature profiles. The equivalence ratio, f, is varied from a near-stoichiometric condition (f=0.86) to the sublean limit (f=0.44) and the stretch rate varies from 90 s{sup -1} to near extinction. For most of these C{sub 3}H{sub 8}-air lean mixtures, hot products are needed to maintain the flame. The significant feature of these flames is the relatively low flame temperatures (1200-1800 K). For this temperature range, the predicted C{sub 3}H{sub 8}-air flame structure is sensitive to the specific chemical kinetic mechanism. Two types of flame structures (a lean self-propagating flame and a lean diffusion-controlled flame) are obtained based on the combined effect of stretch and equivalence ratio. Three different mechanisms, the M5 mechanism, the Optimized mechanism, and the San Diego mechanism, are chosen for the numerical simulations. None of the propane chemical mechanisms give good agreement with the data over the entire range of flame conditions. (author)

  18. Internal Combustion Engine Energy Retention (ICEER)

    Broader source: Energy.gov (indexed) [DOE]

    ICEER Internal Combustion Engine Energy Retention PI: Jeffrey Gonder Team: Eric Wood & Sean Lopp National Renewable Energy Laboratory June 18, 2014 Project ID: VSS126 This...

  19. Workforce Retention Work Group | Department of Energy

    Energy Savers [EERE]

    skilled workforce retention; health, safety and productivity; and especially preventive health care. Inform and support improvement andor development of wellness, fitness, and...

  20. Radionuclide Retention in Concrete Wasteforms

    SciTech Connect (OSTI)

    Wellman, Dawn M.; Jansik, Danielle P.; Golovich, Elizabeth C.; Cordova, Elsa A.

    2012-09-24T23:59:59.000Z

    Assessing long-term performance of Category 3 waste cement grouts for radionuclide encasement requires knowledge of the radionuclide-cement interactions and mechanisms of retention (i.e., sorption or precipitation); the mechanism of contaminant release; the significance of contaminant release pathways; how wasteform performance is affected by the full range of environmental conditions within the disposal facility; the process of wasteform aging under conditions that are representative of processes occurring in response to changing environmental conditions within the disposal facility; the effect of wasteform aging on chemical, physical, and radiological properties; and the associated impact on contaminant release. This knowledge will enable accurate prediction of radionuclide fate when the wasteforms come in contact with groundwater. Data collected throughout the course of this work will be used to quantify the efficacy of concrete wasteforms, similar to those used in the disposal of LLW and MLLW, for the immobilization of key radionuclides (i.e., uranium, technetium, and iodine). Data collected will also be used to quantify the physical and chemical properties of the concrete affecting radionuclide retention.

  1. from the Head

    E-Print Network [OSTI]

    Sally Goeke

    2009-07-14T23:59:59.000Z

    as well as the many weekly seminars and colloquia, continually ... from the Head ... Meyer Jerison) received the 2009 George David Birkhoff Prize. The prize is ..... Virginia Mashin Scholars ... Alan Legg, Mariana Smit Vega Garcia, Lloyd West.

  2. Adaptive low Mach number simulations of nuclear flame microphysics

    E-Print Network [OSTI]

    Bell, John B.

    Adaptive low Mach number simulations of nuclear flame microphysics J. B. Bell, M. S. Day, C. A of nuclear flames in Type Ia su- pernovae. This model is based on a low Mach number formulation nuclear burning. The formulation presented here generalizes low Mach number models used in combustion

  3. Vortex phase-jitter in acoustically excited bluff body flames

    E-Print Network [OSTI]

    Lieuwen, Timothy C.

    Vortex phase-jitter in acoustically excited bluff body flames Santosh J. Shanbhogue, Michael disturbances. Phase locked particle image velocimetry was carried out over a range of conditions", manifested as cycle-to-cycle variation in flame and vorticity field at the same excitation phase. Phase

  4. Iron/soot interaction in a laminar ethylene nonpremixed flame

    SciTech Connect (OSTI)

    Zhang, J.; Megaridis, C.M. [Univ. of Illinois, Chicago, IL (United States). Dept. of Mechanical Engineering

    1994-12-31T23:59:59.000Z

    A laminar, coannular, ethylene/air nonpremixed flame doped with ferrocene additive is employed to address the fundamental question of how iron becomes incorporated into the carbonaceous soot phase, thus interfering with the soot formation processes. The structure and chemical composition of individual aggregates are characterized with respect to flame coordinates via a combination of thermophoretic sampling, transmission electron microscopy, and energy dispersive spectrometry. Soot aggregate microstructure clearly reveals iron occlusion, as well as stratification of soot layers over the occluded phase. The study provides physical evidence that the soot and iron compounds combine in the flame to form a hybrid (inhomogeneous) particulate phase. The reported observations are consistent with the hypothesis that ferrocene decomposes early in the combustion process and before the onset of soot particle inception, thus forming a fine aerosol for the subsequent deposition of carbonaceous substances. Examination of a series of inhomogeneous soot aggregates shows that the flame aerosol composition varies with flame coordinates. In particular, aggregates transported in the soot annulus near the luminous flame front are primarily composed of carbon and oxygen, with traces of iron finely dispersed through the aggregate matrix. On the other hand, carbonaceous soot transported at low heights and near the flame axis contains iron in its elemental form. Finally, soot aggregates in all other areas of the flame contain both iron and oxygen, thus implying the possible presence of iron oxides within the carbonaceous matrix.

  5. Environmentally-benign Flame Retardant Nanocoating for Foam and Fabric 

    E-Print Network [OSTI]

    Cain, Amanda Ashley

    2014-12-09T23:59:59.000Z

    for the purpose of inhibiting or suppressing the combustion cycle. Inspiration for first applying polymer/clay thin films (i.e., nanobrick walls) as flame retardant (FR) coatings to polyurethane foam via LbL came from the final stage of a proposed flame...

  6. Bifurcations of flame filaments in chaotically mixed combustion reactions

    E-Print Network [OSTI]

    Gottwald, Georg A.

    Bifurcations of flame filaments in chaotically mixed combustion reactions Shakti N. Menon and Georg ranging fields. Be- sides in the case of combustion, where mixing-induced bifurcations may lead mixing has a significant effect on combustion processes and in particular on flame filamental structures

  7. SIEMENS-UV OPTICAL FLAME DETECTION MONA HEMENDRA RAITHATHA

    E-Print Network [OSTI]

    Sekhon, Jasjeet S.

    SIEMENS-UV OPTICAL FLAME DETECTION MONA HEMENDRA RAITHATHA College of Engineering University of tests conducted, as well as a cost and market analysis, the recommendation for Siemens would be to use.funginstitute.berkeley.edu #12;SIEMENS-UV OPTICAL FLAME DETECTION BY MONA HEMENDRA RAITHATHA THESIS Submitted in partial

  8. Measurements of Laminar Flame Velocity for Components of Natural Gas

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    flame velocity of components of natural gas, methane, ethane, propane, and nbutane as well as of binary% by volume (1). The laminar flame velocities of methane/air, ethane/air, and propane/air mixtures have on a plenum chamber with the radial temperature distribution measurement made by a series of thermocouples

  9. Modeling of NOx formation in circular laminar jet flames

    E-Print Network [OSTI]

    Siwatch, Vivek

    2007-04-25T23:59:59.000Z

    -premixed isolated circular laminar jet flame. The jet consists of the fuel rich inner region and the O2 rich outer region. The model estimates both thermal NOx and prompt NOx assuming single step kinetics for NOx formation and a thin flame model. Further the amount...

  10. Nanotechnology finding its way into flame retardancy

    SciTech Connect (OSTI)

    Schartel, Bernhard, E-mail: bernhard.schartel@bam.de [BAM Federal Institute for Materials Research and Testing, Unter den Eichen 87, 12205 Berlin (Germany)

    2014-05-15T23:59:59.000Z

    Nanotechnology is one of the key technologies of the 21{sup st} century. The exploitation of 'new' effects that arise from materials structured on the nano-scale has also been proposed successfully for flame retardancy of polymers since the end of the 90s. Of all of the approaches these include, at this time the use of nanocomposites offers the best potential for industrial application, also some other ideas are sketched, such as using electrospun nanofibers mats or layer-by-layer deposits as protection coatings, as well as sub-micrometer multilayer coatings as effective IR-mirrors. The general phenomena, inducing a flow limit in the pyrolysing melt and changing the fire residue, are identified in nanocomposites. Key experiments are performed such as quasi online investigation of the protection layer formation to understand what is going on in detail. The flame retardancy mechanisms are discussed and their impact on fire behaviour quantified. With the latter, the presentation pushes forward the state of the art. For instance, the heat shielding is experimentally quantified for a layered silicate epoxy resin nanocomposite proving that it is the only import mechanism controlling the reduction in peak heat release rate in the investigated system for different irradiations. The flame retardancy performance is assessed comprehensively illuminating not only the strengths but also the weak points of the concepts. Guidelines for materials development are deduced and discussed. Apart from inorganic fillers (layered silicate, boehmite, etc.) not only carbon nanoobjects such as multiwall carbon nanotubes, multilayer graphene and graphene are investigated, but also nanoparticles that are more reactive and harbor the potential for more beneficial interactions with the polymer matrix.

  11. Transition from cool flame to thermal flame in compression ignition process

    SciTech Connect (OSTI)

    Yamada, Hiroyuki; Suzaki, Kotaro; Goto, Yuichi [National Traffic Safety and Environment Laboratory, 7-42-27 Jindaiji-Higashimachi, Chofu, Tokyo 182-0012 (Japan); Tezaki, Atsumu [Department of Mechanical and Intellectual Systems Engineering, University of Toyama, Gofuku 3190, Toyama-shi, Toyama 930-8555 (Japan)

    2008-07-15T23:59:59.000Z

    The mechanism that initiates thermal flames in compression ignition has been studied. Experimentally, a homogeneous charge compression ignition (HCCI) engine was used with DME, n-heptane, and n-decane. Arrhenius plots of the heat release rate in the HCCI experiments showed that rates of heat release with DME, n-heptane, and n-decane exhibited a certain activation energy that is identical to that of the H{sub 2}O{sub 2} decomposition reaction. The same feature was observed in diesel engine operation using ordinary diesel fuel with advanced ignition timing to make ignition occur after the end of fuel injection. These experimental results were reproduced in nondimensional simulations using kinetic mechanisms for DME, n-heptane, and n-decane, the last being developed by extending the n-heptane mechanism. Methanol addition, which suppresses low-temperature oxidation (LTO) and delays the ignition timing, had no effect on the activation energy obtained from the Arrhenius plot of heat release rate. Nevertheless, methanol addition lowered the heat release rates during the prethermal flame process. This is because H{sub 2}O{sub 2} formation during cool flame was reduced by adding methanol. The mechanism during the transition process from cool flame to thermal flame can be explained quantitatively using thermal explosion theory, in which the rate-determining reaction is H{sub 2}O{sub 2} decomposition, assuming that heat release in this period is caused by partial oxidation of DME and HCHO initiated with the reaction with OH produced though H{sub 2}O{sub 2} decomposition. (author)

  12. Lean Flame Stabilization Ring - Energy Innovation Portal

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOEThe Bonneville PowerCherries 82981-1cnHigh SchoolIn12electron 9 5 -of EnergyLeadership Leadership|Lean Flame

  13. Trapping and aerogelation of nanoparticles in negative gravity hydrocarbon flames

    SciTech Connect (OSTI)

    Chakrabarty, Rajan K., E-mail: rajan.chakrabarty@gmail.com [Department of Energy, Environmental and Chemical Engineering, Washington University in St. Louis, St. Louis, Missouri 63130 (United States); Laboratory for Aerosol Science, Spectroscopy, and Optics, Desert Research Institute, Nevada System of Higher Education, Reno, Nevada 89512 (United States); Novosselov, Igor V. [Department of Mechanical Engineering, University of Washington, Seattle, Washington 98195 (United States); Enertechnix Inc., Maple Valley, Washington 98068 (United States); Beres, Nicholas D.; Moosmüller, Hans [Laboratory for Aerosol Science, Spectroscopy, and Optics, Desert Research Institute, Nevada System of Higher Education, Reno, Nevada 89512 (United States); Sorensen, Christopher M. [Condensed Matter Laboratory, Department of Physics, Kansas State University, Manhattan, Kansas 66506 (United States); Stipe, Christopher B. [TSI Incorporated, 500 Cardigan Rd, Shoreview, Minnesota 55126 (United States)

    2014-06-16T23:59:59.000Z

    We report the experimental realization of continuous carbon aerogel production using a flame aerosol reactor by operating it in negative gravity (?g; up-side-down configuration). Buoyancy opposes the fuel and air flow forces in ?g, which eliminates convectional outflow of nanoparticles from the flame and traps them in a distinctive non-tipping, flicker-free, cylindrical flame body, where they grow to millimeter-size aerogel particles and gravitationally fall out. Computational fluid dynamics simulations show that a closed-loop recirculation zone is set up in ?g flames, which reduces the time to gel for nanoparticles by ?10{sup 6}?s, compared to positive gravity (upward rising) flames. Our results open up new possibilities of one-step gas-phase synthesis of a wide variety of aerogels on an industrial scale.

  14. Dynamics of premixed flames in a narrow channel with a step-wise wall temperature

    E-Print Network [OSTI]

    Daraio, Chiara

    . [1], in their experiments on methane/air and propane/air premixed flames in cylindrical tubes of 2 mm al. [10], asymmetric flames were found in fuel-lean methane/air mixtures burning in a rectangular flame structure was experi- mentally observed for lean propane/air flames in tubes at condi- tions close

  15. GRAVITATIONALLY UNSTABLE FLAMES: RAYLEIGH-TAYLOR STRETCHING VERSUS TURBULENT WRINKLING

    SciTech Connect (OSTI)

    Hicks, E. P. [Center for Interdisciplinary Exploration and Research in Astrophysics (CIERA) and the Department of Physics and Astronomy, Northwestern University, Evanston, IL 60208 (United States); Rosner, R., E-mail: eph2001@columbia.edu [Computation Institute, University of Chicago, 5735 S. Ellis Ave., Chicago, IL 60637 (United States)

    2013-07-10T23:59:59.000Z

    In this paper, we provide support for the Rayleigh-Taylor-(RT)-based subgrid model used in full-star simulations of deflagrations in Type Ia supernovae explosions. We use the results of a parameter study of two-dimensional direct numerical simulations of an RT unstable model flame to distinguish between the two main types of subgrid models (RT or turbulence dominated) in the flamelet regime. First, we give scalings for the turbulent flame speed, the Reynolds number, the viscous scale, and the size of the burning region as the non-dimensional gravity (G) is varied. The flame speed is well predicted by an RT-based flame speed model. Next, the above scalings are used to calculate the Karlovitz number (Ka) and to discuss appropriate combustion regimes. No transition to thin reaction zones is seen at Ka = 1, although such a transition is expected by turbulence-dominated subgrid models. Finally, we confirm a basic physical premise of the RT subgrid model, namely, that the flame is fractal, and thus self-similar. By modeling the turbulent flame speed, we demonstrate that it is affected more by large-scale RT stretching than by small-scale turbulent wrinkling. In this way, the RT instability controls the flame directly from the large scales. Overall, these results support the RT subgrid model.

  16. Measurements and large eddy simulation of propagating premixed flames

    SciTech Connect (OSTI)

    Masri, A.R.; Cadwallader, B.J. [School of Aerospace, Mechanical and Mechatronic Engineering, The University of Sydney, Sydney, NSW 2006 (Australia); Ibrahim, S.S. [Department of Aeronautical and Automotive Engineering, Loughborough University, Loughborough LE11 3TU (United Kingdom)

    2006-07-15T23:59:59.000Z

    This paper presents an experimental and numerical study of unsteady turbulent premixed flames igniting in an initially stagnant mixture and propagating past solid obstacles. The objective here is to study the outstanding issue of flow-flame interactions in transient premixed combustion environments. Particular emphasis is placed on the burning rate and the structure of the flame front. The experimental configuration consists of a chamber with a square cross-section filled with a combustible mixture of propane-air ignited from rest. An array of baffle plates as well as geometrical obstructions of varying shapes and blockage ratios, are placed in the path of the flame as it propagates from the ignition source to the vented end of the enclosure. A range of flame propagation conditions are studied experimentally. Measurements are presented for pressure-time traces, high-speed images of the flame front, mean velocities obtained from particle imaging velocimetry and laser induced fluorescence images of the hydroxyl radical OH. Three-dimensional large eddy simulations (LES) are also made for a case where a square obstacle and an array of baffle plates are placed in the chamber. The dynamic Germano model and a simple flamelet combustion model are used at the sub-grid scale. The effects of grid size and sub-grid filter width are also discussed. Calculations and measurements are found to be in good agreement with respect to flame structure and peak overpressure. Turbulence levels increase significantly at the leading edge of the flame as it propagates past the array of baffle plates and the obstacle. With reference to the regime diagrams for turbulent premixed combustion, it is noted that the flame continues to lie in the zones of thin reactions or corrugated flamelets regardless of the stage of propagation along the chamber. (author)

  17. Numerical Investigation of Scaling Properties of Turbulent Premixed Flames

    E-Print Network [OSTI]

    J. C. Niemeyer; A. R. Kerstein

    1997-07-09T23:59:59.000Z

    Gibson scaling and related properties of flame-surface geometry in turbulent premixed combustion are demonstrated using a novel computational model, Deterministic Turbulent Mixing (DTM). In DTM, turbulent advection is represented by a sequence of maps applied to the computational domain. The structure of the mapping sequence incorporates pertinent scaling properties of the turbulent cascade. Here, combustion in Kolmogorov turbulence (kinetic-energy cascade) and in Bolgiano-Obukhov convective turbulence (potential-energy cascade) is simulated. Implications with regard to chemical flames and astrophysical (thermonuclear) flames are noted.

  18. Reactor pressure vessel vented head

    DOE Patents [OSTI]

    Sawabe, James K. (San Jose, CA)

    1994-01-11T23:59:59.000Z

    A head for closing a nuclear reactor pressure vessel shell includes an arcuate dome having an integral head flange which includes a mating surface for sealingly mating with the shell upon assembly therewith. The head flange includes an internal passage extending therethrough with a first port being disposed on the head mating surface. A vent line includes a proximal end disposed in flow communication with the head internal passage, and a distal end disposed in flow communication with the inside of the dome for channeling a fluid therethrough. The vent line is fixedly joined to the dome and is carried therewith when the head is assembled to and disassembled from the shell.

  19. Residential Refrigerator Recycling Ninth Year Retention Study

    E-Print Network [OSTI]

    Residential Refrigerator Recycling Ninth Year Retention Study Study ID Nos. 546B, 563 Prepared RECYCLING PROGRAMS Study ID Nos. 546B and 563 Prepared for Southern California Edison Rosemead, California

  20. Experimental Endeavour on a Pillar of Flame: Space Shuttle Rises...

    Energy Savers [EERE]

    flash and a flame . . . a rush and a roar . . . a bright white bird booming into a deep blue sky: Few science experiments ever begin in such spectacular fashion. Yet the Space...

  1. Temperature field reconstruction of combustion flame based on high

    E-Print Network [OSTI]

    that sound propagates in a different medium with different speed, and its theo- retical cornerstone-known materials of solid, liquid, and gaseous states, flame is a kind of plasma1,2 of which temper- ature is one

  2. TRACES Centre Thermo iCE 3500 Flame AA Spectrometer

    E-Print Network [OSTI]

    Wells, Mathew G. - Department of Physical and Environmental Sciences, University of Toronto

    TRACES Centre Thermo iCE 3500 Flame AA Spectrometer Standard Operating Procedure 1. Turn on the lamp icon a. ID the lamp of choice and click the `Off' button to `On' b. Non-Thermo lamps MUST

  3. Surface wettability studies of PDMS using flame plasma treatment

    E-Print Network [OSTI]

    Wang, Xin C

    2009-01-01T23:59:59.000Z

    The flame plasma treatment studied in this thesis was able to oxidize the surface of Polydimethylsiloxane (PDMS) in a fraction of a second. It was found to be a much faster way to modify PDMS surface wettability than the ...

  4. Physics-based flame dynamics modeling and thermoacoustic instability mitigation

    E-Print Network [OSTI]

    Altay, Hurrem Murat

    2009-01-01T23:59:59.000Z

    The objectives of this work are (i) to investigate the coupled unsteady heat release mechanisms responsible for thermoacoustic instabilities under different flame anchoring configurations, (ii) to develop reduced-order ...

  5. The effect of fuel composition on flame dynamics

    SciTech Connect (OSTI)

    Hendricks, Adam G.; Vandsburger, Uri [Department of Mechanical Engineering - 0238, Virginia Tech, Blacksburg, VA 24061 (United States)

    2007-10-15T23:59:59.000Z

    As fuel sources diversify, the gas turbine industry is under increasing pressure to develop fuel-flexible plants, able to use fuels with a variety of compositions from a large range of sources. However, the dynamic characteristics vary considerably with composition, in many cases altering the thermoacoustic stability of the combustor. We compare the flame dynamics, or the response in heat release rate of the flame to acoustic perturbations, of the three major constituents of natural gas: methane, ethane, and propane. The heat release rate is quantified using OH* chemiluminescence and product gas temperature. Gas temperature is measured by tracking the absorption of two high-temperature water lines, via Tunable Diode Laser Absorption Spectroscopy. The flame dynamics of the three fuels differ significantly. The changes in flame dynamics due to variations in fuel composition have the potential to have a large effect on the thermoacoustic stability of the combustor. (author)

  6. Probing flame chemistry with MBMS, theory, and modeling

    SciTech Connect (OSTI)

    Westmoreland, P.R. [Univ. of Massachusetts, Amherst (United States)

    1993-12-01T23:59:59.000Z

    The objective is to establish kinetics of combustion and molecular-weight growth in C{sub 3} hydrocarbon flames as part of an ongoing study of flame chemistry. Specific reactions being studied are (1) the growth reactions of C{sub 3}H{sub 5} and C{sub 3}H{sub 3} with themselves and with unsaturated hydrocarbons and (2) the oxidation reactions of O and OH with C{sub 3}`s. This approach combines molecular-beam mass spectrometry (MBMS) experiments on low-pressure flat flames; theoretical predictions of rate constants by thermochemical kinetics, Bimolecular Quantum-RRK, RRKM, and master-equation theory; and whole-flame modeling using full mechanisms of elementary reactions.

  7. (K. Martin, Head) University Librarian

    E-Print Network [OSTI]

    He, Chuan

    (Elisabeth Long, Assoc Univ Lib) Law (S. Lewis) Sciences (B. Kern & A. TwissBrooks) Hum, SocSci & Spec Coll. Larsen, Head) Stacks Management (D. Bottorff, Head) Special Projects Reference Instruction Outreach (J

  8. Influence of gas compression on flame acceleration in the early stage of burning in tubes

    E-Print Network [OSTI]

    Valiev, Damir; Kuznetsov, Mikhail; Eriksson, Lars-Erik; Law, Chung K; Bychkov, Vitaly

    2012-01-01T23:59:59.000Z

    The mechanism of finger flame acceleration at the early stage of burning in tubes has been observed experimentally by Clanet and Searby [Combust. Flame 105: 225 (1996)] for slow propane-air flames, and elucidated analytically and computationally by Bychkov et al. [Combust. Flame 150: 263 (2007)] in the limit of an incompressible flow. We analytically, experimentally and computationally study herein the finger flame acceleration for fast burning flames, when the gas compressibility assumes an important role. Specifically, we have developed a theory through small Mach number expansion up to the first-order terms, demonstrating that gas compression reduces the acceleration rate and thereby moderates the finger flame acceleration noticeably. We have also conducted experiments for hydrogen-oxygen mixtures with considerable initial values of the Mach number, showing finger flame acceleration with the acceleration rate much smaller than those obtained previously for hydrocarbon flames. Furthermore, we have performed...

  9. Numerical and experimental investigation of vortical flow-flame interaction

    SciTech Connect (OSTI)

    Najm, H.N.; Schefer, R.W.; Milne, R.B.; Mueller, C.J. [Sandia National Labs., Livermore, CA (United States); Devine, K.D.; Kempka, S.N. [Sandia National Labs., Albuquerque, NM (United States)

    1998-02-01T23:59:59.000Z

    A massively parallel coupled Eulerian-Lagrangian low Mach number reacting flow code is developed and used to study the structure and dynamics of a forced planar buoyant jet flame in two dimensions. The numerical construction uses a finite difference scheme with adaptive mesh refinement for solving the scalar conservation equations, and the vortex method for the momentum equations, with the necessary coupling terms. The numerical model construction is presented, along with computational issues regarding the parallel implementation. An experimental acoustically forced planar jet burner apparatus is also developed and used to study the velocity and scalar fields in this flow, and to provide useful data for validation of the computed jet. Burner design and laser diagnostic details are discussed, along with the measured laboratory jet flame dynamics. The computed reacting jet flow is also presented, with focus on both large-scale outer buoyant structures and the lifted flame stabilization dynamics. A triple flame structure is observed at the flame base in the computed flow, as is theoretically expected, but was not observable with present diagnostic techniques in the laboratory flame. Computed and experimental results are compared, along with implications for model improvements.

  10. On the Evolution of Thermonuclear Flames on Large Scales

    E-Print Network [OSTI]

    Ju Zhang; O. E. Bronson Messer; Alexei M. Khokhlov; Tomasz Plewa

    2006-10-05T23:59:59.000Z

    The thermonuclear explosion of a massive white dwarf in a Type Ia supernova explosion is characterized by vastly disparate spatial and temporal scales. The extreme dynamic range inherent to the problem prevents the use of direct numerical simulation and forces modelers to resort to subgrid models to describe physical processes taking place on unresolved scales. We consider the evolution of a model thermonuclear flame in a constant gravitational field on a periodic domain. The gravitational acceleration is aligned with the overall direction of the flame propagation, making the flame surface subject to the Rayleigh-Taylor instability. The flame evolution is followed through an extended initial transient phase well into the steady-state regime. The properties of the evolution of flame surface are examined. We confirm the form of the governing equation of the evolution suggested by Khokhlov (1995). The mechanism of vorticity production and the interaction between vortices and the flame surface are discussed. The results of our investigation provide the bases for revising and extending previous subgrid-scale model.

  11. Experimental and Computational Study of Flame Inhibition Mechanisms of Halogenated Compounds in C1-C3 Alkanes Flames

    E-Print Network [OSTI]

    Osorio Amado, Carmen H

    2013-07-30T23:59:59.000Z

    suppressants on ignition and laminar flame propagation of C_(1)-C_(3) alkanes premixed mixtures, as good representatives of flammable gas fires (Class B fires). This methodology integrates model formulations and experimental designs in order to examine both...

  12. Comparison of ultraviolet and ultraviolet-infrared flame detection systems

    E-Print Network [OSTI]

    Dayton, Robert Mark

    1986-01-01T23:59:59.000Z

    . 5 Feet Elevation with the Mumber Seven Orifice Height of Heads: 8. 5 feet Sensitivity Settings: Head Head Head Head Head Orifice Size: ?7 (0. 110") ?1, ?2, ?3, ?4, ?5, Genera I Monitors UV/IR - 3. 75 VDC Detector Electronics UV/IR (1888... n = Al 1 Five repetitions measurements are in feet. Maximum error is sl foot. 38 Height of Heads: 8. 5 feet Sens1t1vity Settings: General Monitors UV/IR - 3. 75 VDC ( ? ) Detector Electronics UV- 32 counts/second ( ~ ? ? ) Armtec UV...

  13. Investigation of H2 Concentration and Combustion Instability Effects on the Kinetics of Strained Syngas Flames

    SciTech Connect (OSTI)

    Ahsan R. Choudhuri

    2006-08-07T23:59:59.000Z

    The flame extinction limits of syngas (H{sub 2}-CO) flames were measured using a twin-flame-counter-flow burner. Plots of Extinction limits vs. global stretch rates were generated at different mixture compositions and an extrapolation method was used to calculate the flame extinction limit corresponding to an experimentally unattainable zero-stretch condition. The zero-stretch extinction limit of H{sub 2}-CO mixtures decreases (from rich to lean) with the increase in H{sub 2} concentration in the mixture. The average difference between the measured flame extinction limit and the Le Chatelier's calculation is around {approx} 7%. The measured OH{sup -} chemiluminescent data indicates that regardless of mixture compositions the OH radical concentration reduces (within the experimental uncertainties) to an extinction value prior to the flame extinction. Flame extinction limits of H{sub 2}-CO mixtures measured in a flat-flame burner configuration also show a similar relation. Additionally, the measured laminar flame velocity close to the extinction indicates that regardless of fuel composition the premixed flame of hydrogen fuel blends extinguishes when the mixture laminar flame velocity falls below a critical value. The critical laminar flame velocity at extinction for H{sub 2}-CO premixed flames (measured in the flat flame burner configuration) is found to be 3.77({+-}0.38) cm/s. An externally perturbed H{sub 2}-CO twin flame was not experimentally achievable for the mixture conditions used in the present investigation. A slightest perturbation in the flow-field distorts the H{sub 2}-CO twin-flame. The flame becomes highly unstable with the introduction of an externally excited flow oscillation.

  14. The structure of the carbon black flame

    E-Print Network [OSTI]

    Anderson, W. Kermi

    1945-01-01T23:59:59.000Z

    BLACK FLAME A Dissertation By William Kermit Anderson THEHSR UCOF 120925 TNLKMDiserstsKa aony WHR1mo WdpvmlcyfEyS lnR1 R1WvpS 1nS nvfyARyfh vySS Rm R1y SyuyoWc nvfnunfHWcS Wvf fybWoRgyvRS l1m dmmbyoWRyf Rm gWpy R1nS lmop bmSSnAcy. xbydnWc R1Wvp...S Woy fHy Rm R1y PmccmlnvE gygAyoS mP R1y. SRWPP mP R1y TEondHcRHoWc Wvf tyd1WvndWc NmccyEy mP ayqWS. am eo. joyf D. :yvSyv Pmo Ryd1vndWc 1ycb Wvf Pmo vHgyomHS SHEEySRnmvS mP uWcHy. am eo. N. N. 9yfEyS Pmo PnvWvdnWc Wnf Wvf yqdych cyvR dmmbyo...

  15. Deuterium Retention in NSTX with Lithium Conditioning

    SciTech Connect (OSTI)

    C.H. Skinner, J.P. Allain, W. Blanchard, H.W. Kugel, R. Maingi, L. Roquemore, V. Soukhanovskii, C.N. Taylor

    2010-06-02T23:59:59.000Z

    High (? 90%) deuterium retention was observed in NSTX gas balance measurements both withand without lithiumization of the carbon plasma facing components. The gas retained in ohmic discharges was measured by comparing the vessel pressure rise after a discharge to that of a gasonly pulse with the pumping valves closed. For neutral beam heated discharges the gas input and gas pumped by the NB cryopanels were tracked. The discharges were followed by outgassing of deuterium that reduced the retention. The relationship between retention and surface chemistry was explored with a new plasma-material interface probe connected to an in-vacuo surface science station that exposed four material samples to the plasma. XPS and TDS analysis showed that the binding of D atoms is fundamentally changed by lithium - in particular atoms are weakly bonded in regions near lithium atoms bound to either oxygen or the carbon matrix.

  16. HEAD OF CONTRACTING ACTIVITY

    Office of Environmental Management (EM)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625 1,006 492 742 33 1112011 Strategic2 OPAM Flash2011-12 OPAMGeneralGuiding Documents and Links GuidingTank Farm6HEAD

  17. Nonlinear effects of stretch on the flame front propagation

    SciTech Connect (OSTI)

    Halter, F.; Tahtouh, T.; Mounaim-Rousselle, C. [Institut PRISME, Universite d'Orleans, 8 rue Leonard de Vinci, 45072 Orleans Cedex 2 (France)

    2010-10-15T23:59:59.000Z

    In all experimental configurations, the flames are affected by stretch (curvature and/or strain rate). To obtain the unstretched flame speed, independent of the experimental configuration, the measured flame speed needs to be corrected. Usually, a linear relationship linking the flame speed to stretch is used. However, this linear relation is the result of several assumptions, which may be incorrected. The present study aims at evaluating the error in the laminar burning speed evaluation induced by using the traditional linear methodology. Experiments were performed in a closed vessel at atmospheric pressure for two different mixtures: methane/air and iso-octane/air. The initial temperatures were respectively 300 K and 400 K for methane and iso-octane. Both methodologies (linear and nonlinear) are applied and results in terms of laminar speed and burned gas Markstein length are compared. Methane and iso-octane were chosen because they present opposite evolutions in their Markstein length when the equivalence ratio is increased. The error induced by the linear methodology is evaluated, taking the nonlinear methodology as the reference. It is observed that the use of the linear methodology starts to induce substantial errors after an equivalence ratio of 1.1 for methane/air mixtures and before an equivalence ratio of 1 for iso-octane/air mixtures. One solution to increase the accuracy of the linear methodology for these critical cases consists in reducing the number of points used in the linear methodology by increasing the initial flame radius used. (author)

  18. Reactor pressure vessel vented head

    DOE Patents [OSTI]

    Sawabe, J.K.

    1994-01-11T23:59:59.000Z

    A head for closing a nuclear reactor pressure vessel shell includes an arcuate dome having an integral head flange which includes a mating surface for sealingly mating with the shell upon assembly therewith. The head flange includes an internal passage extending therethrough with a first port being disposed on the head mating surface. A vent line includes a proximal end disposed in flow communication with the head internal passage, and a distal end disposed in flow communication with the inside of the dome for channeling a fluid therethrough. The vent line is fixedly joined to the dome and is carried therewith when the head is assembled to and disassembled from the shell. 6 figures.

  19. Measurements of the structure of turbulent premixed and stratified methane/air flames

    E-Print Network [OSTI]

    Sweeney, Mark

    2011-11-08T23:59:59.000Z

    was entirely due to deviation from stoichiometry and the corresponding reduction in local reaction rate. Poinsot et al [34] performed three-dimensional reduced chemistry simulations of turbulent strat- ified propane/air flames with a Gaussian distribution... that stratification increased the flame propagation rate. The local variation in burning velocity was accompanied by an increase in flame front wrinkling relative to premixed flames, with a corresponding broadening of curvature distributions. Pasquier et al [22...

  20. Fractal characterisation of high-pressure and hydrogen-enriched CH4air turbulent premixed flames

    E-Print Network [OSTI]

    Gülder, �mer L.

    Fractal characterisation of high-pressure and hydrogen-enriched CH4­air turbulent premixed flames measurements were performed to obtain the flame front images, which were further analyzed for fractal of the flame front curvature as a function of the pressure. Fractal dimension showed a strong dependence

  1. Prediction of oxy-coal flame stand-off using high-fidelity thermochemical models

    E-Print Network [OSTI]

    Prediction of oxy-coal flame stand-off using high-fidelity thermochemical models and the one Abstract An Eulerian one-dimensional turbulence (ODT) model is applied to simulate oxy-coal combustion temperature and mixing rate on oxy-coal flame is simulated and discussed where flame stand-off is used

  2. Kinetic effects of toluene blending on the extinction limit of n-decane diffusion flames

    E-Print Network [OSTI]

    Ju, Yiguang

    analyses of kinetic path ways and species transport on flame extinction were also conducted. The results and emission properties, such as the ignition delay times, extinction limits, flame speeds, species profilesKinetic effects of toluene blending on the extinction limit of n-decane diffusion flames Sang Hee

  3. Blowoff characteristics of bluff-body stabilized conical premixed flames under upstream velocity modulation

    SciTech Connect (OSTI)

    Chaparro, Andres A.; Cetegen, Baki M. [Mechanical Engineering Department, University of Connecticut, Storrs, CT 06269-3139 (United States)

    2006-01-01T23:59:59.000Z

    This article presents experimental findings on the blowoff characteristics of conical premixed flames anchored at their apex by three different flame holders (rod, disk, and cone) in the presence of upstream velocity oscillations. Experiments were performed with propane-air mixtures at mixture velocities approaching the flame holder of 5, 10, and 15 m/s. The flow speed was modulated sinusoidally at frequencies up to 400 Hz with a constant-velocity modulation amplitude of u{sub rms}/U{sub m}=0.08 upstream of the flame holder. It was found that the blowoff equivalence ratio exhibits a dependence on the flow modulation frequency. Specifically, at low approach velocities (5 m/s), the effect of upstream flow modulation is to improve flame stability as evidenced by lower flame blowoff equivalence ratios for all three types of flame holders considered. At higher approach velocities (10 and 15 m/s), the disk- and cone-shaped flame holders exhibit less stability with increasing excitation frequency. The rod-shaped flame holder behavior is different at these higher velocities in that the flow modulation still provides enhanced flame stability. The flame stability results are supplemented with a detailed analysis of the flow field in the flame stabilization zone obtained by particle image velocimetry.

  4. Premixed turbulent flame front structure investigation by Rayleigh scattering in the thin

    E-Print Network [OSTI]

    Gülder, Ömer L.

    in propane flames. The probability density function of curvature showed a Gaussian-like distribution at all­air and propane­air stabilized on a bunsen type burner were studied using planar Rayleigh scattering and particle flames, and from 0.7 to stoichiometric for propane flames. The non-dimensional turbulence rms velocity, u

  5. Turbulent Oxygen Flames in Type Ia Supernovae A. J. Aspden1

    E-Print Network [OSTI]

    Turbulent Oxygen Flames in Type Ia Supernovae A. J. Aspden1 , J. B. Bell1 , and S. E. Woosley2 oxygen flames. The two aims of the paper are to examine the response of the inductive oxygen flame to intense levels of turbulence, and to explore the possibility of transition to detonation in the oxygen

  6. LES/probability density function approach for the simulation of an ethanol spray flame

    E-Print Network [OSTI]

    Raman, Venkat

    LES/probability density function approach for the simulation of an ethanol spray flame Colin Heye a an experimental pilot-stabilized ethanol spray flame. In this particular flame, droplet evaporation occurs away: Large-eddy simulation; Probability density function; Flamelet/progress variable approach; Ethanol

  7. High temperature ceramic composition for hydrogen retention

    DOE Patents [OSTI]

    Webb, R.W.

    1974-01-01T23:59:59.000Z

    A ceramic coating for H retention in fuel elements is described. The coating has relatively low thermal neutron cross section, is not readily reduced by H at 1500 deg F, is adherent to the fuel element base metal, and is stable at reactor operating temperatures. (JRD)

  8. Simulation of turbulent flames relevant to spark-ignition engines

    E-Print Network [OSTI]

    Ahmed, Irufan

    2014-04-29T23:59:59.000Z

    -premixed. In premixed flames, fuel and oxidiser are mixed homo- geneously before combustion. Lean-burn gas turbines for power generation and spark-ignition (SI) IC engines are typical examples of this type of combustion. In non-premixed or ‘diffusion flames’, the fuel... and oxidiser are transported sep- arately into the reaction zones by diffusion. Aero-engine gas turbines and diesel engines are typical examples of non-premixed combustion. It is often the case in practical systems that fuel and air is not completely mixed...

  9. Scalar dissipation rate based flamelet modelling of turbulent premixed flames

    E-Print Network [OSTI]

    Kolla, Hemanth

    2010-03-16T23:59:59.000Z

    closure for two mixtures: stoichiometric methane–air with K = 1.0 (•) and lean propane–air with KLe = 1.0 (?). The experimental data of Abdel- Gayed et al. (1987) for K = 1.0 are also shown (?). . . . . . . . . 111 7.9 The comparisons of flame speeds... closure for two mixtures: stoichiometric methane–air with K = 1.0 (•) and lean propane–air with KLe = 1.0 (?). The experimental data of Abdel- Gayed et al. (1987) for K = 1.0 are also shown (?). . . . . . . . . 111 7.9 The comparisons of flame speeds...

  10. INVESTIGATION ON THE FLAME EXTINCTION LIMIT OF FUEL BLENDS

    SciTech Connect (OSTI)

    Ahsan R. Choudhuri

    2005-02-01T23:59:59.000Z

    Lean flame extinction limits of binary fuel mixtures of methane (CH{sub 4}), propane (C{sub 3}H{sub 8}), and ethane (C{sub 2}H{sub 6}) were measured using a twin-flame counter-flow burner. Experiments were conducted to generate an extinction equivalence ratio vs. global stretch rate plot and an extrapolation method was used to calculate the equivalence ratio corresponding to an experimentally unattainable zero-stretch condition. The foregoing gases were selected because they are the primary constitutes of natural gas, which is the primary focus of the present study. To validate the experimental setup and methodology, the flame extinction limit of pure fuels at zero stretch conditions were also estimated and compared with published values. The lean flame extinction limits of methane (f{sub ext} = 4.6%) and propane (f{sub ext} = 2.25%) flames measured in the present study agreed with the values reported in the literature. It was observed that the flame extinction limit of fuel blends have a polynomial relation with the concentration of component fuels in the mixture. This behavior contradicts with the commonly used linear Le Chatelier's approximation. The experimentally determined polynomial relations between the flame extinction limits of fuel blends (i.e. methane-propane and methane-ethane) and methane concentration are as follows: (1) Methane-Propane--%f{sub ext} = (1.05 x 10{sup -9}) f{sup 5}-(1.3644 x 10{sup -7}) f{sup 4}+(6.40299 x 10{sup -6}) f{sup 3}-(1.2108459 x 10{sup -4}) f{sup 2}+(2.87305329 x 10{sup -3}) f+2.2483; (2) Methane-Ethane--%f{sub ext} = (2.1 x 10{sup -9})f{sup 5}-(3.5752 x 10{sup -7}) f{sup 4}+(2.095425 x 10{sup -5}) f{sup 3}-(5.037353 x 10{sup -4}) f{sup 2} + 6.08980409 f + 2.8923. Where f{sub ext} is the extinction limits of methane-propane and methane-ethane fuel blends, and f is the concentration (% volume) of methane in the fuel mixture. The relations were obtained by fitting fifth order curve (polynomial regression) to experimentally measured extinction limits at different mixture conditions. To extend the study to a commercial fuel, the flame extinction limit for Birmingham natural gas (a blend of 95% methane, 5% ethane and 5% nitrogen) was experimentally determined and was found to be 3.62% fuel in the air-fuel mixture.

  11. Spatial resolution of temperature and chemical species in a flame

    E-Print Network [OSTI]

    Albahadily, Fakhrildeen Niema

    1984-01-01T23:59:59.000Z

    by Winefordner et al. (51). AE . /k A. g. I. B. ln ~ + ln ? + 1n? 1 A. g. i B. (36) where: subscript i = the level excited by the source subscript j = the thermally assisted level flame temperature AE . . ij the difference in energy between i and j.... Schweikert (Member) Abdel-Kad Ayou (Memb ) Vaneica . Y ng (Member) May 1984 ABSTRACT Spatial Resolution of Temperature and Chemical Species in a Flame. (May 1984) Fakhrildeen Niema Albahadily, B. S. , University of Basrah/Iraq Chairman of Advisory...

  12. West Virginia University -Main Campus Student Retention and Graduation Rates

    E-Print Network [OSTI]

    Mohaghegh, Shahab

    West Virginia University - Main Campus Student Retention and Graduation Rates First-Time, Full ---------------------------------------------------------------------Continuation Rates and Cumulative Graduation Rates

  13. California Institute of Technology Records Retention and Disposition Policy

    E-Print Network [OSTI]

    of the Records Retention and Disposition Policy is to establish and maintain a uniform records management policy activities and are subject to records management review and evaluation prior to any decisions regarding of Technology Records Retention Schedule ("Retention Schedule"). Department and division management should

  14. California Institute of Technology Records Retention and Disposition Policy

    E-Print Network [OSTI]

    Goddard III, William A.

    management policy for the control, retention, storage, retrieval, and disposal of recorded information, operations, or other activities and are subject to records management review and evaluation prior to any of Technology Records Retention Schedule ("Retention Schedule"). Department and division management should

  15. Role Profile Head of School

    E-Print Network [OSTI]

    Edinburgh, University of

    Role Profile Head of School Purpose of the Role The Head of School is accountable for:- · The provision of academic leadership, developing and delivering School objectives for, in particular, teaching, · The effective governance and management of the School and all of its resources. Context of the Role

  16. Bear Head LNG Corporation and Bear Head LNG (USA), LLC - FE Dkt...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Bear Head LNG Corporation and Bear Head LNG (USA), LLC - FE Dkt. No. - 15-33-LNG Bear Head LNG Corporation and Bear Head LNG (USA), LLC - FE Dkt. No. - 15-33-LNG The Office of...

  17. Effect of Blending on High-Pressure Laminar Flame Speed Measurements, Markstein Lengths, and Flame Stability of Hydrocarbons

    E-Print Network [OSTI]

    Lowry, William Baugh

    2012-02-14T23:59:59.000Z

    . Hydrocarbon blends of methane, ethane, and propane make up a large portion of natural gas and it has been shown that dimethyl ether can be used as a supplement or in its pure form for gas turbine combustion. Because of this, a fundamental understanding... include the flame speeds for binary blends of methane, ethane, propane, and dimethyl ether performed at elevated pressures, up to 10-atm initial pressure, using a spherically expanding flame in a constant-volume vessel. Also included in this thesis is a...

  18. Small-scale Interaction of Turbulence with Thermonuclear Flames in Type Ia Supernovae

    E-Print Network [OSTI]

    J. C. Niemeyer; W. K. Bushe; G. R. Ruetsch

    1999-05-07T23:59:59.000Z

    Microscopic turbulence-flame interactions of thermonuclear fusion flames occuring in Type Ia Supernovae were studied by means of incompressible direct numerical simulations with a highly simplified flame description. The flame is treated as a single diffusive scalar field with a nonlinear source term. It is characterized by its Prandtl number, Pr << 1, and laminar flame speed, S_L. We find that if S_L ~ u', where u' is the rms amplitude of turbulent velocity fluctuations, the local flame propagation speed does not significantly deviate from S_L even in the presence of velocity fluctuations on scales below the laminar flame thickness. This result is interpreted in the context of subgrid-scale modeling of supernova explosions and the mechanism for deflagration-detonation-transitions.

