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1

Correlation between speciated hydrocarbon emissions and flame ionization detector response for gasoline/alcohol blends .  

DOE Green Energy (OSTI)

The U.S. renewable fuel standard has made it a requirement to increase the production of ethanol and advanced biofuels to 36 billion by 2022. Ethanol will be capped at 15 billion, which leaves 21 billion to come from other sources such as butanol. Butanol has a higher energy density and lower affinity for water than ethanol. Moreover, alcohol fueled engines in general have been shown to positively affect engine-out emissions of oxides of nitrogen and carbon monoxide compared with their gasoline fueled counterparts. In light of these developments, the variety and blend levels of oxygenated constituents is likely to increase in the foreseeable future. The effect on engine-out emissions for total hydrocarbons is less clear due to the relative insensitivity of the flame ionization detector (FID) toward alcohols and aldehydes. It is well documented that hydrocarbon (HC) measurement using a conventional FID in the presence of oxygenates in the engine exhaust stream can lead to a misinterpretation of HC emissions trends for alcohol fuel blends. Characterization of the exhaust stream for all expected hydrocarbon constituents is required to accurately determine the actual concentration of unburned fuel components in the exhaust. In addition to a conventional exhaust emissions bench, this characterization requires supplementary instrumentation capable of hydrocarbon speciation and response factor independent quantification. Although required for certification testing, this sort of instrumentation is not yet widely available in engine development facilities. Therefore, an attempt is made to empirically determine FID correction factors for oxygenate fuels. Exhaust emissions of an engine fueled with several blends of gasoline and ethanol, n-butanol and iso-Butanol were characterized using both a conventional FID and a Fourier transform infrared. Based on these results, a response factor predicting the actual hydrocarbon emissions based solely on FID results as a function of alcohol type and content is presented. Finally, the correlation derived from data presented in this study is compared with equations and results found in the literature.

Wallner, T. (Energy Systems)

2011-08-01T23:59:59.000Z

2

Ionizing radiation detector  

DOE Patents (OSTI)

An ionizing radiation detector is provided which is based on the principal of analog electronic integration of radiation sensor currents in the sub-pico to nano ampere range between fixed voltage switching thresholds with automatic voltage reversal each time the appropriate threshold is reached. The thresholds are provided by a first NAND gate Schmitt trigger which is coupled with a second NAND gate Schmitt trigger operating in an alternate switching state from the first gate to turn either a visible or audible indicating device on and off in response to the gate switching rate which is indicative of the level of radiation being sensed. The detector can be configured as a small, personal radiation dosimeter which is simple to operate and responsive over a dynamic range of at least 0.01 to 1000 R/hr.

Thacker, L.H.

1989-06-08T23:59:59.000Z

3

Ionizing radiation detector  

DOE Patents (OSTI)

An ionizing radiation detector is provided which is based on the principle of analog electronic integration of radiation sensor currents in the sub-pico to nano ampere range between fixed voltage switching thresholds with automatic voltage reversal each time the appropriate threshold is reached. The thresholds are provided by a first NAND gate Schmitt trigger which is coupled with a second NAND gate Schmitt trigger operating in an alternate switching state from the first gate to turn either a visible or audible indicating device on and off in response to the gate switching rate which is indicative of the level of radiation being sensed. The detector can be configured as a small, personal radiation dosimeter which is simple to operate and responsive over a dynamic range of at least 0.01 to 1000 R/hr.

Thacker, Louis H. (Knoxville, TN)

1990-01-01T23:59:59.000Z

4

Optical ionization detector  

DOE Patents (OSTI)

An optical ionization detector wherein a beam of light is split so that one arm passes through a fiber optics and the other arm passes through a gas-filled region, and uses interferometry to detect density changes in a gas when charged particles pass through it. The gas-filled region of the detector is subjected to a high electric field and as a charged particle traverses this gas region electrons are freed from the cathode and accelerated so as to generate an electron avalanche which is collected on the anode. The gas density is effected by the electron avalanche formation and if the index or refraction is proportional to the gas density the index will change accordingly. The detector uses this index change by modulating the one arm of the split light beam passing through the gas, with respect to the other arm that is passed through the fiber optic. Upon recombining of the beams, interference fringe changes as a function of the index change indicates the passage of charged particles through the gaseous medium.

Wuest, Craig R. (Danville, CA); Lowry, Mark E. (Castro Valley, CA)

1994-01-01T23:59:59.000Z

5

Optical ionization detector  

DOE Patents (OSTI)

An optical ionization detector wherein a beam of light is split so that one arm passes through a fiber optics and the other arm passes through a gas-filled region, and uses interferometry to detect density changes in a gas when charged particles pass through it. The gas-filled region of the detector is subjected to a high electric field and as a charged particle traverses this gas region electrons are freed from the cathode and accelerated so as to generate an electron avalanche which is collected on the anode. The gas density is effected by the electron avalanche formation and if the index or refraction is proportional to the gas density the index will change accordingly. The detector uses this index change by modulating the one arm of the split light beam passing through the gas, with respect to the other arm that is passed through the fiber optic. Upon recombining of the beams, interference fringe changes as a function of the index change indicates the passage of charged particles through the gaseous medium. 3 figures.

Wuest, C.R.; Lowry, M.E.