  19. Extinction and near-extinction instability of non-premixed tubular flames

    SciTech Connect (OSTI)

    Hu, Shengteng; Pitz, Robert W.; Yu, Wang [Mechanical Engineering Department, Vanderbilt University, Nashville, TN 37235 (United States)

    2009-01-15T23:59:59.000Z

    Tubular non-premixed flames are formed by an opposed tubular burner, a new tool to study the effects of curvature on extinction and flame instability of non-premixed flames. Extinction of the opposed tubular flames generated by burning diluted H{sub 2}, CH{sub 4} or C{sub 3}H{sub 8} with air is investigated for both concave and convex curvature. To examine the effects of curvature on extinction, the critical fuel dilution ratios at extinction are measured at various stretch rates, initial mixture strengths and flame curvature for fuels diluted in N{sub 2}, He, Ar or CO{sub 2}. In addition, the onset conditions of the cellular instability are mapped as a function of stretch rates, initial mixture strengths, and flame curvature. For fuel mixtures with Lewis numbers much less than unity, such as H{sub 2}/N{sub 2}, concave flame curvature towards the fuel suppresses cellular instabilities. (author)

  20. Laser-induced breakdown spectroscopy measurement in methane and biodiesel flames using an ungated detector

    SciTech Connect (OSTI)

    Eseller, Kemal E.; Yueh, Fang Y.; Singh, Jagdish P

    2008-11-01T23:59:59.000Z

    Laser-induced breakdown spectroscopy (LIBS) has been applied to measure the equivalence ratio of CH4/air flames using gated detection. In this work, we have developed an ungated, miniature LIBS-based sensor for studying CH4/air and biodiesel flames. We have used this sensor to characterize the biodiesel flame. LIBS spectra of biodiesel flames were recorded with different ethanol concentrations in the biodiesel and also at different axial locations within the flame. The sensor performance was evaluated with a CH4/air flame. LIBS signals of N, O, and H from a CH4/air flame were used to determine the equivalence ratio. A linear relationship between the intensity ratio of H and O lines and the calculated equivalence ratio were obtained with this sensor.

  1. RICH METHANE PREMIXED LAMINAR FLAMES DOPED BY LIGHT UNSATURATED HYDROCARBONS

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    RICH METHANE PREMIXED LAMINAR FLAMES DOPED BY LIGHT UNSATURATED HYDROCARBONS PART I: ALLENE developed in our laboratory for the reactions of C3-C4 unsaturated hydrocarbons. The main reaction pathways2007 #12;3 INTRODUCTION Soots and polyaromatic hydrocarbons (PAH), which are present in the exhaust gas

  2. Modeling of combustion noise spectrum from turbulent premixed flames

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    Modeling of combustion noise spectrum from turbulent premixed flames Y. Liu, A. P. Dowling, T. D, Nantes, France 2321 #12;Turbulent combustion processes generate sound radiation due to temporal changes, this temporal correlation and its role in the modeling of combustion noise spectrum are studied by analyzing

  3. Flame Synthesis of Carbon Nanotubes Using Low Calorific Value Gases

    SciTech Connect (OSTI)

    Jorge Camacho; Mahesh Subramanya; Ahsan R. Choudhuri

    2007-03-31T23:59:59.000Z

    Nanostructures formed in diffusion flames of pure fuels [CH{sub 4}, C{sub 3}H{sub 8}, and C{sub 2}H{sub 2}] at different fuel flow rates have been analyzed. Synthesis samples have been also collected from diffusion flames of various fuel blends [H{sub 2}-CH{sub 4}, H{sub 2}-CO, H{sub 2}-C{sub 3}H{sub 8}, H{sub 2}-C{sub 2}H{sub 2}] at different combustion conditions. SEM images of particulate samples collected from H{sub 2}-CH{sub 4} diffusion flames show formation of nanostructures. However, the formation of nanostructures only occurs at a narrow window of fuel compositions (< 10% H{sub 2} concentration in the mixture) and flow conditions (Jet Exit Reynolds number Re{sub j} = 200). At higher H{sub 2} concentration and flow velocity, formation of nanostructures diminishes and H{sub 2}-CH{sub 4} flames produce amorphous carbon and soot particles.

  4. Flame/Wall interactions : laminar study of unburnt HC formation

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    and desorption by oil film, deposits in combustion chamber, flame quenching, mixture and incomplete combustion for an important part to the sources of hydrocarbon (HC) emission in a combustion chamber. The aim of this work in gasoline engine. A skeletal mechanism (29 species and 48 reactions) mimicking iso-octane combustion is used

  5. Europium-doped yttrium silicate nanophosphors prepared by flame synthesis

    E-Print Network [OSTI]

    Bernhard, Stefan

    Europium-doped yttrium silicate nanophosphors prepared by flame synthesis Xiao Qin a,*, Yiguang Ju; accepted 7 November 2006 Available online 22 December 2006 Abstract Europium-doped yttrium silicate (Y2SiO5 properties 1. Introduction Yttrium silicate (Y2SiO5) is an important luminescent host material for various

  6. Reaction zone visualisation in swirling spray n-heptane flames

    E-Print Network [OSTI]

    Yuan, R.; Kariuki, J.; Dowlut, A.; Balachandran, R.; Mastorakos, E.

    2014-06-26T23:59:59.000Z

    process and consumed in the subsequent high temperature oxidation. Formaldehyde LIF was used for autoignition of methane jets [6], methanol, ethanol and acetone spray jet flames [7,8], and diesel fuel [9-11] and n-heptane [11,12] in HCCI engines. Najm...

  7. Multiscale Simulation of Titania Nanoparticle Evolution in a Turbulent Flame

    E-Print Network [OSTI]

    Raman, Venkat

    numerous applications in drug delivery, catalysis, energy and semiconductors. Titanium dioxide (TiO2, The University of Texas, Austin, TX 78712, USA Abstract Titanium dioxide nanoparticles are manufactured in flame-based titanium dioxide synthesis are developed. A reduced chemistry mech- anism for gas-phase chemistry

  8. Structure of Partially Premixed Flames Using Detailed Chemistry Simulations

    E-Print Network [OSTI]

    Kluzek, Celine D.

    2010-10-12T23:59:59.000Z

    obtained at Sandia National Labs in 2001. The study is focused on axisymmetric laminar partially-premixed methane/air flames with varying premixture strength values of 1.8, 2.2, and 3.17. The combination of computational and experimental results is used...

  9. Investigation of polarization spectroscopy for detecting atomic hydrogen in flames

    E-Print Network [OSTI]

    Kulatilaka, Waruna Dasal

    2002-01-01T23:59:59.000Z

    . The probe beam was tuned to the single-photon 486-nm n = 2 --> n = 4 resonance of the hydrogen atom by fundamental and frequency-doubled beams from a single 486-nm dye laser were used. The probe beam was linearly polarized entering the flame...

  10. Investigation of polarization spectroscopy for detecting atomic hydrogen in flames 

    E-Print Network [OSTI]

    Kulatilaka, Waruna Dasal

    2002-01-01T23:59:59.000Z

    stabilized on near-adiabatic calibration burner (the Hencken burner). The LIPS signal was found to be nearly proportional to the square of the pump beam intensity over a wide range of flame equivalence ratios. Spectral line shapes of hydrogen 1S-4P...

  11. LES of a Hydrogen-Enriched Lean Turbulent Premixed Flame

    E-Print Network [OSTI]

    Groth, Clinton P. T.

    LES of a Hydrogen-Enriched Lean Turbulent Premixed Flame Francisco E. Hern´andez-P´erez , Clinton the observed behaviour is examined. Hydrogen-hydrocarbon fuel blends appear to be a promising option to synergistically pave the way toward pure hydrogen-based combustion systems while alleviating green-house gas

  12. atomic absorption flame: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    absorption flame First Page Previous Page 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 Next Page Last Page Topic Index 1 Absorption properties of identical...

  13. Real Time Flame Monitoring of Gasifier and Injectors

    SciTech Connect (OSTI)

    Zelepouga, Serguei; Saveliev, Alexei

    2011-12-31T23:59:59.000Z

    This project is a multistage effort with the final goal to develop a practical and reliable nonintrusive gasifier injector monitor to assess burner wear and need for replacement. The project team included the National Energy Technology Laboratory (NETL), Gas Technology Institute (GTI), North Carolina State University, and ConocoPhillips. This report presents the results of the sensor development and testing initially at GTI combustion laboratory with natural gas flames, then at the Canada Energy Technology Center (CANMET), Canada in the atmospheric coal combustor as well as in the pilot scale pressurized entrained flow gasifier, and finally the sensor capabilities were demonstrated at the Pratt and Whitney Rocketdyne (PWR) Gasifier and the Wabash River Repowering plant located in West Terre Haute, IN. The initial tests demonstrated that GTI gasifier sensor technology was capable of detecting shape and rich/lean properties of natural gas air/oxygen enriched air flames. The following testing at the Vertical Combustor Research Facility (VCRF) was a logical transition step from the atmospheric natural gas flames to pressurized coal gasification environment. The results of testing with atmospheric coal flames showed that light emitted by excited OH* and CH* radicals in coal/air flames can be detected and quantified. The maximum emission intensities of OH*, CH*, and black body (char combustion) occur at different axial positions along the flame length. Therefore, the excitation rates of CH* and OH* are distinct at different stages of coal combustion and can be utilized to identify and characterize processes which occur during coal combustion such as devolatilization, char heating and burning. To accomplish the goals set for Tasks 4 and 5, GTI utilized the CANMET Pressurized Entrained Flow Gasifier (PEFG). The testing parameters of the PEFG were selected to simulate optimum gasifier operation as well as gasifier conditions normally resulting from improper operation or failed gasifier injectors. The sensor developed under previous tasks was used to assess the spectroscopic characteristics of the gasifier flame. The obtained spectral data were successfully translated into flame temperature measurements. It was also demonstrated that the reduced spectral data could be very well correlated with very important gasification process parameters such as the air/fuel and water/fuel ratio. Any of these parameters (temperature, air/fuel, and water/fuel) is sufficient to assess burner wear; however, the tested sensor was capable of monitoring all three of them plus the flame shape as functions of burner wear. This will likely be a very powerful tool which should enable significant improvements in gasifier efficiency, reliability, and availability. The sensor technology was presented to the projectâ??s industrial partner (ConocoPhillips). The partner expressed its strong interest in continuing to participate in the field validation phase of GTI's Flame Monitor Project. Finally the sensor was tested in the PWR (Pratt & Whitney Rocketdyne) gasification plant located at GTIâ??s research campus and at the ConocoPhillips industrial scale gasifier at Wabash River Indiana. The field trials of the GTI Gasifier sensor modified to withstand high temperature and pressure corrosive atmosphere of the industrial entrain flow gasifier. The project team successfully demonstrated the Gasifier Sensor system ability to monitor gasifier interior temperature maintaining unobstructed optical access for in excess of six week without any maintenance. The sensor examination upon completion of the trial revealed that the system did not sustain any damage and required minor cleanup of the optics.

  14. Impact limiter retention using a tape joint

    SciTech Connect (OSTI)

    Gonzales, A.; Eakes, R.G.

    1986-01-01T23:59:59.000Z

    The Beneficial Uses Shipping System (BUSS) Cask employs polyurethane foam impact limiters that fit onto the ends of the cask. A foam impact limiter takes energy out of a system during a hypothetical accident condition by allowing foam crush and large deformations to occur. This, in turn, precludes high stresses or deformations from occurring to the cask. Because of the need to transmit significant amounts of heat to the environment, the BUSS cask impact limiters were designed to shield a minimum amount of the cask surface area. With this design impact limiter retention after the initial impact resulting from the 9 meter regulatory drops becomes a concern. Retention is essential to ensure the cask does not experience higher stresses during any secondary or rebound effects without impact limiters than it does during the 9 meter regulatory drop with impact limiters in place.

  15. 300 Area Building Retention Evaluation Mitigation Plan

    SciTech Connect (OSTI)

    D. J. McBride

    2007-07-03T23:59:59.000Z

    Evaluate the long-term retention of several facilities associated with the PNNL Capability Replacement Laboratory and other Hanfor mission needs. WCH prepared a mitigation plan for three scenarios with different release dates for specific buildings. The evaluations present a proposed plan for providing utility services to retained facilities in support of a long-term (+20 year) lifespan in addition to temporary services to buildings with specified delayed release dates.

  16. Heater head for stirling engine

    DOE Patents [OSTI]

    Corey, John A. (R.D. #2, Box 101 E, North Troy, NY 12182)

    1985-07-09T23:59:59.000Z

    A monolithic heater head assembly which augments cast fins with ceramic inserts which narrow the flow of combustion gas and obtains high thermal effectiveness with the assembly including an improved flange design which gives greater durability and reduced conduction loss.

  17. Soot microstructure in steady and flickering laminar methane/air diffusion flames

    SciTech Connect (OSTI)

    Zhang, J.; Megaridis, C.M. [Univ. of Illinois, Chicago, IL (United States). Dept. of Mechanical Engineering

    1998-03-01T23:59:59.000Z

    An experimental investigation is presented to identify the mechanisms responsible for the enhanced sooting behavior of strongly flickering methane/air jet diffusion flames when compared to their steady counterparts. The work extends the implementation of thermophoretic sampling in flickering, co-flow, laminar, diffusion flames. Acoustic forcing of the fuel flow rate is used to phase lock the periodic flame flicker close to the natural flicker frequency ({approximately} 10 Hz for a burner diameter of {approximately} 1 cm). Soot primary sizes, determined as functions of flame coordinates, indicate that the largest soot primary units in strongly flickering methane/air flames are larger by {approximately} 60% than those measured in steady flames with the same mean reactant flow rates. The primary particle size measurements, when combined with the soot volume fractions reported by other investigators, indicate that soot surface areas in the flickering flame are three to four times larger than those under steady conditions. These results, along with the fact that residence times in the flickering flame are twice as long as those in the steady flame, suggest that specific soot surface growth rates under unsteady combustion conditions can be similar or even lower than those in the corresponding steady flames. Finally, the number of densities of soot primaries in flickering flames are found to be higher by 30--50% than those in steady flames, thus suggesting stronger and/or extended soot inception mechanisms under flickering conditions. The combination of longer flow residence times and greater population of incipient soot particles in flickering flames appears to be primarily responsible for the higher sooting propensity of methane under laminar unsteady combustion conditions.

  18. FLAME facility: The effect of obstacles and transverse venting on flame acceleration and transition on detonation for hydrogen-air mixtures at large scale

    SciTech Connect (OSTI)

    Sherman, M.P.; Tieszen, S.R.; Benedick, W.B.

    1989-04-01T23:59:59.000Z

    This report describes research on flame acceleration and deflagration-to-detonation transition (DDT) for hydrogen-air mixtures carried out in the FLAME facility, and describes its relevance to nuclear reactor safety. Flame acceleration and DDT can generate high peak pressures that may cause failure of containment. FLAME is a large rectangular channel 30.5 m long, 2.44 m high, and 1.83 m wide. It is closed on the ignition end and open on the far end. The three test variables were hydrogen mole fraction (12--30%), degree of transverse venting (by moving steel top plates---0%, 13%, and 50%), and the absence or presence of certain obstacles in the channel (zero or 33% blockage ratio). The most important variable was the hydrogen mole fraction. The presence of the obstacles tested greatly increased the flame speeds, overpressures, and tendency for DDT compared to similar tests without obstacles. Different obstacle configurations could have greater or lesser effects on flame acceleration and DDT. Large degrees of transverse venting reduced the flame speeds, overpressures, and possibility of DDT. For small degrees of transverse venting (13% top venting), the flame speeds and overpressures were higher than for no transverse venting with reactive mixtures (>18% H/sub 2/), but they were lower with leaner mixtures. The effect of the turbulence generated by the flow out the vents on increasing flame speed can be larger than the effect of venting gas out of the channel and hence reducing the overpressure. With no obstacles and 50% top venting, the flame speeds and overpressures were low, and there was no DDT. For all other cases, DDT was observed above some threshold hydrogen concentration. DDT was obtained at 15% H/sub 2/ with obstacles and no transverse venting. 67 refs., 62 figs.

  19. On the small-scale stability of thermonuclear flames in Type Ia supernovae

    E-Print Network [OSTI]

    F. K. Roepke; J. C. Niemeyer; W. Hillebrandt

    2003-05-02T23:59:59.000Z

    We present a numerical model which allows us to investigate thermonuclear flames in Type Ia supernova explosions. The model is based on a finite-volume explicit hydrodynamics solver employing PPM. Using the level-set technique combined with in-cell reconstruction and flux-splitting schemes we are able to describe the flame in the discontinuity approximation. We apply our implementation to flame propagation in Chandrasekhar-mass Type Ia supernova models. In particular we concentrate on intermediate scales between the flame width and the Gibson-scale, where the burning front is subject to the Landau-Darrieus instability. We are able to reproduce the theoretical prediction on the growth rates of perturbations in the linear regime and observe the stabilization of the flame in a cellular shape. The increase of the mean burning velocity due to the enlarged flame surface is measured. Results of our simulation are in agreement with semianalytical studies.

  20. Fuel control for gas turbine with continuous pilot flame

    DOE Patents [OSTI]

    Swick, Robert M. (Indianapolis, IN)

    1983-01-01T23:59:59.000Z

    An improved fuel control for a gas turbine engine having a continuous pilot flame and a fuel distribution system including a pump drawing fuel from a source and supplying a line to the main fuel nozzle of the engine, the improvement being a control loop between the pump outlet and the pump inlet to bypass fuel, an electronically controlled throttle valve to restrict flow in the control loop when main nozzle demand exists and to permit substantially unrestricted flow without main nozzle demand, a minimum flow valve in the control loop downstream of the throttle valve to maintain a minimum pressure in the loop ahead of the flow valve, a branch tube from the pilot flame nozzle to the control loop between the throttle valve and the minimum flow valve, an orifice in the branch tube, and a feedback tube from the branch tube downstream of the orifice to the minimum flow valve, the minimum flow valve being operative to maintain a substantially constant pressure differential across the orifice to maintain constant fuel flow to the pilot flame nozzle.

  1. Fuel effects on flame lift-off under diesel conditions

    SciTech Connect (OSTI)

    Persson, Helena; Andersson, Oeivind; Egnell, Rolf [Lund University (Sweden). Dept. of Energy Sciences

    2011-01-15T23:59:59.000Z

    An apparent relation between the lift-off length under diesel conditions and the ignition quality of a fuel has previously been reported. To cast light on the underlying mechanism, the current study aims to separate flame lift-off effects of the chemical ignition delay from those of other fuel properties under diesel conditions. Flame lift-off was measured in an optical diesel engine by high-speed video imaging of OH-chemiluminescence. Fuel and ambient-gas properties were varied during the experiment. Only a weak correlation was found between ignition delay and lift-off length. The data indicate that this correlation is due to a common, stronger correlation with the ambient oxygen concentration. The chemical ignition delay and the fuel type had similar, weak effects on the lift-off length. A recently proposed mechanism for lift-off stabilization was used to interpret the results. It assumes that reactants approaching the lift-off position of the jet are mixed with high-temperature products found along the edges of the flame, which trigger autoignition. In this picture, the fuel effect is most likely due to differences in the amount of mixing with high-temperature products that is required for autoignition. In the current experiment, all lift-off effects seem to arise from variations in the reactant and product temperatures, induced by fuel and ambient properties. (author)

  2. Fabrication of functional nanomaterials using flame assisted spray pyrolysis

    SciTech Connect (OSTI)

    Purwanto, Agus, E-mail: aguspur@uns.ac.id [Chemical Engineering Department, Faculty of Engineering, Sebelas Maret University, Surakarta 632112 (Indonesia)

    2014-02-24T23:59:59.000Z

    Flame assisted spray pyrolysis (FASP) is a class of synthesis method for nanomaterials fabrication. The ability to control nanomaterials characteristics and easy to be-scaled up are the main features of FASP. The crystallinity and particles size of the prepared nanomaterials can be easily controlled by variation of fuel flow rate. The precursor concentration, carrier gas flow rate, and carrier gas can be also used to control the prepared nanomaterials. Energy related nanomaterials preparation uses as the example case in FASP application. These material are yttrium aluminum garnet (YAG:Ce) and tungsten oxide (WO{sub 3}). It needs strategies to produce these materials into nano-sized order. YAG:Ce nanoparticles only can be synthesized by FASP using the urea addition. The decomposition of urea under high temperature of flame promotes the breakage of YAG:Ce particles into nanoparticles. In the preparation of WO{sub 3}, the high temperature flame can be used to gasify WO{sub 3} solid material. As a result, WO{sub 3} nanoparticles can be prepared easily. Generally, to produce nanoparticles via FASP method, the boiling point of the material is important to determine the strategy which will be used.

  3. Flame propagation enhancement by plasma excitation of oxygen. Part I: Effects of O{sub 3}

    SciTech Connect (OSTI)

    Ombrello, Timothy; Won, Sang Hee; Ju, Yiguang [Department of Mechanical and Aerospace Engineering, Engineering Quadrangle, Olden Street, Princeton, NJ 08544 (United States); Williams, Skip [Air Force Research Laboratory, Propulsion Directorate, 1950 Fifth Street, Wright-Patterson AFB, OH 45433 (United States)

    2010-10-15T23:59:59.000Z

    The thermal and kinetic effects of O{sub 3} on flame propagation were investigated experimentally and numerically by using C{sub 3}H{sub 8}/O{sub 2}/N{sub 2} laminar lifted flames. Ozone produced by a dielectric barrier plasma discharge was isolated and measured quantitatively by using absorption spectroscopy. Significant kinetic enhancement by O{sub 3} was observed by comparing flame stabilization locations with and without O{sub 3} production. Experiments at atmospheric pressures showed an 8% enhancement in the flame propagation speed for 1260 ppm of O{sub 3} addition to the O{sub 2}/N{sub 2} oxidizer. Numerical simulations showed that the O{sub 3} decomposition and reaction with H early in the pre-heat zone of the flame produced O and OH, respectively, from which the O reacted rapidly with C{sub 3}H{sub 8} and produced additional OH. The subsequent reaction of OH with the fuel and fuel fragments, such as CH{sub 2}O, provided chemical heat release at lower temperatures to enhance the flame propagation speed. It was shown that the kinetic effect on flame propagation enhancement by O{sub 3} reaching the pre-heat zone of the flame for early oxidation of fuel was much greater than that by the thermal effect from the energy contained within O{sub 3}. For non-premixed laminar lifted flames, the kinetic enhancement by O{sub 3} also induced changes to the hydrodynamics at the flame front which provided additional enhancement of the flame propagation speed. The present results will have a direct impact on the development of detailed plasma-flame kinetic mechanisms and provided a foundation for the study of combustion enhancement by O{sub 2}(a{sup 1}{delta}{sub g}) in part II of this investigation. (author)

  4. Competing retention pathways of uranium upon reaction with Fe...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    upon reaction with Fe(II). Abstract: Biogeochemical retention processes, including adsorption, reductive precipitation, and incorporation into host minerals, are important in...

  5. The speciation and morphology of chromium oxide nanoparticles in a diffusion flame

    E-Print Network [OSTI]

    Guo, B; Kennedy, Ian M

    2004-01-01T23:59:59.000Z

    Shaffer et al. , 2001).Thermophoretic sampling was also usedwithin the flame. The thermophoretic sampling device wasbe discussed shortly. The thermophoretic drift velocity of

  6. Numerical and experimental studies of ethanol flames and autoignition theory for higher alkanes

    E-Print Network [OSTI]

    Saxena, Priyank

    2007-01-01T23:59:59.000Z

    was used to vaporize ethanol fuel. The vaporizer wasmixture of the evaporated ethanol fuel and the nitrogen gas.premixed flames of ethanol and other fuels for comparison

  7. Numerical study of premixed twin edge flames in a counterflow field

    SciTech Connect (OSTI)

    Cho, Seong-Jin; Takita, Kenichi [Department of Aeronautics and Space Engineering, Tohoku University, Aramaki, Sendai 980-8579 (Japan)

    2006-01-01T23:59:59.000Z

    Characteristics of premixed edge flames established in a counterflow field with a stretch-rate gradient were numerically investigated by solving three-dimensional governing equations with detailed chemistry in the general curvilinear coordinates system. Local mole fractions of radicals, such as OH or CH, at the flame edge of a CH{sub 4}/air mixture were found to be larger than those in other parts of the flame. On the other hand, local mole fractions of radicals in the flame edge of a C{sub 3}H{sub 8}/air mixture were smaller than those in other parts. These numerical results agreed well with the experimental results of the present authors. Moreover, it was elucidated that two flame edges of twin counterflow flames did not merge at the edge even in the case of the CH{sub 4}/air mixture. The ratio of the local stretch rate at the flame edge to the extinction stretch rate for planar twin flames with the same equivalence ratio was 0.6 for the CH{sub 4}/air mixture and 0.7 for the C{sub 3}H{sub 8}/air mixture. These numerical results also agreed with results of the past experiments. Moreover, as for relatively low stretch-rate gradients, the stretch-rate gradient had no strong influence on the characteristics of the edge flames.

  8. Turbulent Flame Speeds and NOx Kinetics of HHC Fuels with Contaminants and High Dilution Levels

    SciTech Connect (OSTI)

    Peterson, Eric; Krejci, Michael; Mathieu, Olivier; Vissotski, Andrew; Ravi, Sankat; Plichta, Drew; Sikes, Travis; Levacque, Anthony; Camou, Alejandro; Aul, Christopher

    2013-09-30T23:59:59.000Z

    This final report documents the technical results of the 3-year project entitled, “Turbulent Flame Speeds and NOx Kinetics of HHC Fuels with Contaminants and High Dilution Levels,” funded under the NETL of DOE. The research was conducted under six main tasks: 1) program management and planning; 2) turbulent flame speed measurements of syngas mixtures; 3) laminar flame speed measurements with diluents; 4) NOx mechanism validation experiments; 5) fundamental NOx kinetics; and 6) the effect of impurities on NOx kinetics. Experiments were performed using primary constant-volume vessels for laminar and turbulent flame speeds and shock tubes for ignition delay times and species concentrations. In addition to the existing shock- tube and flame speed facilities, a new capability in measuring turbulent flame speeds was developed under this grant. Other highlights include an improved NOx kinetics mechanism; a database on syngas blends for real fuel mixtures with and without impurities; an improved hydrogen sulfide mechanism; an improved ammonia kintics mechanism; laminar flame speed data at high pressures with water addition; and the development of an inexpensive absorption spectroscopy diagnostic for shock-tube measurements of OH time histories. The Project Results for this work can be divided into 13 major sections, which form the basis of this report. These 13 topics are divided into the five areas: 1) laminar flame speeds; 2) Nitrogen Oxide and Ammonia chemical kinetics; 3) syngas impurities chemical kinetics; 4) turbulent flame speeds; and 5) OH absorption measurements for chemical kinetics.

  9. Numerical and experimental studies of ethanol flames and autoignition theory for higher alkanes

    E-Print Network [OSTI]

    Saxena, Priyank

    2007-01-01T23:59:59.000Z

    ethanol flames”, ASME TURBO EXPO 2006: Power for Land, Seaof GT2006, ASME Turbo Expo 2006: Power for Land, Sea and

  10. Radionuclide Retention in Concrete Wasteforms - FY13

    SciTech Connect (OSTI)

    Snyder, Michelle MV; Golovich, Elizabeth C.; Wellman, Dawn M.; Crum, Jarrod V.; Lapierre, Robert; Dage, Denomy C.; Parker, Kent E.; Cordova, Elsa A.

    2013-10-15T23:59:59.000Z

    Assessing long-term performance of Category 3 waste cement grouts for radionuclide encasement requires knowledge of the radionuclide-cement interactions and mechanisms of retention (i.e., sorption or precipitation); the mechanism of contaminant release; the significance of contaminant release pathways; how wasteform performance is affected by the full range of environmental conditions within the disposal facility; the process of wasteform aging under conditions that are representative of processes occurring in response to changing environmental conditions within the disposal facility; the effect of wasteform aging on chemical, physical, and radiological properties; and the associated impact on contaminant release. This knowledge will enable accurate prediction of radionuclide fate when the wasteforms come in contact with groundwater. Data collected throughout the course of this work will be used to quantify the efficacy of concrete wasteforms, similar to those used in the disposal of low-level waste and mixed low-level waste, for the immobilization of key radionuclides (i.e., uranium, technetium, and iodine). Data collected will also be used to quantify the physical and chemical properties of the concrete affecting radionuclide retention.

  11. Radionuclide Retention in Concrete Waste Forms

    SciTech Connect (OSTI)

    Mattigod, Shas V.; Bovaird, Chase C.; Wellman, Dawn M.; Wood, Marcus I.

    2010-09-30T23:59:59.000Z

    Assessing long-term performance of Category 3 waste cement grouts for radionuclide encasement requires knowledge of the radionuclide-cement interactions and mechanisms of retention (i.e., sorption or precipitation); the mechanism of contaminant release; the significance of contaminant release pathways; how waste form performance is affected by the full range of environmental conditions within the disposal facility; the process of waste form aging under conditions that are representative of processes occurring in response to changing environmental conditions within the disposal facility; the effect of waste form aging on chemical, physical, and radiological properties; and the associated impact on contaminant release. This knowledge will enable accurate prediction of radionuclide fate when the waste forms come in contact with groundwater. The information presented in the report provides data that 1) quantify radionuclide retention within concrete waste form materials similar to those used to encapsulate waste in the Low-Level Waste Burial Grounds (LLBG); 2) measure the effect of concrete waste form properties likely to influence radionuclide migration; and 3) quantify the stability of uranium-bearing solid phases of limited solubility in concrete.

  12. Retention of Halogens in Waste Glass

    SciTech Connect (OSTI)

    Hrma, Pavel R.

    2010-05-01T23:59:59.000Z

    In spite of their potential roles as melting rate accelerators and foam breakers, halogens are generally viewed as troublesome components for glass processing. Of five halogens, F, Cl, Br, I, and At, all but At may occur in nuclear waste. A nuclear waste feed may contain up to 10 g of F, 4 g of Cl, and ?100 mg of Br and I per kg of glass. The main concern is halogen volatility, producing hazardous fumes and particulates, and the radioactive iodine 129 isotope of 1.7x10^7-year half life. Because F and Cl are soluble in oxide glasses and tend to precipitate on cooling, they can be retained in the waste glass in the form of dissolved constituents or as dispersed crystalline inclusions. This report compiles known halogen-retention data in both high-level waste (HLW) and low-activity waste (LAW) glasses. Because of its radioactivity, the main focus is on I. Available data on F and Cl were compiled for comparison. Though Br is present in nuclear wastes, it is usually ignored; no data on Br retention were found.

  13. Cooking utensil with improved heat retention

    DOE Patents [OSTI]

    Potter, T.F.; Benson, D.K.; Burch, S.D.

    1997-07-01T23:59:59.000Z

    A cooking utensil with improved heat retention includes an inner pot received within an outer pot and separated in a closely spaced-apart relationship to form a volume or chamber there between. The chamber is evacuated and sealed with foil leaves at the upper edges of the inner and outer pot. The vacuum created between the inner and outer pot, along with the minimum of thermal contact between the inner and outer pot, and the reduced radiative heat transfer due to low emissivity coatings on the inner and outer pot, provide for a highly insulated cooking utensil. Any combination of a plurality of mechanisms for selectively disabling and re-enabling the insulating properties of the pot are provided within the chamber. These mechanisms may include: a hydrogen gas producing and reabsorbing device such as a metal hydride, a plurality of metal contacts which can be adjusted to bridge the gap between the inner and outer pot, and a plurality of bimetallic switches which can selectively bridge the gap between the inner and outer pot. In addition, phase change materials with superior heat retention characteristics may be provided within the cooking utensil. Further, automatic and programmable control of the cooking utensil can be provided through a microprocessor and associated hardware for controlling the vacuum disable/enable mechanisms to automatically cook and save food. 26 figs.

  14. Cooking utensil with improved heat retention

    DOE Patents [OSTI]

    Potter, Thomas F. (Denver, CO); Benson, David K. (Golden, CO); Burch, Steven D. (Golden, CO)

    1997-01-01T23:59:59.000Z

    A cooking utensil with improved heat retention includes an inner pot received within an outer pot and separated in a closely spaced-apart relationship to form a volume or chamber therebetween. The chamber is evacuated and sealed with foil leaves at the upper edges of the inner and outer pot. The vacuum created between the inner and outer pot, along with the minimum of thermal contact between the inner and outer pot, and the reduced radiative heat transfer due to low emissivity coatings on the inner and outer pot, provide for a highly insulated cooking utensil. Any combination of a plurality of mechanisms for selectively disabling and re-enabling the insulating properties of the pot are provided within the chamber. These mechanisms may include: a hydrogen gas producing and reabsorbing device such as a metal hydride, a plurality of metal contacts which can be adjusted to bridge the gap between the inner and outer pot, and a plurality of bimetallic switches which can selectively bridge the gap between the inner and outer pot. In addition, phase change materials with superior heat retention characteristics may be provided within the cooking utensil. Further, automatic and programmable control of the cooking utensil can be provided through a microprocessor and associated hardware for controlling the vacuum disable/enable mechanisms to automatically cook and save food.

  15. Flame front disturbance induced by a weak pressure wave

    SciTech Connect (OSTI)

    Dobashi, Ritsu; Hirano, Toshisuke; Tsuruda, Takashi [Univ. of Tokyo (Japan)

    1994-12-31T23:59:59.000Z

    An experimental study has been conducted on the effect of unburned mixture properties on flame front disturbance induced by acceleration. Experiments were performed using a rectangular combustion chamber of 80 x 80 x 440 mm. The flame front disturbance was observed in two different directions by high-speed schlieren photography. Mixtures used are of three different concentrations (C = 0.8, 1.0, and 1.25) of methane/air and two different concentrations (C = 1.0 and 1.5) of propane/air. For the methane/air mixture of C = 1.0, experiments were performed at three different initial pressures (P{sub i} = 50, 70, and 101 kPa). The observed disturbance was of a very fine structure of circular spikes, which penetrated into the burned gas. The scales of disturbance were measured and indicated to be in the range of 1.7--4.0 mm. The circular spike shape is a typical structure induced by accelerating the flame front where the density changes steeply. However, the shape of the disturbance observed for a rich propane/air mixture was not of circular spikes but of a net of ridges. For the rich propane/air mixture, the effect by preferential diffusion was remarkable and the disturbance of a different structure was generated. For the methane/air mixtures, the scale was the smallest at C = 1.0 and larger at C = 0.8 and 1.25. The scale for the propane/air mixture of C = 1.0 was slightly larger than that in the methane/air mixture of C = 1.0. The scale became larger with the decrease of the initial pressure. The measure scales were compared with the preheat zone thicknesses of corresponding flames. It was shown that the scale is closely related with the flame thickness. The scale of disturbance is found to be about 15 times as large as the preheat zone thickness.

  16. Heater head for Stirling engine

    SciTech Connect (OSTI)

    White, M.A.; Emigh, S.G.

    1987-06-09T23:59:59.000Z

    This patent describes a heater head for a Stirling engine comprising: a housing for enclosing the heater head with gas at a substantial elevated pressure; insulator means attached to the housing for insulating the heater head; inlet means attached to a regenerator in the housing for admission of relatively high pressure working fluid from the regenerator of a Stirling engine; a first annular heating wall in the housing attached to the inlet means for heating the working fluid; and, a second annular heating wall in the housing concentric with the first heating wall but of lesser diameters so that an annular space is formed between the first heating wall and the second heating wall for heating working fluid; and a third heating wall in the housing concentric with and smaller in diameter than the second heating wall forming the condensing area of a heat pipe between the second heating wall and the third heating wall.

  17. Combustion-derived flame generated ultrafine soot generates reactive oxygen species and activates Nrf2 antioxidants differently in neonatal and adult rat lungs

    E-Print Network [OSTI]

    2013-01-01T23:59:59.000Z

    article as: Chan et al. : Combustion-derived flame generatedRESEARCH Open Access Combustion-derived flame generated6]. Vehicle exhaust from combustion of gasoline, diesel and

  18. Soot aerosol properties in laminar soot-emitting microgravity nonpremixed flames

    SciTech Connect (OSTI)

    Konsur, B.; Megaridis, C.M.; Griffin, D.W.

    1999-09-01T23:59:59.000Z

    The spatial distributions and morphological properties of the soot aerosol are examined experimentally in a series of 0-g laminar gas-jet nonpremixed flames. The methodology deploys round jet diffusion flames of nitrogen-diluted acetylene fuel burning in quiescent air at atmospheric pressure. Full-field laser-light extinction is utilized to determine transient soot spatial distributions within the flames. Thermophoretic sampling is employed in conjunction with transmission electron microscopy to define soot microstructure within the soot-emitting 0-g flames. The microgravity tests indicate that the 0-g flames attain a quasi-steady state roughly 0.7 s after ignition, and sustain their annular structure even beyond their luminous flame tip. The measured peak soot volume fractions show a complex dependence on burner exit conditions, and decrease in a nonlinear fashion with decreasing characteristic flow residence times. Fuel preheat by {approximately}140K appears to accelerate the formation of soot near the flame axis via enhanced field pyrolysis rates. The increased soot presence caused by the elevated fuel injection temperatures triggers higher flame radiative losses, which may account for the premature suppression of soot growth observed along the annular region of preheated-fuel flames. Electron micrographs of soot aggregates collected in 0-g reveal the presence of soot precursor particles near the symmetry axis at midflame height. The observations also verify that soot primary particle sizes are nearly uniform among aggregates present at the same flame location, but vary considerably with radius at a fixed distance from the burner. The maximum primary size in 0-g is found to be by 40% larger than in 1-g, under the same burner exit conditions. Estimates of the number concentration of primary particles and surface area of soot particulate phase per unit volume of the combustion gases are also made for selected in-flame locations.

  19. Effects of fuel type and equivalence ratios on the flickering of triple flames

    SciTech Connect (OSTI)

    Sahu, K.B.; Kundu, A.; Ganguly, R.; Datta, A. [Department of Power Engineering, Jadavpur University, Salt Lake Campus, Kolkata 700098 (India)

    2009-02-15T23:59:59.000Z

    An experimental study has been conducted in axisymmetric, co-flowing triple flames with different equivalence ratios of the inner and outer reactant streams (2<{phi}{sub in}<3 and 0{<=}{phi}{sub out}<0.7). Different fuel combinations, like propane/propane, propane/methane or methane/methane in the inner and outer streams respectively, have been used in the experiments. The structures of the triple flames have been compared for the different fuel combinations and equivalence ratios. The conditions under which triple flames exhibit oscillation have been identified. During the oscillation, the non-premixed flame and the outer lean premixed flame flicker strongly, while the inner rich premixed flame remains more or less stable. The flickering frequency has been evaluated through image processing and fast Fourier transform (FFT) of the average pixel intensity of the image frames. It is observed that, for all the fuel combinations, the frequency decreases with the increase in the outer equivalence ratio, while it is relatively invariant with the change in the inner equivalence ratio. However, an increase in the inner equivalence ratio affects the structure of the flame by increasing the heights of the inner premixed flame and non-premixed flame and also enlarges the yellow soot-laden zone at the tip of the inner flame. A scaling analysis of the oscillating flames has been performed based on the measured parameters, which show a variation of Strouhal number (St) with Richardson number (Ri) as St {proportional_to} Ri{sup 0.5}. The fuel type is found to have no influence on this correlation. (author)

  20. CLINICAL RETENTION EXPECTATIONS AND UNLV ATHLETIC TRAINING PROGRAM

    E-Print Network [OSTI]

    Hemmers, Oliver

    CLINICAL RETENTION EXPECTATIONS AND STANDARDS UNLV ATHLETIC TRAINING PROGRAM The Program Director and Clinical Education Coordinator will evaluate retention in the Athletic Training Program. Athletic training, the athletic training student will be permitted to take the scheduled SIM clinical course and will be given

  1. Phase control in the synthesis of yttrium oxide nano and micro-particles by flame spray pyrolysis

    E-Print Network [OSTI]

    Mukundan, Mallika

    2009-05-15T23:59:59.000Z

    The project synthesizes phase pure Yttria particles using flame spray pyrolysis, and to experimentally determines the effect of various process parameters like residence time, adiabatic flame temperature and precursor droplet size on the phase...

  2. Pressure testing of torispherical heads

    SciTech Connect (OSTI)

    Rana, M.D. [Praxair, Inc., Tonawanda, NY (United States). Research and Development Dept.; Kalnins, A.; Updike, D.P. [Lehigh Univ., Bethlehem, PA (United States)

    1995-12-01T23:59:59.000Z

    Two vessels fabricated from SA516-70 steel with 6% knuckle radius torispherical heads were tested under internal pressure to failure. The D/t ratios of Vessel 1 and Vessel 2 were 238 and 185 respectively. The calculated maximum allowable working pressures of Vessel 1 and 2 heads using the ASME Section 8, Div. 1 rules and measured dimensions were 85 and 110 psi, respectively. Vessel 1 failed at a nozzle weld in the cylindrical shell at 700 psi pressure. Neither buckling nor any other objectionable deformation of the head was observed at a theoretical double-elastic-slope collapse pressure of 241 and a calculated buckling pressure of 270 psi. Buckles were observed developing slowly after 600 psi pressure, and a total of 22 buckles were observed after the test, having the maximum amplitude of 0.15 inch. Vessel 2 failed at the edge of the longitudinal weld of the cylindrical shell at 1,080 psi pressure. Neither buckling nor any other objectionable deformation of the head was observed up to the final pressure, which exceeded the theoretical double-elastic-slope collapse and calculated buckling pressures of 274 psi and 342 psi, respectively.

  3. 207-A retention basins system design description

    SciTech Connect (OSTI)

    Wahlquist, R.A.

    1994-09-29T23:59:59.000Z

    The 242-A Evaporator is a waste treatment facility designed to reduce liquid waste volumes currently stored in the Hanford Area double shell Waste Storage Tanks. The evaporator uses evaporative concentration to achieve this volume reduction, returning the concentrated slurry to the double-shell tanks for storage. The process effluent is transferred to various retention/treatment facilities for eventual release to the environment. The process utilizes an evaporator vessel and various supporting systems for heating, evaporating, and condensing low-heat-generating liquid waste produced it the Hanford Site. The process reduces the total volume of the liquid waste requiring storage in a double shell tank, making it more manageable for current storage as well as for future treatment and disposal. The main components of the 242-A Evaporator are the Reboiler, Vapor-Liquid Separator, Recirculation Pump and Pump Loop, Slurry System, Condenser System, Steam Jet Vacuum System, Condensate Collection Tank, and Ion Exchange System.

  4. Soot formation and temperature field structure in co-flow laminar methaneair diffusion flames

    E-Print Network [OSTI]

    Gülder, Ömer L.

    at higher pressures mean that the thermal diffusion from the hot regions of the flame towards the flame of the spread of unwanted fires. Soot radiation is the major heat load on combustor components causing mainte gas turbine combustors operate at elevated pressures, our understanding of the effects of pressure

  5. 45 (2008-5) Thermal Effect of Wall on Micro Premixed Flame in Quartz Channels

    E-Print Network [OSTI]

    Kasagi, Nobuhide

    E131 45 (2008-5) 225 Thermal Effect of Wall on Micro Premixed Flame in Quartz Channels * Yong flame propagation and quenching in three quartz combustors with chamber depth of 0.7 mm, 1.0 mm and 1 to meet the requirement. Hydrocarbon-fueled micro combustor is of great interest in portable power

  6. Flame transfer function saturation mechanisms in a swirl-stabilized combustor

    E-Print Network [OSTI]

    Lieuwen, Timothy C.

    oscillations using phase-locked, two-dimensional OH PLIF imaging. It focuses upon two repre- sentative An understanding of the amplitude dependence of the flame response to harmonic acoustic excitation is required during the phase of the cycle of peak instantaneous axial velocity. This causes the flame attachment

  7. Growth of diamond films using an enclosed methyl-acetylene and propadiene combustion flame

    E-Print Network [OSTI]

    Dandy, David

    1 Growth of diamond films using an enclosed methyl-acetylene and propadiene combustion flame K Abstract Diamond growth in low pressure combustion flames was studied using a safer, more economical and chemical kinetic time scales in the combustion reactor. 1 Present Address: 3M Corporation, Bldg. 60-1N-01

  8. Timewise morphology of turbulent diffusion flame by means of image processing

    SciTech Connect (OSTI)

    Torii, Shuichi; Yano, Toshiaki; Tsuchino, Fumihiro

    1999-07-01T23:59:59.000Z

    An experimental study is performed to investigate the dynamic behavior of jet diffusion flames from a vertical circular nozzle. A real-time image processing on slow-motion video recording using the high-speed video camera is employed to clarify the flame morphology. Emphasis is placed on the timewise variation of the flame length, H, the peripheral distance of the flame, L, and the projected area of the flame contour, S, based on the RGB values of the flame. Here, RGB implies the three primary colors, i.e., red, green and blue, respectively. Propane is used as fuel and a burner tube of 2.40 mm inside diameter is employed here. It is found from the study that (1) a real-time color image processing with the aid of a slow-motion video recording discriminates the flame shape and discloses the flame behavior with time, (2) H, L and S vary periodically with time, and (3) the time-averaged value of L{sup 2}/S and its turbulence intensity, which is defined here, are intensified with an increase in the Reynolds number.

  9. Simulation of Nitrogen Emissions in a Premixed Hydrogen Flame Stabilized on a Low Swirl Burner

    E-Print Network [OSTI]

    Bell, John B.

    Abstract There is considerable interest in developing fuel-flexible, low emissions turbines for power generation. One ap- proach is based on burning a variety of lean premixed fuels with relatively low flame concentration and a corresponding in- crease in local flame temperature just downstream. In turn, these regions

  10. A LEAN METHANE PREMIXED LAMINAR FLAME DOPED WITH COMPONENTS OF DIESEL FUEL

    E-Print Network [OSTI]

    Boyer, Edmond

    A LEAN METHANE PREMIXED LAMINAR FLAME DOPED WITH COMPONENTS OF DIESEL FUEL PART I: N-BUTYLBENZENE E better understand the chemistry involved during the combustion of components of diesel fuel flow rate analyses. Keywords: Premixed laminar flame, methane, n-butylbenzene, modelling, diesel fuel

  11. Combustion and Flame 153 (2008) 367383 www.elsevier.com/locate/combustflame

    E-Print Network [OSTI]

    Aggarwal, Suresh K.

    for outwardly propagating spherical flames burning a mixture of natural gas and hydrogen. © 2008 The Combustion enrichment on the propagation characteristics of CH4­air triple flames Alejandro M. Briones a , Suresh K 22 February 2008 Available online 7 April 2008 Abstract The effects of H2 enrichment

  12. Combustion and Flame 145 (2006) 765778 www.elsevier.com/locate/combustflame

    E-Print Network [OSTI]

    Gülder, Ömer L.

    2006-01-01T23:59:59.000Z

    and temperature field structure in laminar propane­air diffusion flames at elevated pressures Décio S. Bento and the structure of the temperature field was studied in coflow propane­air laminar diffusion flames over to within 30% and both methods exhibited similar trends in the spatial distribution of soot concentration

  13. The Cellular Burning Regime in Type Ia Supernova Explosions - I. Flame Propagation into Quiescent Fuel

    E-Print Network [OSTI]

    F. K. Roepke; W. Hillebrandt; J. C. Niemeyer

    2003-12-03T23:59:59.000Z

    We present a numerical investigation of the cellular burning regime in Type Ia supernova explosions. This regime holds at small scales (i.e. below the Gibson scale), which are unresolved in large-scale Type Ia supernova simulations. The fundamental effects that dominate the flame evolution here are the Landau-Darrieus instability and its nonlinear stabilization, leading to a stabilization of the flame in a cellular shape. The flame propagation into quiescent fuel is investigated addressing the dependence of the simulation results on the specific parameters of the numerical setup. Furthermore, we investigate the flame stability at a range of fuel densities. This is directly connected to the questions of active turbulent combustion (a mechanism of flame destabilization and subsequent self-turbulization) and a deflagration-to-detonation transition of the flame. In our simulations we find no substantial destabilization of the flame when propagating into quiescent fuels of densities down to ~10^7 g/cm^3, corroborating fundamental assumptions of large-scale SN Ia explosion models. For these models, however, we suggest an increased lower cutoff for the flame propagation velocity to take the cellular burning regime into account.

  14. Studies on non-premixed flame streets in a mesoscale channel

    E-Print Network [OSTI]

    Ju, Yiguang

    Studies on non-premixed flame streets in a mesoscale channel Bo Xu *, Yiguang Ju Department of channel width, wall temperature, and flow rate on the dynamics of non-premix flames in a mesoscale The Combustion Institute. Published by Elsevier Inc. All rights reserved. Keywords: Mesoscale combustion; Non

  15. Combustion and Flame 145 (2006) 324338 www.elsevier.com/locate/combustflame

    E-Print Network [OSTI]

    Gülder, �mer L.

    . Guo et al. / Combustion and Flame 145 (2006) 324­338 325 for ethylene, propane, and butane counterflowCombustion and Flame 145 (2006) 324­338 www.elsevier.com/locate/combustflame Numerical study into account. Radiation heat transfer from CO2, CO, H2O, and soot was calculated using the discrete- ordinates

  16. A New Type of Steady and Stable, Laminar, Premixed Flame in Ultra-Lean, Hydrogen-Air Combustion

    E-Print Network [OSTI]

    Geddes, Cameron Guy Robinson

    A New Type of Steady and Stable, Laminar, Premixed Flame in Ultra-Lean, Hydrogen-Air Combustion in the development of combustion science. Several aspects of these two-dimensional flame cells are identified for premixed combustion when the other types of idealized flames are inapplicable. 1 #12;Nomenclature fuel

  17. Modeling of the formation of short-chain acids in propane flames F. Battin-Leclerc , 1

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    Modeling of the formation of short-chain acids in propane flames F. Battin-Leclerc , 1 , A. Simulations of lean (equivalence ratios from 0.9 to 0.48) laminar premixed flames of propane stabilized in a combustion apparatus which can easily be modeled, a laminar premixed flame of propane at atmospheric pressure

  18. Analyzing pulse from head motions in video

    E-Print Network [OSTI]

    Balakrishnan, Guha

    2014-01-01T23:59:59.000Z

    We extract heart rate and beat lengths from videos by measuring subtle head oscillations that accompany the cardiac cycle. Our method tracks features on the head, temporally filters their trajectories and performs principal ...

  19. In-Vessel Retention Technology Development and Use for Advanced PWR Designs in the USA and Korea

    SciTech Connect (OSTI)

    T.G. Theofanous; S.J. Oh; J.H. Scobel

    2004-05-18T23:59:59.000Z

    In-Vessel Retention (IVR) of molten core debris by means of external reactor vessel flooding is a cornerstone of severe accident management for Westinghouse's AP600 (advanced passive light water reactor) design. The case for its effectiveness (made in previous work by the PI) has been thoroughly documented, reviewed as part of the licensing certification, and accepted by the US Nuclear Regulatory Commission. A successful IVR would terminate a severe accident, passively, with the core in a stable, coolable configuration (within the lower head), thus avoiding the largely uncertain accident evolution with the molten debris on the containment floor. This passive plant design has been upgraded by Westinghouse to the AP1000, a 1000 MWe plant very similar to the AP600. The severe accident management approach is very similar too, including In-Vessel Retention as the cornerstone feature, and initial evaluations indicated that this would be feasible at the higher power as well. A similar strategy is adopted in Korea for the APR1400 plant. The overall goal of this project is to provide experimental data and develop the necessary basic understanding so as to allow the robust extension of the AP600 In-Vessel Retention strategy for severe accident management to higher power reactors, and in particular, to the AP1000 advanced passive design.

  20. Sudden acceleration of flames in open channels driven by hydraulic resistance

    E-Print Network [OSTI]

    Yanez, J; Bykov, V

    2012-01-01T23:59:59.000Z

    Hydrogen-air deflagrations with venting at the end of obstructed tubes are studied experimentally and numerically. A shockless transition to the so-called chocked regime of the flame propagation is reported. Mixtures with 13% vol. of hydrogen were ignited from the open end of the tube at the interface between fuel and the ambient air. Three venting ratios were selected, closed, 40% and 100%. In all cases the flame initially propagates without acceleration at a velocity close to the laminar flame speed. The flame configuration excludes most of conventionally acknowledged phenomena of the DDT, namely, volumetric explosions, igniting shock and shock waves interactions. However, after an induction period, of the order of 1 sec, the flame accelerates more than 100 times, within a period of 3-30 ms, until the steady-state choked regime is established. The mechanism of such rapid acceleration is investigated both numerically and analytically. A one dimensional reduced description was suggested and analyzed to model ...

  1. Spectroscopic analysis of diesel combustion flame by means of streak camera

    SciTech Connect (OSTI)

    Nagase, K.; Funatsu, K.

    1988-01-01T23:59:59.000Z

    Band spectra in ultraviolet and visible ranges contain information on the state of combustion flame. Measurement of those spectra in diesel combustion flame, however, has been regarded as impossible because of the obstruction of bright flame and soot. The phenomena of diesel combustion, therefore, have not been analyzed clearly from the viewpoint of chemical reaction. The authors inserted an optical fiber into the diesel combustion chamber to detect the flame. The combustion flame was recorded by a special spectroscopic apparatus, named Streak camera, and the recorded image was subjected to spectroscopic analysis. The result of the experiments confirmed the existence of band spectra emitted from CH and OH radicals in the ultraviolet and visible ranges. The recorded data made clear the progress of chemical reactions and the formation of intermediate products during the diesel combustion process.

  2. In-vessel coolability and retention of a core melt. Volume 2

    SciTech Connect (OSTI)

    Theofanous, T.G.; Liu, C.; Additon, S.; Angelini, S.; Kymaelaeinen, O.; Salmassi, T. [California Univ., Santa Barbara, CA (United States). Center for Risk Studies and Safety

    1996-10-01T23:59:59.000Z

    The efficacy of external flooding of a reactor vessel as a severe accident management strategy is assessed for an AP600-like reactor design. The overall approach is based on the Risk Oriented Accident Analysis Methodology (ROAAM), and the assessment includes consideration of bounding scenarios and sensitivity studies, as well as arbitrary parametric evaluations that allow the delineation of the failure boundaries. Quantification of the input parameters is carried out for an AP600-like design, and the results of the assessment demonstrate that lower head failure is physically unreasonable. Use of this conclusion for any specific application is subject to verifying the required reliability of the depressurization and cavity-flooding systems, and to showing the appropriateness (in relation to the database presented here, or by further testing as necessary) of the thermal insulation design and of the external surface properties of the lower head, including any applicable coatings. The AP600 is particularly favorable to in-vessel retention. Some ideas to enhance the assessment basis as well as performance in this respect, for applications to larger and/or higher power density reactors are also provided.

  3. In-vessel coolability and retention of a core melt. Volume 1

    SciTech Connect (OSTI)

    Theofanous, T.G.; Liu, C.; Additon, S.; Angelini, S.; Kymaelaeinen, O.; Salmassi, T. [California Univ., Santa Barbara, CA (United States). Center for Risk Studies and Safety

    1996-10-01T23:59:59.000Z

    The efficacy of external flooding of a reactor vessel as a severe accident management strategy is assessed for an AP600-like reactor design. The overall approach is based on the Risk Oriented Accident Analysis Methodology (ROAAM), and the assessment includes consideration of bounding scenarios and sensitivity studies, as well as arbitrary parametric evaluations that allow the delineation of the failure boundaries. Quantification of the input parameters is carried out for an AP600-like design, and the results of the assessment demonstrate that lower head failure is physically unreasonable. Use of this conclusion for any specific application is subject to verifying the required reliability of the depressurization and cavity-flooding systems, and to showing the appropriateness (in relation to the database presented here, or by further testing as necessary) of the thermal insulation design and of the external surface properties of the lower head, including any applicable coatings. The AP600 is particularly favorable to in-vessel retention. Some ideas to enhance the assessment basis as well as performance in this respect, for applications to larger and/or higher power density reactors are also provided.

  4. Effects of thermal radiation heat transfer on flame acceleration and transition to detonation in dust cloud flames: Origins of dust explosion

    E-Print Network [OSTI]

    Ivanov, Michael A Liberman M F

    2015-01-01T23:59:59.000Z

    We examines regimes of the hydrogen flames propagation and ignition of mixtures heated by the radiation emitted from the flame. The gaseous phase is assumed to be transparent for radiation, while the suspended particles of the dust cloud ahead of the flame absorb and reemit the radiation. The radiant heat absorbed by the particles is then lost by conduction to the surrounding unreacted gaseous phase so that the gas phase temperature lags that of the particles. The direct numerical simulations solve the full system of two phase gas dynamic time-dependent equations with a detailed chemical kinetics for a plane flames propagating through a dust cloud. Depending on the spatial distribution of the dispersed particles and on the value of radiation absorption length the consequence of the radiative preheating of the unreacted mixture can be either the increase of the flame velocity for uniformly dispersed particles or ignition deflagration or detonation ahead of the flame via the Zel'dovich gradient mechanism in the...

  5. Hanford Facility dangerous waste permit application, liquid effluent retention facility and 200 area effluent treatment facility

    SciTech Connect (OSTI)

    Coenenberg, J.G.

    1997-08-15T23:59:59.000Z

    The Hanford Facility Dangerous Waste Permit Application is considered to 10 be a single application organized into a General Information Portion (document 11 number DOE/RL-91-28) and a Unit-Specific Portion. The scope of the 12 Unit-Specific Portion is limited to Part B permit application documentation 13 submitted for individual, `operating` treatment, storage, and/or disposal 14 units, such as the Liquid Effluent Retention Facility and 200 Area Effluent 15 Treatment Facility (this document, DOE/RL-97-03). 16 17 Both the General Information and Unit-Specific portions of the Hanford 18 Facility Dangerous Waste Permit Application address the content of the Part B 19 permit application guidance prepared by the Washington State Department of 20 Ecology (Ecology 1987 and 1996) and the U.S. Environmental Protection Agency 21 (40 Code of Federal Regulations 270), with additional information needs 22 defined by the Hazardous and Solid Waste Amendments and revisions of 23 Washington Administrative Code 173-303. For ease of reference, the Washington 24 State Department of Ecology alpha-numeric section identifiers from the permit 25 application guidance documentation (Ecology 1996) follow, in brackets, the 26 chapter headings and subheadings. A checklist indicating where information is 27 contained in the Liquid Effluent Retention Facility and 200 Area Effluent 28 Treatment Facility permit application documentation, in relation to the 29 Washington State Department of Ecology guidance, is located in the Contents 30 Section. 31 32 Documentation contained in the General Information Portion is broader in 33 nature and could be used by multiple treatment, storage, and/or disposal units 34 (e.g., the glossary provided in the General Information Portion). Wherever 35 appropriate, the Liquid Effluent Retention Facility and 200 Area Effluent 36 Treatment Facility permit application documentation makes cross-reference to 37 the General Information Portion, rather than duplicating text. 38 39 Information provided in this Liquid Effluent Retention Facility and 40 200 Area Effluent Treatment Facility permit application documentation is 41 current as of June 1, 1997.

  6. Pocket formation and the flame surface density equation

    SciTech Connect (OSTI)

    Kollman, W. [Univ. of California, Davis, CA (United States); Chen, J.H. [Sandia National Labs., Livermore, CA (United States). Combustion Research Facility

    1998-03-01T23:59:59.000Z

    The occurrence and properties of singularities in the equation for the surface density function {sigma} {triple_bond}{vert_bar}{del}{Phi}{vert_bar} are analyzed analytically and numerically using data from two dimensional direct numerical simulation (DNS) of pocket formation in a premixed methane-air flame. The various stages and the relevant time scales associated with pocket formation were determined in a previous study. It was found that isolated pockets form if and only if a nondegenerate critical point of a saddle point type appears. The appearance of a singularity in the isoline representing the flame front may have implications to modeling of the terms in the surface density function (sdf) approach during such transient events as pocket formation. The sink and source terms in sdf are evaluated in the neighborhood of a critical point using DNS data during pocket formation, and an analytic representation of a scalar in the vicinity of the critical point which allows for the computation of all kinematic properties. The analytic and computational results show that the normal restoration and dissipation terms in the sdf become singular at the critical point when the pocket emerges. Furthermore, the analytic results show that the singularities exactly cancel, and therefore, the main conclusion is that it is unnecessary to model the singular behavior of these terms at critical points. However, closure of their sum is recommended.

  7. Understanding and predicting soot generation in turbulent non-premixed jet flames.

    SciTech Connect (OSTI)

    Wang, Hai (University of Southern California, Los Angeles, CA); Kook, Sanghoon; Doom, Jeffrey; Oefelein, Joseph Charles; Zhang, Jiayao; Shaddix, Christopher R.; Schefer, Robert W.; Pickett, Lyle M.

    2010-10-01T23:59:59.000Z

    This report documents the results of a project funded by DoD's Strategic Environmental Research and Development Program (SERDP) on the science behind development of predictive models for soot emission from gas turbine engines. Measurements of soot formation were performed in laminar flat premixed flames and turbulent non-premixed jet flames at 1 atm pressure and in turbulent liquid spray flames under representative conditions for takeoff in a gas turbine engine. The laminar flames and open jet flames used both ethylene and a prevaporized JP-8 surrogate fuel composed of n-dodecane and m-xylene. The pressurized turbulent jet flame measurements used the JP-8 surrogate fuel and compared its combustion and sooting characteristics to a world-average JP-8 fuel sample. The pressurized jet flame measurements demonstrated that the surrogate was representative of JP-8, with a somewhat higher tendency to soot formation. The premixed flame measurements revealed that flame temperature has a strong impact on the rate of soot nucleation and particle coagulation, but little sensitivity in the overall trends was found with different fuels. An extensive array of non-intrusive optical and laser-based measurements was performed in turbulent non-premixed jet flames established on specially designed piloted burners. Soot concentration data was collected throughout the flames, together with instantaneous images showing the relationship between soot and the OH radical and soot and PAH. A detailed chemical kinetic mechanism for ethylene combustion, including fuel-rich chemistry and benzene formation steps, was compiled, validated, and reduced. The reduced ethylene mechanism was incorporated into a high-fidelity LES code, together with a moment-based soot model and models for thermal radiation, to evaluate the ability of the chemistry and soot models to predict soot formation in the jet diffusion flame. The LES results highlight the importance of including an optically-thick radiation model to accurately predict gas temperatures and thus soot formation rates. When including such a radiation model, the LES model predicts mean soot concentrations within 30% in the ethylene jet flame.

  8. Formation and retention of methane in coal

    SciTech Connect (OSTI)

    Hucka, V.J.; Bodily, D.M.; Huang, H.

    1992-05-15T23:59:59.000Z

    The formation and retention of methane in coalbeds was studied for ten Utah coal samples, one Colorado coal sample and eight coal samples from the Argonne Premium Coal Sample Bank.Methane gas content of the Utah and Colorado coals varied from zero to 9 cm{sup 3}/g. The Utah coals were all high volatile bituminous coals. The Colorado coal was a gassy medium volatile bituminous coal. The Argonne coals cover a range or rank from lignite to low volatile bituminous coal and were used to determine the effect of rank in laboratory studies. The methane content of six selected Utah coal seams and the Colorado coal seam was measured in situ using a special sample collection device and a bubble desorbometer. Coal samples were collected at each measurement site for laboratory analysis. The cleat and joint system was evaluated for the coal and surrounding rocks and geological conditions were noted. Permeability measurements were performed on selected samples and all samples were analyzed for proximate and ultimate analysis, petrographic analysis, {sup 13}C NMR dipolar-dephasing spectroscopy, and density analysis. The observed methane adsorption behavior was correlated with the chemical structure and physical properties of the coals.

  9. The Cellular Burning Regime in Type Ia Supernova Explosions - II. Flame Propagation into Vortical Fuel

    E-Print Network [OSTI]

    F. K. Roepke; W. Hillebrandt; J. C. Niemeyer

    2003-12-08T23:59:59.000Z

    We investigate the interaction of thermonuclear flames in Type Ia supernova explosions with vortical flows by means of numerical simulations. In our study, we focus on small scales, where the flame propagation is no longer dominated by the turbulent cascade originating from large-scale effects. Here, the flame propagation proceeds in the cellular burning regime, resulting from a balance between the Landau-Darrieus instability and its nonlinear stabilization. The interaction of a cellularly stabilized flame front with a vortical fuel flow is explored applying a variety of fuel densities and strengths of the velocity fluctuations. We find that the vortical flow can break up the cellular flame structure if it is sufficiently strong. In this case the flame structure adapts to the imprinted flow field. The transition from the cellularly stabilized front to the flame structure dominated by vortices of the flow proceeds in a smooth way. The implications of the results of our simulations for Type Ia Supernova explosion models are discussed.

  10. Numerical study of the direct pressure effect of acoustic waves in planar premixed flames

    SciTech Connect (OSTI)

    Schmidt, H. [BTU Cottbus, Siemens-Halske-Ring 14, D-03046 Cottbus (Germany); Jimenez, C. [Centro de Investigaciones Energeticas, Medioambientales y Tecnologicas, Avenida Complutense, 22, 28040 Madrid (Spain)

    2010-08-15T23:59:59.000Z

    Recently the unsteady response of 1-D premixed flames to acoustic pressure waves for the range of frequencies below and above the inverse of the flame transit time was investigated experimentally using OH chemiluminescence Wangher (2008). They compared the frequency dependence of the measured response to the prediction of an analytical model proposed by Clavin et al. (1990), derived from the standard flame model (one-step Arrhenius kinetics) and to a similar model proposed by McIntosh (1991). Discrepancies between the experimental results and the model led to the conclusion that the standard model does not provide an adequate description of the unsteady response of real flames and that it is necessary to investigate more realistic chemical models. Here we follow exactly this suggestion and perform numerical studies of the response of lean methane flames using different reaction mechanisms. We find that the global flame response obtained with both detailed chemistry (GRI3.0) and a reduced multi-step model by Peters (1996) lies slightly above the predictions of the analytical model, but is close to experimental results. We additionally used an irreversible one-step Arrhenius reaction model and show the effect of the pressure dependence of the global reaction rate in the flame response. Our results suggest first that the current models have to be extended to capture the amplitude and phase results of the detailed mechanisms, and second that the correlation between the heat release and the measured OH* chemiluminescence should be studied deeper. (author)

  11. Stabilization of turbulent lifted jet flames assisted by pulsed high voltage discharge

    SciTech Connect (OSTI)

    Criner, K.; Cessou, A.; Louiche, J.; Vervisch, P. [CORIA UMR 6614 CNRS-Universite et INSA de Rouen, University of Rouen, 76801 Saint Etienne du Rouvray (France)

    2006-01-01T23:59:59.000Z

    To reduce fuel consumption or the pollutant emissions of combustion (furnaces, aircraft engines, turbo-reactors, etc.), attempts are made to obtain lean mixture combustion regimes. These lead to poor stability of the flame. Thus, it is particularly interesting to find new systems providing more flexibility in aiding flame stabilization than the usual processes (bluff-body, stabilizer, quarl, swirl, etc.). The objective is to enlarge the stability domain of flames while offering flexibility at a low energy cost. Evidence is presented that the stabilization of a turbulent partially premixed flame of more than 10 kW can be enhanced by pulsed high-voltage discharges with power consumption less than 0.1% of the power of the flame. The originality of this work is to demonstrate that very effective stabilization of turbulent flames is obtained when high-voltage pulses with very short rise times are used (a decrease by 300% in terms of liftoff height for a given exit jet velocity can be reached) and to provide measurements of minimum liftoff height obtained with discharge over a large range of the stability domain of the lifted jet flame.

  12. Sensor and model integration for the rapid prediction of concurrent flow flame spread 

    E-Print Network [OSTI]

    Cowlard, Adam

    Fire Safety Engineering is required at every stage in the life cycle of modern-day buildings. Fire safety design, detection and suppression, and emergency response are all vital components of Structural Fire Safety but are usually perceived...Issues of accuracy aside, these models demand heavy resources and computational time periods that are far greater than the time associated with the processes being simulated. To be of use to emergency responders, the output would need to be produced faster than the event itself with lead time to enable planning of an intervention strategy. Therefore in isolation, model output is not robust or fast enough to be implemented in an emergency response scenario. The concept of super-real time predictions steered by measurements is studied in the simple yet meaningful scenario of concurrent flow flame spread. Experiments have been conducted with PMMA slabs to feed sensor data into a simple analytical model. Numerous sensing techniques have been adapted to feed a simple algebraic expression from the literature linking flame spread, flame characteristics and pyrolysis evolution in order to model upward flame spread. The measurements are continuously fed to the computations so that projections of the flame spread velocity and flame characteristics can be established at each instant in time, ahead of the real flame. It was observed that as the input parameters in the analytical models were optimised to the scenario, rapid convergence between the evolving experiment and the predictions was attained....

  13. Retention of Nursing Faculty: Associate Degree Administrators' Perspectives

    E-Print Network [OSTI]

    Harris, Jennifer

    2014-08-31T23:59:59.000Z

    Retention of faculty is a complex and dynamic challenge for nursing education. Nursing is facing the growing dilemma of a shrinking population of current nursing faculty (AACN, 2012; Banks, 2012; Evans, 2013, & Proto & ...

  14. Soot volume fraction and temperature measurements in laminar nonpremixed flames using thermocouples

    SciTech Connect (OSTI)

    Mcenally, C.S.; Koeylue, U.O.; Pfefferle, L.D.; Rosner, D.E. [Yale Univ., New Haven, CT (United States)] [Yale Univ., New Haven, CT (United States)

    1997-06-01T23:59:59.000Z

    Thermocouple particle densitometry (TPD), a new method for measuring absolute soot volume fraction in flames which was suggested by Eisner and Rosner, has been successfully implemented in several laminar nonpremixed flames. This diagnostic relies on measuring the junction temperature history of a thermocouple rapidly inserted into a soot-containing flame region, then optimizing the fit between this history and one calculated from the principles of thermophoretic mass transfer. The TPD method is very simple to implement experimentally, yields spatially resolved volume fractions directly, can easily measure small volume fractions, and does not depend on the prevailing soot particle size, morphology, or optical characteristics. In a series of methane and ethylene counterflow flames whose soot volume fractions varied by more than an order of magnitude, the TPD results agreed to within experimental error with the authors own laser extinction measurements. In axisymmetric methane and ethylene co-flowing flames, the shape of TPD profiles agreed well with published laser extinction measurements, but the TPD concentrations were significantly larger in the early regions of the ethylene flame and throughout the methane flame; these discrepancies are probably attributable to visible light-transparent particles that are detectable with TPD but not with laser extinction. The TPD method is not applicable to the upper regions of these co-flowing flames since OH concentrations there suffice to rapidly oxidize any soot particles that deposit. Gas temperatures were obtained simultaneously with volume fraction by averaging the junction temperature history shortly after insertion. The error in these temperatures due to soot deposition-imposed changes in the junction diameter and emissivity were assessed and found to be moderate, e.g., less than 60 K near the centerline of the ethylene coflowing flame where the volume fraction was 6 ppm and the gas temperature was 1,550 K.

  15. Appearance, temperature, and NO{sub x} emission of two inverse diffusion flames with different port design

    SciTech Connect (OSTI)

    Sze, L.K.; Cheung, C.S.; Leung, C.W. [Department of Mechanical Engineering, The Hong Kong Polytechnic University, Hung Hom, Hong Kong (China)

    2006-01-01T23:59:59.000Z

    Experiments were carried out to investigate the appearance, temperature distribution, and NO{sub x} emission index of two inverse diffusion flames, one with circumferentially arranged ports (CAPs) and the other with co-axial (CoA) jets, both burning LPG with 70% butane and 30% propane. Flame appearances were investigated first with a fixed fueling rate at different airflow rates equivalent to air jet Reynolds numbers (Re) of 1000 to 4500; and then at a fixed airflow rate with different fueling rates equivalent to overall equivalence ratios (F) of 1.0 to 2.0. The CAP flame is found to consist of two zones: a lower entrainment zone and an upper mixing and combustion zone. The CoA flame in most cases is similar to a diffusion flame. The two-zone structure can be observed only at Re larger than 2500. The temperature distributions of the flames are similar at overall equivalence ratios of 1.0 and 1.2 for Re=2500, except that the corresponding CoA flame is longer. The flame temperature is higher in the CAP flame than the CoA flame at higher overall equivalence ratios. A measurement of centerline oxygen concentrations shows that the oxygen concentration reaches a minimum value at a flame height of 50 mm in the CAP flame but decreases more gradually in the CoA flame. It can be concluded that there is more intense air-fuel mixing in a CAP flame than the CoA flame. Investigation of the emission index of NO{sub x} (EINO{sub x}) for both flames at Re=2500 and overall equivalence ratios of 1.0 to 6.0 reveals that the EINO{sub x} curve of each flame is bell-shaped, with a maximum value of 3.2 g/kg at F=1.2 for the CAP flame and 3 g/kg at F=2.2 for the CoA flame.

  16. Temperature measurement of axisymmetric flames under the influence of magnetic field using Talbot interferometry

    SciTech Connect (OSTI)

    Agarwal, Shilpi, E-mail: sipi.agarwal@gmail.com, E-mail: manojklakra@gmail.com, E-mail: cshakher@iddc.iitd.ac.in; Kumar, Manoj, E-mail: sipi.agarwal@gmail.com, E-mail: manojklakra@gmail.com, E-mail: cshakher@iddc.iitd.ac.in; Shakher, Chandra, E-mail: sipi.agarwal@gmail.com, E-mail: manojklakra@gmail.com, E-mail: cshakher@iddc.iitd.ac.in [Instrument Design Development Centre, Indian Institute of Technology Delhi, HauzKhas, New Delhi - 110016 (India)

    2014-10-15T23:59:59.000Z

    Combustion process control is related with ecological improvement and the problem of energy efficiency; hence it has a wide interest at both economical and scientific levels. Application of a magnetic field is one of the most promising methods of combustion control. The presence of magnetic field induces the changes in flame behavior. The effect of uniform magnetic field developed by permanent magnet is studied by Talbot interferometry using circular gratings. Experimental results show a small decrease in flame temperature and increase in flame dimensions.

  17. Simulations of flame acceleration and deflagration-to-detonation transitions in methane-air systems

    SciTech Connect (OSTI)

    Kessler, D.A.; Gamezo, V.N.; Oran, E.S. [Laboratory for Computational Physics and Fluid Dynamics, Naval Research Laboratory, Washington, DC (United States)

    2010-11-15T23:59:59.000Z

    Flame acceleration and deflagration-to-detonation transitions (DDT) in large obstructed channels filled with a stoichiometric methane-air mixture are simulated using a single-step reaction mechanism. The reaction parameters are calibrated using known velocities and length scales of laminar flames and detonations. Calculations of the flame dynamics and DDT in channels with obstacles are compared to previously reported experimental data. The results obtained using the simple reaction model qualitatively, and in many cases, quantitatively match the experiments and are found to be largely insensitive to small variations in model parameters. (author)

  18. Reactor Pressure Vessel Head Packaging & Disposal

    SciTech Connect (OSTI)

    Wheeler, D. M.; Posivak, E.; Freitag, A.; Geddes, B.

    2003-02-26T23:59:59.000Z

    Reactor Pressure Vessel (RPV) Head replacements have come to the forefront due to erosion/corrosion and wastage problems resulting from the susceptibility of the RPV Head alloy steel material to water/boric acid corrosion from reactor coolant leakage through the various RPV Head penetrations. A case in point is the recent Davis-Besse RPV Head project, where detailed inspections in early 2002 revealed significant wastage of head material adjacent to one of the Control Rod Drive Mechanism (CRDM) nozzles. In lieu of making ASME weld repairs to the damaged head, Davis-Besse made the decision to replace the RPV Head. The decision was made on the basis that the required weld repair would be too extensive and almost impractical. This paper presents the packaging, transport, and disposal considerations for the damaged Davis-Besse RPV Head. It addresses the requirements necessary to meet Davis Besse needs, as well as the regulatory criteria, for shipping and burial of the head. It focuses on the radiological characterization, shipping/disposal package design, site preparation and packaging, and the transportation and emergency response plans that were developed for the Davis-Besse RPV Head project.

  19. Pdf modeling of turbulent nonpremixed methane jet flames

    SciTech Connect (OSTI)

    Chen, J.Y.; Kollmann, W.; Dibble, R.W. (Sandia National Labs., Livermore, CA (USA). Combustion Research Faclity)

    1989-01-01T23:59:59.000Z

    An expanded model of turbulent nonpremixed combustion is presented. In the model, the scalar mixing and reactions are described by a probability density function (pdf) submodel capable of handling five scalars, while the turbulent velocity field is described by a second-order moment closure. Two plausible chemical reaction models are considered: a five-scalar, four-step, reduced reaction mechanism, and a four-scalar constrained equilibrium model. Detailed comparisons of model predictions with laser Raman experimental dat provide a valuable evaluation of the model's ability in predicting nonequilibrium chemistry in turbulent nonpremixed flames. Overall, the model fails to predict greater departure from chemical equilibrium as mixing rates are increased. Interestingly, this failure is not due to the chemical model, both of which perform satisfactorily. Instead, the failure to predict greater departure from chemical equilibrium is a subtle artifact of the current Monte Carlo simulation of turbulent mixing and chemical reaction.

  20. The ignition of thermonuclear flames in Type Ia supernovae

    E-Print Network [OSTI]

    L. Iapichino; M. Brüggen; W. Hillebrandt; J. C. Niemeyer

    2005-12-12T23:59:59.000Z

    In the framework of the Chandrasekhar-mass deflagration model for Type Ia supernovae (SNe Ia), a persisting free parameter is the initial morphology of the flame front, which is linked to the ignition process in the progenitor white dwarf. Previous analytical models indicate that the thermal runaway is driven by temperature perturbations (''bubbles'') that develop in the white dwarf's convective core. In order to probe the conditions at ignition (diameters, temperatures and evolutionary timescales), we have performed hydrodynamical 2D simulations of buoyant bubbles in white dwarf interiors. Our results show that fragmentation occurring during the bubble rise affects the outcome of the bubble evolution. Possible implications for the ignition process of SNe Ia are discussed.

  1. The ignition of thermonuclear flames in Type Ia supernovae

    E-Print Network [OSTI]

    Iapichino, L; Hillebrandt, W; Niemeyer, J C

    2005-01-01T23:59:59.000Z

    In the framework of the Chandrasekhar-mass deflagration model for Type Ia supernovae (SNe Ia), a persisting free parameter is the initial morphology of the flame front, which is linked to the ignition process in the progenitor white dwarf. Previous analytical models indicate that the thermal runaway is driven by temperature perturbations (''bubbles'') that develop in the white dwarf's convective core. In order to probe the conditions at ignition (diameters, temperatures and evolutionary timescales), we have performed hydrodynamical 2D simulations of buoyant bubbles in white dwarf interiors. Our results show that fragmentation occurring during the bubble rise affects the outcome of the bubble evolution. Possible implications for the ignition process of SNe Ia are discussed.

  2. FLAME-SAMPLING PHOTOIONIZATION MASS SPECTROSCOPY - FINAL TECHNICAL REPORT

    SciTech Connect (OSTI)

    Hansen, Nils

    2013-02-12T23:59:59.000Z

    Research focused on detailed studies of the complex combustion chemistry of oxygenated, bio-derived fuels. In particular, studies were done of the flame chemistry of simple methyl and ethyl esters chosen as surrogates for the long-chain esters that are primary constituents of biodiesel fuels. The principal goals of these studies were: (1) show how fuel-specific structural differences including degree of unsaturation, linear vs. branched chain structures, and methoxy vs. ethoxy functions affect fueldestruction pathways, (2) understand the chemistry leading to potential increases in the emissions of hazardous air pollutants including aldehydes and ketones inherent in the use of biodiesel fuels, and (3) define the key chemical reaction mechanisms responsible for observed reductions in polycyclic aromatic hydrocarbons and particulate matter when oxygenated fuels are used as replacements for conventional fuels.

  3. The effect of solids retention time on tertiary ozonation and carbon adsorption of petrochemical wastewaters 

    E-Print Network [OSTI]

    Buys, Ronald Earl

    1980-01-01T23:59:59.000Z

    as solids retention time increased. COD concentration decreased after ozonation and its percent removal increased with a lengthening of the solids retention time, Ozone consumption decreased and the ratio of COD reduction to ozone consumed increased..., with and without ozonation. . . . . . . . . . . . . 22 Effect of solids retention time on COD removal. Effect of solids retention time on ozone concentration consumed. 27 Effect of solids retention time on the ratio of COD reduction to ozone consumed. 28...

  4. Stochastic algorithms for the analysis of numerical flame simulations

    SciTech Connect (OSTI)

    Bell, John B.; Day, Marcus S.; Grcar, Joseph F.; Lijewski, Michael J.

    2004-04-26T23:59:59.000Z

    Recent progress in simulation methodologies and high-performance parallel computers have made it is possible to perform detailed simulations of multidimensional reacting flow phenomena using comprehensive kinetics mechanisms. As simulations become larger and more complex, it becomes increasingly difficult to extract useful information from the numerical solution, particularly regarding the interactions of the chemical reaction and diffusion processes. In this paper we present a new diagnostic tool for analysis of numerical simulations of reacting flow. Our approach is based on recasting an Eulerian flow solution in a Lagrangian frame. Unlike a conventional Lagrangian view point that follows the evolution of a volume of the fluid, we instead follow specific chemical elements, e.g., carbon, nitrogen, etc., as they move through the system . From this perspective an ''atom'' is part of some molecule of a species that is transported through the domain by advection and diffusion. Reactions cause the atom to shift from one chemical host species to another and the subsequent transport of the atom is given by the movement of the new species. We represent these processes using a stochastic particle formulation that treats advection deterministically and models diffusion and chemistry as stochastic processes. In this paper, we discuss the numerical issues in detail and demonstrate that an ensemble of stochastic trajectories can accurately capture key features of the continuum solution. The capabilities of this diagnostic are then demonstrated by applications to study the modulation of carbon chemistry during a vortex-flame interaction, and the role of cyano chemistry in rm NO{sub x} production for a steady diffusion flame.

  5. Liquid Effluent Retention Facility (LERF) Final Hazard Category Determination

    SciTech Connect (OSTI)

    HUTH, L.L.

    2001-06-06T23:59:59.000Z

    The Liquid Effluent Retention Facility was designed to store 242-A Evaporator process condensate and other liquid waste streams for treatment at the 200 East Area Effluent Treatment Facility. The Liquid Effluent Retention Facility has been previously classified as a Category 3 Nonreactor Nuclear Facility. As defined in Hazard Categorization and Accident Analysis Techniques for Compliance with DOE Order 5480.23, Nuclear Safety Analysis Reports (DOE 1992, DOE 1997), Category 3 Nuclear Facilities have the potential for significant localized (radiological) consequences. However, based on current facility design, operations, and radioactive constituent concentrations, the Liquid Effluent Retention Facility does not have the potential for significant localized (radiological) consequences and is categorized as a Radiological Facility. This report documents the final hazard categorization process performed in accordance with DOE Order 5480.23, Nuclear Safety Analysis Reports. This report describes the current configuration and operations of the Liquid Effluent Retention Facility. Also included is a preliminary hazard categorization, which is based on current and proposed radioactive and hazardous material inventories, a preliminary hazards and accident analysis, and a final hazard category determination. The results of the hazards and accident analysis, based on the current configuration and operations of the Liquid Effluent Retention Facility and the current and proposed radioactive and hazardous material inventories, demonstrate that the Liquid Effluent Retention Facility does not have the potential for significant localized (radiological) consequences. Based on the final hazard category analysis, the Liquid Effluent Retention Facility is a Radiological Facility. The final hazard category determination is based on a comparative evaluation of the consequence basis for the Category 3 threshold quantities to the calculated consequences for credible releases The basis for the Category 3 threshold quantities is 10 rem-equivalent man at 30 meters (98 feet) (DOE 1992, DOE 1997). The calculated 12 hour consequences to an individual located at 30 meters (98 feet) for two credible scenarios, spray release and a pool release, are 3.50 rem and 1.32 rem, respectively, which based upon the original hazard categorization criteria (DOE 1992) classified the Liquid Effluent Retention Facility as a Radiological Facility. Comparison of the calculated 24 hour consequences to an individual located at 30 meters (98 feet) for two credible scenarios, spray release and a pool release, 7.00 rem and 2.64 rem respectively, confirmed the Liquid Effluent Retention Facility classification as a Radiological Facility under the current hazard categorization criteria (DOE 1997). Both result in dose consequence values less than the allowable, 10 rem, meeting the requirements for categorizing the Liquid Effluent Retention Facility as a Radiological Facility.

  6. Layer-by-Layer Nanocoatings with Flame Retardant and Oxygen Barrier Properties: Moving Toward Renewable Systems

    E-Print Network [OSTI]

    Laufer, Galina 1985-

    2012-10-23T23:59:59.000Z

    to cotton fabric, all coated fabrics retained their weave structure after being exposed to a vertical flame test, while uncoated cotton was completely destroyed. Micro combustion calorimetry confirmed that coated fabrics exhibited a reduced peak heat release...

  7. Acoustic Modes in Combustors with Complex Impedances and Multidimensional Active Flames

    E-Print Network [OSTI]

    Nicoud, Franck

    Acoustic Modes in Combustors with Complex Impedances and Multidimensional Active Flames F. Nicoud for computing the thermoacoustic modes in combustors. In the case of a nonisothermal reacting medium, the wave

  8. Combustion flame-plasma hybrid reactor systems, and chemical reactant sources

    DOE Patents [OSTI]

    Kong, Peter C

    2013-11-26T23:59:59.000Z

    Combustion flame-plasma hybrid reactor systems, chemical reactant sources, and related methods are disclosed. In one embodiment, a combustion flame-plasma hybrid reactor system comprising a reaction chamber, a combustion torch positioned to direct a flame into the reaction chamber, and one or more reactant feed assemblies configured to electrically energize at least one electrically conductive solid reactant structure to form a plasma and feed each electrically conductive solid reactant structure into the plasma to form at least one product is disclosed. In an additional embodiment, a chemical reactant source for a combustion flame-plasma hybrid reactor comprising an elongated electrically conductive reactant structure consisting essentially of at least one chemical reactant is disclosed. In further embodiments, methods of forming a chemical reactant source and methods of chemically converting at least one reactant into at least one product are disclosed.

  9. Combustion and Flame 150 (2007) 400403 www.elsevier.com/locate/combustflame

    E-Print Network [OSTI]

    Gülder, �mer L.

    velocity pro- file as the gases leave the foam elements. Fig. 1 shows the details of the experimental performed pre- viously with methane [1] and propane [2] diffusion flames at elevated pressures. A constant

  10. Layer-by-Layer Nanocoatings with Flame Retardant and Oxygen Barrier Properties: Moving Toward Renewable Systems 

    E-Print Network [OSTI]

    Laufer, Galina 1985-

    2012-10-23T23:59:59.000Z

    to cotton fabric, all coated fabrics retained their weave structure after being exposed to a vertical flame test, while uncoated cotton was completely destroyed. Micro combustion calorimetry confirmed that coated fabrics exhibited a reduced peak heat release...

  11. Curl Flame Fractal Rib cage and neck of a Cretaceous plesiosaur (elasmosaur)

    E-Print Network [OSTI]

    Machel, Hans

    Curl Flame Fractal Rib cage and neck of a Cretaceous plesiosaur (elasmosaur) Fretted terrain (unit of Gusev Crater, Mars narrow channels scarp narrow ridge Basin Floor Assemblage Basin oor unit 1--Forms

  12. Combustion and Flame 139 (2004) 90105 www.elsevier.com/locate/jnlabr/cnf

    E-Print Network [OSTI]

    Aggarwal, Suresh K.

    2004-01-01T23:59:59.000Z

    . Barlow and Carter [1] investigated experimentally the effects of temperature and mixture fraction on NOx formed experimental and numerical investigations on NOx emissions from turbulent propane diffusion flames stabilized lean premixed methane­air

  13. Numerical simulations of perforated plate stabilized premixed flames with detailed chemistry

    E-Print Network [OSTI]

    Kedia, Kushal Sharad

    2010-01-01T23:59:59.000Z

    The objective of this work is to develop a high efficiency two-dimensional reactive flow solver to investigate perforated-plate stabilized laminar premixed flames. The developed code is used to examine the impact of the ...

  14. Large eddy simulations of premixed turbulent flame dynamics : combustion modeling, validation and analysis

    E-Print Network [OSTI]

    Kewlani, Gaurav

    2014-01-01T23:59:59.000Z

    High efficiency, low emissions and stable operation over a wide range of conditions are some of the key requirements of modem-day combustors. To achieve these objectives, lean premixed flames are generally preferred as ...

  15. Assessment of EEM approach for 3D expanding wrinkled premixed flames

    E-Print Network [OSTI]

    Boyer, Edmond

    /methane, air/propane and air/hydrogen flames are measured at atmo- spheric pressure. An internal combustion engine-like configuration, with an optically accessible cylindrical combustion chamber has also been

  16. Studies of n-Propanol, iso-Propanol, and Propane Flames

    SciTech Connect (OSTI)

    Veloo, Peter S.; Egolfopoulos, Fokion N.

    2011-01-01T23:59:59.000Z

    The phenomena of propagation and extinction of flames of saturated C{sub 3} alcohols and propane were studied experimentally and numerically in order to assess the effects of the presence and location of the hydroxyl radical in the fuel molecular structure. The experiments were carried out in the counterflow configuration under atmospheric pressure and for unreacted fuel-carrying stream temperature of 343 K. The simulations included detailed descriptions of molecular transport and chemical kinetics using a recently developed kinetic model for C{sub 3} alcohols. The experimental results revealed that the laminar flame speeds and extinction strain rates of n-propanol/air and propane/air flames are close to each other whereas those of iso-propanol/air flames are consistently lower. Similar behavior was observed also for the extinction strain rates of non-premixed n-propanol and iso-propanol flames. It was shown through sensitivity and reaction path analyses that there are two major differences between the intermediates of n-propanol/air and iso-propanol/air flames. In iso-propanol/air flames there are notably higher concentrations of propene whose consumption pathway results in the relatively unreactive allyl radicals, retarding thus the overall reactivity. In n-propanol/air flames there are notably higher concentrations of formaldehyde that reacts readily to form formyl radicals whose subsequent reactions enhance the overall reactivity. The kinetic model used in this study was found to overpredict the experimental results for rich n-propanol/air and propane/air flames. Analysis revealed that those discrepancies are most likely caused by deficiencies in the C{sub 3} alkane kinetics. Through sensitivity analysis, it was determined also that the propagation and extinction of n-propanol/air and iso-propanol/air flames are sensitive largely to hydrogen, carbon monoxide, and C{sub 1}–C{sub 3} kinetics and not to fuel-specific reactions. Finally, the relative sooting propensities of flames of these three fuels were assessed computationally.

  17. HeadLock : wide-range head pose estimation for low resolution video

    E-Print Network [OSTI]

    DeCamp, Philip (Philip James)

    2008-01-01T23:59:59.000Z

    This thesis focuses on data mining technologies to extract head pose information from low resolution video recordings. Head pose, as an approximation of gaze direction, is a key indicator of human behavior and interaction. ...

  18. OH radical imaging in a DI diesel engine and the structure of the early diffusion flame

    SciTech Connect (OSTI)

    Dec, J.E.; Coy, E.B.

    1996-03-01T23:59:59.000Z

    Laser-sheet imaging studies have considerably advanced our understanding of diesel combustion; however, the location and nature of the flame zones within the combusting fuel jet have been largely unstudied. To address this issue, planar laser-induced fluorescence (PLIF) imaging of the OH radical has been applied to the reacting fuel jet of a direct-injection diesel engine of the ``heavy-duty`` size class, modified for optical access. An Nd:YAG-based laser system was used to pump the overlapping Q{sub 1}9 and Q{sub 2}8 lines of the (1,0) band of the A{yields}X transition at 284.01 nm, while the fluorescent emission from both the (0,O) and (1, I) bands (308 to 320 nm) was imaged with an intensified video camera. This scheme allowed rejection of elastically scattered laser light, PAH fluorescence, and laser-induced incandescence. OH PLIF is shown to be an excellent diagnostic for diesel diffusion flames. The signal is strong, and it is confined to a narrow region about the flame front because the threebody recombination reactions that reduce high flame-front OH concentrations to equilibrium levels occur rapidly at diesel pressures. No signal was evident in the fuel-rich premixed flame regions where calculations and burner experiments indicate that OH concentrations will be below detectable limits. Temporal sequences of OH PLIF images are presented showing the onset and development of the early diffusion flame up to the time that soot obscures the images. These images show that the diffusion flame develops around the periphery of the-downstream portion of the reacting fuel jet about half way through the premixed burn spike. Although affected by turbulence, the diffusion flame remains at the jet periphery for the rest of the imaged sequence.