1994-03-29T23:59:59.000Z

6

Light collection device for flame emission detectors  

DOE Patents (OSTI)

This report describes a light collection device for use in a flame emission detection system such as an on-line, real-time alkali concentration process stream monitor. The device comprises a sphere coated on its interior with a highly diffuse reflective paint which is positioned over a flame emission source and one or more fiber optic cables which transfer the light generated at the interior of the sphere to a detecting device. The diffuse scattering of the light emitted by the flame uniformly distributes the light in the sphere, and the collection efficiency of the device is greater than that obtainable in the prior art. The device of the present invention thus provides enhanced sensitivity and reduces the noise associated with flame emission detectors, and can achieve substantial improvements in alkali detection levels. 2 figs.

Woodruff, S.D.; Logan, R.G.; Pineault, R.L.

1989-04-14T23:59:59.000Z

7

Light collection device for flame emission detectors  

DOE Patents (OSTI)

A light collection device for use in a flame emission detection system such as an on-line, real-time alkali concentration process stream monitor is disclosed which comprises a sphere coated on its interior with a highly diffuse reflective paint which is positioned over a flame emission source, and one or more fiber optic cables which transfer the light generated at the interior of the sphere to a detecting device. The diffuse scattering of the light emitted by the flame uniformly distributes the light in the sphere, and the collection efficiency of the device is greater than that obtainable in the prior art. The device of the present invention thus provides enhanced sensitivity and reduces the noise associated with flame emission detectors, and can achieve substantial improvements in alkali detection levels.

Woodruff, Stephen D. (Morgantown, WV); Logan, Ronald G. (Morgantown, WV); Pineault, Richard L. (Morgantown, WV)

1990-01-01T23:59:59.000Z

8

Ionizing Radiation Detector  

Science Conference Proceedings (OSTI)

A CdZnTe (CZT) crystal provided with a native CdO dielectric coating to reduce surface leakage currents and thereby, improve the resolution of instruments incorporating detectors using CZT crystals is disclosed. A two step process is provided for forming the dielectric coating which includes etching the surface of a CZT crystal with a solution of the conventional bromine/methanol etch treatment, and passivating the CZT crystal surface with a solution of 10 w/o NH.sub.4 F and 10 w/o H.sub.2 O.sub.2 in water after attaching electrical contacts to the crystal surface.

Wright, Gomez W. (Nashville, TN); James, Ralph B. (Livermore, CA); Burger, Arnold (Nashville, TN); Chinn, Douglas A. (Livermore, CA)

2003-11-18T23:59:59.000Z

9

Development of a micro-FID using a diffusion flame.  

E-Print Network (OSTI)

??A micro-flame ionization detector (micro-FID) was developed operating with a diffusion flame with a folded flame structure. Unlike conventional FIDs, an air-hydrogen diffusion flame was… (more)

Kim, Jihyung

2011-01-01T23:59:59.000Z

10

Gas amplified ionization detector for gas chromatography  

DOE Patents (OSTI)

A gas-amplified ionization detector for gas chromatography which possesses increased sensitivity and a very fast response time is described. Solutes eluding from a gas chromatographic column are ionized by uv photoionization of matter eluting therefrom. The detector is capable of generating easily measured voltage signals by gas amplification/multiplication of electron products resulting from the uv photoionization of at least a portion of each solute passing through the detector. 4 figs.

Huston, G.C.

1989-11-27T23:59:59.000Z

11

High-resolution ionization detector and array of such detectors  

DOE Patents (OSTI)

A high-resolution ionization detector and an array of such detectors are described which utilize a reference pattern of conductive or semiconductive material to form interaction, pervious and measurement regions in an ionization substrate of, for example, CdZnTe material. The ionization detector is a room temperature semiconductor radiation detector. Various geometries of such a detector and an array of such detectors produce room temperature operated gamma ray spectrometers with relatively high resolution. For example, a 1 cm.sup.3 detector is capable of measuring .sup.137 Cs 662 keV gamma rays with room temperature energy resolution approaching 2% at FWHM. Two major types of such detectors include a parallel strip semiconductor Frisch grid detector and the geometrically weighted trapezoid prism semiconductor Frisch grid detector. The geometrically weighted detector records room temperature (24.degree. C.) energy resolutions of 2.68% FWHM for .sup.137 Cs 662 keV gamma rays and 2.45% FWHM for .sup.60 Co 1.332 MeV gamma rays. The detectors perform well without any electronic pulse rejection, correction or compensation techniques. The devices operate at room temperature with simple commercially available NIM bin electronics and do not require special preamplifiers or cooling stages for good spectroscopic results.

McGregor, Douglas S. (Ypsilanti, MI); Rojeski, Ronald A. (Pleasanton, CA)

2001-01-16T23:59:59.000Z

12

High pressure xenon ionization detector  

DOE Patents (OSTI)

A method is provided for detecting ionization comprising allowing particles that cause ionization to contact high pressure xenon maintained at or near its critical point and measuring the amount of ionization. An apparatus is provided for detecting ionization, the apparatus comprising a vessel containing a ionizable medium, the vessel having an inlet to allow high pressure ionizable medium to enter the vessel, a means to permit particles that cause ionization of the medium to enter the vessel, an anode, a cathode, a grid and a plurality of annular field shaping rings, the field shaping rings being electrically isolated from one another, the anode, cathode, grid and field shaping rings being electrically isolated from one another in order to form an electric field between the cathode and the anode, the electric field originating at the anode and terminating at the cathode, the grid being disposed between the cathode and the anode, the field shaping rings being disposed between the cathode and the grid, the improvement comprising the medium being xenon and the vessel being maintained at a pressure of 50 to 70 atmospheres and a temperature of 0.degree. to 30.degree. C.

Markey, John K. (New Haven, CT)

1989-01-01T23:59:59.000Z

13

High pressure xenon ionization detector  

DOE Patents (OSTI)

A method is provided for detecting ionization comprising allowing particles that cause ionization to contact high pressure xenon maintained at or near its critical point and measuring the amount of ionization. An apparatus is provided for detecting ionization, the apparatus comprising a vessel containing a ionizable medium, the vessel having an inlet to allow high pressure ionizable medium to enter the vessel, a means to permit particles that cause ionization of the medium to enter the vessel, an anode, a cathode, a grid and a plurality of annular field shaping rings, the field shaping rings being electrically isolated from one another, the anode, cathode, grid and field shaping rings being electrically isolated from one another in order to form an electric field between the cathode and the anode, the electric field originating at the anode and terminating at the cathode, the grid being disposed between the cathode and the anode, the field shaping rings being disposed between the cathode and the grid, the improvement comprising the medium being xenon and the vessel being maintained at a pressure of 50 to 70 atmospheres and a temperature of 0 to 30 C. 2 figs.

Markey, J.K.

1989-11-14T23:59:59.000Z

14

Ionization-chamber smoke detector system  

DOE Patents (OSTI)

This invention relates to an improved smoke-detection system of the ionization-chamber type. In the preferred embodiment, the system utilizes a conventional detector head comprising a measuring ionization chamber, a reference ionization chamber, and a normally non-conductive gas triode for discharging when a threshold concentration of airborne particulates is present in the measuring chamber. The improved system is designed to reduce false alarms caused by fluctuations in ambient temperature. Means are provided for periodically firing the gas discharge triode and each time recording the triggering voltage required. A computer compares each triggering voltage with its predecessor. The computer is programmed to energize an alarm if the difference between the two compared voltages is a relatively large value indicative of particulates in the measuring chamber and to disregard smaller differences typically resulting from changes in ambient temperature.

Roe, Robert F. (Jackson, OH)

1976-10-19T23:59:59.000Z

15

Multiplexed electronically programmable multimode ionization detector for chromatography  

DOE Patents (OSTI)

Method and apparatus for detecting and differentiating organic compounds based on their electron affinity. An electron capture detector cell (ECD) is operated in a plurality of multiplexed electronically programmable operating modes to alter the detector response during a single sampling cycle to acquire multiple simultaneous chromatograms corresponding to each of the different operating modes. The cell is held at a constant subatmospheric pressure while the electron collection bias voltage applied to the cell is modulated electronically to allow acquisition of multiple chromatograms for a single sample elution from a chromatograph representing three distinctly different response modes. A system is provided which automatically controls the programmed application of bias pulses at different intervals and/or amplitudes to switch the detector from an ionization mode to the electron capture mode and various degrees therebetween to provide an improved means of tuning an ECD for multimode detection and improved specificity. 6 figs.

Wise, M.B.; Buchanan, M.V.

1988-05-19T23:59:59.000Z

16

Ionization detector, electrode configuration and single polarity charge detection method  

DOE Patents (OSTI)

An ionization detector, an electrode configuration and a single polarity charge detection method each utilize a boundary electrode which symmetrically surrounds first and second central interlaced and symmetrical electrodes. All of the electrodes are held at a voltage potential of a first polarity type. The first central electrode is held at a higher potential than the second central or boundary electrodes. By forming the first and second central electrodes in a substantially interlaced and symmetrical pattern and forming the boundary electrode symmetrically about the first and second central electrodes, signals generated by charge carriers are substantially of equal strength with respect to both of the central electrodes. The only significant difference in measured signal strength occurs when the charge carriers move to within close proximity of the first central electrode and are received at the first central electrode. The measured signals are then subtracted and compared to quantitatively measure the magnitude of the charge.

He, Zhong (Ann Arbor, MI)

1998-01-01T23:59:59.000Z

17

Ionization detector, electrode configuration and single polarity charge detection method  

DOE Patents (OSTI)

An ionization detector, an electrode configuration and a single polarity charge detection method each utilize a boundary electrode which symmetrically surrounds first and second central interlaced and symmetrical electrodes. All of the electrodes are held at a voltage potential of a first polarity type. The first central electrode is held at a higher potential than the second central or boundary electrodes. By forming the first and second central electrodes in a substantially interlaced and symmetrical pattern and forming the boundary electrode symmetrically about the first and second central electrodes, signals generated by charge carriers are substantially of equal strength with respect to both of the central electrodes. The only significant difference in measured signal strength occurs when the charge carriers move to within close proximity of the first central electrode and are received at the first central electrode. The measured signals are then subtracted and compared to quantitatively measure the magnitude of the charge. 10 figs.

He, Z.

1998-07-07T23:59:59.000Z

18

TIME-VARYING FLAME IONIZATION SENSING APPLIED TO NATURAL GAS AND PROPANE BLENDS IN A PRESSURIZED LEAN PREMIXED (LPM) COMBUSTOR  

SciTech Connect

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.