  19. Soot formation in laminar premixed ethylene/air flames at atmospheric pressure

    SciTech Connect (OSTI)

    Xu, F.; Sunderland, P.B.; Faeth, G.M. [Univ. of Michigan, Ann Arbor, MI (United States). Dept. of Aerospace Engineering] [Univ. of Michigan, Ann Arbor, MI (United States). Dept. of Aerospace Engineering

    1997-03-01T23:59:59.000Z

    Soot formation was studied within laminar premixed ethylene/air flames (C/O ratios of 0.78--0.98) stabilized on a flat-flame burner operating at atmospheric pressure. Measurements included soot volume fractions by both laser extinction and gravimetric methods, temperatures by multiline emission, soot structure by thermophoretic sampling and transmission electric microscopy, major gas species concentrations by sampling and gas chromatography, concentrations of condensable hydrocarbons by gravimetric sampling, and velocities by laser velocimetry. These data were used to find soot surface growth rates and primary soot particle nucleation rates along the axes of the flames. Present measurements of soot surface growth rates were correlated successfully by predictions based on typical hydrogen-abstraction/carbon-addition (HACA) mechanisms of Frenklach and co-workers and Colket and Hall. These results suggest that reduced soot surface growth rates with increasing residence time seen in the present and other similar flames were mainly caused by reduced rates of surface activation due to reduced H atom concentrations as temperatures decrease as a result of radiative heat losses. Primary soot particle nucleation rates exhibited variations with temperature and acetylene concentrations that were similar to recent observations for diffusion flames; however, nucleation rates in the premixed flames were significantly lower than in the diffusion flames for reasons that still must be explained. Finally, predictions of yields of major gas species based on mechanisms from both Frenklach and co-workers and Leung and Lindstedt were in good agreement with present measurements and suggest that H atom concentrations (relevant to HACA mechanisms) approximate estimates based on local thermodynamic equilibrium in the present flames.

  20. EIS-0351: Operation of Flaming Gorge Dam, Colorado River Storage Project, Colorado River, UT

    Broader source: Energy.gov [DOE]

    The Secretary of the United States Department of the Interior (Secretary), acting through the Bureau of Reclamation (Reclamation), is considering whether to implement a proposed action under which Flaming Gorge Dam would be operated to achieve the flow and temperature regimes recommended in the September 2000 report Flow and Temperature Recommendations for Endangered Fishes in the Green River Downstream of Flaming Gorge Dam (2000 Flow and Temperature Recommendations), published by the Upper Colorado River Endangered Fish Recovery Program (Recovery Program).

  1. Investigation of the processes controlling the flame generation of refractory materials

    SciTech Connect (OSTI)

    Katz, J.L.

    1992-01-01T23:59:59.000Z

    The processes involved in the formation of mixed oxides powders were studied using the counterflow diffusion flame burner. Powders of different morphologies were obtained by varying the flame conditions (temperature, residence time) and the concentration ratio of the oxides precursors. In-situ particle size and number density were determined using dynamic light scattering and 90{degrees} light scattering. A thermophoretic sampling method and a larger scale powder collection device also was used to collect particles, and their size and morphology examined using transmission electron microscopy, X-ray diffraction and surface area measurement by gas absorption (BET). Our emphasis has been on TiO{sub 2}-SiO{sub 2}, SiO{sub 2}-GeO{sub 2} and Al{sub 2}O{sub 3}-TiO{sub 2}. The powders had a core-mantle-like (one oxide coated by the other) at low elevations in the burner and uniform mixture at higher elevations. They form chain-like structures in a low temperature flame and spherical particles in a higher temperature flame. Nanometer sized homogeneous particles of Aluminum Titanate could be obtained using Al(CH{sub 3}){sub 3} and TiCl{sub 4} as precursors both in a hydrogen fueled and a methane fueled counterflow diffusion flame burner, as well as in a hydrogen fueled parallel-flow diffusion flame burner.

  2. Pressure change and transport process on flames formed in a stretched, rotating flow

    SciTech Connect (OSTI)

    Yamamoto, Kazuhiro [Toyohashi Univ. of Technology, Aichi (Japan). Dept. of Mechanical Engineering] [Toyohashi Univ. of Technology, Aichi (Japan). Dept. of Mechanical Engineering

    1999-08-01T23:59:59.000Z

    Flame characteristics in a stretched, rotating flow have been investigated by numerical simulation of tubular laminar flames for lean hydrogen, methane, and propane/air mixtures. Twin planar flames in counterflow have been also simulated for comparison. A fixed inlet velocity at the porous wall of the burner was assumed in all cases, and the cylindrical containing tube (radius R = 9.5 mm) was either maintained stationary or rotated. Results showed that, within the range studied, the flame temperatures always increase monotonically with increasing fuel concentration, and at the same time the reaction zones move outwards. However, while the introduction of rotation also causes a monotonic temperature increase of hydrogen and methane air mixtures, that of a propane/air mixture decreases. The temperature change with rotation becomes smaller with an increase of the fuel concentration. As a consequence of the centrifugal force, {rho}{nu}{sub {theta}}{sup 2}/r, induced by the rotation, a pressure gradient is formed in the cylindrical containing tube, with low pressure along the axis. The pressure gradient at the outer, unburnt edge of the flame reaction zone becomes smaller as the fuel concentration increases. The resultant decreased mass transport by pressure diffusion provides an explanation for part of the above-mentioned temperature change associated with rotation. The remainder of the effect is associated with changed stretch characteristics of the flames.

  3. Autoignited laminar lifted flames of propane in coflow jets with tribrachial edge and mild combustion

    SciTech Connect (OSTI)

    Choi, B.C.; Kim, K.N.; Chung, S.H. [School of Mechanical and Aerospace Engineering, Seoul National University, Seoul 151-744 (Korea)

    2009-02-15T23:59:59.000Z

    Characteristics of laminar lifted flames have been investigated experimentally by varying the initial temperature of coflow air over 800 K in the non-premixed jets of propane diluted with nitrogen. The result showed that the lifted flame with the initial temperature below 860 K maintained the typical tribrachial structure at the leading edge, which was stabilized by the balance mechanism between the propagation speed of tribrachial flame and the local flow velocity. For the temperature above 860 K, the flame was autoignited without having any external ignition source. The autoignited lifted flames were categorized in two regimes. In the case with tribrachial edge structure, the liftoff height increased nonlinearly with jet velocity. Especially, for the critical condition near blowout, the lifted flame showed a repetitive behavior of extinction and reignition. In such a case, the autoignition was controlled by the non-adiabatic ignition delay time considering heat loss such that the autoignition height was correlated with the square of the adiabatic ignition delay time. In the case with mild combustion regime at excessively diluted conditions, the liftoff height increased linearly with jet velocity and was correlated well with the square of the adiabatic ignition delay time. (author)

  4. Effects of multi-component diffusion and heat release on laminar diffusion flame liftoff

    SciTech Connect (OSTI)

    Li, Zhiliang; Chen, Ruey-Hung [Department of Mechanical, Materials and Aerospace Engineering, University of Central Florida, Orlando, FL 32816-2450 (United States); Phuoc, Tran X. [National Energy Technology Laboratory, Department of Energy, P.O. Box 10940, MS 84-340, Pittsburgh, PA 15261 (United States)

    2010-08-15T23:59:59.000Z

    Numerical simulations were conducted of the liftoff and stabilization phenomena of laminar jet diffusion flames of inert-diluted C{sub 3}H{sub 8} and CH{sub 4} fuels. Both non-reacting and reacting jets were investigated, including multi-component diffusivities and heat release effects (buoyancy and gas expansion). The role of Schmidt number for non-reacting jets was investigated, with no conclusive Schmidt number criterion for liftoff previously arrived at in similarity solutions. The cold-flow simulation for He-diluted CH{sub 4} fuel does not predict flame liftoff; however, adding heat release reaction lead to the prediction of liftoff, which is consistent with experimental observations. Including reaction was also found to improve liftoff height prediction for C{sub 3}H{sub 8} flames, with the flame base location differing from that in the similarity solution - the intersection of the stoichiometric and iso-velocity (equal to 1-D flame speed) is not necessary for flame stabilization (and thus liftoff). Possible mechanisms other than that proposed for similarity solution may better help to explain the stabilization and liftoff phenomena. (author)

  5. Experimental and numerical study of the accuracy of flame-speed measurements for methane/air combustion in a slot burner

    SciTech Connect (OSTI)

    Selle, L.; Ferret, B. [Universite de Toulouse, INPT, UPS, IMFT, Institut de Mecanique des Fluides de Toulouse (France); CNRS, IMFT, Toulouse (France); Poinsot, T. [Universite de Toulouse, INPT, UPS, IMFT, Institut de Mecanique des Fluides de Toulouse (France); CNRS, IMFT, Toulouse (France); CERFACS, Toulouse (France)

    2011-01-15T23:59:59.000Z

    Measuring the velocities of premixed laminar flames with precision remains a controversial issue in the combustion community. This paper studies the accuracy of such measurements in two-dimensional slot burners and shows that while methane/air flame speeds can be measured with reasonable accuracy, the method may lack precision for other mixtures such as hydrogen/air. Curvature at the flame tip, strain on the flame sides and local quenching at the flame base can modify local flame speeds and require corrections which are studied using two-dimensional DNS. Numerical simulations also provide stretch, displacement and consumption flame speeds along the flame front. For methane/air flames, DNS show that the local stretch remains small so that the local consumption speed is very close to the unstretched premixed flame speed. The only correction needed to correctly predict flame speeds in this case is due to the finite aspect ratio of the slot used to inject the premixed gases which induces a flow acceleration in the measurement region (this correction can be evaluated from velocity measurement in the slot section or from an analytical solution). The method is applied to methane/air flames with and without water addition and results are compared to experimental data found in the literature. The paper then discusses the limitations of the slot-burner method to measure flame speeds for other mixtures and shows that it is not well adapted to mixtures with a Lewis number far from unity, such as hydrogen/air flames. (author)

  6. Transfer function characteristics of bluff-body stabilized, conical V-shaped premixed turbulent propane-air flames

    SciTech Connect (OSTI)

    Chaparro, Andres; Landry, Eric; Cetegen, Baki M. [Mechanical Engineering Department, University of Connecticut, 191 Auditorium Road, Storrs, CT 06269-3139 (United States)

    2006-04-15T23:59:59.000Z

    The response of bluff-body stabilized conical V-shaped premixed flames to periodic upstream velocity oscillations was characterized as a function of oscillation frequency, mean flow velocity, and equivalence ratio. The flame heat release response to the imposed velocity oscillations was determined from the CH* chemiluminescence captured by two photomultiplier (PMT) detectors at a wavelength of 430 nm. One of the PMTs viewed flame radiation in a 10-mm horizontal slice, 50 mm above the bluff-body. The second PMT observed the overall flame radiation. The flame transfer function characteristics were determined from the spectral analysis of the velocity and PMT signals. It was found that the flame heat release amplitude response is confined to low-frequency excitation below a Strouhal number of 4. The phase relationship of the transfer function for these turbulent flames was evaluated using the signal from the spatially masked PMT. The transfer function estimate based on these data exhibits second-order characteristics with a phase lag between the velocity and heat release signals. The localized heat-release response contains frequencies that are multiples of the excitation frequency, suggesting splitting and tilting of flame structures as well as some nonlinear effects. Increase of flame equivalence ratio from lean toward stoichiometric resulted in slight amplification of the high-frequency response. (author)

  7. Retention and switching kinetics of protonated gate field effect transistors

    SciTech Connect (OSTI)

    DEVINE,R.A.B.; HERRERA,GILBERT V.

    2000-05-23T23:59:59.000Z

    The switching and memory retention time has been measured in 50 {micro}m gatelength pseudo-non-volatile memory MOSFETS containing, protonated 40 nm gate oxides. Times of the order of 3.3 seconds are observed for fields of 3 MV cm{sup {minus}1}. The retention time with protons placed either at the gate oxide/substrate or gate oxide/gate electrode interfaces is found to better than 96{percent} after 5,000 seconds. Measurement of the time dependence of the source-drain current during switching provides clear evidence for the presence of dispersive proton transport through the gate oxide.

  8. Retention and Switching Kinetics of Protonated Gate Field Effect Transistors

    SciTech Connect (OSTI)

    DEVINE,R.A.B.; HERRERA,GILBERT V.

    2000-06-27T23:59:59.000Z

    The switching and memory retention time has been measured in 50 {micro}m gatelength pseudo-non-volatile memory MOSFETs containing, protonated 40 nm gate oxides. Times of the order of 3.3 seconds are observed for fields of 3 MV cm{sup {minus}1}. The retention time with protons placed either at the gate oxide/substrate or gate oxide/gate electrode interfaces is found to better than 96% after 5,000 seconds. Measurement of the time dependence of the source-drain current during switching provides clear evidence for the presence of dispersive proton transport through the gate oxide.

  9. Measurements and modeling of soot formation and radiation in microgravity jet diffusion flames

    SciTech Connect (OSTI)

    Ku, J.C.; Tong, L. [Wayne State Univ., Detroit, MI (United States). Mechanical Engineering Dept.; Greenberg, P.S. [NASA Lewis Research Center, Cleveland, OH (United States). Microgravity Combustion Branch

    1996-12-31T23:59:59.000Z

    This is a computational and experimental study for soot formation and radiative heat transfer in jet diffusion flames under normal gravity (1-g) and microgravity (0-g) conditions. Instantaneous soot volume fraction maps are measured using a full-field imaging absorption technique developed by the authors. On modeling, the authors have coupled flame structure and soot formation models with detailed radiation transfer calculations. Favre-averaged boundary layer equations with a k-e-g turbulence model are used to predict the flow field, and a conserved scalar approach with an assumed {beta}-pdf are used to predict gaseous species mole fraction. Scalar transport equations are used to describe soot volume fraction and number density distributions, with formation and oxidation terms modeled by one-step rate equations and thermophoretic effects included. An energy equation is included to couple flame structure and radiation analyses through iterations, neglecting turbulence-radiation interactions. The YIX solution for a finite cylindrical enclosure is used for radiative heat transfer calculations. The spectral absorption coefficient for soot aggregates is calculated from the Rayleigh solution using complex refractive index data from a Drude-Lorentz model. The exponential-wide-band model is used to calculate the spectral absorption coefficient for H{sub 2}O and CO{sub 2}. Predicted soot volume fraction and temperature results agree well with published data for a normal gravity co-flow laminar flames and turbulent jet flames. Predicted soot volume fraction results also agree with the data for 1-g and 0-g laminar jet flames as well as 1-g turbulent jet flames.

  10. Flame structure of wall-impinging diesel fuel sprays injected by group-hole nozzles

    SciTech Connect (OSTI)

    Gao, Jian; Moon, Seoksu; Nishida, Keiya; Matsumoto, Yuhei [Department of Mechanical System Engineering, University of Hiroshima, Higashi-Hiroshima, 739-8527 (Japan); Zhang, Yuyin [Department of Mechanical Engineering, Tokyo Denki University, Tokyo, 101-8457 (Japan)

    2009-06-15T23:59:59.000Z

    This paper describes an investigation of the flame structure of wall-impinging diesel sprays injected by group-hole nozzles in a constant-volume combustion vessel at experimental conditions typical of a diesel engine. The particular emphasis was on the effect of the included angle between two orifices (0-15 deg. in current study) on the flame structure and combustion characteristics under various simulated engine load conditions. The laser absorption scattering (LAS) technique was applied to analyze the spray and mixture properties. Direct flame imaging and OH chemiluminescence imaging were utilized to quantify the ignition delay, flame geometrical parameters, and OH chemiluminescence intensity. The images show that the asymmetric flame structure emerges in wall-impinging group-hole nozzle sprays as larger included angle and higher engine load conditions are applied, which is consistent with the spray shape observed by LAS. Compared to the base nozzle, group-hole nozzles with large included angles yield higher overall OH chemiluminescence intensity, wider flame area, and greater proportion of high OH intensity, implying the better fuel/air mixing and improved combustion characteristics. The advantages of group-hole nozzle are more pronounced under high load conditions. Based on the results, the feasibility of group-hole nozzle for practical direct injection diesel engines is also discussed. It is concluded that the asymmetric flame structure of a group-hole nozzle spray is favorable to reduce soot formation over wide engine loads. However, the hole configuration of the group-hole nozzle should be carefully considered so as to achieve proper air utilization in the combustion chamber. Stoichiometric diesel combustion is another promising application of group-hole nozzle. (author)

  11. Bear Head LNG Corporation and Bear Head LNG (USA), LLC FE Docket No. 15-14-NG

    Broader source: Energy.gov [DOE]

    On January 23, 2015, Bear Head LNG Corporation and Bear Head LNG (USA), LLC (together, “Bear Head LNG”), filed an application for long-term, multi-contract authorization to engage in imports from,...

  12. Bear Head LNG Corporation and Bear Head LNG (USA), LLC- FE Dkt No. 15-14-NG

    Broader source: Energy.gov [DOE]

    On January 23, 2015, Bear Head LNG Corporation and Bear Head LNG (USA), LLC (together, “Bear Head LNG”), filed an application for long-term, multi-contract authorization to engage in imports from,...

  13. Cylinder Head Gasket with Integrated Combustion Pressure Sensors...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Cylinder Head Gasket with Integrated Combustion Pressure Sensors Cylinder Head Gasket with Integrated Combustion Pressure Sensors Poster presented at the 16th Directions in...

  14. acceleration head injury: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    activity in the ADRIA project concerns the performance of numerical simulations of the brain response to human head loading during car Verhoeve Bovendeerd Wismans 2 Head injury...

  15. Laboratory Demonstration of a New American Low-Head Hydropower...

    Broader source: Energy.gov (indexed) [DOE]

    Laboratory Demonstration of a New American Low-Head Hydropower Turbine Laboratory Demonstration of a New American Low-Head Hydropower Turbine Laboratory Demonstration of a New...

  16. Nanotechnology in Head and Neck Cancer: The Race Is On

    E-Print Network [OSTI]

    El-Sayed, Ivan H.

    2010-01-01T23:59:59.000Z

    10.1007/s11912-010-0087-2 Nanotechnology in Head and Neckthe applications of nanotechnology in head and neck cancer,plasmonic gold nanotechnology. Keywords Nanotechnology .

  17. Blowoff characteristics of bluff-body stabilized conical premixed flames with upstream spatial mixture gradients and velocity oscillations

    SciTech Connect (OSTI)

    Chaudhuri, Swetaprovo; Cetegen, Baki M. [Mechanical Engineering Department, University of Connecticut, Storrs, CT 06269-3139 (United States)

    2008-06-15T23:59:59.000Z

    This experimental study concerns determination of blowoff equivalence ratios for lean premixed conical flames for different mixture approach velocities ranging from 5 to 16 m/s in the presence of spatial mixture gradients and upstream velocity modulation. Conical flames were anchored on a disk-shaped bluff body that was attached to a central rod in the burner nozzle. A combustible propane-air mixture flowed through a converging axisymmetric nozzle with a concentric insert, allowing radial mixture variation by tailoring the composition in the inner and outer parts of the nozzle. The radial mixture profiles were characterized near the location of the flame holder by laser Rayleigh light scattering. Additionally, a loudspeaker at the nozzle base allowed introduction of periodic velocity oscillations with an amplitude of 9% of the mean flow velocity up to a frequency of 350 Hz. The flame blowoff equivalence ratio was experimentally determined by continuously lowering the fuel flow rates and determining the flame detachment point from the flame holder. Flame detachment was detected by a rapid reduction of CH* emission from the flame base imaged by a photomultiplier detector. It was found that the flame blowoff is preceded by progressive narrowing of the flame cone for the case of higher inner jet equivalence ratios. In this case, the fuel-lean outer flow cannot sustain combustion, and clearly this is not a good way of operating a combustor. Nevertheless, the overall blowoff equivalence ratio is reduced by inner stream fuel enrichment. A possible explanation for this behavior is given based on the radial extent of the variable-equivalence-ratio mixture burning near the flame stabilization region. Fuel enrichment in the outer flow was found to have no effect on blowoff as compared to the case of uniform mixture. The results were similar for the whole range of mean flow velocities and upstream excitation frequencies. (author)

  18. KU alumna to head Spencer Research Library

    E-Print Network [OSTI]

    2009-06-18T23:59:59.000Z

    12/5/13 KU alumna to head Spencer Research Library www.lib.ku.edu/news/spencer_head_announced.shtml 1/2 The University of Kansas Libraries Libraries Home Articles & Databases Catalog: books & more E-journals Research by Subject Course Reserves... Library Pages A-Z Images KU ScholarWorks KU Digital Collections Hours My Account Request Articles, Books,… Friends & Benefactors Suggestions University of Kansas alumna Beth M. Whittaker will become the next head of KU’s Kenneth Spencer Research Library...

  19. Faculty Retention and Gender Adrienne Kertzer and Jenny Godley

    E-Print Network [OSTI]

    Calgary, University of

    1 Faculty Retention and Gender Adrienne Kertzer and Jenny Godley Advisory Committee on the Status, and home faculty; by year, rank, and total number of faculty members across the 1 E-mail Adrienne Kertzer, and total number of faculty members in the home faculty.3 In January 2013, Jenny Godley, Department

  20. Evolutionary Computing for Detection of Retentive Structures in Coastal Waters

    E-Print Network [OSTI]

    Fernandez, Thomas

    ,robillia,poty,fonlupt}@lil.univ-littoral.fr, Abstract-- The demography of anchovy fishes in the Gulf of Biscay seems to be related to the presence of so- called "retentive" hydrodynamical structures, that keep fish eggs and larvae in a favorable environment be used to decide fishing quotas or bans for the sake of preserving the natural resource. We propose two

  1. Predicting Student Retention and Academic Success at New Mexico Tech

    E-Print Network [OSTI]

    Borchers, Brian

    Predicting Student Retention and Academic Success at New Mexico Tech by Julie Luna Submitted Research and Statistics Option New Mexico Institute of Mining and Technology Socorro, New Mexico August at the New Mexico Institute of Mining and Technology. Joe Franklin of the Information Services Department

  2. Techniques and Technology Article Optimizing Radio Retention and Minimizing Radio

    E-Print Network [OSTI]

    Sandercock, Brett K.

    Techniques and Technology Article Optimizing Radio Retention and Minimizing Radio Impacts the duration of transmitter attachment and minimizing the impacts of radios on the behavior and demography of the study animal. We tested 4 methods of radio attachment for a breeding population of upland sandpipers

  3. Guidelines for the Management and Retention of Public Record

    E-Print Network [OSTI]

    Sheridan, Jennifer

    v1.2 1 11/23/2010 Guidelines for the Management and Retention of Public Record E-Mail Wisconsin Public Records Board #12;v1.2 2 11/23/2010 Contents Introduction .............................................................................................................................3 Determine if you have a public record

  4. ORIGINAL PAPER Argon retention properties of silicate glasses and implications

    E-Print Network [OSTI]

    Harrison, Mark

    data from rocks depends on many factors, knowing the Ar transport properties of any dated materialORIGINAL PAPER Argon retention properties of silicate glasses and implications for 40 Ar/39 Ar age fused from igneous-derived cohesive fault rock and igneous rock, and step-heated from $400 to >1,200 °C

  5. Retention of ferrite in AluminiumAlloyed TRIPassisted steels

    E-Print Network [OSTI]

    Cambridge, University of

    Retention of ­ferrite in Aluminium­Alloyed TRIP­assisted steels Young Joo Choi1, Dong­Woo Suh1 properties (Yi et al., 2011a). It is known in this context, that alloying with aluminium makes the ­phase), thus necessitating the empirical study of a series of seven alloys with varying aluminium contents

  6. Arsenate and Chromate Retention Mechanisms on Goethite. 1.

    E-Print Network [OSTI]

    Sparks, Donald L.

    Research Arsenate and Chromate Retention Mechanisms on Goethite. 1. Surface Structure S C O T T F E environment of two environmental contaminants, arsenate and chromate, on the mineral goethite (R-FeOOH). Based on the oxyanion- Fe distances, it was concluded that three different surface complexes exist on goethite for both

  7. Arsenate and Chromate Retention Mechanisms on Goethite. 2.

    E-Print Network [OSTI]

    Sparks, Donald L.

    Arsenate and Chromate Retention Mechanisms on Goethite. 2. Kinetic Evaluation Using a Pressure on goethite (R-FeOOH) were investigated using apressure-jump(p-jump)relaxationtechnique. Information provided. The adsorption/desorption of these oxyanions on goethite involved a double relaxation event. The proposed

  8. PLASTICIZER RETENTION IN PVC GEOMEMBRANES T. D. Stark1

    E-Print Network [OSTI]

    1 PLASTICIZER RETENTION IN PVC GEOMEMBRANES T. D. Stark1 , H. Choi2 , and P. W. Diebel3 1, Ontario, Canada, N1R 5T6; PH (519)623-1630; email: PDiebel@cgtower.com ABSTRACT: Plasticizers are used to make PVC flexible so it can be used as a geomembrane for containment purposes. Plasticizers can migrate

  9. Effect of a uniform electric field on soot in laminar premixed ethylene/air flames

    SciTech Connect (OSTI)

    Wang, Y.; Yao, Q. [Key Laboratory of Thermal Science and Power Engineering of Ministry of Education, Department of Thermal Engineering, Tsinghua University, 100084 Beijing (China); Nathan, G.J. [School of Mechanical Engineering, Centre for Energy Technology, The University of Adelaide, S.A. 5005 (Australia); Alwahabi, Z.T.; King, K.D.; Ho, K. [School of Chemical Engineering, Centre for Energy Technology, The University of Adelaide, S.A. 5005 (Australia)

    2010-07-15T23:59:59.000Z

    The effect of a nominally uniform electric field on the initially uniform distribution of soot has been assessed for laminar premixed ethylene/air flames from a McKenna burner. An electrophoretic influence on charged soot particles was measured through changes to the deposition rate of soot on the McKenna plug, using laser extinction (LE). Soot volume fraction was measured in situ using laser-induced incandescence (LII). Particle size and morphologies were assessed through ex situ transmission electron microscopy (TEM) using thermophoretic sampling particle diagnostics (TSPD). The results show that the majority of these soot particles are positively charged. The presence of a negatively charged plug was found to decrease the particle residence times in the flame and to influence the formation and oxidation progress. A positively charged plug has the opposite effect. The effect on soot volume fraction, particles size and morphology with electric field strength is also reported. Flame stability was also found to be affected by the presence of the electric field, with the balance of the electrophoretic force and drag force controlling the transition to unstable flame flicker. The presence of charged species generated by the flame was found to reduce the dielectric field strength to one seventh that of air. (author)

  10. Soot formation in laminar premixed methane/oxygen flames at atmospheric pressure

    SciTech Connect (OSTI)

    Xu, F.; Lin, K.C.; Faeth, G.M. [Univ. of Michigan, Ann Arbor, MI (United States). Dept. of Aerospace Engineering] [Univ. of Michigan, Ann Arbor, MI (United States). Dept. of Aerospace Engineering

    1998-10-01T23:59:59.000Z

    Flame structure and soot formation were studied within soot-containing laminar premixed methane/oxygen flames at atmospheric pressure. The following measurements were made: soot volume fractions by laser extinction, soot temperatures by multiline emission, gas temperatures (where soot was absent) by corrected fine-wire thermocouples, soot structure by thermophoretic sampling and transmission electron microscope (TEM), major gas species concentrations by sampling and gas chromatography, and gas velocities by laser velocimetry. Present measurements of gas species concentrations were in reasonably good agreement with earlier measurements due to Ramer et al. as well as predictions based on the detailed mechanisms of Frenklach and co-workers and Leung and Lindstedt; the predictions also suggest that H atom concentrations are in local thermodynamic equilibrium throughout the soot formation region. Using this information, it was found that measured soot surface growth rates could be correlated successfully by predictions based on the hydrogen-abstraction/carbon-addition (HACA) mechanisms of both Frenklach and co-workers and Colket and Hall, extending an earlier assessment of these mechanisms for premixed ethylene/air flames to conditions having larger H/C ratios and acetylene concentrations. Measured primary soot particle nucleation rates were somewhat lower than the earlier observations for laminar premixed ethylene/air flames and were significantly lower than corresponding rates in laminar diffusion flames, for reasons that still must be explained.

  11. Reduction of soot emissions by iron pentacarbonyl in isooctane diffusion flames

    SciTech Connect (OSTI)

    Kim, K.B.; Masiello, K.A.; Hahn, D.W. [Department of Mechanical and Aerospace Engineering, University of Florida, Gainesville, FL 32611 (United States)

    2008-07-15T23:59:59.000Z

    Light-scattering measurements, in situ laser-induced fluorescence, and thermophoretic sampling with transmission electron microscopy (TEM) analysis, were performed in laboratory isooctane diffusion flames seeded with 4000 ppm iron pentacarbonyl. These measurements allowed the determination of the evolution of the size, number density, and volume fraction of soot particles through the flame. Comparison to unseeded flame data provided a detailed assessment of the effects of iron addition on soot particle inception, growth, and oxidation processes. Iron was found to produce a minor soot-enhancing effect at early residence times, while subsequent soot particle growth was largely unaffected. It is concluded that primarily elemental iron is incorporated within the soot particles during particle inception and growth. However, iron addition was found to enhance the rate of soot oxidation during the soot burnout regime, yielding a two-thirds reduction in overall soot emissions. In situ spectroscopic measurements probed the transient nature of elemental iron throughout the flame, revealing significant loss of elemental iron, presumably to iron oxides, with increasing flame residence, suggesting catalysis of soot oxidation via iron oxide species. (author)

  12. Soot suppression by ferrocene in laminar ethylene/air nonpremixed flames

    SciTech Connect (OSTI)

    Zhang, J.; Megaridis, C.M. [Univ. of Illinois, Chicago, IL (United States). Dept. of Mechanical Engineering] [Univ. of Illinois, Chicago, IL (United States). Dept. of Mechanical Engineering

    1996-06-01T23:59:59.000Z

    An experimental investigation is presented on the origin of the soot suppressing role of ferrocene additive in laminar, coannular, ethylene/air nonpremixed flames. The conditions examined involve laminar flames operating above and below their smoke point. In-flame diagnostics are employed to discern the interaction between the soot matrix and additive combustion products. The data presented in a previous study, as produced by thermophoretic sampling, transmission electron microscopy and high-resolution microanalysis techniques, are supplemented by soot volume fraction, temperature, and soot primary size measurements to unravel the mechanisms through which ferrocene combustion products influence soot formation processes. Furthermore, Z-contrast scanning/transmission electron microscopy is used to examine the over-fire aerosol and, in turn, provide insight on the fine-scale dispersion of iron fragments within the carbonaceous soot matrix. It is shown that ferrocene seeding of the fuel stream accelerates the particular inception mechanisms, but does not influence soot loadings when soot growth is dominant. Ferrocene is also found to enhance soot oxidation rates near the flame terminus. It is concluded that the fine-scale incorporation of iron compounds within the soot matrix is a primary factor for the soot suppressing role of ferrocene in nonpremixed flames.

  13. In situ flame chemistry tracing by imaging photoelectron photoion coincidence spectroscopy

    SciTech Connect (OSTI)

    Oßwald, P.; Köhler, M. [German Aerospace Center (DLR) – Institute of Combustion Technology, Stuttgart 70569 (Germany)] [German Aerospace Center (DLR) – Institute of Combustion Technology, Stuttgart 70569 (Germany); Hemberger, P.; Bodi, A.; Gerber, T. [Molecular Dynamics Group, Paul Scherrer Institut, CH-5232 Villigen (Switzerland)] [Molecular Dynamics Group, Paul Scherrer Institut, CH-5232 Villigen (Switzerland); Bierkandt, T.; Akyildiz, E.; Kasper, T., E-mail: tina.kasper@uni-due.de [Mass Spectrometry in Reactive Flows - Thermodynamics (IVG), University of Duisburg-Essen, Duisburg (Germany)

    2014-02-15T23:59:59.000Z

    Adaptation of a low-pressure flat flame burner with a flame-sampling interface to the imaging photoelectron photoion coincidence spectrometer (iPEPICO) of the VUV beamline at the Swiss Light Source is presented. The combination of molecular-beam mass spectrometry and iPEPICO provides a new powerful analytical tool for the detailed investigation of reaction networks in flames. First results demonstrate the applicability of the new instrument to comprehensive flame diagnostics and the potentially high impact for reaction mechanism development for conventional and alternative fuels. Isomer specific identification of stable and radical flame species is demonstrated with unrivaled precision. Radical detection and identification is achieved for the initial H-abstraction products of fuel molecules as well as for the reaction controlling H, O, and OH radicals. Furthermore, quantitative evaluation of changing species concentrations during the combustion process and the applicability of respective results for kinetic model validation are demonstrated. Utilization of mass-selected threshold photoelectron spectra is shown to ensure precise signal assignment and highly reliable spatial profiles.

  14. Experimental and modeling investigation of aromatic and polycyclic aromatic hydrocarbon formation in a premixed ethylene flame

    SciTech Connect (OSTI)

    Castaldi, M.J.; Marinov, N.M.; Melius, C.F. [and others

    1996-02-01T23:59:59.000Z

    Experimental and detailed chemical kinetic modeling has been performed to investigate aromatic and polyaromatic hydrocarbon formation pathways in a rich, sooting, ethylene-oxygen-argon premixed flame. An atmospheric pressure, laminar flat flame operated at an equivalence ratio of 2.5 was used to acquire experimental data for model validation. Gas composition analysis was conducted by an on-line gas chromatograph/mass spectrometer (GC/MS) technique. Measurements were made in the flame and post-flame zone for a number of low molecular weight species, aliphatics, aromatics and polycyclic aromatic hydrocarbons (PAHs) ranging from two to five-aromatic fused rings. The modeling results show the key reaction sequences leading to aromatic and polycyclic aromatic hydrocarbon growth involve the combination of resonantly stabilized radicals. In particular, propargyl and 1-methylallenyl combination reactions lead to benzene and methyl substituted benzene formation, while polycyclic aromatics are formed from cyclopentadienyl radicals and fused rings that have a shared C{sub 5} side structure. Naphthalene production through the reaction step of cyclopentadienyl self-combination and phenanthrene formation from indenyl and cyclopentadienyl combination were shown to be important in the flame modeling study. The removal of phenyl by O{sub 2} leading to cyclopentadienyl formation is expected to play a pivotal role in the PAH or soot precursor growth process under fuel-rich oxidation conditions.

  15. Flame acceleration and DDT in channels with obstacles: Effect of obstacle spacing

    SciTech Connect (OSTI)

    Gamezo, Vadim N.; Oran, Elaine S. [Laboratory for Computational Physics and Fluid Dynamics, Naval Research Laboratory, Washington, DC 20375 (United States); Ogawa, Takanobu [Department of Mechanical Engineering, Seikei University, Kichijoji-Kitamachi, Musashino-shi, Tokyo, 180-8633 (Japan)

    2008-10-15T23:59:59.000Z

    We study flame acceleration and deflagration-to-detonation transition (DDT) in obstructed channels using 2D reactive Navier-Stokes numerical simulations. The energy release rate for the stoichiometric hydrogen-air mixture is modeled by one-step Arrhenius kinetics. Computations performed for channels with symmetrical and staggered obstacle configurations show two main effects of obstacle spacing S. First, more obstacles per unit length create more perturbations that increase the flame surface area more quickly, and therefore the flame speed grows faster. Second, DDT occurs more easily when the obstacle spacing is large enough for Mach stems to form between obstacles. These two effects are responsible for three different regimes of flame acceleration and DDT observed in simulations: (1) Detonation is ignited when a Mach stem formed by the diffracting shock reflecting from the side wall collides with an obstacle, (2) Mach stems do not form, and the detonation is not ignited, and (3) Mach stems do not form, but the leading shock becomes strong enough to ignite a detonation by direct collision with the top of an obstacle. Regime 3 is observed for small S and involves multiple isolated detonations that appear between obstacles and play a key role in final stages of flame and shock acceleration. For Regime 1 and staggered obstacle configurations, we observe resonance phenomena that significantly reduce the DDT time when S/2 is comparable to the channel width. Effects of imposed symmetry and stochasticity on DDT phenomena are also considered. (author)

  16. Aromatics oxidation and soot formation in flames. Progress report, August 15, 1990--August 14, 1993

    SciTech Connect (OSTI)

    Howard, J.B.; Pope, C.J.; Shandross, R.A.; Yadav, T.

    1993-04-01T23:59:59.000Z

    This project is concerned with the kinetics and mechanisms of aromatics oxidation and soot and fullerenes formation in flames. The scope includes detailed measurements of profiles of stable and radical species concentrations in low-pressure one-dimensional premixed flames. Intermediate species identifications and mole fractions, fluxes, and net reaction rates calculated from the measured profiles are used to test postulated reaction mechanisms. Particular objectives are to identify, and to confirm or determine rate constants for, the main benzene oxidation reactions in flames, and to characterize soot and fullerenes and their formation mechanisms and kinetics. Stable and radical species profiles in the aromatics oxidation study are measured using molecular beam sampling with on-line mass spectrometry. The rate of soot formation measured by conventional optical techniques is found to support the hypotheses that particle inception occurs through reactive coagulation of high molecular weight PAH in competition with destruction by OHattack, and that the subsequent growth of the soot mass occurs through addition reactions of PAH and C{sub 2}H{sub 2} with the soot particles. During the first year of this reporting period, fullerenes C{sub 60} and C{sub 70} in substantial quantities were found in the flames being studied. The fullerenes were recovered, purified and spectroscopically identified. The yields of C{sub 60} and C{sub 70} were then determined over ranges of conditions in low-pressure premixed flames of benzene and oxygen.

  17. Soil Water Retention Measurements Using a Combined Tensiometer-Coiled Time Domain Reflectometry Probe

    E-Print Network [OSTI]

    Wildenschild, Dorthe

    Soil Water Retention Measurements Using a Combined Tensiometer-Coiled Time Domain Reflectometry al., 1975; Arya et al.,that can be used to determine soil water retention curves in both 1975; Royer of a standard tensiometer. The combined tensiometer-coiled TDR probe was con- of soil water retention curves

  18. Offering Sign-On and Retention Bonus Payments to Faculty March 12, 2012

    E-Print Network [OSTI]

    Acton, Scott

    Offering Sign-On and Retention Bonus Payments to Faculty March 12, 2012 page 1 Policy on Offering Sign-On and Retention Bonus Payments to Faculty Date: March 12, 2012 Policy ID: 1.600 Status: Final for Policy: This policy was developed to clarify the approval required to offer a sign ­on or retention bonus

  19. Epistemological resources 1 Running Head: EPISTEMOLOGICAL RESOURCES

    E-Print Network [OSTI]

    Elby, Andy

    Epistemological resources 1 Running Head: EPISTEMOLOGICAL RESOURCES Epistemological resources University Maryland, College Park Trisha Kagey Montgomery County Public Schools #12;Epistemological resources are better understood as made up of finer-grained cognitive resources whose activation depends sensitively

  20. SPATIAL TRANSFORMATIONS 1 Running head: Spatial transformations

    E-Print Network [OSTI]

    Zacks, Jeffrey M.

    SPATIAL TRANSFORMATIONS 1 Running head: Spatial transformations Multiple Systems for Spatial Imagery: Transformations of Objects and Bodies Jeffrey M. Zacks* and Barbara Tversky * Washington COGNITION & COMPUTATION #12;SPATIAL TRANSFORMATIONS 2 Abstract Problem-solving often requires imagining

  1. Vacuum compatible miniature CCD camera head

    DOE Patents [OSTI]

    Conder, Alan D. (Tracy, CA)

    2000-01-01T23:59:59.000Z

    A charge-coupled device (CCD) camera head which can replace film for digital imaging of visible light, ultraviolet radiation, and soft to penetrating x-rays, such as within a target chamber where laser produced plasmas are studied. The camera head is small, capable of operating both in and out of a vacuum environment, and is versatile. The CCD camera head uses PC boards with an internal heat sink connected to the chassis for heat dissipation, which allows for close(0.04" for example) stacking of the PC boards. Integration of this CCD camera head into existing instrumentation provides a substantial enhancement of diagnostic capabilities for studying high energy density plasmas, for a variety of military industrial, and medical imaging applications.

  2. Head & base production optimization : setup time reduction

    E-Print Network [OSTI]

    Guo, Haiqing

    2009-01-01T23:59:59.000Z

    At Schlumberger, the make-to-order strategy and number of Head & Base product types (about 1000 types) requires a flexible manufacturing system in which the machine setup is frequent. However, the lengthy CNC machine setup ...

  3. Facilitating Forgiveness 1 Running head: FACILITATING FORGIVENESS

    E-Print Network [OSTI]

    Ahmad, Sajjad

    Facilitating Forgiveness 1 Running head: FACILITATING FORGIVENESS FACILITATING FORGIVENESS. Infidelity causes significant damage for couples and results in a loss of trust and relationship stability undermine a relationship's stability and security, resulting in confusion, loss of trust, and tremendous

  4. On Flame-Wall Thermal-Coupling in Micro Combustors Yong Fan, Yuji Suzuki, and Nobuhide Kasagi

    E-Print Network [OSTI]

    Kasagi, Nobuhide

    On Flame-Wall Thermal-Coupling in Micro Combustors Yong Fan, Yuji Suzuki, and Nobuhide Kasagi Department of Mechanical Engineering, The University of Tokyo, Japan Keywords: Micro combustor, Premixed of premixed CH4/Air flame propagation and quenching in three quartz combustors with chamber depth of 0.7 mm, 1

  5. Oscillating Flame in Wall Temperature-Controlled Ultra-Thin Quartz Channels Yong FAN, Yuji SUZUKI and Nobuhide Kasagi

    E-Print Network [OSTI]

    Kasagi, Nobuhide

    associated with combustion in micro combustors lead to the finding that wall thermal and chemical conditions shows that the flame is quenched by wall heat loss. Key Words: Micro combustor, Oscillating flame, Phase of intense investigations on micro combustors. On the other hand, studies on new phenomena and physics

  6. Mapping of soot particles in a weakly sooting diffusion flame by aerosol techniques

    SciTech Connect (OSTI)

    Hepp, H.; Siegmann, K. [Federal Inst. of Tech., Zuerich (Switzerland). Lab. for Solid State Physics] [Federal Inst. of Tech., Zuerich (Switzerland). Lab. for Solid State Physics

    1998-10-01T23:59:59.000Z

    The evolution of detailed particle size distributions has been measured along the centerline of an axisymmetric diffusion flame of CH{sub 4} + Ar burning in air at 1 atm. Soot particles with mean diameters of 3--18 nm were observed. Changes in the size distribution exhibited zones where either nucleation, coagulation, or destruction of soot particles dominated. These highly sensitive measurements were made by microprobe sampling with an immediate dilution of 1:400, to quench the aerosol, and by subsequent application of aerosol measurement techniques. In parallel, the yield of photoemitted electrons from size-selected particles was determined. The yield shows a characteristic dependence on location in the flame, indicating changes of the particle`s surface. Multiphoton, time-of-flight mass spectrometry was used to investigate the correlation between polycyclic aromatic hydrocarbons in the flame and enhanced photoemission yield from the soot particles.

  7. Kilohertz PIV/PLMS of low-gravity turbulent flames in a drop tower I.G. Boxx, C.A. Idicheria, N.T. Clemens(1)

    E-Print Network [OSTI]

    Clemens, Noel T.

    -flame in a crossflow (JFICF). The system developed represents a major advance in the state of the art of microgravity to examine a hydrogen jet-flame in a crossflow (momentum flux ratio of 7, Re = 900) under normal and low. INTRODUCTION The turbulent jet-flame in a crossflow (JFICF) is a flowfield of theoretical and applied

  8. Electro-optic voltage sensor head

    DOE Patents [OSTI]

    Crawford, Thomas M. (Idaho Falls, ID); Davidson, James R. (Idaho Falls, ID); Woods, Gregory K. (Cornelius, OR)

    1999-01-01T23:59:59.000Z

    The invention is an electro-optic voltage sensor head designed for integration with existing types of high voltage transmission and distribution apparatus. The sensor head contains a transducer, which comprises a transducing material in which the Pockels electro-optic effect is observed. In the practice of the invention at least one beam of electromagnetic radiation is routed into the transducing material of the transducer in the sensor head. The beam undergoes an electro-optic effect in the sensor head when the transducing material is subjected to an E-field. The electro-optic effect is observed as a differential phase a shift, also called differential phase modulation, of the beam components in orthogonal planes of the electromagnetic radiation. In the preferred embodiment the beam is routed through the transducer along an initial axis and then reflected by a retro-reflector back substantially parallel to the initial axis, making a double pass through the transducer for increased measurement sensitivity. The preferred embodiment of the sensor head also includes a polarization state rotator and at least one beam splitter for orienting the beam along major and minor axes and for splitting the beam components into two signals which are independent converse amplitude-modulated signals carrying E-field magnitude and hence voltage information from the sensor head by way of optic fibers.

  9. Electro-optic voltage sensor head

    DOE Patents [OSTI]

    Crawford, T.M.; Davidson, J.R.; Woods, G.K.