D. L. Straub; B. T. Chorpening; E. D. Huckaby; J. D. Thornton; W. L. Fincham

2008-06-13T23:59:59.000Z

19

Neutron And Gamma Detector Using An Ionization Chamber With An Integrated  

NLE Websites -- All DOE Office Websites (Extended Search)

Neutron And Gamma Detector Using An Ionization Chamber Neutron And Gamma Detector Using An Ionization Chamber Neutron And Gamma Detector Using An Ionization Chamber With An Integrated Body And Moderator A detector for detecting neutrons and gamma radiation includes a cathode that defines an interior surface and an interior volume. Available for thumbnail of Feynman Center (505) 665-9090 Email Neutron And Gamma Detector Using An Ionization Chamber With An Integrated Body And Moderator A detector for detecting neutrons and gamma radiation includes a cathode that defines an interior surface and an interior volume. A conductive neutron-capturing layer is disposed on the interior surface of the cathode and a plastic housing surrounds the cathode. A plastic lid is attached to the housing and encloses the interior volume of the cathode forming an

20

Thin layer chromatography - flame ionization detection analysis of in-situ petroleum biodegradation  

E-Print Network (OSTI)

This research was initiated after a 100-year flood caused an oil spill on the San Jacinto River (Houston, Texas) in October of 1994. After the floodwaters subsided the released petroleum floating on the water was deposited on the surrounding lands. The petroleum spill was used as an opportunity to research intrinsic petroleum biodegradation in a 9-acre petroleum impacted estuarine wetland. The first phase of this research (Phase I) began in December 1994, approximately 1.5 months after the spill of opportunity and involved the study and quantification of in-situ petroleum biodegradation. The second phase of the research (Phase II) began in March 1996 with a controlled oil release to study and evaluate the success of two bioremediation treatments versus natural biodegradation. The study of in-situ petroleum hydrocarbon degradation and the evaluation of bioremediation amendments were successfully quantified using GC-MS analytical techniques. However, the GC-MS technique is limited to the analyses of hydrocarbon compounds, a disadvantage that precludes the overall characterization of petroleum degradation. The research presented here details an analytical technique that was used to provide a full characterization of temporal petroleum biodegradation. This technique uses thin layer chromatography coupled with flame ionization detection (TLC-FID) to characterize the saturate and aromatic (hydrocarbon) fractions and the resin and asphaltene (non-hydrocarbon, polar) fractions. Other analysis techniques, such as HPLC-SARA analysis, are available for the full characterization of the four petroleum fractions. However, these techniques do not lend themselves well to the application of large sample set analysis. A significant advantage of the TLC-FID analysis to other petroleum analysis techniques is the ability to analyze several samples concurrently and quickly with relative ease and few resources. For the purposes of the Phase I and Phase II research the TLC-FID analysis method was evaluated, refined and applied to quantify the temporal biodegradation and bioremediation of petroleum. While the TLC-FID analysis produces a full characterization, it cannot supplant the GC-MS analysis for petroleum bioremediation research. However, it can be used in conjunction with the GC-MS to expand the knowledge of petroleum bioremediation and remediation strategies.

Stephens, Frank Lanier

2004-08-01T23:59:59.000Z

Note: This page contains sample records for the topic "flame ionization detector" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


21

Computational Fluid Dynamics Modeling of the Operation of a Flame Ionization Sensor  

Science Conference Proceedings (OSTI)

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.

Huckaby, E.D.; Chorpening, B.T.; Thornton, J.D.

2007-03-01T23:59:59.000Z

22

Review Article: Physics and Monte Carlo Techniques as Relevant to Cryogenic, Phonon and Ionization Readout of CDMS Radiation-Detectors  

E-Print Network (OSTI)

This review discusses detector physics and Monte Carlo techniques for cryogenic, radiation detectors that utilize combined phonon and ionization readout. A general review of cryogenic phonon and charge transport is provided along with specific details of the Cryogenic Dark Matter Search detector instrumentation. In particular this review covers quasidiffusive phonon transport, which includes phonon focusing, anharmonic decay and isotope scattering. The interaction of phonons in the detector surface is discussed along with the downconversion of phonons in superconducting films. The charge transport physics include a mass tensor which results from the crystal band structure and is modeled with a Herring Vogt transformation. Charge scattering processes involve the creation of Neganov-Luke phonons. Transition-edge-sensor (TES) simulations include a full electric circuit description and all thermal processes including Joule heating, cooling to the substrate and thermal diffusion within the TES, the latter of which is necessary to model normal-superconducting phase separation. Relevant numerical constants are provided for these physical processes in germanium, silicon, aluminum and tungsten. Random number sampling methods including inverse cumulative distribution function (CDF) and rejection techniques are reviewed. To improve the efficiency of charge transport modeling, an additional second order inverse CDF method is developed here along with an efficient barycentric coordinate sampling method of electric fields. Results are provided in a manner that is convenient for use in Monte Carlo and references are provided for validation of these models.

S. W. Leman

2011-09-06T23:59:59.000Z

23

Detectors  

NLE Websites -- All DOE Office Websites (Extended Search)

Detectors Elementary Particles Detectors Accelerators Visit World Labs For Children - for younger people For Children The Event For Children Testing a Theory For Children...

24

detectors  

NLE Websites -- All DOE Office Websites (Extended Search)

Detectors are made of many layers specialized to identify and record Detectors are made of many layers specialized to identify and record information about the many particles that result from a collision of a proton and an antiproton. A sphere would be the best shape to surround the collision point, but it is cheaper to make cylindrical detectors. Because the particles in the Fermilab accelerator have so much energy, detectors may be 3-5 stories high. The layers of a generic detector: (Run the cursor over the names.) Beam Pipe Tracker Electromagnetic Calorimeter Hadron Calorimeter Magnet Muon Detector Anatomy of a Detector - Identifying Particles - CDF Detector - D0 Detector - Links Project Contact: Thomas Jordan - jordant@fnal.gov Web Maintainer: qnet-webmaster@fnal.gov Last Update: April 13, 2001 http://quarknet.fnal.gov/run2/news

25

FLAME STRUCTURE MEASUREMENT OF POLYMER DIFFUSION FLAMES  

E-Print Network (OSTI)

of counterflow diffusion flames above condensed fuels:of counterflow diffusion flames in the forward stagnationCA, October 15-16, 1979 FLAME STRUCTURE MEASUREMENT OF

Pitz, W. J.

2011-01-01T23:59:59.000Z

26

Examination system utilizing ionizing radiation and a flexible, miniature radiation detector probe  

DOE Patents (OSTI)

An optimized examination system and method based on the Reverse Geometry X-Ray.RTM. (RGX.RTM.) radiography technique are presented. The examination system comprises a radiation source, at least one flexible, miniature radiation detector probe positioned in appropriate proximity to the object to be examined and to the radiation source with the object located between the source and the probe, a photodetector device attachable to an end of the miniature radiation probe, and a control unit integrated with a display device connected to the photodetector device. The miniature radiation detector probe comprises a scintillation element, a flexible light guide having a first end optically coupled to the scintillation element and having a second end attachable to the photodetector device, and an opaque, environmentally-resistant sheath surrounding the flexible light guide. The probe may be portable and insertable, or may be fixed in place within the object to be examined. An enclosed, flexible, liquid light guide is also presented, which comprises a thin-walled flexible tube, a liquid, preferably mineral oil, contained within the tube, a scintillation element located at a first end of the tube, closures located at both ends of the tube, and an opaque, environmentally-resistant sheath surrounding the flexible tube. The examination system and method have applications in non-destructive material testing for voids, cracks, and corrosion, and may be used in areas containing hazardous materials. In addition, the system and method have applications for medical and dental imaging.

Majewski, Stanislaw (Grafton, VA); Kross, Brian J. (Yorktown, VA); Zorn, Carl J. (Yorktown, VA); Majewski, Lukasz A. (Grafton, VA)

1996-01-01T23:59:59.000Z

27

Examination system utilizing ionizing radiation and a flexible, miniature radiation detector probe  

DOE Patents (OSTI)

An optimized examination system and method based on the Reverse Geometry X-Ray{trademark} (RGX{trademark}) radiography technique are presented. The examination system comprises a radiation source, at least one flexible, miniature radiation detector probe positioned in appropriate proximity to the object to be examined and to the radiation source with the object located between the source and the probe, a photodetector device attachable to an end of the miniature radiation probe, and a control unit integrated with a display device connected to the photodetector device. The miniature radiation detector probe comprises a scintillation element, a flexible light guide having a first end optically coupled to the scintillation element and having a second end attachable to the photodetector device, and an opaque, environmentally-resistant sheath surrounding the flexible light guide. The probe may be portable and insertable, or may be fixed in place within the object to be examined. An enclosed, flexible, liquid light guide is also presented, which comprises a thin-walled flexible tube, a liquid, preferably mineral oil, contained within the tube, a scintillation element located at a first end of the tube, closures located at both ends of the tube, and an opaque, environmentally-resistant sheath surrounding the flexible tube. The examination system and method have applications in non-destructive material testing for voids, cracks, and corrosion, and may be used in areas containing hazardous materials. In addition, the system and method have applications for medical and dental imaging. 5 figs.

Majewski, S.; Kross, B.J.; Zorn, C.J.; Majewski, L.A.

1996-10-22T23:59:59.000Z

28

Detectors  

NLE Websites -- All DOE Office Websites (Extended Search)

Detectores Detectores Avanzar Volver Principal ESTOY PERDIDO!!! Rutherford utilizó el sulfuro de zinc para detectar la presencia de partículas alfa invisibles, y mediante este conocimiento pudo determinar las trayectorias de las partículas alfa; del mismo modo los físicos modernos deben observar los productos, resultantes del decaimiento de las partículas, y deducir así la existencia de partículas. Para detectar las distintas partículas y los productos de decaimiento, los físicos han diseñado detectores multicomponentes que examinan diferentes aspectos de un evento. Cada componente de un detector moderno se emplea para medir la energía y el ímpetu de una partícula, y/o para distinguir entre sí partículas de diferentes tipos. Cuando todos los componentes

29

FLAT FLAME BURNER ANALYSES  

E-Print Network (OSTI)

J. C. , Combustion and Flame 34, pp. 85-98 (1979). Carrier.Effects on a One-Dimensional Flame," Combust. Sci. and Tech.Uniformity in Edge Cooled F1at Flame Burners," Combust. Sci.

Pagni, P.J.