    1999-08-17T23:59:59.000Z

    The invention is an electro-optic voltage sensor head designed for integration with existing types of high voltage transmission and distribution apparatus. The sensor head contains a transducer, which comprises a transducing material in which the Pockels electro-optic effect is observed. In the practice of the invention at least one beam of electromagnetic radiation is routed into the transducing material of the transducer in the sensor head. The beam undergoes an electro-optic effect in the sensor head when the transducing material is subjected to an E-field. The electro-optic effect is observed as a differential phase a shift, also called differential phase modulation, of the beam components in orthogonal planes of the electromagnetic radiation. In the preferred embodiment the beam is routed through the transducer along an initial axis and then reflected by a retro-reflector back substantially parallel to the initial axis, making a double pass through the transducer for increased measurement sensitivity. The preferred embodiment of the sensor head also includes a polarization state rotator and at least one beam splitter for orienting the beam along major and minor axes and for splitting the beam components into two signals which are independent converse amplitude-modulated signals carrying E-field magnitude and hence voltage information from the sensor head by way of optic fibers. 6 figs.

  10. Enhancement of a laminar premixed methane/oxygen/nitrogen flame speed using femtosecond-laser-induced plasma

    SciTech Connect (OSTI)

    Yu Xin; Peng Jiangbo; Yi Yachao; Zhao Yongpeng; Chen Deying; Yu Junhua [National Key Laboratory of Science and Technology on Tunable Laser, Harbin Institute of Technology, Harbin 150080 (China); Institute of Opto-electronics, Harbin Institute of Technology, Harbin 150080 (China); Yang Peng; Sun Rui [Institute of Combustion Engineering, Harbin Institute of Technology, Harbin 150001 (China)

    2010-07-05T23:59:59.000Z

    We first investigate the effects of femtosecond-laser-induced plasma on the flame speed of a laminar premixed methane/oxygen/nitrogen flame with a wide range of the equivalence ratios (0.8-1.05) at atmospheric pressure. It is experimentally found that the flame speed increases 20.5% at equivalence ratios 1.05. The self-emission spectra from the flame and the plasma are studied and an efficient production of active radicals under the action of femtosecond (fs)-laser pulses has been observed. Based on the experimental data obtained, the presence of oxygen atom and hydrocarbon radicals is suggested to be a key factor enhancing flame speed.

  11. Soot formation and temperature structure in small methane-oxygen diffusion flames at subcritical and supercritical pressures

    SciTech Connect (OSTI)

    Joo, Hyun I.; Guelder, Oemer L. [University of Toronto, Institute for Aerospace Studies, 4925 Dufferin Street, Toronto, Ont. (Canada)

    2010-06-15T23:59:59.000Z

    An experimental study was conducted to examine the characteristics of laminar methane-oxygen diffusion flames up to 100 atmospheres. The influence of pressure on soot formation and on the structure of the temperature field was investigated over the pressure range of 10-90 atmospheres in a high-pressure combustion chamber using a non-intrusive, line-of-sight spectral soot emission diagnostic technique. Two distinct zones characterized the appearance of a methane and pure oxygen diffusion flame: an inner luminous zone similar to the methane-air diffusion flames, and an outer diffusion flame zone which is mostly blue. The flame height, marked by the visible soot radiation emission, was reduced by over 50% over the pressure range of 10-100 atmospheres. Between 10 and 40 atmospheres, the soot levels increased with increasing pressure; however, above 40 atmospheres the soot concentrations decreased with increasing pressure. (author)

  12. Mitigation of thermoacoustic instability utilizing steady air injection near the flame anchoring zone

    SciTech Connect (OSTI)

    Murat Altay, H.; Hudgins, Duane E.; Speth, Raymond L.; Annaswamy, Anuradha M.; Ghoniem, Ahmed F. [Massachusetts Institute of Technology, Department of Mechanical Engineering, Cambridge, MA 02139 (United States)

    2010-04-15T23:59:59.000Z

    The objective of this work is to investigate the effectiveness of steady air injection near the flame anchoring zone in suppressing thermoacoustic instabilities driven by flame-vortex interaction mechanism. We perform a systematic experimental study which involves using two different configurations of air injection in an atmospheric pressure backward-facing step combustor. The first configuration utilizes a row of micro-diameter holes allowing for air injection in the cross-stream direction just upstream of the step. The second configuration utilizes an array of micro-diameter holes located on the face of the step, allowing for air injection in the streamwise direction. The effects of each of these configurations are analyzed to determine which one is more effective in suppressing thermoacoustic instabilities at different operating conditions. The tests are conducted while varying the equivalence ratio and the inlet temperature. The secondary air temperature is always the same as the inlet temperature. We used pure propane or propane/hydrogen mixtures as fuels. Combustion dynamics are explored through simultaneous pressure and heat release-rate measurements, and high-speed video images. When the equivalence ratio of the reactant mixture is high, it causes the flame to flashback towards the inlet channel. When air is injected in the cross-stream direction, the flame anchors slightly upstream of the step, which suppresses the instability. When air is injected in the streamwise direction near the edge of step, thermoacoustic instability could be eliminated at an optimum secondary air flow rate, which depends on the operating conditions. When effective, the streamwise air injection prevents the shedding of an unsteady vortex, thus eliminating the flame-vortex interaction mechanism and resulting in a compact, stable flame to form near the step. (author)

  13. Turbulent flame speeds in ducts and the deflagration/detonation transition

    SciTech Connect (OSTI)

    Bradley, D.; Lawes, M.; Liu, Kexin [School of Mechanical Engineering, University of Leeds, Leeds LS2 9JT (United Kingdom)

    2008-07-15T23:59:59.000Z

    A methodology is proposed for determining whether a deflagration-to-detonation transition (DDT) might occur for flame propagation along a duct with baffles, closed at the ignition end. A flammable mixture can attain a maximum turbulent burning velocity. If this is sufficiently high, a strong shock is formed ahead of the flame. It is assumed that this maximum burning velocity is soon attained and on the basis of previous studies, this value can be obtained for the given conditions. The increase in temperature and pressure of the reactants, due to the shock, further increases the maximum turbulent burning velocity. The gas velocity ahead of the flame is linked to one-dimensional shock wave equations in a numerical analysis. The predicted duct flame speeds with the appropriate maximum turbulent burning velocities are in good agreement with those measured in the slow and fast flame regimes of a range of CH{sub 4}-air and H{sub 2}-air mixtures. DDTs are possible if autoignition of the reactants occurs in the time available, and if the projected flame speed approaches the Chapman-Jouguet velocity at the same temperature and pressure. Prediction of the first condition requires values of the autoignition delay time of the mixture at the shocked temperatures and pressures. Prediction of the second requires values of the laminar burning velocity and Markstein number. With the appropriate values of these parameters, it is shown numerically that there is no DDT with CH{sub 4}-air. With H{sub 2}-air, the onset of DDT occurs close to the values of equivalence ratio at which it has been observed experimentally. The effects of different duct sizes also are predicted, although details of the DDT cannot be predicted. Extension of the study to a wider range of fuels requires more data on their laminar burning velocities and Markstein numbers at higher temperatures and pressures and on autoignition delay times at lower temperatures and pressures. (author)

  14. Probe measurements and numerical model predictions of evolving size distributions in premixed flames

    SciTech Connect (OSTI)

    De Filippo, A.; Sgro, L.A.; Lanzuolo, G.; D'Alessio, A. [Dipartimento di Ingegneria Chimica, Universita degli Studi di Napoli Federico II, Piazzale Tecchio 80, 80125 Napoli (Italy)

    2009-09-15T23:59:59.000Z

    Particle size distributions (PSDs), measured with a dilution probe and a Differential Mobility Analyzer (DMA), and numerical predictions of these PSDs, based on a model that includes only coagulation or alternatively inception and coagulation, are compared to investigate particle growth processes and possible sampling artifacts in the post-flame region of a C/O = 0.65 premixed laminar ethylene-air flame. Inputs to the numerical model are the PSD measured early in the flame (the initial condition for the aerosol population) and the temperature profile measured along the flame's axial centerline. The measured PSDs are initially unimodal, with a modal mobility diameter of 2.2 nm, and become bimodal later in the post-flame region. The smaller mode is best predicted with a size-dependent coagulation model, which allows some fraction of the smallest particles to escape collisions without resulting in coalescence or coagulation through the size-dependent coagulation efficiency ({gamma}{sub SD}). Instead, when {gamma} = 1 and the coagulation rate is equal to the collision rate for all particles regardless of their size, the coagulation model significantly under predicts the number concentration of both modes and over predicts the size of the largest particles in the distribution compared to the measured size distributions at various heights above the burner. The coagulation ({gamma}{sub SD}) model alone is unable to reproduce well the larger particle mode (mode II). Combining persistent nucleation with size-dependent coagulation brings the predicted PSDs to within experimental error of the measurements, which seems to suggest that surface growth processes are relatively insignificant in these flames. Shifting measured PSDs a few mm closer to the burner surface, generally adopted to correct for probe perturbations, does not produce a better matching between the experimental and the numerical results. (author)

  15. Increasing the chemical content of turbulent flame models through the use of parallel computing

    SciTech Connect (OSTI)

    Yam, C.G.; Armstrong, R.; Koszykowski, M.L. [Sandia National Labs., Livermore, CA (United States); Chen, J.Y. [California Univ., Berkeley, CA (United States); Bui-Pham, M.N. [Lawrence Berkeley National Lab., CA (United States)

    1996-10-01T23:59:59.000Z

    This report outlines the effort to model a time-dependent, 2- dimensional, turbulent, nonpremixed flame with full chemistry with the aid of parallel computing tools. In this study, the mixing process and the chemical reactions occurring in the flow field are described in terms of the single-point probability density function (PDF), while the turbulent viscosity is determined by the standard kappa-epsilon model. The initial problem solved is a H[sub 2]/Air flame whose chemistry is described by 28 elementary reactions involving 9 chemical species.

  16. Method for Producing Flame Retardant Porous Products and Products Produced Thereby

    DOE Patents [OSTI]

    Salyer, Ival O. (Dayton, OH)

    1998-08-04T23:59:59.000Z

    A method for fire retarding porous products used for thermal energy storage and products produced thereby is provided. The method includes treating the surface of the phase change material-containing porous products with a urea fire-retarding agent. Upon exposure to a flame, the urea forms an adduct with the phase change material which will not sustain combustion (is self-extinguishing) in air. No halogens or metal oxides are contained in the fire retardant, so no potentially noxious halide smoke or fumes are emitted if the product is continuously exposed to a flame.

  17. Method for producing flame retardant porous products and products produced thereby

    DOE Patents [OSTI]

    Salyer, I.O.

    1998-08-04T23:59:59.000Z

    A method for fire retarding porous products used for thermal energy storage and products produced thereby is provided. The method includes treating the surface of the phase change material-containing porous products with a urea fire-retarding agent. Upon exposure to a flame, the urea forms an adduct with the phase change material which will not sustain combustion (is self-extinguishing) in air. No halogens or metal oxides are contained in the fire retardant, so no potentially noxious halide smoke or fumes are emitted if the product is continuously exposed to a flame. 1 fig.

  18. Method for producing flame retardant porous products and products produced thereby

    DOE Patents [OSTI]

    Salyer, Ival O. (Dayton, OH)

    1998-08-04T23:59:59.000Z

    A method for fire retarding porous products used for thermal energy storage and products produced thereby is provided. The method includes treating the surface of the phase change material-containing porous products with a urea fire-retarding agent. Upon exposure to a flame, the urea forms an adduct with the phase change material which will not sustain combustion (is self-extinguishing) in air. No halogens or metal oxides are contained in the fire retardant, so no potentially noxious halide smoke or fumes are emitted if the product is continuously exposed to a flame.

  19. Investigation on Flame Characteristics and Burner Operability Issues of Oxy-Fuel Combustion

    SciTech Connect (OSTI)

    Choudhuri, Ahsan

    2013-05-30T23:59:59.000Z

    Oxy-fuel combustion has been used previously in a wide range of industrial applications. Oxy- combustion is carried out by burning a hydrocarbon fuel with oxygen instead of air. Flames burning in this configuration achieve higher flame temperatures which present opportunities for significant efficiency improvements and direct capture of CO{sub 2} from the exhaust stream. In an effort to better understand and characterize the fundamental flame characteristics of oxy-fuel combustion this research presents the experimental measurements of flame stability of various oxyfuel flames. Effects of H{sub 2} concentration, fuel composition, exhaust gas recirculation ratio, firing inputs, and burner diameters on the flame stability of these fuels are discussed. Effects of exhaust gas recirculation i.e. CO{sub 2} and H{sub 2}O (steam) acting as diluents on burner operability are also presented. The roles of firing input on flame stability are then analyzed. For this study it was observed that many oxy-flames did not stabilize without exhaust gas recirculation due to their higher burning velocities. In addition, the stability regime of all compositions was observed to decrease as the burner diameter increased. A flashback model is also presented, using the critical velocity gradient g{sub F}) values for CH{sub 4}-O{sub 2}-CO{sub 2} flames. The scaling relation (𝐠{sub F} = 𝐜 𝐒{sub 𝐋}{sup 2}/𝛂) for different burner diameters was obtained for various diameter burners. The report shows that results correlated linearly with a scaling value of c =0.0174. The second part of the study focuses on the experimental measurements of the flow field characteristics of premixed CH{sub 4}/21%O{sub 2}/79%N{sub 2} and CH{sub 4}/38%O{sub 2}/72%CO{sub 2} mixtures at constant firing input of 7.5 kW, constant, equivalence ratio of 0.8, constant swirl number of 0.92 and constant Reynolds Numbers. These measurements were taken in a swirl stabilized combustor at atmospheric pressure. The flow field visualization using Particle Imaging Velocimetry (PIV) technique is implemented to make a better understanding of the turbulence characteristics of CH{sub 4}/air and CH{sub 4}/38%O{sub 2}/72%CO{sub 2} combustion. The velocity fluctuations, turbulence intensities and local propagation velocities along the combustion chamber have been determined. The turbulent intensities increase as we move away from the combustor axis. CH{sub 4}-38%O{sub 2}-72%CO{sub 2} flames have low radial velocity and turbulent intensity distributions at different axial distances when compared with CH{sub 4}-Air flames.

  20. Sulfate Retention and Segregation in Simulated Radioactive Waste Borosilicate Glasses

    SciTech Connect (OSTI)

    Li, Hong; Hrma, Pavel R.; Vienna, John D.

    2000-04-19T23:59:59.000Z

    Sulfate segregation from processing radioactive waste glasses causes an acceleration of the melter refractory corrosion and partitioning of radionuclides in the segregated layer. A sulfate retention (SR)-composition relationship has been established for various simulated high-level and low-activity waste glass compositions in terms of the relative non-bridging oxygen (NBO) concentration in the melt. Phosphate was found to significantly increase sulfate retention. However, the correlation between SR and NBO could not explain the sulfate segregation tendency. For instance, glasses with a higher ratio of boron to sodium suppress sulfate segreation in the melt in which SR is expected to be lower. As sulfate segregation is a kinetic process, occurring in the batch to glass conversion process, initial reactions of the batch materials are considered to have stronger effects on the sulfate segregation tendency, pointing out the need to study the impact of batch materials on sulfate segregation.

  1. Average Soil Water Retention Curves Measured by Neutron Radiography

    SciTech Connect (OSTI)

    Cheng, Chu-Lin [ORNL; Perfect, Edmund [University of Tennessee, Knoxville (UTK); Kang, Misun [ORNL; Voisin, Sophie [ORNL; Bilheux, Hassina Z [ORNL; Horita, Juske [Texas Tech University (TTU); Hussey, Dan [NIST Center for Neutron Research (NCRN), Gaithersburg, MD

    2011-01-01T23:59:59.000Z

    Water retention curves are essential for understanding the hydrologic behavior of partially-saturated porous media and modeling flow transport processes within the vadose zone. In this paper we report direct measurements of the main drying and wetting branches of the average water retention function obtained using 2-dimensional neutron radiography. Flint sand columns were saturated with water and then drained under quasi-equilibrium conditions using a hanging water column setup. Digital images (2048 x 2048 pixels) of the transmitted flux of neutrons were acquired at each imposed matric potential (~10-15 matric potential values per experiment) at the NCNR BT-2 neutron imaging beam line. Volumetric water contents were calculated on a pixel by pixel basis using Beer-Lambert s law after taking into account beam hardening and geometric corrections. To remove scattering effects at high water contents the volumetric water contents were normalized (to give relative saturations) by dividing the drying and wetting sequences of images by the images obtained at saturation and satiation, respectively. The resulting pixel values were then averaged and combined with information on the imposed basal matric potentials to give average water retention curves. The average relative saturations obtained by neutron radiography showed an approximate one-to-one relationship with the average values measured volumetrically using the hanging water column setup. There were no significant differences (at p < 0.05) between the parameters of the van Genuchten equation fitted to the average neutron radiography data and those estimated from replicated hanging water column data. Our results indicate that neutron imaging is a very effective tool for quantifying the average water retention curve.

  2. Training and Certification of Lock Operators IMTS Heads-up Paper Heads-up Paper

    E-Print Network [OSTI]

    US Army Corps of Engineers

    Training and Certification of Lock Operators IMTS Heads-up Paper 1 Heads-up Paper Training called "Training and Certification of Lock and Dam Operators." Interested individuals can send ideas of the Training and Certification program. Examples of what will be in those draft documents are as follows

  3. Most Workers Who Suffer Head Injuries- Were Not Wearing Head Protection

    Broader source: Energy.gov [DOE]

    A survey by the U.S. Department of Labor’s Bureau of Labor Statistics (BLS) of accidents and injuries noted that most workers who suffered impact injuries to the head were not wearing head protection. In addition, the same survey showed that the majority of workers were injured while performing their normal jobs at their regular worksites.

  4. Multi-timescale modeling of ignition and flame regimes of n-heptane-air mixtures near spark assisted homogeneous charge compression ignition conditions

    SciTech Connect (OSTI)

    Ju, Yiguang; Sun, Wenting; Burke, M. P.; Gou, Xiaolong; Chen, Zheng

    2011-01-01T23:59:59.000Z

    The flame regimes of ignition and flame propagation as well as transitions between different flame regimes of n-heptane-air mixtures in a one-dimensional, cylindrical, spark assisted homogeneously charged compression ignition (HCCI) reactor are numerically modeled using a multi-timescale method with reduced kinetic mechanism. It is found that the initial mixture temperature and pressure have a dramatic impact on flame dynamics. Depending on the initial temperature gradient, there exist at least six different combustion regimes, an initial single flame front propagation regime, a coupled low temperature and high temperature double-flame regime, a decoupled low temperature and high temperature double-flame regime, a low temperature ignition regime, a single high temperature flame regime, and a hot ignition regime. The results show that the low temperature and high temperature flames have distinct kinetic and transport properties as well as flame speeds, and are strongly influenced by the low temperature chemistry. The pressure and heat release rates are affected by the appearance of different flame regimes and the transitions between them. Furthermore, it is found that the critical temperature gradient for ignition and acoustic wave coupling becomes singular at the negative temperature coefficient (NTC) region. The results show that both the NTC effect and the acoustic wave propagation in a closed reactor have a dramatic impact on the ignition front and acoustic interaction.

  5. A Decentralized Public Key Infrastructure with Identity Retention Conner Fromknecht (conner@mit.edu), Dragos Velicanu (velicanu@mit.edu),

    E-Print Network [OSTI]

    provided by cryptocurrencies such as Bitcoin and Namecoin to build a PKI that ensures identity retention

  6. Flame Stability Analysis in an Ultra Compact Combustor Using Large-Eddy Simulation

    E-Print Network [OSTI]

    Raman, Venkat

    Flame Stability Analysis in an Ultra Compact Combustor Using Large-Eddy Simulation C. Lietz , C Base, Ohio 45433 Large eddy simulation (LES) of an experimental ultra-compact combustor (UCC as a conven- tional combustor path. In order to reduce the penalty due to increased weight of these burners

  7. Combustion and Flame 145 (2006) 128144 www.elsevier.com/locate/combustflame

    E-Print Network [OSTI]

    Im, Hong G.

    2006-01-01T23:59:59.000Z

    Combustion and Flame 145 (2006) 128­144 www.elsevier.com/locate/combustflame Direct numerical , Hong G. Im c a Reacting Flow Research Department, Combustion Research Facility, Sandia National with a view to providing better understanding and modeling of combustion processes in homogeneous charge

  8. Testing of a Hydrogen Diffusion Flame Array Injector at Gas Turbine Conditions

    SciTech Connect (OSTI)

    Weiland, Nathan T.; Sidwell, Todd G.; Strakey, Peter A.

    2013-07-03T23:59:59.000Z

    High-hydrogen gas turbines enable integration of carbon sequestration into coal-gasifying power plants, though NO{sub x} emissions are often high. This work explores nitrogen dilution of hydrogen diffusion flames to reduce thermal NO{sub x} emissions and avoid problems with premixing hydrogen at gas turbine pressures and temperatures. The burner design includes an array of high-velocity coaxial fuel and air injectors, which balances stability and ignition performance, combustor pressure drop, and flame residence time. Testing of this array injector at representative gas turbine conditions (16 atm and 1750 K firing temperature) yields 4.4 ppmv NO{sub x} at 15% O{sub 2} equivalent. NO{sub x} emissions are proportional to flame residence times, though these deviate from expected scaling due to active combustor cooling and merged flame behavior. The results demonstrate that nitrogen dilution in combination with high velocities can provide low NO{sub x} hydrogen combustion at gas turbine conditions, with significant potential for further NO{sub x} reductions via suggested design changes.

  9. Cellular burning in lean premixed turbulent hydrogen-air flames: coupling experimental and

    E-Print Network [OSTI]

    Cellular burning in lean premixed turbulent hydrogen-air flames: coupling experimental. Beckner1, M. J. Lijewski1 1 Center for Computational Science and Engineering, Lawrence Berkeley National for burning the fuel-lean mixtures of hydrogen or hydrogen-rich syngas fuels obtained from the gasification

  10. Large-eddy simulation of lean hydrogenemethane turbulent premixed flames in the methane-

    E-Print Network [OSTI]

    Gülder, �mer L.

    -based to hydrogen-based economy are still under discussion and the implementation of the hydrogen- based economy methane flame in the methane- dominated regime. Copyright ª 2014, Hydrogen Energy Publications, LLC appear to be a promising option to synergistically pave the way toward pure hydrogen- based combustion

  11. Establishing criteria for the design of a combination parallel and cross-flaming covered burner

    E-Print Network [OSTI]

    Stark, Christopher Charles

    2003-01-01T23:59:59.000Z

    it with the two open flame practices. This evaluation was performed by moving the burners over an area that would monitor the temperatures at specified heights and locations. Temperatures were measured using thermocouples placed at heights 7-mm, 150-mm, and 300...

  12. Electric fields effect on liftoff and blowoff of nonpremixed laminar jet flames in a coflow

    SciTech Connect (OSTI)

    Kim, M.K.; Ryu, S.K.; Won, S.H. [School of Mechanical and Aerospace Engineering, Seoul National University, Seoul 151-742 (Korea); Chung, S.H. [Clean Combustion Research Center, King Abdullah University of Science and Technology, Thuwal (Saudi Arabia)

    2010-01-15T23:59:59.000Z

    The stabilization characteristics of liftoff and blowoff in nonpremixed laminar jet flames in a coflow have been investigated experimentally for propane fuel by applying AC and DC electric fields to the fuel nozzle with a single-electrode configuration. The liftoff and blowoff velocities have been measured by varying the applied voltage and frequency of AC and the voltage and the polarity of DC. The result showed that the AC electric fields extended the stabilization regime of nozzle-attached flame in terms of jet velocity. As the applied AC voltage increased, the nozzle-attached flame was maintained even over the blowout velocity without having electric fields. In such a case, a blowoff occurred directly without experiencing a lifted flame. While for the DC cases, the influence on liftoff was minimal. There existed three different regimes depending on the applied AC voltage. In the low voltage regime, the nozzle-detachment velocity of either liftoff or blowoff increased linearly with the applied voltage, while nonlinearly with the AC frequency. In the intermediate voltage regime, the detachment velocity decreased with the applied voltage and reasonably independent of the AC frequency. At the high voltage regime, the detachment was significantly influenced by the generation of discharges. (author)

  13. Effect of Hydrogen Addition on the Flammability Limit of Stretched Methane/Air Premixed Flames

    E-Print Network [OSTI]

    Im, Hong G.

    ], thereby enabling stable combustion at lean mixture conditions. In the case of natural gas engines, enriching the fuel with hydrogen has the proven benefits of improving the combustion stability and reducingEffect of Hydrogen Addition on the Flammability Limit of Stretched Methane/Air Premixed Flames

  14. Soot formation and temperature field structure in laminar propane-air diffusion flames at elevated pressures

    SciTech Connect (OSTI)

    Bento, Decio S.; Guelder, OEmer L. [Institute for Aerospace Studies, University of Toronto, 4925 Dufferin Street, Toronto, ON M3H 5T6 (Canada); Thomson, Kevin A. [National Research Council, ICPET Combustion Technology, 1200 Montreal Road M-9, Ontario K1A 0R6 (Canada)

    2006-06-15T23:59:59.000Z

    The effect of pressure on soot formation and the structure of the temperature field was studied in coflow propane-air laminar diffusion flames over the pressure range of 0.1 to 0.73 MPa in a high-pressure combustion chamber. The fuel flow rate was selected so that the soot was completely oxidized within the visible flame and the flame was stable at all pressures. Spectral soot emission was used to measure radially resolved soot volume fraction and soot temperature as a function of pressure. Additional soot volume fraction measurements were made at selected heights using line-of-sight light attenuation. Soot concentration values from these two techniques agreed to within 30% and both methods exhibited similar trends in the spatial distribution of soot concentration. Maximum line-of-sight soot concentration along the flame centerline scaled with pressure; the pressure exponent was about 1.4 for pressures between 0.2 and 0.73 MPa. Peak carbon conversion to soot, defined as the percentage of fuel carbon content converted to soot, also followed a power-law dependence on pressure, where the pressure exponent was near to unity for pressures between 0.2 and 0.73 MPa. Soot temperature measurements indicated that the overall temperatures decreased with increasing pressure; however, the temperature gradients increased with increasing pressure. (author)

  15. Nonlinear self-excited thermoacoustic oscillations of a ducted premixed flame: bifurcations and routes to chaos

    E-Print Network [OSTI]

    Kashinath, Karthik; Waugh, Iain C.; Juniper, Matthew P.

    2014-01-01T23:59:59.000Z

    Thermoacoustic systems can oscillate self-excitedly, and often non-periodically, due to coupling between unsteady heat release and acoustic waves. We study a slot-stabilized two-dimensional premixed flame in a duct via numerical simulations of a G...

  16. Multiscale Modeling of TiO2 Nanoparticle Production in Flame Reactors: Effect of Chemical Mechanism

    E-Print Network [OSTI]

    Raman, Venkat

    , catalysis, energy, and semiconductors. Titanium dioxide (TiO2) nanoparticles are traditionally used and Engineering Mechanics, The UniVersity of Texas, Austin, Texas 78712 For titanium dioxide (TiO2) nanoparticles in the flame with detailed titanium oxidation chemistry, compared to one-step chemistry. Finally, a large

  17. Carbon nanotubes grow in combustion flames Issued on March 31, 2014

    E-Print Network [OSTI]

    Takahashi, Ryo

    Carbon nanotubes grow in combustion flames Issued on March 31, 2014 Quantum chemical simulations reveal an unprecedented relationship between the mechanism of carbon nanotube growth and hydrocarbon of carbon nanotube (CNT) growth and hydrocarbon combustion actually share many similarities. In studies

  18. NOx emission characteristics of counterflow syngas diffusion flames with airstream dilution

    E-Print Network [OSTI]

    Aggarwal, Suresh K.

    NOx emission characteristics of counterflow syngas diffusion flames with airstream dilution Daniel Abstract Syngas is produced through a gasification process using variety of fossil fuels, including coal. Due to its wide flexibility in fuel sources and superior pollutants characteristics, the syngas

  19. A numerical and experimental study of counterflow syngas flames at different pressures

    E-Print Network [OSTI]

    Aggarwal, Suresh K.

    A numerical and experimental study of counterflow syngas flames at different pressures S. Som, A Synthesis gas or ``Syngas'' is being recognized as a viable energy source worldwide, particularly. There are, however, gaps in the fundamental understanding of syngas combustion and emissions characteristics

  20. Copyright 2007 by ASME1 Laminar Flame Speeds and Strain Sensitivities of Mixtures of H2

    E-Print Network [OSTI]

    Seitzman, Jerry M.

    to rich. [Keywords: Syngas, laminar flame speed, reactant preheat, CO2 dilution, N2 dilution] INTRODUCTION emissions. Synthetic gas (syngas) fuels derived from coal are particularly promising in this regard. Syngas, provides a significant barrier to syngas usage. Understanding the impact of this variability on combustor

  1. Development of an Experimental Facility for Flame Speed Measurements in Powdered Aerosols

    E-Print Network [OSTI]

    Vissotski, Andrew John

    2012-10-19T23:59:59.000Z

    with both dispersion techniques, a pure dust-air system would not ignite due to the current spark ignition system. Thus, a hybrid mixture of Al/CH4/O2/N2 was employed to achieve the project goal of demonstrating a system for controlled laminar flame speed...

  2. Kinetic effects of non-equilibrium plasma-assisted methane oxidation on diffusion flame extinction limits

    E-Print Network [OSTI]

    Ju, Yiguang

    08544, USA b US Air Force Research Laboratory, Propulsion Directorate, Wright-Patterson AFB, OH 45433 plasma assisted combustion resulted in fast chemical heat release and extended the extinction limits processes in plasma­flame interactions [1­17]. However, plasma assisted combustion involves strong coupling

  3. Effects of Lewis number and ignition energy on the determination of laminar flame speed

    E-Print Network [OSTI]

    Ju, Yiguang

    , it affects the fuel burning rate in internal combustion engines and the engine's performance and emissions Engineering, Princeton University, Princeton, NJ 08544, USA Abstract The trajectories of outwardly propagating. Published by Elsevier Inc. on behalf of The Combustion Institute. Keywords: Laminar flame speed; Spherical

  4. Finite-rate chemistry and transient effects in Direct Numerical Simulations of turbulent non-premixed flames

    SciTech Connect (OSTI)

    Mahalingam, S. [Colorado Univ., Boulder, CO (United States). Dept. of Mechanical Engineering; Chen, J.H. [Sandia National Labs., Livermore, CA (United States); Vervisch, L. [Institut de Mecanique des Fluides, Numeriques (France)

    1994-01-01T23:59:59.000Z

    Three-dimensional Direct Numerical Simulations (DNS) of turbulent non-premixed flames including finite-rate chemistry and heat release effects were performed. Two chemical reaction models were considered: (1) a single-step global reaction model in which the heat release and activation energy parameters are chosen to model methane-air combustion, and (2) a two-step reaction model to simulate radical production and consumption and to compare against the single-step model. The model problem consists of the interaction between an initially unstrained laminar diffusion flame and a three-dimensional field of homogeneous turbulence. Conditions ranging from fast chemistry to the pure mixing limit were studied by varying a global Damkoehler number. Results suggest that turbulence-induced mixing acting along the stoichiometric line leads to a strong modification of the inner structure of the turbulent flame compared with a laminar strained flame, resulting in intermediate species concentrations well above the laminar prediction. This result is consistent with experimental observations. Comparison of the response of the turbulent flame structure due to changes in the scalar dissipation rate with a steady strained laminar flame reveals that unsteady strain rates experienced by the turbulent flame may be responsible for the observed high concentrations of reaction intermediates.

  5. Effects of radiation and compression on propagating spherical flames of methane/air mixtures near the lean flammability limit

    SciTech Connect (OSTI)

    Chen, Zheng [State Key Laboratory for Turbulence and Complex Systems, Department of Mechanics and Aerospace Engineering, College of Engineering, Peking University, Beijing 100871 (China)

    2010-12-15T23:59:59.000Z

    Large discrepancies between the laminar flame speeds and Markstein lengths measured in experiments and those predicted by simulations for ultra-lean methane/air mixtures bring a great concern for kinetic mechanism validation. In order to quantitatively explain these discrepancies, a computational study is performed for propagating spherical flames of lean methane/air mixtures in different spherical chambers using different radiation models. The emphasis is focused on the effects of radiation and compression. It is found that the spherical flame propagation speed is greatly reduced by the coupling between thermal effect (change of flame temperature or unburned gas temperature) and flow effect (inward flow of burned gas) induced by radiation and/or compression. As a result, for methane/air mixtures near the lean flammability limit, the radiation and compression cause large amounts of under-prediction of the laminar flame speeds and Markstein lengths extracted from propagating spherical flames. Since radiation and compression both exist in the experiments on ultra-lean methane/air mixtures reported in the literature, the measured laminar flame speeds and Markstein lengths are much lower than results from simulation and thus cannot be used for kinetic mechanism validation. (author)

  6. Chapter 3.5: Freshman Undergraduate Retention1 Improve retention and graduation rates for all first-year engineering undergraduate students,

    E-Print Network [OSTI]

    Chapter 3.5: Freshman Undergraduate Retention1 Objective Improve retention and graduation rates graduation rate for transfer student. Strategies 1. Develop a program that continuously improves the delivery pass/fail efforts, either continue or adopt best practices form project for long-term implementation. 2

  7. Physical characterization of laminar spray flames in the pressure range 0.1-0.9 MPa

    SciTech Connect (OSTI)

    Russo, Stefano; Gomez, Alessandro [Yale Center for Combustion Studies, Department of Mechanical Engineering, Yale University, P.O. Box 208286, New Haven, CT 06520-8286 (United States)

    2006-04-15T23:59:59.000Z

    An experimental study is reported on the physical characterization of the structure of ethanol/argon/oxygen coflow laminar spray diffusion flames in the pressure range 0.1-0.9 MPa. Diagnostic techniques include phase Doppler anemometry to measure the droplet size distribution and the axial and radial velocity components of the droplets. The gas-phase velocity is determined using measurements from the smallest (low Stokes number) droplets and is corrected for thermophoretic effects. Temperature information is obtained using thin-film pyrometry combined with an infrared camera. All flames present a cold inner core, in which little or no vaporization takes place, surrounded by an envelope flame buried in a thermal boundary layer, where most of the droplet evaporation occurs. The thickness of this thermal boundary layer scales with the inverse of the Peclet number. Especially near the base of the flame, photographic evidence of streaks, which in some case even reveal the presence of soot, suggests that some droplets survive the common envelope flame and burn isolated on the oxidizer side in a mixed regime of internal/external group combustion. The reconstruction of the entire droplet vaporization history confirms this evidence quantitatively. A criterion for droplet survival beyond the envelope flame based on the critical value of a suitably defined vaporization Damkohler number is proposed. The scaling and self-similar behavior of the investigated flames suggest that a mixed regime is established, with a momentum-controlled cold core and a buoyancy-controlled high-temperature boundary layer, the thickness of which varies significantly with pressure, as expected from Peclet number scaling. The growth of this layer and the thickness of the vaporization region are reduced at pressures above atmospheric because of density effects on thermal diffusivity. Some aspects of the design of the combustion chamber and of the atomizer system are discussed in detail since they are critical to the suppression of instabilities and to the establishment of a well-defined high-pressure quasi-steady laminar environment. (author)

  8. NON-SOOTING, LOW FLAME TEMPERATURE MIXING-CONTROLLED DI DIESEL COMBUSTION

    SciTech Connect (OSTI)

    Pickett, L; Siebers, D

    2003-08-24T23:59:59.000Z

    Methods of producing non-sooting, low flame temperature diesel combustion were investigated in an optically-accessible, quiescent constant-volume combustion vessel under mixing-controlled diesel combustion conditions. Combustion and soot processes of single, isolated fuel jets were studied after auto-ignition and transient premixed combustion and while the injector was fully-open (i.e. during the mixing-controlled phase of heat release for diesel combustion). The investigation showed that small injector tip orifices could be used to produce non-sooting and low flame temperature combustion simultaneously. The use of small orifices was shown to enable non-sooting and low flame temperature combustion in two different ways as summarized below. A more detailed description of the experimental methods and results is provided in Ref. [1-3]. First, using an injector tip with a 50 micron orifice and ambient oxygen concentrations as low as 10% (simulating the use of extensive EGR), a fuel jet was non-sooting at typical diesel ambient temperatures (1000 K). Second, using the same injector tip at a reduced ambient gas temperature (850 K), but with 21% oxygen, it was shown that non-sooting, mixing-controlled combustion occurred at the lift-off length in a fuel-air mixture with a cross-sectional average equivalence ratio of approximately 0.6-suggesting that the quasi-steady combustion was fuel-lean and thereby avoided the formation of a diffusion flame. The adiabatic flame temperature with reduced ambient oxygen concentration or fuel-lean combustion was approximately 2000 K, compared to typical diesel flame temperatures that exceed 2600 K. The 50 micron orifice results above were obtained using a No.2 diesel fuel. However, using an oxygenated fuel (20 wt% oxygen), the investigation showed that the same low temperature combustion, either with reduced ambient oxygen concentration or fuel-lean combustion, was realized with a 100 micron orifice. Although these single, isolated jets do not have jet-jet interactions that would occur in realistic engines, the results are useful for understanding limiting-case behavior of single-jet mixing and combustion during an injection event. The non-sooting and low flame temperature mixing-controlled combustion realized using small orifice tips suggests that the use of small orifices offers the potential for a simultaneous soot and NOx reduction in an engine, much like diesel HCCI combustion. However, further research is needed to determine whether these methods could be successfully implemented in real engines.

  9. Flame-vortex interaction driven combustion dynamics in a backward-facing step combustor

    SciTech Connect (OSTI)

    Altay, H. Murat; Speth, Raymond L.; Hudgins, Duane E.; Ghoniem, Ahmed F. [Massachusetts Institute of Technology, Department of Mechanical Engineering, Cambridge, MA 02139 (United States)

    2009-05-15T23:59:59.000Z

    The combustion dynamics of propane-hydrogen mixtures are investigated in an atmospheric pressure, lean, premixed backward-facing step combustor. We systematically vary the equivalence ratio, inlet temperature and fuel composition to determine the stability map of the combustor. Simultaneous pressure, velocity, heat release rate and equivalence ratio measurements and high-speed video from the experiments are used to identify and characterize several distinct operating modes. When fuel is injected far upstream from the step, the equivalence ratio entering the flame is temporally and spatially uniform, and the combustion dynamics are governed only by flame-vortex interactions. Four distinct dynamic regimes are observed depending on the operating parameters. At high but lean equivalence ratios, the flame is unstable and oscillates strongly as it is wrapped around the large unsteady wake vortex. At intermediate equivalence ratios, weakly oscillating quasi-stable flames are observed. Near the lean blowout limit, long stable flames extending from the corner of the step are formed. At atmospheric inlet temperature, the unstable mode resonates at the 1/4 wavemode of the combustor. As the inlet temperature is increased, the 5/4 wavemode of the combustor is excited at high but lean equivalence ratios, forming the high-frequency unstable flames. Higher hydrogen concentration in the fuel and higher inlet temperatures reduce the equivalence ratios at which the transitions between regimes are observed. We plot combustion dynamics maps or the response curves, that is the overall sound pressure level as a function of the equivalence ratio, for different operating conditions. We demonstrate that numerical results of strained premixed flames can be used to collapse the response curves describing the transitions among the dynamic modes onto a function of the heat release rate parameter alone, rather than a function dependent on the equivalence ratio, inlet temperature and fuel composition separately. We formulate a theory for predicting the critical values of the heat release parameter at which quasi-stable to unstable and unstable to high-frequency unstable modes take place. (author)

  10. Compact organic vapor jet printing print head

    DOE Patents [OSTI]

    Forrest, Stephen R; McGraw, Gregory

    2013-12-24T23:59:59.000Z

    A first device is provided. The first device includes a print head, and a first gas source hermetically sealed to the print head. The print header further includes a first layer comprising a plurality of apertures, each aperture having a smallest dimension of 0.5 to 500 microns. A second layer is bonded to the first layer. The second layer includes a first via in fluid communication with the first gas source and at least one of the apertures. The second layer is made of an insulating material.

  11. Radiation turbulence interactions in pulverized coal flames. Technical progress report, third year, second quarter, December 15, 1995--March 15, 1996

    SciTech Connect (OSTI)

    Menguec, M.P.; McDonough, J.M.; Manickavasagam, S.; Mukerji, S.; Swabb, S.; Ghosal, S.

    1996-09-01T23:59:59.000Z

    In this paper, the authors discuss an experimental and theoretical methodology to characterize soot volume fraction fluctuations in turbulent diffusion flames via chaotic maps. The approach is based on the hypothesis that the fluctuations of properties in turbulent flames is deterministic in nature, rather than statistical. To this extent, the authors measured the time series of soot scattering coefficient in an ethylene diffusion flame from light scattering experiments. Following this, corresponding power spectra and delay maps were calculated. It was shown that if the data were averaged, the characteristics of the fluctuations were almost completely washed out. The psds from experiments were successfully modeled using a series of logistic maps.

  12. Multicomponent aerosol dynamic of the Pb-O[sub 2] system in a bench scale flame incinerator

    SciTech Connect (OSTI)

    Lin, W.Y.; Sethi, V.; Biswas, P.

    1992-01-01T23:59:59.000Z

    The article gives results of a study to understand the formation and growth of lead particles in a flame incinerator. A bench scale flame incinerator was used to perform controlled experiments with lead acetate as a test compound. A dilution probe (in conjunction with real-time aerosol instruments) was used to measure the evolution of the particle size distribution at different locations in the flame region. A multicomponent lognormal aerosol model was developed accounting for the chemistry of the lead-oxygen system, and for such aerosol dynamic phenomena as nucleation, coagulation, and condensation. Reasonable agreement was obtained between the predictions of the model using appropriate kinetic parameters and the experimental results.

  13. The retention time of inorganic mercury in the brain — A systematic review of the evidence

    SciTech Connect (OSTI)

    Rooney, James P.K., E-mail: jrooney@rcsi.ie

    2014-02-01T23:59:59.000Z

    Reports from human case studies indicate a half-life for inorganic mercury in the brain in the order of years—contradicting older radioisotope studies that estimated half-lives in the order of weeks to months in duration. This study systematically reviews available evidence on the retention time of inorganic mercury in humans and primates to better understand this conflicting evidence. A broad search strategy was used to capture 16,539 abstracts on the Pubmed database. Abstracts were screened to include only study types containing relevant information. 131 studies of interest were identified. Only 1 primate study made a numeric estimate for the half-life of inorganic mercury (227–540 days). Eighteen human mercury poisoning cases were followed up long term including autopsy. Brain inorganic mercury concentrations at death were consistent with a half-life of several years or longer. 5 radionucleotide studies were found, one of which estimated head half-life (21 days). This estimate has sometimes been misinterpreted to be equivalent to brain half-life—which ignores several confounding factors including limited radioactive half-life and radioactive decay from surrounding tissues including circulating blood. No autopsy cohort study estimated a half-life for inorganic mercury, although some noted bioaccumulation of brain mercury with age. Modelling studies provided some extreme estimates (69 days vs 22 years). Estimates from modelling studies appear sensitive to model assumptions, however predications based on a long half-life (27.4 years) are consistent with autopsy findings. In summary, shorter estimates of half-life are not supported by evidence from animal studies, human case studies, or modelling studies based on appropriate assumptions. Evidence from such studies point to a half-life of inorganic mercury in human brains of several years to several decades. This finding carries important implications for pharmcokinetic modelling of mercury and potentially for the regulatory toxicology of mercury.

  14. Use of Gold in Head and Neck

    E-Print Network [OSTI]

    Walter, Peter

    Use of Gold in Head and Neck Cancer Treatments Q & A with Dr. Frank McCormick UCSF Helen Diller Family Comprehensive Cancer Center Cancer Center Connection Frank McCormick, PhD, FRS, is the director of the UCSF Helen Diller Family Comprehensive Cancer Center (HDFCCC) and is Associate Dean of the UCSF School

  15. Probability Primer 1 Running head: PROBABILITY PRIMER

    E-Print Network [OSTI]

    Yuille, Alan L.

    provides the opportunity to draw upon work in computer science, engineering, mathematics, and statisticsProbability Primer 1 Running head: PROBABILITY PRIMER A Primer on Probabilistic Inference Thomas L. Griffiths Department of Psychology University of California, Berkeley Alan Yuille Department of Statistics

  16. VICE CHANCELLOR Signature of Head of School

    E-Print Network [OSTI]

    Tobar, Michael

    VICE CHANCELLOR Signature of Head of School Date (dd/mm/yy) Following is a report on the professional and consultative work of my School/section over the twelve months of (year) School/Section One. Yes No (Nil Return) Total number of staff within School/Section at year end who are eligible to engage

  17. Department Heads Meeting March15, 2012

    E-Print Network [OSTI]

    Wechsler, Risa H.

    Department Heads Meeting March15, 2012 David B. MacFarlane #12;Science program news Update on LBNE » Significant advance in our understanding of the neutrino sector » Centerpiece of the national program » SLAC Neutrinos Science interest beyond neutrino properties » Colleagues from KIPAC Energy release from core

  18. The effects of strain rate and curvature on surface density function transport in turbulent premixed methane-air and hydrogen-air flames: A comparative study

    SciTech Connect (OSTI)

    Chakraborty, N. [Engineering Department, University of Liverpool, Brownlow Hill, Liverpool L69 3GH (United Kingdom); Hawkes, E.R. [School of Photovoltaic and Renewable Energy Engineering, University of New South Wales, Sydney, NSW 2052 (Australia); Chen, J.H. [Combustion Research Facility, Sandia National Laboratories, Livermore, CA 94551 (United States); Cant, R.S. [Engineering Department, Cambridge University, Trumpington Street, Cambridge CB2 1PZ (United Kingdom)

    2008-07-15T23:59:59.000Z

    The effects of tangential strain rate and curvature on the surface density function (SDF) and on source terms within the SDF transport equation are studied for lean methane-air and hydrogen-air flames using two-dimensional direct numerical simulations with detailed chemistry. A positive correlation is observed between the SDF and the tangential strain rate, and this is explained in terms of the interaction between the local tangential strain rate and the dilatation rate due to heat release. Curvature is also seen to affect the SDF through the curvature response of both tangential strain rate and dilatation rate on a given flame isosurface. Strain rate and curvature are found to have an appreciable effect on several terms of the SDF transport equation. The SDF straining term in both methane and hydrogen flames is correlated positively with tangential strain rate, as expected, and is also correlated negatively with curvature. For methane flames, the SDF propagation term is found to correlate negatively with flame curvature toward the reactant side of the flame and positively toward the product side. By contrast, for hydrogen flames the SDF propagation term is negatively correlated with curvature throughout the flame brush. The variation of the SDF curvature term with local flame curvature for both methane and hydrogen flames is found to be nonlinear due to the additional stretch induced by the tangential diffusion component of the displacement speed. Physical explanations are provided for all of these effects, and the modeling implications are considered in detail. (author)

  19. Adherence to Head Computed Tomography Guidelines in the Setting of Mild Traumatic Brain Injury

    E-Print Network [OSTI]

    Jones, Landon A; Morley, Eric J; Grant, William D; Wojcik, Susan M; Paolo, William F

    2014-01-01T23:59:59.000Z

    Adherence to Head Computed Tomography Guidelines for Mildal Adherence to Head Computed Tomography Guidelines system,non-contrast head computed tomography (CT) in patients with

  20. Radiation-turbulence interactions in pulverized-coal flames. Quarterly report No. III, March 15, 1994--June 15, 1994

    SciTech Connect (OSTI)

    Menguec, M.P.; McDonough, J.M.

    1994-09-01T23:59:59.000Z

    The work concerns the development of computer codes for the simulation of radiation turbulence interactions in coal flames. Experimental studies in tandem with the turbulence calculations are based on optical observation of scattered light from coal particles under combustion conditions.

  1. The Effects of Charge Motion and Laminar Flame Speed on Late Robust Combustion in a Spark-Ignition Engine

    E-Print Network [OSTI]

    Cheng, Wai K.

    The effects of charge motion and laminar flame speeds on combustion and exhaust temperature have been studied by using an air jet in the intake flow to produce an adjustable swirl or tumble motion, and by replacing the ...

  2. A New Type of Steady and Stable, Laminar, Premixed Flame in Ultra-Lean, Hydrogen-Air Combustion

    E-Print Network [OSTI]

    Grcar, Joseph F

    2008-01-01T23:59:59.000Z

    411–422. [9] I. Glassman, Combustion, 3rd Edition, AcademicB. Lewis, G. von Elbe, Combustion, Flames and Explosions ofin Ultra-Lean, Hydrogen-Air Combustion Joseph F. Grcar a a

  3. The time evolution of a vortex-flame interaction observed via planar imaging of CH and OH

    SciTech Connect (OSTI)

    Nguyen, Quang-Viet; Paul, P.H.

    1996-05-01T23:59:59.000Z

    Planar laser-induced fluorescence imaging diagnostics of OH and CH are used to examine a premixed laminar flame subjected to a strong line-vortex pair. Results are reported for a fuel-rcih lamiar CH{sub 4}-air-N{sub 2} rod-stabilized flame. The flow studied was highly reproducible, which enabled the use of phase-sampled imaging to provide time-resolved image sequences. Image sequences are shown for a condition sufficient to produce localized extinction of the primary flame. Results indicate that a breakage in the CH front is not preceded by any distinct change in the OH front. The structure of the CH and OH profiles during the transient leading up to, and through the breakage of the CH front do not appear to be consistent with the concept of a strained laminar flame.

  4. Investigation of the Difference in Cool Flame Characteristics between Petroleum Diesel and Soybean Biodiesel Operating in Low Temperature Combustion Mode

    E-Print Network [OSTI]

    Muthu Narayanan, Aditya

    2014-01-16T23:59:59.000Z

    . The focus of this study is to investigate the difference in the cool flame combustion characteristics between petroleum diesel and soybean biodiesel, when operating in low temperature combustion mode. Previous studies have attributed the absence of the cool...

  5. Nuclear reactor melt-retention structure to mitigate direct containment heating

    DOE Patents [OSTI]

    Tutu, Narinder K. (Manorville, NY); Ginsberg, Theodore (East Setauket, NY); Klages, John R. (Mattituck, NY)

    1991-01-01T23:59:59.000Z

    A light water nuclear reactor melt-retention structure to mitigate the extent of direct containment heating of the reactor containment building. The structure includes a retention chamber for retaining molten core material away from the upper regions of the reactor containment building when a severe accident causes the bottom of the pressure vessel of the reactor to fail and discharge such molten material under high pressure through the reactor cavity into the retention chamber. In combination with the melt-retention chamber there is provided a passageway that includes molten core droplet deflector vanes and has gas vent means in its upper surface, which means are operable to deflect molten core droplets into the retention chamber while allowing high pressure steam and gases to be vented into the upper regions of the containment building. A plurality of platforms are mounted within the passageway and the melt-retention structure to direct the flow of molten core material and help retain it within the melt-retention chamber. In addition, ribs are mounted at spaced positions on the floor of the melt-retention chamber, and grid means are positioned at the entrance side of the retention chamber. The grid means develop gas back pressure that helps separate the molten core droplets from discharged high pressure steam and gases, thereby forcing the steam and gases to vent into the upper regions of the reactor containment building.

  6. Hamerschlag Hall Green Roof Storm Water Retention and Runoff Reduction Performance Lucheng Chen

    E-Print Network [OSTI]

    Andrews, Peter B.

    Hamerschlag Hall Green Roof Storm Water Retention and Runoff Reduction Performance ......................................................................................................................... 2 2. Hamerschlag Hall Green Roof .............................................................................. 13 4. Methods of Storm Analysis and Green Roof Performance Analysis

  7. Gas cushion control of OVJP print head position

    DOE Patents [OSTI]

    Forrest, Stephen R

    2014-10-07T23:59:59.000Z

    An OVJP apparatus and method for applying organic vapor or other flowable material to a substrate using a printing head mechanism in which the print head spacing from the substrate is controllable using a cushion of air or other gas applied between the print head and substrate. The print head is mounted for translational movement towards and away from the substrate and is biased toward the substrate by springs or other means. A gas cushion feed assembly supplies a gas under pressure between the print head and substrate which opposes the biasing of the print head toward the substrate so as to form a space between the print head and substrate. By controlling the pressure of gas supplied, the print head separation from the substrate can be precisely controlled.

  8. Type B Accident Investigation Board Report on the Head Injury...

    Office of Environmental Management (EM)

    on the Head Injury to a Miner at the Waste Isolation Pilot Plant, Carlsbad, New Mexico - August 25, 2004 Type B Accident Investigation Board Report on the Head Injury to a Miner at...

  9. World's Largest Solar Energy Project Heads to Mojave | Department...

    Broader source: Energy.gov (indexed) [DOE]

    World's Largest Solar Energy Project Heads to Mojave World's Largest Solar Energy Project Heads to Mojave April 16, 2010 - 4:47pm Addthis A California company will harness the...

  10. 1 INTRODUCTION High-head storage hydropower plants operate

    E-Print Network [OSTI]

    Floreano, Dario

    1 INTRODUCTION High-head storage hydropower plants operate their turbines during periods of high Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland ABSTRACT: High-head storage hydropower plants

  11. Evolution of soot size distribution in premixed ethylene/air and ethylene/benzene/air flames: Experimental and modeling study

    SciTech Connect (OSTI)

    Echavarria, Carlos A.; Sarofim, Adel F.; Lighty, JoAnn S. [Department of Chemical Engineering, University of Utah, Salt Lake City, UT (United States); D'Anna, Andrea [Dipartimento di Ingegneria Chimica, Universita ''Federico II'' di Napoli, Naples (Italy)

    2011-01-15T23:59:59.000Z

    The effect of benzene concentration in the initial fuel on the evolution of soot size distribution in ethylene/air and ethylene/benzene/air flat flames was characterized by experimental measurements and model predictions of size and number concentration within the flames. Experimentally, a scanning mobility particle sizer was used to allow spatially resolved and online measurements of particle concentration and sizes in the nanometer-size range. The model couples a detailed kinetic scheme with a discrete-sectional approach to follow the transition from gas-phase to nascent particles and their coagulation to larger soot particles. The evolution of soot size distribution (experimental and modeled) in pure ethylene and ethylene flames doped with benzene showed a typical nucleation-sized (since particles do not actually nucleate in the classical sense particle inception is often used in place of nucleation) mode close to the burner surface, and a bimodal behavior at greater height above burner (HAB). However, major features were distinguished between the data sets. The growth of nucleation and agglomeration-sized particles was faster for ethylene/benzene/air flames, evidenced by the earlier presence of bimodality in these flames. The most significant changes in size distribution were attributed to an increase in benzene concentration in the initial fuel. However, these changes were more evident for high temperature flames. In agreement with the experimental data, the model also predicted the decrease of nucleation-sized particles in the postflame region for ethylene flames doped with benzene. This behavior was associated with the decrease of soot precursors after the main oxidation zone of the flames. (author)

  12. Investigation of the processes controlling the flame generation of refractory materials. Progress report, July 1, 1991--June 30, 1992

    SciTech Connect (OSTI)

    Katz, J.L.

    1992-01-01T23:59:59.000Z

    The processes involved in the formation of mixed oxides powders were studied using the counterflow diffusion flame burner. Powders of different morphologies were obtained by varying the flame conditions (temperature, residence time) and the concentration ratio of the oxides precursors. In-situ particle size and number density were determined using dynamic light scattering and 90{degrees} light scattering. A thermophoretic sampling method and a larger scale powder collection device also was used to collect particles, and their size and morphology examined using transmission electron microscopy, X-ray diffraction and surface area measurement by gas absorption (BET). Our emphasis has been on TiO{sub 2}-SiO{sub 2}, SiO{sub 2}-GeO{sub 2} and Al{sub 2}O{sub 3}-TiO{sub 2}. The powders had a core-mantle-like (one oxide coated by the other) at low elevations in the burner and uniform mixture at higher elevations. They form chain-like structures in a low temperature flame and spherical particles in a higher temperature flame. Nanometer sized homogeneous particles of Aluminum Titanate could be obtained using Al(CH{sub 3}){sub 3} and TiCl{sub 4} as precursors both in a hydrogen fueled and a methane fueled counterflow diffusion flame burner, as well as in a hydrogen fueled parallel-flow diffusion flame burner.

  13. Experimental study on thermophoretic deposition of soot particles in laminar diffusion flames along a solid wall in microgravity

    SciTech Connect (OSTI)

    Choi, Jae-Hyuk; Chung, Suk Ho [School of Mechanical and Aerospace Engineering, Seoul National University, Seoul 151-742 (Korea); Fujita, Osamu; Tsuiki, Takafumi [Division of Mechanical and Space Engineering, Hokkaido University, Sapporo 060-8628 (Japan); Kim, Junhong [Laboratoire E.M2.C., UPR 288 C.N.R.S Ecole Centrale Paris, Grande Voie des Vignes 92295 (France)

    2008-09-15T23:59:59.000Z

    Soot deposition process in diffusion flames along a solid wall has been investigated experimentally under a microgravity environment. An ethylene (C{sub 2}H{sub 4}) diffusion flame was formed around a cylindrical rod-burner with the surrounding air velocities of V{sub a} = 2.5, 5, and 10 cm/s, the oxygen concentration of 35%, and the burner wall temperature of 300 K. A laser extinction method was adopted to measure the distribution of soot volume fraction. The experiments determined the trace of maximum soot concentration together with the relative distance of the trace of flame. Results showed that the distance was about 2-5 mm. As the surrounding air velocity increased, the region of the soot particle distribution moved closer to the burner wall. The soot particles near the flame zone tended to move away from the flame zone because of the thermophoretic force and to concentrate at a certain narrow region inside the flame. Because of the simultaneous effects of convection and the thermophoresis, soot particles finally adhered to the burner wall. It has been found that there existed an optimal air velocity for the early deposition of soot on the furnace wall. (author)

  14. Physical and chemical comparison of soot in hydrocarbon and biodiesel fuel diffusion flames: A study of model and commercial fuels

    SciTech Connect (OSTI)

    Matti Maricq, M. [Research and Advanced Engineering, Ford Motor Company, Dearborn, MI (United States)

    2011-01-15T23:59:59.000Z

    Data are presented to compare soot formation in both surrogate and practical fatty acid methyl ester biodiesel and petroleum fuel diffusion flames. The approach here uses differential mobility analysis to follow the size distributions and electrical charge of soot particles as they evolve in the flame, and laser ablation particle mass spectrometry to elucidate their composition. Qualitatively, these soot properties exhibit a remarkably similar development along the flames. The size distributions begin as a single mode of precursor nanoparticles, evolve through a bimodal phase marking the onset of aggregate formation, and end in a self preserving mode of fractal-like particles. Both biodiesel and hydrocarbon fuels yield a common soot composition dominated by C{sub x}H{sub y}{sup +} ions, stabilomer PAHs, and fullerenes in the positive ion mass spectrum, and C{sub x}{sup -} and C{sub 2x}H{sup -} in the negative ion spectrum. These ion intensities initially grow with height in the diffusion flames, but then decline during later stages, consistent with soot carbonization. There are important quantitative differences between fuels. The surrogate biodiesel fuel methyl butanoate substantially reduces soot levels, but soot formation and evolution in this flame are delayed relative to both soy and petroleum fuels. In contrast, soots from soy and hexadecane flames exhibit nearly quantitative agreement in their size distribution and composition profiles with height, suggesting similar soot precursor chemistry. (author)

  15. MODEL BUILDING FOR INTERACTIVE SEGMENTATION OF THE FEMORAL HEAD

    E-Print Network [OSTI]

    McKenzie, Rick

    MODEL BUILDING FOR INTERACTIVE SEGMENTATION OF THE FEMORAL HEAD G ZSEMLYE 1 , G SZÉKELY 1 1 by the user. Our first #12;study concentrates on the femoral head, containing only two well defined point the femoral neck at its smallest perimeter with a circle and the femoral head with a half-sphere. After

  16. Contact Stress in Hips with Osteonecrosis of the Femoral Head

    E-Print Network [OSTI]

    Iglic, Ales

    Contact Stress in Hips with Osteonecrosis of the Femoral Head Matej Daniel, PhD*; Srecko Herman, MD by elevated con- tact stress. Osteonecrosis of the femoral head is a relatively common disorder of the human of the hip are af- fected by osteonecrosis of the femoral head,8 they have been the subject of numerous

  17. Automatic Tissue Classification for the Human Head from Multispectral MRI

    E-Print Network [OSTI]

    Utah, University of

    1 Automatic Tissue Classification for the Human Head from Multispectral MRI Tolga Tasdizen, David for classifying multispectral MR scans of the human head into nine tissue classes. User initialization is adopted. #12;Chapter 1 Introduction Classification of head magnetic resonance imaging (MRI) data

  18. Oculomotor Responses to Active Head Movements in Darkness

    E-Print Network [OSTI]

    Ramat, Stefano

    information on head rotation from the vestibular system to the saccade-generating mechanism in the brain stem482 Oculomotor Responses to Active Head Movements in Darkness Formulation and Testing Sistemistica, Università di Pavia, Pavia, Italy Passive head rotation in darkness produces vestibular nystagmus

  19. Computational Modeling of Brain Dynamics during Repetitive Head Motions

    E-Print Network [OSTI]

    Burtscher, Martin

    Computational Modeling of Brain Dynamics during Repetitive Head Motions Igor Szczyrba School the HIC scale to arbitrary head motions. Our simulations of the brain dynamics in sagittal and horizontal injury modeling, resonance effects 1 Introduction A rapid head motion can result in a severe brain injury

  20. Investigation of the flame speeds of propane/methanol gas mixtures

    SciTech Connect (OSTI)

    Foote, K.L.; Villareal, J.

    1985-05-02T23:59:59.000Z

    A series of tests was conducted in an acoustically tuned flame tube in order to determine the laminar burning velocities in air of various propane/methanol gas mixtures. The experimental method is explained in detail, along with the tabular results. A 90% propane, 10% methanol mixture is shown to have a maximum burning velocity of 40.8 cm/s. A 65% propane, 35% methanol mixture has a maximum velocity of 41.8 cm/s. These maximum flame speeds are shown to be about the same as that of pure propane by the same method. Gulder has found evidence that the presence of methanol in some hydrocarbon fuels may actually inhibit combustion, but we see no apparent modifications in the combustion of propane when mixed with methanol.

  1. Second Law Comparisons of Volumetric and Flame Combustion in an Ideal Engine with Exhaust Heat Recovery

    SciTech Connect (OSTI)

    Chakravarthy, Veerathu K [ORNL; Daw, C Stuart [ORNL; Graves, Ronald L [ORNL

    2006-01-01T23:59:59.000Z

    We summarize the results of a theoretical second law (exergy) analysis of an idealized internal combustion engine operating in flame versus volumetric (e.g., HCCI-like) combustion modes. We also consider the impact of exhaust heat recovery. Our primary objective is to better understand the fundamental differences (if any) in thermodynamic irreversibility among these different combustion modes and the resulting impact on engine work output. By combustion irreversibility, we mean that portion of the fuel energy that becomes unavailable for producing useful work due to entropy generation in the combustion process, exclusive of all other heat and friction losses. A key question is whether or not volumetric combustion offers any significant irreversibility advantage over conventional flame combustion. Another key issue is how exhaust heat recovery would be expected to change the net work output of an ideal piston engine. Based on these results, we recommend specific research directions for improving the fuel efficiency of advanced engines.

  2. The oxidation of soot and carbon monoxide in hydrocarbon diffusion flames

    SciTech Connect (OSTI)

    Puri, R.; Santoro, R.J. (Pennsylvania State Univ., University Park, PA (United States). Dept. of Mechanical Engineering); Smyth, K.C. (National Inst. of Standards and Technology, Gaithersburg, MD (United States). Building and Fire Research Lab.)

    1994-05-01T23:59:59.000Z

    Quantitative hydroxyl radical concentrations and primary soot particle sizes have been determined in the soot oxidation regions of axisymmetric diffusion flames burning methane, methane/butane, and methane/1-butene in air at atmospheric pressure. The total carbon flow rate was held constant in these flames while the maximum amount of soot varied by a factor of seven along the centerline. Laser-induced fluorescence measurements of OH were placed on an absolute basis by calibration against earlier absorption results. The primary size measurements of the soot particles were made using thermophoretic sampling and transmission electron microscopy. OH concentrations are greatly reduced in the presence of soot particles. Whereas large super-equilibrium ratios are observed in the high-temperature reaction zones in the absence of soot, the OH concentrations approach equilibrium values when the soot loading is high. The diminished OH concentrations are found to arise from reactions with the soot particles and only to a minor degree from lower temperatures due to soot radiation losses. Analysis of the soot oxidation rates computed from the primary particle size profiles as a function of time along the flame centerlines shows that OH is the dominant oxidizer of soot, with O[sub 2] making only a small contribution. Higher collision efficiencies of OH reactions with soot particles are found for the flames containing larger soot concentrations at lower temperatures. A comparison of the soot and CO oxidation rates shows that although CO is inherently more reactive than soot, the soot successfully competes with CO for OH and hence suppresses CO oxidation for large soot concentrations.

  3. Soot formation in weakly buoyant acetylene-fueled laminar jet diffusion flames burning in air

    SciTech Connect (OSTI)

    Sunderland, P.B.; Koeylue, U.O.; Faeth, G.M. (Univ. of Michigan, Ann Arbor, MI (United States). Dept. of Aerospace Engineering)

    1995-01-01T23:59:59.000Z

    The structure and soot properties of weakly buoyant, acetylene-fueled, laminar jet diffusion flames were studied experimentally for combustion in air at pressures of 0.125--0.250 atm. The following measurements were made: soot volume fractions using laser extinction, temperatures using both thermocouples and multiline emission, soot structure using thermophoretic sampling and analysis by transmission electron microscopy, concentrations of major gas species using sampling and analysis by gas chromatography, and velocities using laser velocimetry. As distance increased along the axis of the present acetylene-fueled flames, significant soot formation began when temperatures exceeded roughly 1250 K, and ended when fuel-equivalence ratios decreased to roughly 1.7, where the concentration of acetylene became small. This behavior allowed observations of soot growth and nucleation for acetylene concentrations of 6 [times] 10[sup [minus]6]--1 [times] 10[sup [minus]3] and temperatures of 1,000--2,100 K. Over this range of conditions, soot growth rates were comparable to past observations of new soot in premixed flames, and after correction for effects of soot oxidation yielded essentially first-order growth with respect to acetylene concentrations with a negligible activation energy, and an acetylene/soot collision efficiency of 0.53%. Present measurements of soot nucleation rates also suggested first-order behavior with respect to acetylene concentrations but with an activation energy of 32 kcal/gmol and with rates that were significantly lower than earlier estimates in the literature. Nevertheless, uncertainties about the effects of soot oxidation and age on soot growth, and about effects of surface area estimates and translucent objects on soot nucleation, must be resolved in order to adequately define soot formation processes in diffusion flames.

  4. The use of particle tracking to obtain planar velocity measurements in an unsteady laminar diffusion flame

    SciTech Connect (OSTI)

    Lewis, G.S.; Cantwell, B.J.; Lecuona, A.

    1987-01-01T23:59:59.000Z

    An investigation of the flame-flow interaction in an unsteady laminar co-flowing jet diffusion flame is underway. The flame is made periodic by acoustic excitation of the fuel stream. The objective of the research is to develop a better understanding of the relationship between the flowfield and combustion process by superimposing measurements of the vector velocity field on planar measurements of reactive and passive scalars. In this connection a technique is being developed to obtain instantaneous two-dimensional velocity measurements from multiply-exposed photographic images of scattered light from speed particles in the flow. The technique involves simple photographic images taken at a right angle to a thin laser sheet on the diametric center of the jet. The illumination source is pulsed Cu vapor laser. The important issues considered have included the particle type and size as they relate to the particle's ability to follow the flow and to withstand combustion temperatures. Also of concern is the effect of thermophoretic forces on the measurement accuracy. Both Al/sub 2/O/sub 3/ and TiO/sub 2/ have been used successfully and detailed information about the size and geometry of TiO/sub 2/ particles has been obtained through scanning electron microscope photographs. The TiO/sub 2/ particles have been produced from the reaction of TiCl/sub 4/ and water. The technique has been successfully demonstrated by measuring a cold laminar jet exit velocity profile. Also, good particle images have been obtained in a pulsed diffusion flame.

  5. On the structure, propagation, and stabilization of laminar premixed flames. Final report

    SciTech Connect (OSTI)

    Law, Chung K.

    1999-07-01T23:59:59.000Z

    The primary objective of the funded program was to qualitatively understand and quantitatively determine the structure and dynamics of laminar premixed flames. The investigation was conducted using laser-based experimentation, computational simulation with detailed chemistry and transport, and activation energy asymptotic analysis. Highlights of accomplishments were discussed in the annual reports submitted to the program monitor for this project. Details are reported in the thirty journal publications cited in the journal article list which is the major component of this final report.

  6. Temperature of aircraft cargo flame exposure during accidents involving fuel spills

    SciTech Connect (OSTI)

    Mansfield, J.A.

    1993-01-01T23:59:59.000Z

    This report describes an evaluation of flame exposure temperatures of weapons contained in alert (parked) bombers due to accidents that involve aircraft fuel fires. The evaluation includes two types of accident, collisions into an alert aircraft by an aircraft that is on landing or take-off, and engine start accidents. Both the B-1B and B-52 alert aircraft are included in the evaluation.

  7. The influence of initial temperature on flame acceleration and deflagration-to-detonation transition

    SciTech Connect (OSTI)

    Ciccarelli, G.; Boccio, J.L.; Ginsberg, T. [and others

    1996-07-01T23:59:59.000Z

    The influence of initial mixture temperature on deflagration-to-detonation transition (DDT) has been investigated experimentally. The experiments were carried out in a 27-cm-inner diameter, 21.3-meter-long heated detonation tube, which was equipped with periodic orifice plates to promote flame acceleration. Hydrogen-air-steam mixtures were tested at a range of temperatures up to 650K and at an initial pressure of 0.1 MPa. In most cases, the limiting hydrogen mole fraction which resulted in transition to detonation corresponded to the mixture whose detonation cell size, {lambda}, was approximately equal to the inner diameter of the orifice plate, d (e.g., d/{lambda}{approximately}1). The only exception was in dry hydrogen-air mixtures at 650K where the DDT limit was observed to be 11 percent hydrogen, corresponding to a value of d/{lambda} equal to 5.5. For a 10.5 percent hydrogen mixture at 650K, the flame accelerated to a maximum velocity of about 120 m/s and then decelerated to below 2 m/s. This observation indicates that the d/{lambda} = 1 DDT limit criterion provides a necessary condition but not a sufficient one for the onset of DDT in obstacle-laden ducts. In this particular case, the mixture initial condition (i.e., temperature) resulted in the inability of the mixture to sustain flame acceleration to the point where DDT could occur. It was also observed that the distance required for the flame to accelerate to the onset of detonation was a function of both the hydrogen mole fraction and the mixture initial temperature. For example, decreasing the hydrogen mole fraction or increasing the initial mixture temperature resulted in longer transition distances.

  8. Low and High Temperature Combustion Chemistry of Butanol Isomers in Premixed Flames and Autoignition Systems

    SciTech Connect (OSTI)

    Sarathy, S M; Pitz, W J; Westbrook, C K; Mehl, M; Yasunaga, K; Curran, H J; Tsujimura, T; Osswald, P; Kohse-Hoinghaus, K

    2010-12-12T23:59:59.000Z

    Butanol is a fuel that has been proposed as a bio-derived alternative to conventional petroleum derived fuels. The structural isomer in traditional 'bio-butanol' fuel is n-butanol, but newer conversion technologies produce iso-butanol as a fuel. In order to better understand the combustion chemistry of bio-butanol, this study presents a comprehensive chemical kinetic model for all the four isomers of butanol (e.g., 1-, 2-, iso- and tert-butanol). The proposed model includes detailed high temperature and low temperature reaction pathways. In this study, the primary experimental validation target for the model is premixed flat low-pressure flame species profiles obtained using molecular beam mass spectrometry (MBMS). The model is also validated against previously published data for premixed flame velocity and n-butanol rapid compression machine and shock tube ignition delay. The agreement with these data sets is reasonably good. The dominant reaction pathways at the various pressures and temperatures studied are elucidated. At low temperature conditions, we found that the reaction of alphahydroxybutyl with O{sub 2} was important in controlling the reactivity of the system, and for correctly predicting C{sub 4} aldehyde profiles in low pressure premixed flames. Enol-keto isomerization reactions assisted by HO{sub 2} were also found to be important in converting enols to aldehydes and ketones in the low pressure premixed flames. In the paper, we describe how the structural features of the four different butanol isomers lead to differences in the combustion properties of each isomer.

  9. Head erosion with emittance growth in PWFA

    SciTech Connect (OSTI)

    Li, S. Z.; Adli, E.; England, R. J.; Frederico, J.; Gessner, S. J.; Hogan, M. J.; Litos, M. D.; Walz, D. R.; Muggli, P.; An, W.; Clayton, C. E.; Joshi, C.; Lu, W.; Marsh, K. A.; Mori, W.; Vafaei, N. [SLAC National Accelerator Laboratory, Menlo Park, CA 94025 (United States) and SLAC National Accelerator Laboratory, Menlo Park, CA 94025 (United States) and University of Oslo, Oslo, N-0316 (Norway) and SLAC National Accelerator Laboratory, Menlo Park, CA 94025 (United States); Max Planck Institute for Physics, Munich (Germany); University of California, Los Angeles, CA 90095 (United States)

    2012-12-21T23:59:59.000Z

    Head erosion is one of the limiting factors in plasma wakefield acceleration (PWFA). We present a study of head erosion with emittance growth in field-ionized plasma from the PWFA experiments performed at the FACET user facility at SLAC. At FACET, a 20.3 GeV bunch with 1.8 Multiplication-Sign 10{sup 10} electrons is optimized in beam transverse size and combined with a high density lithium plasma for beam-driven plasma wakefield acceleration experiments. A target foil is inserted upstream of the plasma source to increase the bunch emittance through multiple scattering. Its effect on beamplasma interaction is observed with an energy spectrometer after a vertical bend magnet. Results from the first experiments show that increasing the emittance has suppressed vapor field-ionization and plasma wakefields excitation. Plans for the future are presented.

  10. Large eddy simulation of soot formation in a turbulent non-premixed jet flame

    SciTech Connect (OSTI)

    El-Asrag, Hossam [Center For Turbulence Research, Stanford, CA 94305 (United States); Menon, Suresh [School of Aerospace Engineering, Georgia Institute of Technology, Atlanta, GA 30332 (United States)

    2009-02-15T23:59:59.000Z

    A recently developed subgrid model for soot dynamics [H. El-Asrag, T. Lu, C.K. Law, S. Menon, Combust. Flame 150 (2007) 108-126] is used to study the soot formation in a non-premixed turbulent flame. The model allows coupling between reaction, diffusion and soot (including soot diffusion and thermophoretic forces) processes in the subgrid domain without requiring ad hoc filtering or model parameter adjustments. The combined model includes the entire process, from the initial phase, when the soot nucleus diameter is much smaller than the mean free path, to the final phase, after coagulation and aggregation, where it can be considered in the continuum regime. A relatively detailed but reduced kinetics for ethylene-air is used to simulate an experimentally studied non-premixed ethylene/air jet diffusion flame. Acetylene is used as a soot precursor species. The soot volume fraction order of magnitude, the location of its maxima, and the soot particle size distribution are all captured reasonably. Along the centerline, an initial region dominated by nucleation and surface growth is established followed by an oxidation region. The diffusion effect is found to be most important in the nucleation regime, while the thermophoretic forces become more influential downstream of the potential core in the oxidation zone. The particle size distribution shows a log-normal distribution in the nucleation region, and a more Gaussian like distribution further downstream. Limitations of the current approach and possible solution strategies are also discussed. (author)

  11. OH and CH luminescence in opposed flow methane oxy-flames

    SciTech Connect (OSTI)

    De Leo, Maurizio; Saveliev, Alexei; Kennedy, Lawrence A. [Department of Mechanical and Industrial Engineering, University of Illinois at Chicago, Chicago, IL 60607 (United States); Zelepouga, Serguei A. [Gas Technology Institute, Des Plaines, IL 60018 (United States)

    2007-06-15T23:59:59.000Z

    Emission spectroscopy is a 2-D nonintrusive diagnostic technique that offers spatially resolved data for combustion optimization and control. The UV and visible chemiluminescence of the excited radicals CH(A{sup 2}{delta},B{sup 2}{sigma}{sup -}) and OH(A{sup 2}{sigma}{sup +}) is studied experimentally and numerically in opposed-flow diffusion flames of methane and oxygen-enriched air. The oxidized oxygen content is varied from 21 to 100% while the range of the studied strain rates spans from 20 to 40 s{sup -1}. The spectrally resolved imaging is obtained by two different methods: scattering through a grating monochromator and interposition of interference filters along the optical path. Absolute measured chemiluminescence intensities, coupled with a numerical model based on the opposed flow flame code, are used to evaluate the chemical kinetics of the excited species. The predictions of the selected model are in good agreement with the experimental data over the range of the studied flame conditions. (author)

  12. Rotational effects in thermonuclear Type I Bursts: equatorial crossing and directionality of flame spreading

    E-Print Network [OSTI]

    Cavecchi, Yuri; Levin, Yuri; Braithwaite, Jonathan

    2014-01-01T23:59:59.000Z

    In a previous study on thermonuclear (Type I) Bursts on accreting neutron stars we addressed and demonstrated the importance of the effects of rotation, through the Coriolis force, on the propagation of the burning flame. However, that study only analysed cases of longitudinal propagation, where the Coriolis force coefficient $2\\Omega\\cos\\theta$ was constant. In this paper, we study the effects of rotation on propagation in the meridional (latitudinal) direction, where the Coriolis force changes from its maximum at the poles to zero at the equator. We find that the zero Coriolis force at the equator, while affecting the structure of the flame, does not prevent its propagation from one hemisphere to another. We also observe structural differences between the flame propagating towards the equator and that propagating towards the pole, the second being faster. In the light of the recent discovery of the low spin frequency of burster IGR~J17480-2446 rotating at 11 Hz (for which Coriolis effects should be negligib...

  13. Evidence of thermonuclear flame spreading on neutron stars from burst rise oscillations

    E-Print Network [OSTI]

    Chakraborty, Manoneeta

    2014-01-01T23:59:59.000Z

    Burst oscillations during the rising phases of thermonuclear X-ray bursts are usually believed to originate from flame spreading on the neutron star surface. However, the decrease of fractional oscillation amplitude with rise time, which provides a main observational support for the flame spreading model, have so far been reported from only a few bursts. Moreover, the non-detection and intermittent detections of rise oscillations from many bursts are not yet understood considering the flame spreading scenario. Here, we report the decreasing trend of fractional oscillation amplitude from an extensive analysis of a large sample of Rossi X-ray Timing Explorer Proportional Counter Array bursts from ten neutron star low-mass X-ray binaries. This trend is 99.99% significant for the best case, which provides, to the best of our knowledge, by far the strongest evidence of such trend. Moreover, it is important to note that an opposite trend is not found from any of the bursts. The concave shape of the fractional ampli...

  14. Molecular Characterization of Organic Content of Soot along the Centerline of a Coflow Diffusion Flame

    SciTech Connect (OSTI)

    Cain, Jeremy P.; Laskin, Alexander; Kholghy, Mohammad Reza; Thomson, Murray; Wang, Hai

    2014-10-29T23:59:59.000Z

    High-resolution mass spectrometry coupled with nanospray desorption electrospray ionization was used to probe chemical constituents of young soot particles sampled along the centerline of a coflow diffusion flame of a three-component Jet-A1 surrogate. In lower positions where particles are transparent to light extinction (n= 632.8 nm), peri-condensed polycyclic aromatic hydrocarbons (PAHs) are found to be the major components of the particle material. These particles become enriched with aliphatic components as they grow in mass and size. Before carbonization occurs, the constituent species in young soot particles are aliphatic and aromatic compounds 200-600 amu in mass, some of which are oxygenated. Particles dominated by PAHs or mixtures of PAHs and aliphatics can both exhibit liquid-like appearance observed by electron microscopy and be transparent to visible light. The variations in chemical composition observed here indicate that the molecular processes of soot formation in coflow diffusion flames may be more complex than previously thought. For example, the mass growth and enrichment of aliphatic components in an initially, mostly aromatic structure region of the flame that is absent of H atoms or other free radicals indicates that there must exist at least another mechanism of soot mass growth in addition to the hydrogen-abstraction-carbon addition mechanism currently considered in fundamental models of soot formation.

  15. Computation in CC 2.0 Senior Scientist and Department Head

    E-Print Network [OSTI]

    Eisen, Michael

    of thermodiffusively unstable lean hydrogen flames and provides insight into experimental diagnostics Fuel Experimental simulation at effective resolution of 8B cells (20483) · Simulation captures cellular structure

  16. Local coordination of Zn in hydroxy-interlayered minerals and implications for Zn retention in soils

    E-Print Network [OSTI]

    -interlayered minerals (HIM) for Zn retention in contaminated soils. Published and newly collected extended XLocal coordination of Zn in hydroxy-interlayered minerals and implications for Zn retention. In a second part, we determined the spe- ciation of Zn in eight contaminated soils (251­1039 mg/kg Zn

  17. UNC Tomorrow Phase II Campus Response Faculty and Staff Recruitment and Retention

    E-Print Network [OSTI]

    1 UNC Tomorrow Phase II Campus Response Faculty and Staff Recruitment and Retention Submitted to/Tenure Track Faculty Hires 2009-2017 #12; 4 The projected demand for faculty and EPA and SPA staff create a range of implications for recruitment and retention in academic and non- academic units. The most

  18. QSPR models of boiling point, octanolwater partition coefficient and retention time index of polycyclic aromatic hydrocarbons

    E-Print Network [OSTI]

    Ferreira, Márcia M. C.

    QSPR models of boiling point, octanol­water partition coefficient and retention time index Structure­Property Relationship (QSPR) analysis and study of polycyclic aromatic hydrocarbons (PAHs (bp), octanol­ water partition coefficient ðlog KowÞ and retention time index (RI) for reversed

  19. PPPL-3311, Preprint: August 1998, UC-420, 423 Modeling of Tritium Retention in TFTR*

    E-Print Network [OSTI]

    - 1 - PPPL-3311, Preprint: August 1998, UC-420, 423 Modeling of Tritium Retention in TFTR* C Fusion Test Reactor tritium retention experience is reviewed and the data related to models of plasma surface interactions. Over 3.5 years of TFTR DT operations, approximately 51% of the tritium injected

  20. Retention of Butt-End Aluminum Leg Bands by Wild Turkeys

    E-Print Network [OSTI]

    Butler, Matthew J.

    Note Retention of Butt-End Aluminum Leg Bands by Wild Turkeys MATTHEW J. BUTLER,1,2 Department wild turkeys (Meleagris gallopavo intermedia) captured in Texas and Kansas, USA, 2000­2009. We examined 187 recaptured or harvested radiotagged wild turkeys to determine band retention and modeled band

  1. Oxygen plasma immersion ion implantation treatment to enhance data retention of tungsten nanocrystal nonvolatile memory

    SciTech Connect (OSTI)

    Wang, Jer-Chyi, E-mail: jcwang@mail.cgu.edu.tw; Chang, Wei-Cheng; Lai, Chao-Sung, E-mail: cslai@mail.cgu.edu.tw [Department of Electronic Engineering, Chang Gung University, Kweishan 333, Taoyuan, Taiwan (China); Chang, Li-Chun [Department of Material Engineering and Center for Thin Film Technologies and Applications, Ming Chi University of Technology, Taishan 24301, New Taipei City, Taiwan (China); Ai, Chi-Fong; Tsai, Wen-Fa [Institute of Nuclear Energy Research, Atomic Energy Council, Longtan 325, Taoyuan, Taiwan (China)

    2014-03-15T23:59:59.000Z

    Data retention characteristics of tungsten nanocrystal (W-NC) memory devices using an oxygen plasma immersion ion implantation (PIII) treatment are investigated. With an increase of oxygen PIII bias voltage and treatment time, the capacitance–voltage hysteresis memory window is increased but the data retention characteristics become degraded. High-resolution transmission electron microscopy images show that this poor data retention is a result of plasma damage on the tunneling oxide layer, which can be prevented by lowering the bias voltage to 7?kV. In addition, by using the elevated temperature retention measurement technique, the effective charge trapping level of the WO{sub 3} film surrounding the W-NCs can be extracted. This measurement reveals that a higher oxygen PIII bias voltage and treatment time induces more shallow traps within the WO{sub 3} film, degrading the retention behavior of the W-NC memory.

  2. The effect of initial temperature on flame acceleration and deflagration-to-detonation transition phenomenon

    SciTech Connect (OSTI)

    Ciccarelli, G.; Boccio, J.L.; Ginsberg, T.; Finfrock, C.; Gerlach, L. [Brookhaven National Lab., Upton, NY (United States); Tagawa, H. [Nuclear Power Engineering Corp., Tokyo (Japan); Malliakos, A. [Nuclear Regulatory Commission, Washington, DC (United States)

    1998-05-01T23:59:59.000Z

    The High-Temperature Combustion Facility at BNL was used to conduct deflagration-to-detonation transition (DDT) experiments. Periodic orifice plates were installed inside the entire length of the detonation tube in order to promote flame acceleration. The orifice plates are 27.3-cm-outer diameter, which is equivalent to the inner diameter of the tube, and 20.6-cm-inner diameter. The detonation tube length is 21.3-meters long, and the spacing of the orifice plates is one tube diameter. A standard automobile diesel engine glow plug was used to ignite the test mixture at one end of the tube. Hydrogen-air-steam mixtures were tested at a range of temperatures up to 650K and at an initial pressure of 0.1 MPa. In most cases, the limiting hydrogen mole fraction which resulted in DDT corresponded to the mixture whose detonation cell size, {lambda}, was equal to the inner diameter of the orifice plate, d (e.g., d/{lambda}=1). The only exception was in the dry hydrogen-air mixtures at 650K where the DDT limit was observed to be 11 percent hydrogen, corresponding to a value of d/{lambda} equal to 5.5. For a 10.5 percent hydrogen mixture at 650K, the flame accelerated to a maximum velocity of about 120 mIs and then decelerated to below 2 mIs. By maintaining the first 6.1 meters of the vessel at the ignition end at 400K, and the rest of the vessel at 650K, the DDT limit was reduced to 9.5 percent hydrogen (d/{lambda}=4.2). This observation indicates that the d/{lambda}=1 DDT limit criteria provides a necessary condition but not a sufficient one for the onset of DDT in obstacle laden ducts. In this particular case, the mixture initial condition (i.e., temperature) resulted in the inability of the mixture to sustain flame acceleration to the point where DDT could occur. It was also observed that the distance required for the flame to accelerate to the point of detonation initiation, referred to as the run-up distance, was found to be a function of both the hydrogen mole fraction and the mixture initial temperature. Decreasing the hydrogen mole fraction or increasing the initial mixture temperature resulted in longer run-up distances. The density ratio across the flame and the speed of sound in the unburned mixture were found to be two parameters which influence the run-up distance.

  3. RETENTION OF SULFATE IN HIGH LEVEL RADIOACTIVE WASTE GLASS

    SciTech Connect (OSTI)

    Fox, K.

    2010-09-07T23:59:59.000Z

    High level radioactive wastes are being vitrified at the Savannah River Site for long term disposal. Many of the wastes contain sulfate at concentrations that can be difficult to retain in borosilicate glass. This study involves efforts to optimize the composition of a glass frit for combination with the waste to improve sulfate retention while meeting other process and product performance constraints. The fabrication and characterization of several series of simulated waste glasses are described. The experiments are detailed chronologically, to provide insight into part of the engineering studies used in developing frit compositions for an operating high level waste vitrification facility. The results lead to the recommendation of a specific frit composition and a concentration limit for sulfate in the glass for the next batch of sludge to be processed at Savannah River.

  4. Deuterium Retention in Beryllium Exposed to a 60kV Deuterium Beam ­ Consequences for Next Step Devices

    E-Print Network [OSTI]

    Deuterium Retention in Beryllium Exposed to a 60kV Deuterium Beam ­ Consequences for Next Step Devices

  5. Integrated head package for top mounted nuclear instrumentation

    DOE Patents [OSTI]

    Malandra, Louis J. (McKeesport, PA); Hornak, Leonard P. (Forest Hills, PA); Meuschke, Robert E. (Monroeville, PA)

    1993-01-01T23:59:59.000Z

    A nuclear reactor such as a pressurized water reactor has an integrated head package providing structural support and increasing shielding leading toward the vessel head. A reactor vessel head engages the reactor vessel, and a control rod guide mechanism over the vessel head raises and lowers control rods in certain of the thimble tubes, traversing penetrations in the reactor vessel head, and being coupled to the control rods. An instrumentation tube structure includes instrumentation tubes with sensors movable into certain thimble tubes disposed in the fuel assemblies. Couplings for the sensors also traverse penetrations in the reactor vessel head. A shroud is attached over the reactor vessel head and encloses the control rod guide mechanism and at least a portion of the instrumentation tubes when retracted. The shroud forms a structural element of sufficient strength to support the vessel head, the control rod guide mechanism and the instrumentation tube structure, and includes radiation shielding material for limiting passage of radiation from retracted instrumentation tubes. The shroud is thicker at the bottom adjacent the vessel head, where the more irradiated lower ends of retracted sensors reside. The vessel head, shroud and contents thus can be removed from the reactor as a unit and rested safely and securely on a support.

  6. Estimating IMU heading error from SAR images.

    SciTech Connect (OSTI)

    Doerry, Armin Walter

    2009-03-01T23:59:59.000Z

    Angular orientation errors of the real antenna for Synthetic Aperture Radar (SAR) will manifest as undesired illumination gradients in SAR images. These gradients can be measured, and the pointing error can be calculated. This can be done for single images, but done more robustly using multi-image methods. Several methods are provided in this report. The pointing error can then be fed back to the navigation Kalman filter to correct for problematic heading (yaw) error drift. This can mitigate the need for uncomfortable and undesired IMU alignment maneuvers such as S-turns.

  7. A Study of Strain Rate Effects for Turbulent Premixed Flames with Application to LES of a Gas Turbine Combustor Model

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Kemenov, Konstantin A.; Calhoon, William H.

    2015-03-24T23:59:59.000Z

    Large-scale strain rate field, a resolved quantity which is easily computable in large-eddy simulations (LES), could have profound effects on the premixed flame properties by altering the turbulent flame speed and inducing local extinction. The role of the resolved strain rate has been investigated in a posterior LES study of GE lean premixed dry low NOx emissions LM6000 gas turbine combustor model. A novel approach which is based on the coupling of the lineareddy model with a one-dimensional counter-flow solver has been applied to obtain the parameterizations of the resolved premixed flame properties in terms of the reactive progress variable, the local strain rate measure, and local Reynolds and Karlovitz numbers. The strain rate effects have been analyzed by comparing LES statistics for several models of the turbulent flame speed, i.e, with and without accounting for the local strain rate effects, with available experimental data. The sensitivity of the simulation results to the inflow velocity conditions as well as the grid resolution have been also studied. Overall, the results suggest the necessity to represent the strain rate effects accurately in order to improve LES modeling of the turbulent flame speed.

  8. A Study of Strain Rate Effects for Turbulent Premixed Flames with Application to LES of a Gas Turbine Combustor Model

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Kemenov, Konstantin A.; Calhoon, William H.