2012-01-01T23:59:59.000Z

30

Longevity effects on the performance of fire detectors  

E-Print Network (OSTI)

Smoke detectors, a critical part of any fire detection system, are employed as safety devices to warn building inhabitants of life threatening particles resulting from combustion. Two types of detectors are currently on the market: ionization and photoelectric. How longevity effects the performance of smoke detectors is a growing concern, not only for industry, but the American citizen as well. To determine longevity effects on the performance of detectors, a testing chamber was designed and constructed to measure the percent obscuration/ft, of smoke particles at the point of detector activation. Three different tests were conducted: smoldering tests using Douglas fir wood and urethane foam as a fuel source, and a flaming fire test using newspaper as the fuel source. A total of three hundred eighty tests were conducted using new, five (5), ten (10), and fifteen (15) year old ionization and photoelectric smoke detectors in an uncleaned and cleaned condition. Comparisons between the detectors performance was analyzed and reviewed. The results indicate that smoke detectors are often unreliable and are inconsistent in their pattern of activating within an acceptable operating range of 0.5% - 4.0% obscuration/ft. This study indicates that fifteen (15) year old detectors generally activate at a percentage exceeding 4.0% obscuration/ft., or often do not activate. Because of this finding and the fact that homeowners tend to not replace detectors once they are installed, further investigation into the causes for this shortcoming is warranted. Additionally, because of the generally unreliable behavior of current detectors, further research into the development of detectors that are durable and reliable is also warranted.

Dedear, Timothy Keith

1993-01-01T23:59:59.000Z

31

Oscillation and extinction in flames.  

E-Print Network (OSTI)

?? Oscillation phenomena in flames were theoretically investigated for both diffusion and premixed flames. For diffusion flames, oscillations develop intrinsically as a result of thermal-diffusive… (more)

Wang, Heyang

2008-01-01T23:59:59.000Z

32

Studies on upward flame spread  

E-Print Network (OSTI)

5.7 Flame Heights . . . . . . . . . . . . . . . . . .3.4.1 Flame Heights . . . . . . . . . . . . . . 3.5Chapter 4 Upward Flame Spread of an Inclined Fuel Surface

Gollner, Michael J.

2012-01-01T23:59:59.000Z

33

FLAME STRUCTURE MEASUREMENT OF POLYMER DIFFUSION FLAMES  

E-Print Network (OSTI)

diffusion flame of gaseous propane and methane provide aCurrent study Tsuji and Yamoaka (propane fuel, -f Oxidizeris air and propane flow rate is constant Nozzle velocity

Pitz, W. J.

2011-01-01T23:59:59.000Z

34

Pulsed helium ionization detection system  

DOE Patents (OSTI)

A helium ionization detection system is provided which produces stable operation of a conventional helium ionization detector while providing improved sensitivity and linearity. Stability is improved by applying pulsed dc supply voltage across the ionization detector, thereby modifying the sampling of the detectors output current. A unique pulse generator is used to supply pulsed dc to the detector which has variable width and interval adjust features that allows up to 500 V to be applied in pulse widths ranging from about 150 nsec to about dc conditions.

Ramsey, R.S.; Todd, R.A.

1985-04-09T23:59:59.000Z

35

Flame Height Measurement of Laminar Inverse Diffusion Flames  

E-Print Network (OSTI)

Shin, E.J. Lee, Combust. Flame 140 (3) (2005) 249-254. [8].Du, R.L. Axelbaum, Combust. Flame 100 (3) (1995) 367-375. [A.C. Cunningham, Combust. Flame 29 (1977) 227-234. [13].

Mikofski, Mark A.; Williams, Timothy C.; Shaddix, Christopher R.; Blevins, Linda G.

2006-01-01T23:59:59.000Z

36

Studies on upward flame spread  

E-Print Network (OSTI)

and A. Alkidas. Combustion of wood in methanol flames.of wet and dry wood by radiation. Combustion and Flame, 11(

Gollner, Michael J.

2012-01-01T23:59:59.000Z

37

Studies on upward flame spread.  

E-Print Network (OSTI)

??Experimental techniques have been used to investigate three upward flame spread phenomena of particular importance for fire safety applications. First, rates of upward flame spread… (more)

Gollner, Michael J.

2012-01-01T23:59:59.000Z

38

Propagation of premixed flames in confined channels.  

E-Print Network (OSTI)

??The propagation of premixed flames in confined channels is investigated. In the unconfined case, the structure of the flame and the flame speed for the… (more)

Navaneetha, Arjun

2013-01-01T23:59:59.000Z

39

Ionizing Radiation  

Science Conference Proceedings (OSTI)

*. Bookmark and Share. Ionizing Radiation Measurements. Fees for services are located directly below the technical contacts ...

2013-04-09T23:59:59.000Z

40

Flame Doctor for Cyclone Boilers  

Science Conference Proceedings (OSTI)

This development program was designed to enhance monitoring and diagnostic technology for cyclone furnaces using the Flame Doctor combustion diagnostic system. First developed for wall-fired pulverized-coal burner systems and boilers, Flame Doctor allows simultaneous, continuous monitoring and evaluation of each burner in a boiler using signals from optical flame scanners. An initial feasibility test conducted at the AmerenUE Sioux cyclone boiler indicated Flame Doctor technology could be extended to cyc...

2007-12-12T23:59:59.000Z

Note: This page contains sample records for the topic "flame ionization detector" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


41

High efficiency photoionization detector  

DOE Patents (OSTI)

A high efficiency photoionization detector is described using tetraaminoethylenes in a gaseous state having a low ionization potential and a relative photoionization cross section which closely matches the emission spectrum of xenon gas. Imaging proportional counters are also disclosed using the novel photoionization detector of the invention. The compound of greatest interest is TMAE which comprises tetrakis(dimethylamino)ethylene which has a measured ionization potential of 5.36 [+-] 0.02 eV, and a vapor pressure of 0.35 torr at 20 C. 6 figs.