    2015-03-24T23:59:59.000Z

    Large-scale strain rate field, a resolved quantity which is easily computable in large-eddy simulations (LES), could have profound effects on the premixed flame properties by altering the turbulent flame speed and inducing local extinction. The role of the resolved strain rate has been investigated in a posterior LES study of GE lean premixed dry low NOx emissions LM6000 gas turbine combustor model. A novel approach which is based on the coupling of the lineareddy model with a one-dimensional counter-flow solver has been applied to obtain the parameterizations of the resolved premixed flame properties in terms of the reactive progress variable,more »the local strain rate measure, and local Reynolds and Karlovitz numbers. The strain rate effects have been analyzed by comparing LES statistics for several models of the turbulent flame speed, i.e, with and without accounting for the local strain rate effects, with available experimental data. The sensitivity of the simulation results to the inflow velocity conditions as well as the grid resolution have been also studied. Overall, the results suggest the necessity to represent the strain rate effects accurately in order to improve LES modeling of the turbulent flame speed.« less

  9. Phase-locked OH-PLIF of Oscillating Flame in Micro Channels FAN, Yong1*, SUZUKI, Yuji1, KASAGI, Nobuhide1

    E-Print Network [OSTI]

    Kasagi, Nobuhide

    excitation lines [6]. Experimental setup of phase-locked OH-PLIF imaging has been developedPhase-locked OH-PLIF of Oscillating Flame in Micro Channels FAN, Yong1*, SUZUKI, Yuji1, KASAGI in the oscillation process are investigated with phase-locked OH-PLIF imaging technique. 2. Flame velocity Figures. 1

  10. Plasmas and Polymers, Vol. 8, No. 1, March 2003 ( C 2003) A Comparison of Corona-Treated and Flame-Treated

    E-Print Network [OSTI]

    Kushner, Mark

    Plasmas and Polymers, Vol. 8, No. 1, March 2003 ( C 2003) A Comparison of Corona-Treated and Flame-Treated of corona-treated and flame-treated polypropylene (PP) films provides insight into the mechanism-ray photoelectron spectroscopy (XPS or ESCA) were used to characterize surface-treated biaxially oriented PP. While

  11. Enhancements of a Combustion Vessel to Determine Laminar Flame Speeds of Hydrocarbon Blends with Helium Dilution at Elevated Temperatures and Pressures

    E-Print Network [OSTI]

    Plichta, Drew

    2013-04-03T23:59:59.000Z

    of importance comes the need for baseline data such as laminar flame speed of said fuels. While flame speeds at standard temperature and pressure have been extensively studied in the literature, experimental data at turbine-like conditions are still lacking...

  12. Council on Environmental Quality - Memorandum for Heads of Federal...

    Open Energy Info (EERE)

    navigation, search OpenEI Reference LibraryAdd to library Memorandum: Council on Environmental Quality - Memorandum for Heads of Federal Departments and Agencies Abstract This...

  13. antigenic polar heads: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Stenger; Robert L. Modlin; Ian A. Wilson; Steven A. Porcelli; Michael B. Brenner 1999-01-01 11 Head: Vacancy Quality & Standards Mathematics Websites Summary: : Dr Sarah...

  14. adaptive head motion: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    and performs principal ... Balakrishnan, Guha 2014-01-01 7 Computational Modeling of Brain Dynamics during Repetitive Head Motions Computer Technologies and Information...

  15. Global modes, receptivity, and sensitivity analysis of diffusion flames coupled with duct

    E-Print Network [OSTI]

    Magri, Luca; Juniper, Matthew P.

    2015-01-01T23:59:59.000Z

    to the performance of the system. These oscillations are a persistent problem. Their comprehension, prediction and control in the design of gas turbines and rocket engines are areas of current research, as reviewed by Lieuwen & Yang (2005); Culick (2006... ,B,C,D and in the online supplementary material. 2. Thermo-acoustic model The thermo-acoustic model consists of a diffusion flame placed in an acoustic duct (figure 1). The acoustic waves cause perturbations in the velocity field. In turn, these Receptivity and sensitivity...

  16. OPPDIF: A Fortran program for computing opposed-flow diffusion flames

    SciTech Connect (OSTI)

    Lutz, A.E.; Kee, R.J.; Grcar, J.F.; Rupley, F.M. [Sandia National Labs., Livermore, CA (United States). Thermal and Plasma Processes Dept.

    1997-05-01T23:59:59.000Z

    OPPDIF is a Fortran program that computes the diffusion flame between two opposing nozzles. A similarity transformation reduces the two-dimensional axisymmetric flow field to a one-dimensional problem. Assuming that the radial component of velocity is linear in radius, the dependent variables become functions of the axial direction only. OPPDIF solves for the temperature, species mass fractions, axial and radial velocity components, and radial pressure gradient, which is an eigenvalue in the problem. The TWOPNT software solves the two-point boundary value problem for the steady-state form of the discretized equations. The CHEMKIN package evaluates chemical reaction rates and thermodynamic and transport properties.

  17. Horsehead Resource Development Company, Inc. , flame reactor technology. Technology demonstration summary

    SciTech Connect (OSTI)

    Not Available

    1992-10-01T23:59:59.000Z

    Under the Superfund Innovative Technology Evaluation (SITE) program, the Horsehead Resource Development Company, Inc., (HRD) Flame Reactor was evaluated during a series of test runs. The tests were conducted at the HRD facility in Monaca, PA, using 72 tons of secondary lead smelter soda slag (waste feed) from the National Smelting and Refining Company, Inc., site in Atlanta, GA. The waste feed contained lead, zinc, iron, and many other metals and inorganic compounds. This summary includes an overview of the demonstration, a technology description, analytical results, and conclusions.

  18. Fiber optic spectroscopic digital imaging sensor and method for flame properties monitoring

    DOE Patents [OSTI]

    Zelepouga, Serguei A. (Hoffman Estates, IL); Rue, David M. (Chicago, IL); Saveliev, Alexei V. (Chicago, IL)

    2011-03-15T23:59:59.000Z

    A system for real-time monitoring of flame properties in combustors and gasifiers which includes an imaging fiber optic bundle having a light receiving end and a light output end and a spectroscopic imaging system operably connected with the light output end of the imaging fiber optic bundle. Focusing of the light received by the light receiving end of the imaging fiber optic bundle by a wall disposed between the light receiving end of the fiber optic bundle and a light source, which wall forms a pinhole opening aligned with the light receiving end.

  19. Systems and methods for detecting a flame in a fuel nozzle of a gas turbine

    DOE Patents [OSTI]

    Kraemer, Gilbert Otto; Storey, James Michael; Lipinski, John; Mestroni, Julio Enrique; Williamson, David Lee; Marshall, Jason Randolph; Krull, Anthony

    2013-05-07T23:59:59.000Z

    A system may detect a flame about a fuel nozzle of a gas turbine. The gas turbine may have a compressor and a combustor. The system may include a first pressure sensor, a second pressure sensor, and a transducer. The first pressure sensor may detect a first pressure upstream of the fuel nozzle. The second pressure sensor may detect a second pressure downstream of the fuel nozzle. The transducer may be operable to detect a pressure difference between the first pressure sensor and the second pressure sensor.

  20. Retention of Hydrogen Isotopes in Neutron Irradiated Tungsten

    SciTech Connect (OSTI)

    Yuji Hatano; Masashi Shimada; Yasuhisa Oya; Guoping Cao; Makoto Kobayashi; Masanori Hara; Brad J. Merrill; Kenji Okuno; Mikhail A. Sokolov; Yutai Katoh

    2013-03-01T23:59:59.000Z

    To investigate the effects of neutron irradiation on hydrogen isotope retention in tungsten, disk-type specimens of pure tungsten were irradiated in the High Flux Isotope Reactor in Oak Ridge National Laboratory followed by exposure to high flux deuterium (D) plasma in Idaho National Laboratory. The results obtained for low dose n-irradiated specimens (0.025 dpa for tungsten) are reviewed in this paper. Irradiation at coolant temperature of the reactor (around 50 degrees C) resulted in the formation of strong trapping sites for D atoms. The concentrations of D in n-irradiated specimens were ranging from 0.1 to 0.4 mol% after exposure to D plasma at 200 and 500 degrees C and significantly higher than those in non-irradiated specimens because of D-trapping by radiation defects. Deep penetration of D up to a depth of 50-100 µm was observed at 500 degrees C. Release of D in subsequent thermal desorption measurements continued up to 900 degrees C. These results were compared with the behaviour of D in ion-irradiated tungsten, and distinctive features of n-irradiation were discussed.

  1. Formation and retention of methane in coal. Final report

    SciTech Connect (OSTI)

    Hucka, V.J.; Bodily, D.M.; Huang, H.

    1992-05-15T23:59:59.000Z

    The formation and retention of methane in coalbeds was studied for ten Utah coal samples, one Colorado coal sample and eight coal samples from the Argonne Premium Coal Sample Bank.Methane gas content of the Utah and Colorado coals varied from zero to 9 cm{sup 3}/g. The Utah coals were all high volatile bituminous coals. The Colorado coal was a gassy medium volatile bituminous coal. The Argonne coals cover a range or rank from lignite to low volatile bituminous coal and were used to determine the effect of rank in laboratory studies. The methane content of six selected Utah coal seams and the Colorado coal seam was measured in situ using a special sample collection device and a bubble desorbometer. Coal samples were collected at each measurement site for laboratory analysis. The cleat and joint system was evaluated for the coal and surrounding rocks and geological conditions were noted. Permeability measurements were performed on selected samples and all samples were analyzed for proximate and ultimate analysis, petrographic analysis, {sup 13}C NMR dipolar-dephasing spectroscopy, and density analysis. The observed methane adsorption behavior was correlated with the chemical structure and physical properties of the coals.

  2. Pilot-Scale Benzene Retention and Release Demonstration

    SciTech Connect (OSTI)

    Marek, J.C.

    2003-11-10T23:59:59.000Z

    During the initial months of In-Tank Precipitation radioactive operation in 1995 the process experienced high rates of tetraphenylborate decomposition with assumed corresponding high rates of benzene generation. In March 1996 after a two month quiescent period, a water addition to Tank 48H resulted in an unexpected benzene release to the tank vapor phase. This was the first time a low energy input resulted in a significant release rate. This led to questions about how benzene, generated in-situ by TPB decomposition, was retained in the surrounding potassium tetraphenylborate slurry. It was postulated the retention mechanism may have changed during the quiescent period prior to March so the benzene present became readily releasable to the vapor phase with low energy input to the slurry or that enough benzene accumulated that some of it was in a different, more releasable form. Readily releasable is a qualitative term defined as a rapid release of benzene at a rate approaching evaporation of a free benzene layer. It is intended to distinguish between benzene in a form with high liquid phase resistance to mass transfer diffusion controlled from benzene in a form with minimal liquid phase resistance to mass transfer free benzene layer evaporation. If a readily releasable form of benzene was present, the vapor space profile during release tests was anticipated to have an initial benzene vapor space concentration peak followed by a lower vapor concentration, longer duration release.

  3. Two-dimensional imaging of gas-to-particle transition in flames by laser-induced nanoplasmas

    SciTech Connect (OSTI)

    Zhang, Yiyang [Key Laboratory for Thermal Science and Power Engineering of Ministry of Education, Department of Thermal Engineering, Tsinghua University, Beijing 100084 (China); Key Laboratory of Advanced Reactor Engineering and Safety of Ministry of Education, Institute of Nuclear and New Energy Technology, Tsinghua University, Beijing 100084 (China); Li, Shuiqing, E-mail: lishuiqing@tsinghua.edu.cn; Ren, Yihua; Yao, Qiang [Key Laboratory for Thermal Science and Power Engineering of Ministry of Education, Department of Thermal Engineering, Tsinghua University, Beijing 100084 (China); Law, Chung K. [Center for Combustion Energy, Tsinghua University, Beijing 100084 (China); Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, New Jersey 08544-5263 (United States)

    2014-01-13T23:59:59.000Z

    Two-dimensional imaging of gas/particle phase transition of metal oxides in their native high-temperature flow conditions, using laser-driven localized nanoplasmas, was obtained by utilizing the gap between the excitation energies of the gas and particle phases such that only the Ti atoms in the particle phase were selectively excited without detectable Bremsstrahlung background. These in situ images of the particle phase Ti distribution allow the quantitative visualization of the transition of the gas precursors to the nanoparticle phase across the flame sheet as well as diffusion of the particle concentration in the post-flame zone.

  4. A STUDY ON SPHERICAL EXPANDING FLAME SPEEDS OF METHANE, ETHANE, AND METHANE/ETHANE MIXTURES AT ELEVATED PRESSURES 

    E-Print Network [OSTI]

    De Vries, Jaap

    2010-07-14T23:59:59.000Z

    .......................................................................... 25? Figure 19. Number of GE gas turbines by fuel type, (source Campbell et al. [4]). ............ 28? Figure 20. Flame sheet dividing unburned reactants from the burned products. ............... 36? Figure 21. Mole fraction of CH 4 , O 2 , H... Situation in the US This study focuses on flame speeds of Natural-Gas (NG) fuel blends used by power- generation gas turbines. Demand for high-pressure combustion data of current and future candidate fuels is directly connected to changes in the world?s...

  5. Transparent hydrogel with enhanced water retention capacity by introducing highly hydratable salt

    E-Print Network [OSTI]

    Suo, Zhigang

    Transparent hydrogel with enhanced water retention capacity by introducing highly hydratable salt 2014; published online 14 October 2014) Polyacrylamide hydrogels containing salt as electrolyte have of polyacrylamide hydrogel by introducing highly hydratable salts into the hydrogel. These hydrogels show enhanced

  6. Abnormal Acidification of Melanoma Cells Induces Tyrosinase Retention in the Early Secretory Pathway*

    E-Print Network [OSTI]

    Hebert, Daniel N.

    Abnormal Acidification of Melanoma Cells Induces Tyrosinase Retention in the Early Secretory, Pennsylvania 19107 In tyrosinase-positive amelanotic melanoma cells, in- active tyrosinase accumulates-ATPase)-mediated proton transport in melanoma cells disrupts tyrosinase trafficking through the secretory pathway

  7. CHEMICAL TRACER RETENTION IN POROUS MEDIA Submitted to the Department of Petroleum Engineering

    E-Print Network [OSTI]

    Stanford University

    * CHEMICAL TRACER RETENTION IN POROUS MEDIA A Report Submitted to the Department of Petroleum Engineering of Stanford University in Fulfillment of the Requirement for the Degree of Master of Science

  8. Comparison of Different Forms of Creatine on Creatine Availability, Retention, and Training Adaptations 

    E-Print Network [OSTI]

    Jagim, Andrew Ryan

    2013-03-25T23:59:59.000Z

    The purpose of this study was to determine if a buffered creatine monohydrate (KA) that has been purported to promote greater creatine retention and training adaptations with fewer side effects at lower doses is more ...

  9. Closure head for a nuclear reactor

    DOE Patents [OSTI]

    Wade, Elman E. (South Huntingdon, PA)

    1980-01-01T23:59:59.000Z

    A closure head for a nuclear reactor includes a stationary outer ring integral with the reactor vessel with a first rotatable plug disposed within the stationary outer ring and supported from the stationary outer ring by a bearing assembly. A sealing system is associated with the bearing assembly to seal the annulus defined between the first rotatable plug and the stationary outer ring. The sealing system comprises tubular seal elements disposed in the annulus with load springs contacting the tubular seal elements so as to force the tubular seal elements against the annulus in a manner to seal the annulus. The sealing system also comprises a sealing fluid which is pumped through the annulus and over the tubular seal elements causing the load springs to compress thereby reducing the friction between the tubular seal elements and the rotatable components while maintaining a gas-tight seal therebetween.

  10. Light water reactor lower head failure analysis

    SciTech Connect (OSTI)

    Rempe, J.L.; Chavez, S.A.; Thinnes, G.L. [EG and G Idaho, Inc., Idaho Falls, ID (United States)] [and others

    1993-10-01T23:59:59.000Z

    This document presents the results from a US Nuclear Regulatory Commission-sponsored research program to investigate the mode and timing of vessel lower head failure. Major objectives of the analysis were to identify plausible failure mechanisms and to develop a method for determining which failure mode would occur first in different light water reactor designs and accident conditions. Failure mechanisms, such as tube ejection, tube rupture, global vessel failure, and localized vessel creep rupture, were studied. Newly developed models and existing models were applied to predict which failure mechanism would occur first in various severe accident scenarios. So that a broader range of conditions could be considered simultaneously, calculations relied heavily on models with closed-form or simplified numerical solution techniques. Finite element techniques-were employed for analytical model verification and examining more detailed phenomena. High-temperature creep and tensile data were obtained for predicting vessel and penetration structural response.

  11. Head Observation Organizer (HObO)

    SciTech Connect (OSTI)

    Steven Predmore

    2008-03-06T23:59:59.000Z

    The Head Observation Organizer, HObO, is a computer program that stores and manages measured ground-water levels. HObO was developed to help ground-water modelers compile, manage, and document water-level data needed to calibrate ground-water models. Well-construction and water-level data from the U.S. Geological Survey National Water Database (NWIS) easily can be imported into HObO from the NWIS web site (NWISWeb). The water-level data can be flagged to determine which data will be included in the calibration data set. The utility program HObO_NWISWeb was developed to simplify the down loading of well and water-level data from NWISWeb. An ArcGIS NWISWeb Extension was developed to retrieve site information from NWISWeb. A tutorial is presented showing the basic elements of HObO.

  12. An Analysis of Texas Superintendents' Bilingual/ESL Teacher Recruitment and Retention Practices

    E-Print Network [OSTI]

    Lara-Alecio, Rafael; Galloway, Martha; Irby, Beverly J.; Brown, Genevieve

    2010-10-22T23:59:59.000Z

    year prior to the AAEE report, the Urban Teacher Collaborative Bilingual/ESL Teacher Recruitment/Retention 4 had already determined that bilingual educators were in very high demand, as were ESL teachers (The Urban Teacher Collaborative, 2000... organizations/conferences. Bilingual/ESL Teacher Recruitment/Retention 13 Several other questions related to recruitment were included on the survey. Response to a question related to in-district/in-state recruitment indicated that 53.4% (N=285...

  13. Retention of passive integrated transponder tags in largemouth bass brood fish

    SciTech Connect (OSTI)

    Harvey, W.D.; Campbell, D.L. (Texas Parks and Wildlife Dept., Austin (USA))

    1989-07-01T23:59:59.000Z

    Passive integrated transponder (PIT) tags were injected into 22 largemouth bass (Micropterus salmoides) brood fish to determine the retention rate of the tags, the effect on spawning success, and the utility of the tags as a means of individual fish identification. Fish were evaluated 12, 17, and 24 months after implantation. All tags were retained and all tagged fish were recognized. Tag injection and retention had no discernible effect on spawning success.

  14. Review of fission product retention experiment results and application to the LWR design

    SciTech Connect (OSTI)

    Lischer, D.J.; Elia, F.A. Jr. (Stone and Webster Engineering Corp., Boston, MA (United States))

    1992-01-01T23:59:59.000Z

    This paper examines the available literature on pipe retention of aerosols to determine the feasiblity of taking credit for attenuation of radioactive release from the plant through pipes when calculating off-site dose rates for plant licensing and emergency planning considerations. The results show that deposition in pipes can be significant. Experimental work on aerosol plugging shows that this phenomenon may provide the dominant mechanism for fission product retention.

  15. The retention and distribution of Salmonella typhimurium in the channel catfish (Ictalurus punctatus) 

    E-Print Network [OSTI]

    Cook, Gary Lee

    1981-01-01T23:59:59.000Z

    THE RETENTION AND DISTRIBUTION OF SALMONELLA TYPHIMURIUM IN THE CHANNEL CATFISH (ICTALURUS PUNCTATUS) A Thesis by GARY LEE COON Submitted to the Graduate College of' Texas A8d~ University in partial fulfillment of the requirement... for the degree of MASTER OF SCIENCE December Ig81 Major Subject: Veterinary Microbiology THE RETENTION AND DISTRIBUTION OF SALMONELLA TYPHIMURIUM IN THE CHANNEL CATFISH (ICTALURUS PUNCTATUS) A Thesis by GARY LEE COON Approved as to style and content by...

  16. Topic Models to Interpret MeSH MEDLINE's Medical Subject Headings

    E-Print Network [OSTI]

    Newman, David

    ://ii.nlm.nih.gov/mti.shtml #12;MeSH heading Major MeSH heading Major qualifier MeSH-qualifier combination Humans Brain metabolism Brain (metabolism) Table 1. Most frequent MeSH headings, major MeSH headings, major qualifiers and MeTopic Models to Interpret MeSH ­ MEDLINE's Medical Subject Headings David Newman12 , Sarvnaz Karimi

  17. Computational Fluid Dynamics Modeling of the Operation of a Flame Ionization Sensor

    SciTech Connect (OSTI)

    Huckaby, E.D.; Chorpening, B.T.; Thornton, J.D.

    2007-03-01T23:59:59.000Z

    The sensors and controls research group at the United States Department of Energy (DOE) National Energy Technology Laboratory (NETL) is continuing to develop the Combustion Control and Diagnostics Sensor (CCADS) for gas turbine applications. CCADS uses the electrical conduction of the charged species generated during the combustion process to detect combustion instabilities and monitor equivalence ratio. As part of this effort, combustion models are being developed which include the interaction between the electric field and the transport of charged species. The primary combustion process is computed using a flame wrinkling model (Weller et. al. 1998) which is a component of the OpenFOAM toolkit (Jasak et. al. 2004). A sub-model for the transport of charged species is attached to this model. The formulation of the charged-species model similar that applied by Penderson and Brown (1993) for the simulation of laminar flames. The sub-model consists of an additional flux due to the electric field (drift flux) added to the equations for the charged species concentrations and the solution the electric potential from the resolved charge density. The subgrid interactions between the electric field and charged species transport have been neglected. Using the above procedure, numerical simulations are performed and the results compared with several recent CCADS experiments.

  18. Flow field studies of a new series of turbulent premixed stratified flames

    SciTech Connect (OSTI)

    Seffrin, F.; Fuest, F.; Dreizler, A. [Technische Universitaet Darmstadt, Center of Smart Interfaces, Reaktive Stroemungen und Messtechnik, Petersenstr. 32, 64287 Darmstadt (Germany); Geyer, D. [Hochschule Darmstadt, Thermodynamik und Alternative Antriebe, Haardtring 100, 64295 Darmstadt (Germany)

    2010-02-15T23:59:59.000Z

    This paper presents a new burner design for lean premixed stratified combustion for experiments to validate models for numerical simulations. The burner demonstrates combustion phenomena relevant to technological applications, where flames are often turbulent, lean premixed, and stratified. The generic burner was designed for high Reynolds number flows and can stabilize a variety of different lean premixed flames. The burner's design and its versatile operational conditions are introduced. Shear, stratification, and fuel type are parametrically varied to provide a sound database of related flow configurations. Reacting and corresponding non-reacting configurations are examined. Experimental setups and the results of laser Doppler velocimetry (LDV) and particle image velocimetry (PIV) are presented and discussed. LDV measurements provide radial profiles of mean axial velocity, mean radial velocity, and turbulent kinetic energy as well as integral time scales. High-speed PIV is introduced as a novel technique to determine integral time and length scales and provide 2D 2-component velocity fields and related quantities, such as vorticity. (author)

  19. Modeling of the formation of short-chain acids in propane flames

    E-Print Network [OSTI]

    Battin-Leclerc, Frédérique; Jaffrezo, J L; Legrand, M

    2009-01-01T23:59:59.000Z

    In order to better understand their potential formation in combustion systems, a detailed kinetic mechanism for the formation of short-chain monocarboxylic acids, formic (HCOOH), acetic (CH3COOH), propionic (C2H5COOH) and propenic (C2H3COOH)) acids, has been developed. Simulations of lean (equivalence ratios from 0.9 to 0.48) laminar premixed flames of propane stabilized at atmospheric pressure with nitrogen as diluent have been performed. It was found that amounts up to 25 ppm of acetic acid, 15 ppm of formic acid and 1 ppm of C3 acid can be formed for some positions in the flames. Simulations showed that the more abundant C3 acid formed is propenic acid. A quite acceptable agreement has been obtained with the scarce results from the literature concerning oxygenated compounds, including aldehydes (CH2O, CH3CHO) and acids. A reaction pathways analysis demonstrated that each acid is mainly derived from the aldehyde of similar structure.

  20. Simulations of spray autoignition and flame establishment with two-dimensional CMC

    SciTech Connect (OSTI)

    Wright, Y.M.; Boulouchos, K. [Aerothermochemistry and Combustion Technology Laboratory, ETH Zurich (Switzerland); De Paola, G.; Mastorakos, E. [Hopkinson Laboratory, Department of Engineering, University of Cambridge, Cambridge CB2 1PZ (United Kingdom)

    2005-12-01T23:59:59.000Z

    The unsteady two-dimensional conditional moment closure (CMC) model with first-order closure of the chemistry and supplied with standard models for the conditional convection and turbulent diffusion terms has been interfaced with a commercial engine CFD code and analyzed with two numerical methods, an 'exact' calculation with the method of lines and a faster fractional-step method. The aim was to examine the sensitivity of the predictions to the operator splitting errors and to identify the extent to which spatial transport terms are important for spray autoignition problems. Despite the underlying simplifications, solution of the full CMC equations allows a single model to be used for the autoignition, flame propagation ('premixed mode'), and diffusion flame mode of diesel combustion, which makes CMC a good candidate model for practical engine calculations. It was found that (i) the conditional averages have significant spatial gradients before ignition and during the premixed mode and (ii) that the inclusion of physical-space transport affects the calculation of the autoignition delay time, both of which suggest that volume-averaged CMC approaches may be inappropriate for diesel-like problems. A balance of terms in the CMC equation before and after autoignition shows the relative magnitude of spatial transport and allows conjectures on the structure of the premixed phase of diesel combustion. Very good agreement with available experimental data is found concerning ignition delays and the effect of background air turbulence on them.

  1. Transported PDF Modeling of Nonpremixed Turbulent CO/H-2/N-2 Jet Flames

    SciTech Connect (OSTI)

    Zhao, xinyu; Haworth, D. C.; Huckaby, E. David

    2012-01-01T23:59:59.000Z

    Turbulent CO/H{sub 2}/N{sub 2} (“syngas”) flames are simulated using a transported composition probability density function (PDF) method. A consistent hybrid Lagrangian particle/Eulerian mesh algorithm is used to solve the modeled PDF transport equation. The model includes standard k–? turbulence, gradient transport for scalars, and Euclidean minimum spanning tree (EMST) mixing. Sensitivities of model results to variations in the turbulence model, the treatment of radiation heat transfer, the choice of chemical mechanism, and the PDF mixing model are explored. A baseline model reproduces the measured mean and rms temperature, major species, and minor species profiles reasonably well, and captures the scaling that is observed in the experiments. Both our results and the literature suggest that further improvements can be realized with adjustments in the turbulence model, the radiation heat transfer model, and the chemical mechanism. Although radiation effects are relatively small in these flames, consideration of radiation is important for accurate NO prediction. Chemical mechanisms that have been developed specifically for fuels with high concentrations of CO and H{sub 2} perform better than a methane mechanism that was not designed for this purpose. It is important to account explicitly for turbulence–chemistry interactions, although the details of the mixing model do not make a large difference in the results, within reasonable limits.

  2. Thermonuclear Flame Spreading on Rapidly Spinning Neutron Stars: Indications of the Coriolis Force?

    E-Print Network [OSTI]

    Sudip Bhattacharyya; Tod E. Strohmayer

    2007-08-27T23:59:59.000Z

    Millisecond period brightness oscillations during the intensity rise of thermonuclear X-ray bursts are likely caused by an azimuthally asymmetric, expanding burning region on the stellar surface. The time evolution of the oscillation amplitude during the intensity rise encodes information on how the thermonuclear flames spread across the stellar surface. This process depends on properties of the accreted burning layer, surface fluid motions, and the surface magnetic field structure, and thus can provide insight into these stellar properties. We present two examples of bursts from different sources that show a decrease in oscillation amplitude during the intensity rise. Using theoretical modeling, we demonstrate that the observed amplitude evolution of these bursts is not well described by a uniformly expanding circular burning region. We further show that by including in our model the salient aspects of the Coriolis force (as described by Spitkovsky, Levin, and Ushomirsky) we can qualitatively reproduce the observed evolution curves. Our modeling shows that the evolutionary structure of burst oscillation amplitude is sensitive to the nature of flame spreading, while the actual amplitude values can be very useful to constrain some source parameters.

  3. Proceedings of the international workshop on measurement and computation of turbulent nonpremixed flames

    SciTech Connect (OSTI)

    Barlow, R.S. [ed.

    1996-10-01T23:59:59.000Z

    This report documents the proceedings of the International Workshop on Measurement and Computation of Turbulent Nonpremixed Flames, held in Naples, Italy on July 26--27, 1996. Contents include materials that were distributed to participants at the beginning of the workshop, as well as a Summary of Workshop Accomplishments that was generated at the close to this Naples meeting. The Naples workshop involved sixty-one people from eleven countries. The primary objectives were: (1) to select a set of well-documented and relatively simple flames that would be appropriate for collaborative comparisons of model predictions; and (2) to specify common submodels to be used in these predictions, such that models for the coupling of turbulence and chemistry might be isolated and better understood. Studies involve hydrogen and natural gas fuels. These proceedings are also published on the Web and those interested in the ongoing process of data selection and model comparison should consult the workshop page for the most recent and complete information on these collaborative research efforts. The URL is: http://www/ca.sandia/gov/tdf/Workshop.html.

  4. Mobile Museum Tours 1 RUNNING HEAD: MOBILE MUSEUM TOURS

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    Mobile Museum Tours 1 RUNNING HEAD: MOBILE MUSEUM TOURS Using mobile technologies for multimedia MUSEUM TOURS Abstract Mobile technology was used to deliver learner-centred experiences to visitors: Across generations and cultures, Banff : Canada (2006)" #12;Mobile Museum Tours 2 RUNNING HEAD: MOBILE

  5. Poverty and Productivity in Female-Headed Households in Zimbabwe

    E-Print Network [OSTI]

    Horrell, Sara; Krishnan, Pramila

    A household survey conducted in rural Zimbabwe in 2001 is used to compare the position of de facto and de jure female-headed households to those with a male head. These households are characterised by different forms of poverty that impinge...

  6. High-temperature aerosol formation in wood pellets flames: Spatially resolved measurements

    SciTech Connect (OSTI)

    Wiinikka, Henrik; Gebart, Rikard [Energy Technology Centre, Box 726, S-941 28 Piteaa (Sweden); Boman, Christoffer; Bostroem, Dan; Nordin, Anders; OEhman, Marcus [Energy Technology and Thermal Process Chemistry, Umeaa University, S-901 87 Umeaa (Sweden)

    2006-12-15T23:59:59.000Z

    The formation and evolution of high-temperature aerosols during fixed bed combustion of wood pellets in a realistic combustion environment were investigated through spatially resolved experiments. The purpose of this work was to investigate the various stages of aerosol formation from the hot flame zone to the flue gas channel. The investigation is important both for elucidation of the formation mechanisms and as a basis for development and validation of particle formation models that can be used for design optimization. Experiments were conducted in an 8-kW-updraft fired-wood-pellets combustor. Particle samples were withdrawn from the centerline of the combustor through 10 sampling ports by a rapid dilution sampling probe. The corresponding temperatures at the sampling positions were in the range 200-1450{sup o}C. The particle sample was size-segregated in a low-pressure impactor, allowing physical and chemical resolution of the fine particles. The chemical composition of the particles was investigated by SEM/EDS and XRD analysis. Furthermore, the experimental results were compared to theoretical models for aerosol formation processes. The experimental data show that the particle size distribution has two peaks, both of which are below an aerodynamic diameter of 2.5 {mu}m (PM{sub 2.5}). The mode diameters of the fine and coarse modes in the PM{sub 2.5} region were {approx}0.1 and {approx}0.8 {mu}m, respectively. The shape of the particle size distribution function continuously changes with position in the reactor due to several mechanisms. Early, in the flame zone, both the fine mode and the coarse mode in the PM{sub 2.5} region were dominated by particles from incomplete combustion, indicated by a significant amount of carbon in the particles. The particle concentrations of both the fine and the coarse mode decrease rapidly in the hot oxygen-rich flame due to oxidation of the carbon-rich particles. After the hot flame, the fine mode concentration and particle diameter increase gradually when the temperature of the flue gas drops. The main contribution to this comes from condensation on preexisting particles in the gas of alkali sulfates, alkali chlorides, and Zn species formed from constituents vaporized in the fuel bed. The alkali sulfates were found to condense at a temperature of {approx}950{sup o} and alkali chlorides condensed later at {approx}600{sup o}. This agrees well with results of chemical equilibrium calculation of the gas-to-particle conversion temperature. After the hot flame the coarse mode concentration decreased very little when the flue gas was cooled. In addition to carbon, the coarse mode consists of refractory metals and also considerable amounts of alkali. (author)

  7. Quantitative determination of vortex core dimensions in head-to-head domain walls using off-axis electron holography

    E-Print Network [OSTI]

    Dunin-Borkowski, Rafal E.

    transformations.7 Recent experimental reports confirm these predictions of domain wall movement8Quantitative determination of vortex core dimensions in head-to-head domain walls using off-dimensional characterization of vortex core spin structures, which is important for future magnetic data storage based

  8. 61.99.01.V1.01 RETENTION OF STATE RECORDS Supplements System Regulation 61.99.01, Retention and

    E-Print Network [OSTI]

    ) will maintain an active and continuing state records management program in compliance with the Texas A&M System to manage and retain state records according to the Texas A&M System Regulations, Records Retention Schedule, and disposition of public records are established by the State and Local Records Management Division of the Texas

  9. An analytical investigation of primary zone combustion temperatures and NOx production for turbulent jet flames using low-BTU fuels 

    E-Print Network [OSTI]

    Carney, Christopher Mark

    1995-01-01T23:59:59.000Z

    The objective of this research project was to identify and determine the effect of jet burner operating variables that influence combustion of low-BTU gases. This was done by simulating the combustion of a low-BTU fuel in a jet flame and predicting...

  10. Fractal Analysis of Flame-Synthesized Nanostructured Silica and Titania Powders Using Small-Angle X-ray

    E-Print Network [OSTI]

    Beaucage, Gregory

    Fractal Analysis of Flame-Synthesized Nanostructured Silica and Titania Powders Using Small-Angle X these powders display mass-fractal morphologies, which are composed of ramified aggregates of nanoscale primary particles. Primary particle size, aggregate size, fractal dimension, and specific surface area are obtained

  11. Nonpremixed ignition, laminar flame propagation, and mechanism reduction of n-butanol, iso-butanol, and methyl butanoate

    SciTech Connect (OSTI)

    Lu, Wei; Kelley, A. P.; Law, C. K.

    2011-01-01T23:59:59.000Z

    The non-premixed ignition temperature of n-butanol (CH{sub 3}CH{sub 2}CH{sub 2}CH{sub 2}OH), iso-butanol ((CH{sub 3}){sub 2}CHCH{sub 2}OH) and methyl butanoate (CH{sub 3}CH{sub 2}CH{sub 2}COOCH{sub 3}) was measured in a liquid pool assembly by heated oxidizer in a stagnation flow for system pressures of 1 and 3 atm. In addition, the stretch-corrected laminar flame speeds of mixtures of air–n-butanol/iso-butanol/methyl butanoate were determined from the outwardly propagating spherical flame at initial pressures of up to 2 atm, for an extensive range of equivalence ratio. The ignition temperature and laminar flame speeds of n-butanol and methyl butanoate were computationally simulated with three recently developed kinetic mechanisms in the literature. Dominant reaction pathways to ignition and flame propagation were identified and discussed through a chemical explosive mode analysis (CEMA) and sensitivity analysis. The detailed models were further reduced through a series of systematic strategies. The reduced mechanisms provided excellent agreement in both homogeneous and diffusive combustion environments and greatly improved the computation efficiency.

  12. Proceedings of the Combustion Institute, Volume 28, 2000/pp. 903910 TURBULENT FLAME DYNAMICS OF HOMOGENEOUS SOLID PROPELLANT

    E-Print Network [OSTI]

    Apte, Sourabh V.

    903 Proceedings of the Combustion Institute, Volume 28, 2000/pp. 903­910 TURBULENT FLAME DYNAMICS University Park, PA 16802, USA A comprehensive numerical analysis has been conducted to study the combustion development and its influence on propellant combustion. The formulation is based on the Favre

  13. Simultaneous measurements of soot volume fraction and particle size/microstructure in flames using a thermophoretic sampling technique

    SciTech Connect (OSTI)

    Koeylue, U.O.; McEnally, C.S.; Rosner, D.E.; Pfefferle, L.D. [Yale Univ., New Haven, CT (United States). Dept. of Chemical Engineering] [Yale Univ., New Haven, CT (United States). Dept. of Chemical Engineering

    1997-09-01T23:59:59.000Z

    A new particle volume fraction measurement technique was developed using electron microscope analysis of thermophoretically sampled particles/aggregates based on a theoretical treatment of particle deposition to a cold surface immersed in a flame. This experimental method, referred to as the thermophoretic sampling particle diagnostic (TSPD), can yield all particle parameters of principal interest (particle volume fraction, particle and aggregate sizes, and fractal properties) without requiring knowledge of particle bulk density and refractive index. To assess its reliability, the TSPD technique was implemented at various heights on the centerline of a soot-containing coflowing ethylene/air nonpremixed laminar flame. Inferred soot volume fractions agreed with previous laser extinction and thermocouple particle densitometry measurements within experimental uncertainties at sampling positions where only aggregates of mature particles were present. However, TSPD-soot volume fractions were about a factor of 3 higher than light extinction results in the lower part of the flame. This significant difference was evidently a result of the presence of translucent precursor soot particles, which do not absorb as much visible light as mature particles, but can be quantified with the electron microscope. Clearly, this ability of TSPD to separately measure the concentration and morphology of each type of soot is a significant advantage over other available diagnostics, making it extremely valuable for studying particle formation in flames.

  14. Detailed investigation of a pulverized fuel swirl flame in CO{sub 2}/O{sub 2} atmosphere

    SciTech Connect (OSTI)

    Toporov, D.; Bocian, P.; Heil, P.; Kellermann, A.; Stadler, H.; Tschunko, S.; Foerster, M.; Kneer, R. [Institute of Heat and Mass Transfer, RWTH Aachen University, Eilfschornsteinstrasse 18, D-52056 Aachen (Germany)

    2008-12-15T23:59:59.000Z

    A novel approach to oxycoal flame stabilization has been developed at the Institute of Heat and Mass Transfer at RWTH Aachen University [D. Toporov, M. Foerster, R. Kneer, in: Third Int. Conf. on Clean Coal Technologies for Our Future, Cagliari, Sardinia, Italy, 15-17 May 2007]. The swirl burner design and its operating conditions have been adjusted in order to enforce CO formation thus stabilizing the flame and obtaining a full burnout at levels of O{sub 2} content in the O{sub 2}/CO{sub 2} mixture similar to those in air. The paper presents results of detailed numerical and experimental investigations of a stable oxy-fired pulverized coal swirl flame (type-2) obtained with a 21 vol% O{sub 2} concentration. The combustion tests were performed in a vertical pilot-scale furnace (100 kW{sub th}) in the framework of the OXYCOAL-AC research project aiming to develop a membrane-based oxyfuel process. The experimental results concerning gas velocities, gas and particle temperatures, and gas compositions are presented and discussed, focusing on the underlying mechanisms as well as on the aerodynamics of the oxycoal flame. A comparison between measurements and simulations has shown the validity of the numerical method used. The reported data set can be used for validation of numerical models developed for prediction of oxyfuel combustion. (author)

  15. An analytical investigation of primary zone combustion temperatures and NOx production for turbulent jet flames using low-BTU fuels

    E-Print Network [OSTI]

    Carney, Christopher Mark

    1995-01-01T23:59:59.000Z

    The objective of this research project was to identify and determine the effect of jet burner operating variables that influence combustion of low-BTU gases. This was done by simulating the combustion of a low-BTU fuel in a jet flame and predicting...

  16. Assessment of kinetic modeling for lean H2/CH4/O2/diluent flames at high pressures

    E-Print Network [OSTI]

    Ju, Yiguang

    : Hydrogen; Methane; Syngas; Flame speed; Chemical mechanism 1. Introduction The H2/O2 reaction system CO, CO2, H2O, CH4 and other small hydrocarbons (synthetic gas or "syngas") from coal or biomass gasification [2]. Typical syngas mixtures can contain significant amounts of small molecular weight

  17. Kinetic and Friction Head Loss Impacts on Horizontal Water Supply and Aquifer Storage and Recovery Wells 

    E-Print Network [OSTI]

    Blumenthal, Benjamin

    2014-12-02T23:59:59.000Z

    well construction or intra-wellbore head loss. Currently no analytical groundwater model rigorously accounts for intra-wellbore kinetic and friction head loss. We have developed a semi-analytical, intra-wellbore head loss model dynamically linked...

  18. NO{sub x} emissions of a jet diffusion flame which is surrounded by a shroud of combustion air

    SciTech Connect (OSTI)

    Tran, P.X.; White, F.P.; Mathur, M.P.; Ekmann, J.M.

    1996-08-01T23:59:59.000Z

    The present work reports an experimental study on the behavior of a jet flame surrounded by a shroud of combustion air. Measurements focussed on the flame length and the emissions of NO{sub x}, total unburned hydrocarbons, CO{sub 2}, and O{sub 2}. Four different fuel flow rates (40.0, 78.33, 138.33, and 166.6 cm/s), air flow rates up to 2500 cm{sup 3}/s and four different air injector diameters (0.079 cm, 0. 158 cm, 0.237 cm, and 0.316 cm) were used. The shroud of combustion air causes the flame length to decrease by a factor proportional to 1/[p{sub a}/p{sub f} + C{sub 2}({mu}{sub a}Re,a/{mu}{sub f}Re,f){sup 2}]{sup {1/2}}. A substantial shortening of the flame length occurred by increasing the air injection velocity keeping fuel rate fixed or conversely by lowering the fuel flow rate keeping air flow rate constant. NO{sub x} emissions ranging from 5 ppm to 64 ppm were observed and the emission of NO{sub x} decreased strongly with the increased air velocity. The decrease of NO{sub x} emissions was found to follow a similar scaling law as does the flame length. However, the emission of the total hydrocarbons increased with the increased air velocity or the decreased fuel flow rate. A crossover condition where both NO{sub x} and unburned- hydrocarbon emissions are low, was identified. At an air-to-fuel velocity ratio of about 1, the emissions of NO{sub x} and the total hydrocarbons were found to be under 20 ppm.

  19. High energy activation data library (HEAD-2009)

    SciTech Connect (OSTI)

    Mashnik, Stepan G [Los Alamos National Laboratory; Korovin, Yury A [NON LANL; Natalenko, Anatoly A [NON LANL; Konobeyev, Alexander Yu [NON LANL; Stankovskiy, A Yu [NON LANL

    2010-01-01T23:59:59.000Z

    A proton activation data library for 682 nuclides from 1 H to 210Po in the energy range from 150 MeV up to 1 GeV was developed. To calculate proton activation data, the MCNPX 2.6.0 and CASCADE/INPE codes were chosen. Different intranuclear cascade, preequilibrium, and equilibrium nuclear reaction models and their combinations were used. The optimum calculation models have been chosen on the basis of statistical correlations for calculated and experimental proton data taken from the EXFOR library of experimental nuclear data. All the data are written in ENDF-6 format. The library is called HEPAD-2008 (High-Energy Proton Activation Data). A revision of IEAF-2005 neutron activation data library has been performed. A set of nuclides for which the cross-section data can be (and were) updated using more modern and improved models is specified, and the corresponding calculations have been made in the present work. The new version of the library is called IEAF-2009. The HEPAD-2008 and IEAF-2009 are merged to the final HEAD-2009 library.

  20. Correlation of gas-chromatographic retention indices and high-order bonding indices for polycyclic aromatic hydrocarbons

    SciTech Connect (OSTI)

    Bulycheva, Z.Y.; Dylevskaya, L.V.; Kutenev, V.F.; Rudenko, B.A.

    1985-08-10T23:59:59.000Z

    The authors apply multifactor correlation equations between the retention indices on OV-101, OV-17, and PFMS-6 polysiloxanes and the bonding indices from the zeroth to fourth orders. Certain fragment descriptors are also applied which give higher significance levels and standard deviations for the retention indices less by 18-25 units, than do correlation equations between the retention indices and the first-order bonding indices.

  1. Sorghum head silage, with and without haylage, for fattening steers

    E-Print Network [OSTI]

    Stilwell, Daniel Emerson

    1963-01-01T23:59:59.000Z

    steers in all treatment groups during the first few days of the trial. A ma)ority of the cases occurred in the group fed soxghum heads and 2 lb. CSM and most of these cases wex'e during the first three days of the experiment when s dry ground mixture..., and 2 lb. CSM (285 lb. ). The steers fed heads, haylage, and 1 lb. CSM had the lowest total gain (254 lb. ), but this was not significantly diffexent from the group fed heads, haylage, and 2 lb. of CSM (264 lb. ), ox the group fed grain, haylage...

  2. Non-normality in combustion-acoustic interaction in diffusion flames: a critical revision

    E-Print Network [OSTI]

    Magri, Luca; Sujith, R I; Juniper, Matthew P

    2013-01-01T23:59:59.000Z

    Perturbations in a non-normal system can grow transiently even if the system is linearly stable. If this transient growth is sufficiently large, it can trigger self-sustained oscillations from small initial disturbances. This has important practical consequences for combustion-acoustic oscillations, which are a continual problem in rocket and aircraft engines. Balasubramanian and Sujith (Journal of Fluid Mechanics, 2008, 594, 29-57) modelled an infinite-rate chemistry diffusion flame in an acoustic duct and found that the transient growth in this system can amplify the initial energy by a factor, $G_{max}$, of order $10^5$ to $10^7$. However, recent investigations by L. Magri & M. P. Juniper have brought to light certain errors in that paper. When the errors are corrected, $G_{max}$ is found to be of order 1 to 10, revealing that non-normality is not as influential as it was thought to be.