Anderson, D.F.

1984-01-31T23:59:59.000Z

42

High efficiency photoionization detector  

DOE Patents (OSTI)

A high efficiency photoionization detector using tetraaminoethylenes in a gaseous state having a low ionization potential and a relative photoionization cross section which closely matches the emission spectrum of xenon gas. Imaging proportional counters are also disclosed using the novel photoionization detector of the invention. The compound of greatest interest is TMAE which comprises tetrakis(dimethylamino)ethylene which has a measured ionization potential of 5.36.+-.0.02 eV, and a vapor pressure of 0.35 torr at 20.degree. C.

Anderson, David F. (3055 Trinity, Los Alamos, NM 87544)

1984-01-01T23:59:59.000Z

43

Ionization detection system for aerosols  

DOE Patents (OSTI)

This invention relates to an improved smoke-detection system of the ionization-chamber type. In the preferred embodiment, the system utilizes a conventional detector head comprising a measuring ionization chamber, a reference ionization chamber, and a normally non-conductive gas triode for discharging when a threshold concentration of airborne particulates is present in the measuring chamber. The improved system utilizes a measuring ionization chamber which is modified to minimize false alarms and reductions in sensitivity resulting from changes in ambient temperature. In the preferred form of the modification, an annular radiation shield is mounted about the usual radiation source provided to effect ionization in the measuring chamber. The shield is supported by a bimetallic strip which flexes in response to changes in ambient temperature, moving the shield relative to the source so as to vary the radiative area of the source in a manner offsetting temperature-induced variations in the sensitivity of the chamber.

Jacobs, Martin E. (Chillicothe, OH)

1977-01-01T23:59:59.000Z

44

Active control for turbulent premixed flame simulations  

E-Print Network (OSTI)

Poinsot, T. J. , Combust. Flame, 121:395–417 [8] Trouve, A.Rutland, C. J. , Combust. Flame, 102:447–461 (1995). [10]Control for Turbulent Premixed Flame Simulations J. B. Bell,

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

2004-01-01T23:59:59.000Z

45

Structure of Laminar Sooting Inverse Diffusion Flames  

E-Print Network (OSTI)

Drop down lines indicate stoichiometric flame height.A.F. Sarofim, Combust. Flame 146 (1-2) (2006) 52-62. [26].J.H. Miller, Combust. Flame 79 (3-4 ) [28]. K.C. Smyth, J.H.

Mikofski, Mark A

2007-01-01T23:59:59.000Z

46

Laser Extinction in Laminar Inverse Diffusion Flames  

E-Print Network (OSTI)

Smyth, Combustion and Flame 99 (3-4 ) [11]. M.A. Mikofski,R.A. Dobbins, Combustion and Flame 51 (2) [8]. C.R.K.C. Smyth, Combustion and Flame 107 (4) (1996) 418-452. [

Macko, Kevin; Mikofski, Mark A; Fernandez-Pello, Carlos; Blevins, Linda G; Davis, Ronald W.

2005-01-01T23:59:59.000Z

47

Displacement speeds in turbulent premixed flame simulations  

E-Print Network (OSTI)

Wycko?, P. S. , Combust. Flame, 110(1–2):92–112 (1997). [9]Carter, C. D. , Combust. Flame, 133(3):323–334 (2003). [12]and Faeth, G. M. , Combust. Flame, 95:410–425 (1993). [15

Day, Marcus S.; Shepherd, Ian G.; Bell, J.; Grcar, Joseph F.; Lijewski, Michael J.

2008-01-01T23:59:59.000Z

48

Diffusion Flame Measurements: Notes B  

Science Conference Proceedings (OSTI)

... Profiles in steady and flickering methane/air, ethylene/air, and propane/air diffusion flames at atmospheric pressure using an axisymmetric burner ...

2012-10-17T23:59:59.000Z

49

Diffusion Flame Measurements: Literature Citations C  

Science Conference Proceedings (OSTI)

... Partial Equilibrium in the Reaction Zone of Methane-Air Diffusion Flames; and Combustion and Flame 37:227-244 (1980). ...

2012-10-17T23:59:59.000Z

50

Long range alpha particle detector  

DOE Patents (OSTI)

An alpha particle detector capable of detecting alpha radiation from distant sources. A high voltage is generated near a conductive mesh while a fan draws air containing air molecules ionized by alpha particles across the mesh. The current in the mesh can be detected and used for measurement or alarm. The detector can be used for area, personnel and equipment monitoring.

Wolf, M.A.; McAdtee, J.L. III; Unruh, W.P.; Cucchiadra, A.L.; Huchton, R.L.