  3. MODELING SHALLOW GROUNDWATER TABLE CONTRIBUTION TO SOIL WATER RETENTION IN THE UNSATURATED ZONE OF A CALCAREOUS SOIL OF SOUTH

    E-Print Network [OSTI]

    Migliaccio, Kati White

    1 MODELING SHALLOW GROUNDWATER TABLE CONTRIBUTION TO SOIL WATER RETENTION IN THE UNSATURATED ZONE...................................................................................................................................13 CHAPTER 1 GENERAL INTRODUCTION.............................................................................................................................15 Shallow Groundwater Capillarity

  4. Distribution of copper, silver and gold during thermal treatment with brominated flame retardants

    SciTech Connect (OSTI)

    Oleszek, Sylwia, E-mail: sylwia_oleszek@yahoo.com [Institute of Multidisciplinary Research for Advanced Materials (IMRAM), Tohoku University, 1,1 Katahira, 2-Chome, Sendai 980-8577 (Japan); Institute of Environmental Engineering of the Polish Academy of Sciences, 34 M. Sklodowska-Curie St., 41-819 Zabrze (Poland); Grabda, Mariusz, E-mail: mariusz@mail.tagen.tohoku.ac.jp [Institute of Multidisciplinary Research for Advanced Materials (IMRAM), Tohoku University, 1,1 Katahira, 2-Chome, Sendai 980-8577 (Japan); Institute of Environmental Engineering of the Polish Academy of Sciences, 34 M. Sklodowska-Curie St., 41-819 Zabrze (Poland); Shibata, Etsuro, E-mail: etsuro@tagen.tohoku.ac.jp [Institute of Multidisciplinary Research for Advanced Materials (IMRAM), Tohoku University, 1,1 Katahira, 2-Chome, Sendai 980-8577 (Japan); Nakamura, Takashi, E-mail: ntakashi@tagen.tohoku.ac.jp [Institute of Multidisciplinary Research for Advanced Materials (IMRAM), Tohoku University, 1,1 Katahira, 2-Chome, Sendai 980-8577 (Japan)

    2013-09-15T23:59:59.000Z

    Highlights: • Copper, silver and gold during thermal treatment with brominated flame retardants. • Distribution of copper, silver and gold during thermal processing. • Thermodynamic considerations of the bromination reactions. - Abstract: The growing consumption of electric and electronic equipment results in creating an increasing amount of electronic waste. The most economically and environmentally advantageous methods for the treatment and recycling of waste electric and electronic equipment (WEEE) are the thermal techniques such as direct combustion, co-combustion with plastic wastes, pyrolysis and gasification. Nowadays, this kind of waste is mainly thermally treated in incinerators (e.g. rotary kilns) to decompose the plastics present, and to concentrate metals in bottom ash. The concentrated metals (e.g. copper, precious metals) can be supplied as a secondary raw material to metal smelters, while the pyrolysis of plastics allows the recovery of fuel gases, volatilising agents and, eventually, energy. Indeed, WEEE, such as a printed circuit boards (PCBs) usually contains brominated flame retardants (BFRs). From these materials, hydrobromic acid (HBr) is formed as a product of their thermal decomposition. In the present work, the bromination was studied of copper, silver and gold by HBr, originating from BFRs, such as Tetrabromobisphenol A (TBBPA) and Tetrabromobisphenol A-Tetrabromobisophenol A diglycidyl ether (TTDE) polymer; possible volatilization of the bromides formed was monitored using a thermo-gravimetric analyzer (TGA) and a laboratory-scale furnace for treating samples of metals and BFRs under an inert atmosphere and at a wide range of temperatures. The results obtained indicate that up to about 50% of copper and silver can evolve from sample residues in the form of volatile CuBr and AgBr above 600 and 1000 °C, respectively. The reactions occur in the molten resin phase simultaneously with the decomposition of the brominated resin. Gold is resistant to HBr and remains unchanged in the residue.

  5. Chemiluminescence-based multivariate sensing of local equivalence ratios in premixed atmospheric methane-air flames

    SciTech Connect (OSTI)

    Tripathi, Markandey M.; Krishnan, Sundar R.; Srinivasan, Kalyan K.; Yueh, Fang-Yu; Singh, Jagdish P.

    2012-03-01T23:59:59.000Z

    Chemiluminescence emissions from OH*, CH*, C2, and CO2 formed within the reaction zone of premixed flames depend upon the fuel-air equivalence ratio in the burning mixture. In the present paper, a new partial least square regression (PLS-R) based multivariate sensing methodology is investigated and compared with an OH*/CH* intensity ratio-based calibration model for sensing equivalence ratio in atmospheric methane-air premixed flames. Five replications of spectral data at nine different equivalence ratios ranging from 0.73 to 1.48 were used in the calibration of both models. During model development, the PLS-R model was initially validated with the calibration data set using the leave-one-out cross validation technique. Since the PLS-R model used the entire raw spectral intensities, it did not need the nonlinear background subtraction of CO2 emission that is required for typical OH*/CH* intensity ratio calibrations. An unbiased spectral data set (not used in the PLS-R model development), for 28 different equivalence ratio conditions ranging from 0.71 to 1.67, was used to predict equivalence ratios using the PLS-R and the intensity ratio calibration models. It was found that the equivalence ratios predicted with the PLS-R based multivariate calibration model matched the experimentally measured equivalence ratios within 7%; whereas, the OH*/CH* intensity ratio calibration grossly underpredicted equivalence ratios in comparison to measured equivalence ratios, especially under rich conditions ( > 1.2). The practical implications of the chemiluminescence-based multivariate equivalence ratio sensing methodology are also discussed.

  6. arsenic affects head: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    and ecological analyses. In A. Kirlik (Ed Gray, Wayne 430 Energy Savings from Floating Head Pressure in Ammonia Refrigeration Systems Texas A&M University - TxSpace Summary:...

  7. acute head injury: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    and ecological analyses. In A. Kirlik (Ed Gray, Wayne 336 Energy Savings from Floating Head Pressure in Ammonia Refrigeration Systems Texas A&M University - TxSpace Summary:...

  8. active head lice: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    and ecological analyses. In A. Kirlik (Ed Gray, Wayne 251 Energy Savings from Floating Head Pressure in Ammonia Refrigeration Systems Texas A&M University - TxSpace Summary:...

  9. acute head trauma: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    and ecological analyses. In A. Kirlik (Ed Gray, Wayne 278 Energy Savings from Floating Head Pressure in Ammonia Refrigeration Systems Texas A&M University - TxSpace Summary:...

  10. affects head kidney: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    and ecological analyses. In A. Kirlik (Ed Gray, Wayne 344 Energy Savings from Floating Head Pressure in Ammonia Refrigeration Systems Texas A&M University - TxSpace Summary:...

  11. advanced inoperable head: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    and ecological analyses. In A. Kirlik (Ed Gray, Wayne 208 Energy Savings from Floating Head Pressure in Ammonia Refrigeration Systems Texas A&M University - TxSpace Summary:...

  12. acute severe head: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    and ecological analyses. In A. Kirlik (Ed Gray, Wayne 252 Energy Savings from Floating Head Pressure in Ammonia Refrigeration Systems Texas A&M University - TxSpace Summary:...

  13. adult human head: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    and ecological analyses. In A. Kirlik (Ed Gray, Wayne 350 Energy Savings from Floating Head Pressure in Ammonia Refrigeration Systems Texas A&M University - TxSpace Summary:...

  14. Printed circuit board for a CCD camera head

    DOE Patents [OSTI]

    Conder, Alan D. (Tracy, CA)

    2002-01-01T23:59:59.000Z

    A charge-coupled device (CCD) camera head which can replace film for digital imaging of visible light, ultraviolet radiation, and soft to penetrating x-rays, such as within a target chamber where laser produced plasmas are studied. The camera head is small, capable of operating both in and out of a vacuum environment, and is versatile. The CCD camera head uses PC boards with an internal heat sink connected to the chassis for heat dissipation, which allows for close (0.04" for example) stacking of the PC boards. Integration of this CCD camera head into existing instrumentation provides a substantial enhancement of diagnostic capabilities for studying high energy density plasmas, for a variety of military industrial, and medical imaging applications.

  15. Zeroth-order inversion of transient head observations

    SciTech Connect (OSTI)

    Vasco, D.W.

    2007-08-15T23:59:59.000Z

    A high-frequency, asymptotic solution for transient head,appropriate for a medium containing smoothly varying heterogeneity,provides a basis for efficient inverse modeling. The semi analyticsolution is trajectory based, akin to ray methods used in modeling wavepropagation, and may be constructed by post processing the output of anumerical simulator. For high frequencies, the amplitude sensitivities,the relationship between changes in flow properties and changes in headampliude, are dominated by the phase term which may be computed directlyfrom the output of the simulator. Thus, transient head waveforms may beinverted with little more computation than is required to invert arrivaltimes. An applicatino to synthetic head values indicates that thetechnique can be used to improve the fit to waveforms. An application totransient head data from the Migration experiment in Switzerland revealsa narrow, high conductivity pathway within a 0.5 m thick zone offracturing.

  16. Theoretical collapse pressures for two pressurized torispherical heads

    SciTech Connect (OSTI)

    Kalnins, A.; Updike, D.P. [Lehigh Univ., Bethlehem, PA (United States); Rana, M.D. [Praxair, Inc., Tonawanda, NY (United States). Research and Development Dept.

    1995-12-01T23:59:59.000Z

    In order to determine the pressures at which real torispherical heads fail upon a single application of pressure, two heads were pressurized in recent Praxair tests, and displacements and strains were recorded at various locations. In this paper, theoretical results for the two test heads are presented in the form of curves of pressure versus crown deflections, using the available geometry and material parameters. From these curves, limit and collapse pressures are calculated, using procedures permitted by the ASME B and PV Code Section 8/Div.2. These pressures are shown to vary widely, depending on the method and model used to calculate them. The effect of no stress relief on the behavior of the Praxair test heads is also evaluated and found to be of no significance for neither the objectives of the tests nor the objectives of this paper. The results of this paper are submitted as an enhancement to the experimental results recorded during the Praxair tests.

  17. Metastasis of genitourinary tumors to the head and neck region

    E-Print Network [OSTI]

    Ogunyemi, Ore; Rojas, A.; Hematpour, K.; Rogers, D.; Head, C.; Bennett, C.

    2010-01-01T23:59:59.000Z

    · D. Rogers · C. Head · C. Bennett Received: 14 SeptemberO. Ogunyemi · A. Rojas · C. Bennett David GeVen School ofLos Angeles, CA, USA C. Bennett Department of Urology,

  18. Influence of rainfall on the retention of sludge trace metals by the leaves of forage crops

    E-Print Network [OSTI]

    Jones, Stephen Grady

    1977-01-01T23:59:59.000Z

    INFLUENCE OF RAINFALL ON THE RETENTION OF SLUDGE TRACE METALS BY THE LEAVES OF FORAGE CROPS A Thesis STEPHEN GRADY JONES Submitted to the Graduate College of Texas A&M University in partial fulfillment of the requirement for the degree... of MASTER OF SCIENCE December 1977 Major Subject: Soil Science INFLUENCE OF RAINFALL ON THE RETENTION OF SLUDGE TRACE MFTALS BY THE LEAVES OF FORAGE CROPS A Thesis by STEPHEN GRADY JONES Approved a to style and content by: 1 (Chairman of Committee...

  19. Retention by vegetation of radionuclides deposited in rainfall: A literature summary

    SciTech Connect (OSTI)

    Anspaugh, L.R.

    1987-06-01T23:59:59.000Z

    Data include the results of experiments with artificial tracers and information from direct measurements of naturally occurring and fallout-produced radionuclides washed out or rained out by storms. Individual measurements of retention varied from negative to over 100%. The conclusion is that a value of 0.4 to 0.5 would be appropriate for average retention, and a value of 1.0 would not be unreasonable if one wished to be conservative, particularly where high vegetation densities might be expected. 35 refs., 16 tabs.

  20. Bear Head LNG Corporation and Bear Head LNG (USA), LLC- FE Dkt. No.- 15-33-LNG

    Broader source: Energy.gov [DOE]

    The Office of Fossil Energy gives notice of receipt of an application filed on February 25, 2015, by Bear Head LNG, requesting long-term multi-contract authority as further described in their...

  1. Chapter 17 Eye-head Gaze shifts Oxford Handbook on Eye Movements

    E-Print Network [OSTI]

    Corneil, Brian D.

    1 Chapter 17 Eye-head Gaze shifts Oxford Handbook on Eye Movements "The Neural Basis of Gaze Shifts" 1. Kinematics of eye-head gaze shifts a. Terminology for describing eye-head gaze shifts b. Variability in eye and head motion during gaze shifts c. Gaze shifts in complex environments d. Bottom

  2. SAYA's head-eye coordination system Correspondence of image-width and angle

    E-Print Network [OSTI]

    Beimel, Amos

    SAYA's head-eye coordination system Correspondence of image-width and angle 335 - 359 [deg] 0 - 25 - 25 [deg] is input, head and eyes move to right side. b) If the angle within 335 - 359 [deg] is input, head and eyes move to left side. SAYA's head-eye coordination system Correspondence of image

  3. The Mechatonic Design of a Human-like Robot Head Karsten Berns1

    E-Print Network [OSTI]

    Berns, Karsten

    The Mechatonic Design of a Human-like Robot Head Karsten Berns1 Carsten Hillenbrand1 and Krzystof. In this paper the design concept as well as the constructed human-like robot head is introduced. Main goal of the head design is the support of an adequate human machine interaction. Therefore, our robots head should

  4. Exhibit 1C Patent Rights Retention by the Seller ITER UT-B Contracts Div Page 1 of 5

    E-Print Network [OSTI]

    Pennycook, Steve

    Exhibit 1C ­ Patent Rights ­ Retention by the Seller ­ ITER UT-B Contracts Div March 2007 Page 1 of 5 ex1c-ITER-mar07.doc Exhibit 1C ­ ITER Ref: DEAR 952.227-11 PATENT RIGHTS - RETENTION BY THE SELLER is or may be patentable or otherwise protectable under title 35 of the United States Code, or any novel

  5. Radiation-turbulence interactions in pulverized-coal flames. Quarterly reports I and II, September 15, 1993--March 15, 1994

    SciTech Connect (OSTI)

    Menguec, M.P.; McDonough, J.M.

    1994-05-01T23:59:59.000Z

    This is the First Report of the project titled {open_quotes}Radiation-Turbulence Interactions in Pulverized-Coal Flames{close_quotes}. The report covers the period of 6 months from September 15, 1993 to March 15, 1994. During the period covered, the authors have started to modify the experimental facilities for this research and worked on the formulation. This period has been more like a planning time. They expect to have more accomplishments within the next three months.

  6. TIME-VARYING FLAME IONIZATION SENSING APPLIED TO NATURAL GAS AND PROPANE BLENDS IN A PRESSURIZED LEAN PREMIXED (LPM) COMBUSTOR

    SciTech Connect (OSTI)

    D. L. Straub; B. T. Chorpening; E. D. Huckaby; J. D. Thornton; W. L. Fincham

    2008-06-13T23:59:59.000Z

    In-situ monitoring of combustion phenomena is a critical need for optimal operation and control of advanced gas turbine combustion systems. The concept described in this paper is based on naturally occurring flame ionization processes that accompany the combustion of hydrocarbon fuels. Previous work has shown that flame ionization techniques may be applied to detect flashback, lean blowout, and some aspects of thermo-acoustic combustion instabilities. Previous work has focused on application of DC electric fields. By application of time-varying electric fields, significant improvements to sensor capabilities have been observed. These data have been collected in a lean premixed combustion test rig operating at 0.51-0.76 MPa (5-7.5 atm) with air preheated to 588 K (600°F). Five percent of the total fuel flow is injected through the centerbody tip as a diffusion pilot. The fuel composition is varied independently by blending approximately 5% (volume) propane with the pipeline natural gas. The reference velocity through the premixing annulus is kept constant for all conditions at a nominal value of 70 m/s. The fuel-air equivalence ratio is varied independently from 0.46 – 0.58. Relative to the DC field version, the time-varying combustion control and diagnostic sensor (TV-CCADS) shows a significant improvement in the correlation between the measured flame ionization current and local fuel-air equivalence ratio. In testing with different fuel compositions, the triangle wave data show the most distinct change in flame ionization current in response to an increase in propane content. Continued development of this sensor technology will improve the capability to control advanced gas turbine combustion systems, and help address issues associated with variations in fuel supplies.

  7. Development and technology transfer of the BNL flame quality indicator for oil-fired applications: Project report

    SciTech Connect (OSTI)

    Butcher, T.A.; Litzke, Wai Lin; McDonald, R.J.

    1994-09-01T23:59:59.000Z

    The purpose of a flame quality indicator is to continuously and closely monitor the quality of the flame to determine a heating system`s operating performance. The most efficient operation of a system is achieved under clean burning conditions at low excess air level. By adjusting a burner to function in such a manner, monitoring the unit to maintain these conditions can be accomplished with a simple, cheap and reliable device. This report details the development of the Flame Quality Indicator (FQI) at Brookhaven National Laboratory for residential oil-heating equipment. It includes information on the initial testing of the original design, field testing with other cooperating organizations, changes and improvements to the design, and finally technology transfer and commercialization activities geared towards the development of commercially available products designed for the oil heat marketplace. As a result of this work, a patent for the technology was obtained by the U.S. Department of Energy (DOE). Efforts to commercialize the technology have resulted in a high level of interest amongst industry members including boiler manufacturers, controls manufacturers, oil dealers, and service organizations. To date DOE has issued licenses to three different manufacturers, on a non-exclusive basis, to design, build, and sell FQIs.

  8. Dynamic light scattering in sooting premixed atmospheric-pressure methane-, propane-, ethene-, and propene-oxygen flames

    SciTech Connect (OSTI)

    Lamprecht, A.; Eimer, W.; Kohse-Hoeinghaus, K. [Univ. Bielefeld (Germany)] [Univ. Bielefeld (Germany)

    1999-07-01T23:59:59.000Z

    In a systematic investigation under well-defined flame conditions, dynamic light scattering (DLS) was applied to the determination of soot particle radii with the aim of examining the suitability of this technique for accurate soot particle sizing. In particular, flat premixed methane-, propane-, ethene-, and propene-oxygen flames at atmospheric pressure were investigated, and particle sizes were obtained as a function of stoichiometry and height above the burner surface. In combination with absorption measurements, soot volume fraction and particle number density were determined; also, the temperature was measured at each flame condition. In comparison to absorption techniques, attractive features of DLS are its independence of the particle refractive index and its insensitivity to fluorescence interference; also, it offers spatial resolution. In principle, additional information on the particle size distribution as well as on the global shape of the particles may be obtained from DLS experiments. This study is therefore an evaluation of the potential of DLS as a complement to other soot diagnostic techniques.

  9. Flame aerosol nano-technology has been developed to preparation of thin and defect-free porous membrane from the gas phase as a one step method in preparation of membrane for gas

    E-Print Network [OSTI]

    Abstract Flame aerosol nano-technology has been developed to preparation of thin and defect on deposition of nano particles (-Al2O3, MgO or spinel MgAl2O4), formed in the premixed flame reactor through/or aluminium precursors in the flame to form nano-particles of -Al2O3, MgO or MgAl2O4 spinel. The generated

  10. Finance Program Retention for FALL 2014 Instructions for Transcript Review Form

    E-Print Network [OSTI]

    Kostic, Milivoje M.

    Finance Program ­ Retention for FALL 2014 Instructions for Transcript Review Form College of Business at Northern Illinois University The Department of Finance Transcript Review Form should in the finance core). All NIU students are eligible to declare a major in Finance; however, students must meet

  11. REVIEW ARTICLE Pakistan Vet. J., 24(1): 2004 FACTORS CONTRIBUTING TO YOLK RETENTION

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    REVIEW ARTICLE Pakistan Vet. J., 24(1): 2004 46 FACTORS CONTRIBUTING TO YOLK RETENTION IN POULTRY Department of Microbiology, University of Veterinary and Animal Sciences, Lahore, Pakistan ABSTRACT Yolk) stated that it was the commonest cause of early chick mortality in Pakistan. Jordan (1990) and Singh et

  12. NMR investigations of water retention mechanism by cellulose ethers in cement-based materials

    E-Print Network [OSTI]

    Boyer, Edmond

    1 NMR investigations of water retention mechanism by cellulose ethers in cement-based materials J of freshly-mixed white cement pastes. NMRD is useful to determine the surface diffusion coefficient of water, the specific surface area and the hydration kinetics of the cement-based material. In spite of modifications

  13. Digestibility and energy retention by young rabbits fed different levels of intake

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    Note Digestibility and energy retention by young rabbits fed different levels of intake Fernando in digestibility cages, were fed a standard diet at four levels of intake: ad libitum (AL), 60, 40 and 10 % of the AL intake. Digestibility of dietary dry matter, organic matter, crude protein, ether extract and ash

  14. Influence of addition order and contact time on thorium (IV) retention by hematite in the presence

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    1 Influence of addition order and contact time on thorium (IV) retention by hematite.reiller@cea.fr The influence of addition order and contact time in the system hematite (-Fe2O3) ­ humic acid (HA) ­ thorium (IV) was studied in batch experiments. Thorium (IV) is considered here as a chemical analogue of other actinides

  15. Trace Metal Retention in the Incorporation Zone of Land-Applied

    E-Print Network [OSTI]

    Walter, M.Todd

    , with agricultural, forest, and range lands as well as land reclamation sites increasingly used for land applicationTrace Metal Retention in the Incorporation Zone of Land-Applied Sludge T A M M O S . S T E E N H U, Ithaca, New York 14853 Recycling nutrients in wastewater sludge (biosolids) via land application

  16. PRIMARY RESEARCH PAPER Effects of travertine and flow on leaf retention

    E-Print Network [OSTI]

    Marks, Jane

    retention. Travertine, or calcium carbonate (CaCO3), is a mineral precipitate deposited when turbulence- induced CO2 out-gassing shifts the bicarbonate equilibrium, causing CaCO3 to deposit in the stream channel-fed, karst streams with supersaturated levels of CaCO3 (frequently 5­10 times saturation with respect

  17. Mesh Width Influences Prey Retention in Spider Orb Webs Todd A. Blackledge & Jacquelyn M. Zevenbergen

    E-Print Network [OSTI]

    Blackledge, Todd

    Mesh Width Influences Prey Retention in Spider Orb Webs Todd A. Blackledge & Jacquelyn M. Zevenbergen Department of Biology, The University of Akron, Akron, OH, USA Introduction Orb webs depend upon threads, the sticky spirals of orb webs perform two important functions during prey cap- ture. First

  18. Toxicity of nickel to the earthworm and the applicability of the neutral red retention assay

    E-Print Network [OSTI]

    Hopkin, Steve

    Toxicity of nickel to the earthworm and the applicability of the neutral red retention assay JANECK of nickel on survival, growth, and reproduction of Eisenia veneta were investigated following 4 weeks of exposure to a nickel-chloride spiked loamy sand soil. The ability of a simple earthworm biomarker

  19. Background: Subsurface Water Retention Technology (SWRT) Durable and easy to install: Water

    E-Print Network [OSTI]

    Background: Subsurface Water Retention Technology (SWRT) Benefits Durable and easy to install: Water retaining membranes can last at least 40 years and can be installed quickly and costeffectively permeable marginal soils converting them to much higher production levels of food crops. Better water

  20. Endoplasmic reticulum retention is a common defect associated with tyrosinase-negative albinism

    E-Print Network [OSTI]

    Hebert, Daniel N.

    Endoplasmic reticulum retention is a common defect associated with tyrosinase-negative albinism, March 16, 2000 (received for review February 17, 2000) Tyrosinase is a melanocyte-specific enzyme albino substitution TYR(T373K), and the temperature-sensitive tyrosinase TYR(R402Q) Tyr(H402A) found

  1. Influence of plasticizer molecular weight on plasticizer retention in PVC geomembranes

    E-Print Network [OSTI]

    PROOFS Influence of plasticizer molecular weight on plasticizer retention in PVC geomembranes T. D, accepted 31 October 2004 ABSTRACT: Plasticizers are used to make PVC flexible so it can be used as a geomembrane. Plasticizers can migrate from PVC geomembranes over time because of contact with air, liquid, and

  2. Recent Advances on Hydrogenic Retention in ITER's Plasma-Facing Materials: BE, C, W.

    SciTech Connect (OSTI)

    Skinner, C H; Alimov, Kh; Bekris, N; Causey, R A; Clark, R.E.H.; Coad, J P; Davis, J W; Doerner, R P; Mayer, M; Pisarev, A; Roth, J

    2008-03-29T23:59:59.000Z

    Management of tritium inventory remains one of the grand challenges in the development of fusion energy and the choice of plasma-facing materials is a key factor for in-vessel tritium retention. The Atomic and Molecular Data Unit of the International Atomic Energy Agency organized a Coordinated Research Project (CRP) on the overall topic of tritium inventory in fusion reactors during the period 2001-2006. This dealt with hydrogenic retention in ITER's plasma-facing materials, Be, C, W, and in compounds (mixed materials) of these elements as well as tritium removal techniques. The results of the CRP are summarized in this article together with recommendations for ITER. Basic parameters of diffusivity, solubility and trapping in Be, C and W are reviewed. For Be, the development of open porosity can account for transient hydrogenic pumping but long term retention will be dominated by codeposition. Codeposition is also the dominant retention mechanism for carbon and remains a serious concern for both Be and C containing layers. Hydrogenic trapping in unirradiated tungsten is low but will increase with ion and neutron damage. Mixed materials will be formed in a tokamak and these can also retain significant amounts of hydrogen isotopes. Oxidative and photon-based techniques for detritiation of plasma-facing components are described.

  3. Integrated head package cable carrier for a nuclear power plant

    DOE Patents [OSTI]

    Meuschke, Robert E. (Monroeville, PA); Trombola, Daniel M. (Murrysville, PA)

    1995-01-01T23:59:59.000Z

    A cabling arrangement is provided for a nuclear reactor located within a containment. Structure inside the containment is characterized by a wall having a near side surrounding the reactor vessel defining a cavity, an operating deck outside the cavity, a sub-space below the deck and on a far side of the wall spaced from the near side, and an operating area above the deck. The arrangement includes a movable frame supporting a plurality of cables extending through the frame, each connectable at a first end to a head package on the reactor vessel and each having a second end located in the sub-space. The frame is movable, with the cables, between a first position during normal operation of the reactor when the cables are connected to the head package, located outside the sub-space proximate the head package, and a second position during refueling when the cables are disconnected from the head package, located in the sub-space. In a preferred embodiment, the frame straddles the top of the wall in a substantially horizontal orientation in the first position, pivots about an end distal from the head package to a substantially vertically oriented intermediate position, and is guided, while remaining about vertically oriented, along a track in the sub-space to the second position.

  4. Remote controlled ISI devices for RPV bottom head

    SciTech Connect (OSTI)

    Shiga, S. [Toshiba Corp., Yokohama (Japan); Mori, H. [Tokyo Electric Power Co. (Japan); Kobayashi, K. Sasaki, T. [Ishikawajima-Harima Heavy Industries Co., Ltd., Yokohama (Japan)

    1995-08-01T23:59:59.000Z

    The bottom head of a reactor pressure vessel (RPV) of the boiling water reactor (BWR) is one of the areas on which it is very difficult to perform an inservice inspection (ISI). Welds in a bottom head central disk and a drain nozzle are required to be inspected, but its accessibility is restricted by a RPV skirt, a thermal insulation, control rod drive housings and incore monitor housings. Therefore, the remote mechanized scanners are necessary to access and examine the welds. Two kinds of new device were developed to accomplish this inspection. The bottom head central disk weld inspection device has a parallel link mechanism scanning arm with a combined-transducer module to get as much as wide scanning area between control rod drive housings. The device is driven along the weld by moving on the separable track which is set temporally on the bottom head insulation. The drain nozzle weld inspection device has a horseshoe shaped gear mechanism to drive a combined-transducer module. The device is set up on to the drain nozzle using an insertion handle. Both devices have an emergency retrieval mechanism to withdraw the devices in case of power loss accident. Those devices were demonstrated by a mock-up test to be applicable to the inspection of the RPV bottom head.

  5. Strong-Sludge Gas Retention and Release Mechanisms in Clay Simulants

    SciTech Connect (OSTI)

    Gauglitz, Phillip A.; Buchmiller, William C.; Probert, Samuel G.; Owen, Antionette T.; Brockman, Fred J.

    2012-02-24T23:59:59.000Z

    The Hanford Site has 28 double-shell tanks (DSTs) and 149 single-shell tanks (SSTs) containing radioactive wastes that are complex mixes of radioactive and chemical products. The mission of the Department of Energy's River Protection Project is to retrieve and treat the Hanford tank waste for disposal and close the tank farms. A key aspect of the mission is to retrieve and transfer waste from the SSTs, which are at greater risk for leaking, into DSTs for interim storage until the waste is transferred to and treated in the Waste Treatment and Immobilization Plant. There is, however, limited space in the existing DSTs to accept waste transfers from the SSTs, and approaches to overcoming the limited DST space will benefit the overall mission. The purpose of this study is to summarize and analyze the key previous experiment that forms the basis for the relaxed controls and to summarize progress and results on new experiments focused on understanding the conditions that result in low gas retention. The previous large-scale test used about 50 m3 of sediment, which would be unwieldy for doing multiple parametric experiments. Accordingly, experiments began with smaller-scale tests to determine whether the desired mechanisms can be studied without the difficulty of conducting very large experiments. The most significant results from the current experiments are that progressively lower gas retention occurs in tests with progressively deeper sediment layers and that the method of gas generation also affects the maximum retention. Based on the results of this study, it is plausible that relatively low gas retention could occur in sufficiently deep tank waste in DSTs. The current studies and previous work, however, have not explored how gas retention and release will behave when two or more layers with different properties are present.

  6. Numerical analysis of the effect of acetylene and benzene addition to low-pressure benzene-rich flat flames on polycyclic aromatic hydrocarbon formation

    SciTech Connect (OSTI)

    Kunioshi, Nilson [Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871 (Japan); Komori, Seisaku [6th Group, Central Research Laboratory, Hamamatsu Photonics K. K. 500 Hirakuchi, Hamakita City, Shizuoka 434-8601 (Japan); Fukutani, Seishiro [Department of System Engineering, Okayama Prefectural University, 111 Kuboki, Soja, Okayama 719-1197 (Japan)

    2006-10-15T23:59:59.000Z

    A modification of the CHEMKIN II package has been proposed for modeling addition of an arbitrary species at an arbitrary temperature to an arbitrary distance from the burner along a flat flame. The modified program was applied to the problem of addition of acetylene or benzene to different positions of a 40-Torr, {phi}=2.4 benzene/O{sub 2}/40%-N{sub 2} premixed flame to reach final equivalence ratios of {phi}=2.5 and 2.681. The results obtained showed that acetylene addition to early positions of the flame led to significant increase in pyrene production rates, but pyrene concentrations were lower in the flames with acetylene addition in both the {phi}=2.5 and 2.681 cases. Addition of benzene to the flame did not alter pyrene production rates in either the {phi}=2.5 or 2.681 cases; however, for {phi}=2.5, pyrene concentrations increased with benzene addition, while for {phi}=2.681, pyrene contents decreased in comparison to the correspondent flames with no addition. Acetylene addition led to a significant increase in pyrene production rates, but the pyrene levels dropped due to increase in the flow velocity. Pyrene production rates were not sensitive to benzene addition, but pyrene contents increased with benzene addition when the flow velocity decreased. These results show that PAH concentration changes accompanying species addition to flames should be interpreted carefully, because an increase or decrease in the content of a PAH species does not necessarily reflect an effect on its formation rate or mechanism. (author)

  7. Implementation of two-equation soot flamelet models for laminar diffusion flames

    SciTech Connect (OSTI)

    Carbonell, D.; Oliva, A.; Perez-Segarra, C.D. [Centre Tecnologic de Transferencia de Calor (CTTC), Universitat Politecnica de Catalunya (UPC), ETSEIAT, Colom 11, E-08222, Terrassa (Barcelona) (Spain)

    2009-03-15T23:59:59.000Z

    The two-equation soot model proposed by Leung et al. [K.M. Leung, R.P. Lindstedt, W.P. Jones, Combust. Flame 87 (1991) 289-305] has been derived in the mixture fraction space. The model has been implemented using both Interactive and Non-Interactive flamelet strategies. An Extended Enthalpy Defect Flamelet Model (E-EDFM) which uses a flamelet library obtained neglecting the soot formation is proposed as a Non-Interactive method. The Lagrangian Flamelet Model (LFM) is used to represent the Interactive models. This model uses direct values of soot mass fraction from flamelet calculations. An Extended version (E-LFM) of this model is also suggested in which soot mass fraction reaction rates are used from flamelet calculations. Results presented in this work show that the E-EDFM predict acceptable results. However, it overpredicts the soot volume fraction due to the inability of this model to couple the soot and gas-phase mechanisms. It has been demonstrated that the LFM is not able to predict accurately the soot volume fraction. On the other hand, the extended version proposed here has been shown to be very accurate. The different flamelet mathematical formulations have been tested and compared using well verified reference calculations obtained solving the set of the Full Transport Equations (FTE) in the physical space. (author)

  8. Chemical response of methane/air diffusion flames to unsteady strain rate

    SciTech Connect (OSTI)

    Im, H.G.; Chen, J.H. [Sandia National Labs., Livermore, CA (United States); Chen, J.Y. [Univ. of California, Berkeley, CA (United States). Dept. of Mechanical Engineering

    1998-03-01T23:59:59.000Z

    Effects of unsteady strain rate on the response of methane/air diffusion flames are studied. The authors use the finite-domain opposed flow configuration in which the nozzle exit velocity is imposed as a function of time. The GRI mechanism v2.11 is used for the detailed methane/air chemistry. The response of individual species to monochromatic oscillation in strain rate with various frequencies reveals that the fluctuation of slow species, such as CO and NO{sub x}, is more rapidly suppressed as the flow time scale decreases. It is also observed that the maximum CO concentration is very insensitive to the variation in the scalar dissipation rate. An extinction event due to an abrupt imposition of high strain rates is also simulated by an impulsive velocity with various frequencies. For a fast impulse, a substantial overshoot in NO{sub 2} concentration is observed after extinction. Finally, the overall fuel burning rate shows a nonmonotonic response to the variation in characteristic unsteady time scale, while the emission indices for NO{sub x} shows monotonic decay in response as frequency is increased.

  9. Study on premixed combustion in cylindrical micro combustors: Transient flame behavior and wall heat flux

    SciTech Connect (OSTI)

    Li, J.; Chou, S.K.; Huang, G.; Yang, W.M. [Department of Mechanical Engineering, National University of Singapore, 9 Engineering Drive 1, Singapore 117576 (Singapore); Li, Z.W. [SSLS, National University of Singapore, 5 Research Link, Singapore 117603 (Singapore)

    2009-04-15T23:59:59.000Z

    The micro combustor is a key component of the micro thermophotovoltaic (TPV) system. Improving the wall temperature of the micro combustor is an effective way to elevate the system efficiency. An experimental study on the wall temperature and radiation heat flux of a series of cylindrical micro combustors (with a backward-facing step) was carried out. For the micro combustors with d = 2 mm, the regime of successful ignition (under the cold wall condition) was identified for different combustor lengths. Acoustic emission was detected for some cases and the emitted sound was recorded and analyzed. Under the steady-state condition, the effects of the combustor diameter (d), combustor length (L), flow velocity (u{sub 0}) and fuel-air equivalence ratio ({phi}) on the wall temperature distribution were investigated by measuring the detailed wall temperature profiles. In the case that the micro combustor is working as an emitter, the optimum efficiency was found at {phi} {approx} 0.8, independent of the combustor dimensions (d and L) and the flow velocity. Under the experimental conditions employed in the present study, the positions of the peak wall temperature were found to be about 8-11 mm and 4-6 mm from the step for the d = 3 mm and d = 2 mm micro combustors, respectively, which are 8-11 and 8-12 times of their respective step heights. This result suggests that the backward-facing step employed in the combustor design is effective in stabilizing the flame position. (author)

  10. Development of flame retardant PV module encapsulants: Volume 1. Final report

    SciTech Connect (OSTI)

    Galica, J.P.

    1998-06-01T23:59:59.000Z

    This Phase 1 final report covers the work performed by Springborn Testing and Research, Inc., for the period October 1, 1997 to June 30, 1998 under the Department of Energy Cooperative Agreement Number DE-FC36-97GO10255, entitled Development of Flame Retardant PV Module Encapsulants. While use of roof-mounted arrays has always been an attractive means of deploying PV, only within recent years have such building integrated concepts (BIPV) found renewed interest among module makers and end-users. Prior to building integrated and rooftop applications, flammability requirements for modules have not been a great industry concern. However, with growing interest in BIPV and the requirement for building code requirements for commercial and industrial structures, flammability issues have become a barrier to entry for many module constructions into this potentially huge domestic market for PV. The overall goal of the 3 phase PV BONUS two project is to develop and commercialize a line of fire retardant encapsulation materials to serve the emerging building integrated and building mounted PV market. The objectives of the Phase 1 effort are limited to concept development and business planning activities.

  11. Multi-ported, internally recuperated burners for direct flame impingement heating applications

    SciTech Connect (OSTI)

    Abbasi, Hamid A. (Naperville, IL); Kurek, Harry (Dyer, IN); Chudnovsky, Yaroslav (Skokie, IL); Lisienko, Vladimir G. (Ekaterinburg, RU); Malikov, German K. (Ekaterinburg, RU)

    2010-08-03T23:59:59.000Z

    A direct flame impingement method and apparatus employing at least one multi-ported, internally recuperated burner. The burner includes an innermost coaxial conduit having a first fluid inlet end and a first fluid outlet end, an outermost coaxial conduit disposed around the innermost coaxial conduit and having a combustion products outlet end proximate the first fluid inlet end of the innermost coaxial conduit and a combustion products inlet end proximate the first fluid outlet end of the innermost coaxial conduit, and a coaxial intermediate conduit disposed between the innermost coaxial conduit and the outermost coaxial conduit, whereby a second fluid annular region is formed between the innermost coaxial conduit and the intermediate coaxial conduit and a combustion products annular region is formed between the intermediate coaxial conduit and the outermost coaxial conduit. The intermediate coaxial conduit has a second fluid inlet end proximate the first fluid inlet end of the innermost coaxial conduit and a second fluid outlet end proximate the combustion products inlet end of the outermost coaxial conduit.

  12. In-vessel Retention Strategy for High Power Reactors - K-INERI Final Report (includes SBLB Test Results for Task 3 on External Reactor Vessel Cooling (ERVC) Boiling Data and CHF Enhancement Correlations)

    SciTech Connect (OSTI)

    F. B. Cheung; J. Yang; M. B. Dizon; J. Rempe

    2005-01-01T23:59:59.000Z

    In-vessel retention (IVR) of core melt is a key severe accident management strategy adopted by some operating nuclear power plants and proposed for some advanced light water reactors (ALWRs). If there were inadequate cooling during a reactor accident, a significant amount of core material could become molten and relocate to the lower head of the reactor vessel, as happened in the Three Mile Island Unit 2 (TMI-2) accident. If it is possible to ensure that the vessel head remains intact so that relocated core materials are retained within the vessel, the enhanced safety associated with these plants can reduce concerns about containment failure and associated risk. For example, the enhanced safety of the Westinghouse Advanced 600 MWe PWR (AP600), which relied upon External Reactor Vessel Cooling (ERVC) for IVR, resulted in the U.S. Nuclear Regulatory Commission (US NRC) approving the design without requiring certain conventional features common to existing LWRs. However, it is not clear that currently proposed external reactor vessel cooling (ERVC) without additional enhancements could provide sufficient heat removal for higher-power reactors (up to 1500 MWe). Hence, a collaborative, three-year, U.S. - Korean International Nuclear Energy Research Initiative (INERI) project was completed in which the Idaho National Engineering and Environmental Laboratory (INEEL), Seoul National University (SNU), Pennsylvania State University (PSU), and the Korea Atomic Energy Research Institute (KAERI) investigated the performance of ERVC and an in-vessel core catcher (IVCC) to determine if IVR is feasible for reactors up to 1500 MWe.

  13. Experimental study of head loss and filtration for LOCA debris

    SciTech Connect (OSTI)

    Rao, D.V.; Souto, F.J. [Science and Engineering Associates, Inc., Albuquerque, NM (United States)

    1996-02-01T23:59:59.000Z

    A series of controlled experiments were conducted to obtain head loss and filtration characteristics of debris beds formed of NUKON{trademark} fibrous fragments, and obtain data to validate the semi-theoretical head loss model developed in NUREG/CR-6224. A thermally insulated closed-loop test set-up was used to conduct experiments using beds formed of fibers only and fibers intermixed with particulate debris. A total of three particulate mixes were used to simulate the particulate debris. The head loss data were obtained for theoretical fiber bed thicknesses of 0.125 inches to 4.0 inches; approach velocities of 0.15 to 1.5 ft/s; temperatures of 75 F and 125 F; and sludge-to-fiber nominal concentration ratios of 0 to 60. Concentration measurements obtained during the first flushing cycle were used to estimate the filtration efficiencies of the debris beds. For test conditions where the beds are fairly uniform, the head loss data were predictable within an acceptable accuracy range by the semi-theoretical model. The model was equally applicable for both pure fiber beds and the mixed beds. Typically the model over-predicted the head losses for very thin beds and for thin beds at high sludge-to-fiber mass ratios. This is attributable to the non-uniformity of such debris beds. In this range the correlation can be interpreted to provide upper bound estimates of head loss. This is pertinent for loss of coolant accidents in boiling water reactors.

  14. An improved dosimetric model of the head and brain

    E-Print Network [OSTI]

    Bouchet, Lionel Gerard

    1995-01-01T23:59:59.000Z

    Br). Other radionuclides considered may deposit in bone withm the head region (cranium or the spinal skeleton) (is'I, 2P, ssP, tssRe, 'ssRe, 'ssSm, "7~Sb, ssSr, s Sr, "nY, ss~Tc, tsiCs, ss"Ra), or m the thyroid fss~ Tc, and all iodme radionuclides... tagged to them (i. e. , radiopharmaceuticals). Nevertheless, studies of the small-scale dosimetry of the bram, and more generally, the organs of the head (brain, eyes thyroid, skull, skin), have not kept pace with the current advances in nuclear...

  15. A Discussion of SY-101 Crust Gas Retention and Release Mechanisms

    SciTech Connect (OSTI)

    SD Rassat; PA Gauglitz; SM Caley; LA Mahoney; DP Mendoza

    1999-02-23T23:59:59.000Z

    The flammable gas hazard in Hanford waste tanks was made an issue by the behavior of double-shell Tank (DST) 241-SY-101 (SY-101). Shortly after SY-101 was filled in 1980, the waste level began rising periodically, due to the generation and retention of gases within the slurry, and then suddenly dropping as the gases were released. An intensive study of the tank's behavior revealed that these episodic releases posed a safety hazard because the released gas was flammable, and, in some cases, the volume of gas released was sufficient to exceed the lower flammability limit (LFL) in the tank headspace (Allemann et al. 1993). A mixer pump was installed in SY-101 in late 1993 to prevent gases from building up in the settled solids layer, and the large episodic gas releases have since ceased (Allemann et al. 1994; Stewart et al. 1994; Brewster et al. 1995). However, the surface level of SY-101 has been increasing since at least 1995, and in recent months the level growth has shown significant and unexpected acceleration. Based on a number of observations and measurements, including data from the void fraction instrument (VFI), we have concluded that the level growth is caused largely by increased gas retention in the floating crust. In September 1998, the crust contained between about 21 and 43% void based on VFI measurements (Stewart et al. 1998). Accordingly, it is important to understand the dominant mechanisms of gas retention, why the gas retention is increasing, and whether the accelerating level increase will continue, diminish or even reverse. It is expected that the retained gas in the crust is flammable, with hydrogen as a major constituent. This gas inventory would pose a flammable gas hazard if it were to release suddenly. In May 1997, the mechanisms of bubble retention and release from crust material were the subject of a workshop. The evaluation of the crust and potential hazards assumed a more typical void of roughly 15% gas. It could be similar to percolati on in single-shell tank (SST) waste forms. The much higher void being currently observed in SY-101 represents essentially a new crust configuration, and the mechanisms for sudden gas release need to be evaluated. The purpose of this study is to evaluate the situation of gas bubbles in crust based on the previous work on gas bubble retention, migration, and release in simulants and actual waste. We have also conducted some visual observations of bubble migration through simulated crusts to help understand the interaction of the various mechanisms.

  16. Running Head: TESTOSTERONE AND POWER Testosterone and power

    E-Print Network [OSTI]

    Schultheiss, Oliver C.

    Running Head: TESTOSTERONE AND POWER Testosterone and power Steven J. Stanton and Oliver C. Schultheiss University of Michigan, Ann Arbor, MI, USA To appear in: K. Dowding (Ed.), Encyclopedia of power-647-9440, email: stantons@umich.edu #12;Testosterone and power 2 Across many studies in humans, two functional

  17. Associate Professor, Head, Research Institute of Circuits and Systems

    E-Print Network [OSTI]

    Wang, Yu

    ), and power and reliability aware system design methodology. Dr. Wang has authored and coauthored over 100.1-2017.12 § Research on LTE-Advanced Soft-Baseband Processing System o National Key Technology Program, o PI: Yu WangRESUME Yu Wang Associate Professor, Head, Research Institute of Circuits and Systems Department

  18. New Director Heads Actuarial Science Program - Department of ...

    E-Print Network [OSTI]

    Sally

    2002-01-03T23:59:59.000Z

    Department of Mathematics x Purdue University x West Lafayette, Indiana. Summer 2001 ... information as well as the current (new) plan of study. ... Allen Weitsman, Associate Head. Lawrence Brown .... Professor J. J. Price was the featured speaker in Purdue's “Focus on Teaching” ..... Virginia Mashin Scholarship ($2,500).

  19. HIGH RESOLUTION, MRI-BASED, SEGMENTED, COMPUTERIZED HEAD PHANTOM.

    E-Print Network [OSTI]

    Duncan, James S.

    was created from 124 transverse MRI images of a healthy normal. The transverse T2 slices, recorded in a 256x. Internal volumes compare favorably to those described in the ICRP Reference Man. Conclusion and improved. We have developed a voxel based head phantom by manually drawing contours on 124 transverse MRI

  20. IMAGINED TRANSFORMATIONS 1 Running head: IMAGINED TRANSFORMATION OF BODIES

    E-Print Network [OSTI]

    Zacks, Jeffrey M.

    IMAGINED TRANSFORMATIONS 1 Running head: IMAGINED TRANSFORMATION OF BODIES Imagined Transformations TRANSFORMATIONS 2 Abstract A number of spatial reasoning problems can be solved by performing an imagined transformation of one's egocentric perspective. A series of experiments were carried out to characterize