1990-03-13T23:59:59.000Z

51

Effects of buoyancy on premixed flame stabilization  

Science Conference Proceedings (OSTI)

The stabilization limits of v-flame and conical flames are investigated in normal gravity (+g) and reversed gravity (up-side-down burner, -g) to compare with observations of flame stabilization during microgravity experiments. The results show that buoyancy has most influence on the stabilization of laminar V-flames. Under turbulent conditions, the effects are less significant. For conical flames stabilized with a ring, the stabilization domain of the +g and -g cases are not significantly different. Under reversed gravity, both laminar v-flames and conical flames show flame behaviors that were also found in microgravity. The v-flames reattached to the rim and the conical flame assumed a top-hat shape. One of the special cases of -g conical flame is the buoyancy stabilized laminar flat flame that is detached from the burner. These flame implies a balance between the flow momentum and buoyant forces. The stretch rates of these flames are sufficiently low (laminar burning speed S{sub L}{sup 0}. An analysis based on evaluating the Richardson number is used to determine the relevant parameters that describe the buoyancy/momentum balance. A perfect balance i.e. Ri = l can be attained when the effect of heat loss from the flame zone is low. For the weaker lean cases, our assumption of adiabaticity tends to overestimate the real flame temperature. This interesting low stretch laminar flame configuration can be useful for fundamental studies of combustion chemistry.

Bedat, B.; Cheng, R.K.

1995-10-01T23:59:59.000Z

52

Semiconductor radiation detector  

DOE Patents (OSTI)

A semiconductor detector for ionizing electromagnetic radiation, neutrons, and energetic charged particles. The detecting element is comprised of a compound having the composition I-III-VI.sub.2 or II-IV-V.sub.2 where the "I" component is from column 1A or 1B of the periodic table, the "II" component is from column 2B, the "III" component is from column 3A, the "IV" component is from column 4A, the "V" component is from column 5A, and the "VI" component is from column 6A. The detecting element detects ionizing radiation by generating a signal proportional to the energy deposited in the element, and detects neutrons by virtue of the ionizing radiation emitted by one or more of the constituent materials subsequent to capture. The detector may contain more than one neutron-sensitive component.

Bell, Zane W. (Oak Ridge, TN); Burger, Arnold (Knoxville, TN)

2010-03-30T23:59:59.000Z

53

NSLS Detectors  

NLE Websites -- All DOE Office Websites (Extended Search)

Detectors Multi-Element Silicon Detectors High-rate multi-element detector for fluorescence measurements Powder diffraction and x-ray scattering User interface Avalanche photodiode...

54

Turbulence-Flame Interactions in Type Ia Supernovae  

E-Print Network (OSTI)

Turbulence-Flame Interactions in Type Ia Supernovae A. J.Normalised time (e) Normalised flame speed Normalised time (length scale (cm) Laminar flame width Gibson scale Cell

Aspden, Andrew J; Lawrence Berkeley National Laboratory, 1 Cyclotron Road, MS 50A-1148, Berkeley, CA 94720 (Authors 1, 2 & 3); Department of Astronomy and Astrophysics, University of California at Santa Cruz, Santa Cruz, CA 95064 (Author 4); Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY 11794 (Author 5)

2008-01-01T23:59:59.000Z

55

Effect of Varied Air Flow on Flame Structure of Laminar Inverse Diffusion Flames  

E-Print Network (OSTI)

D.A. , Combustion and Flame, 111:185, Table 1 IDF OperatingEffect of Varied Air Flow on Flame Structure ofLaminar Inverse Diffusion Flames Western States Section/

Mikofski, Mark A; Williams, Timothy C; Shaddix, Christopher R; Blevins, Linda G

2004-01-01T23:59:59.000Z

56

Flame Structure and Soot Formation in Inverse Diffusion Flames (Ph.D. Dissertation)  

E-Print Network (OSTI)

Lindsey, D.H. Napier, Combust. Flame 2 (1958) 267-272. [23].26]. R.A. Dobbins, Combust. Flame 130 (3) (2002) 204-214. [Du, R.L. Axelbaum, Combust. Flame 100 (3) (1995) 367-375. [

Mikofski, Mark A

2005-01-01T23:59:59.000Z

57

Investigation of the principle of flame rectification in order to improve detection of the propane flame in absorption refrigerators.  

E-Print Network (OSTI)

?? Electrical properties of a propane flame was investigated to improve detection of the flame in absorption refrigerators. The principle of flame rectification, which uses… (more)

Möllberg, Andreas

2005-01-01T23:59:59.000Z

58

Rayleigh temperature profiles in a hydrogen diffusion flame  

DOE Green Energy (OSTI)

Rayleigh scattering from a hydrogen-air laminar jet diffusion flame in combination with a numerical model of the flame has been used to determine temperature profiles. The model predictions of species concentration are used to calculate a mean Rayleigh cross-section which is used to relate the Rayleigh scattered intensity to temperature. Using an argon ion laser producing 7.5 watts at 488 nm and an optical multichannel analyzer (OMA), the scattered light was imaged into a spectrometer. The OMA was rotated 90 degrees to its normal orientation, allowing scans to be taken along the spectrometer exit slit. This resulted in a spatially resolved Rayleigh signal along the laser beam through the entire flame. Spatial resolution of 0.18 mm on each of the 500 detector elements with good signal-to-noise ratios was achieved even with integration times of only 0.03 second. Since the entire profile is made simultaneously, particulate perturbed profiles are easily recognized and discarded. Transverse profiles are presented to show flame structure. Axial profiles are compared to radiation corrected thermocouple measurements.

Smith, J.R.

1978-09-01T23:59:59.000Z

59

On the theory of turbulent flame velocity  

E-Print Network (OSTI)

The renormalization ideas of self-similar dynamics of a strongly turbulent flame front are applied to the case of a flame with realistically large thermal expansion of the burning matter. In that case a flame front is corrugated both by external turbulence and the intrinsic flame instability. The analytical formulas for the velocity of flame propagation are obtained. It is demonstrated that the flame instability is of principal importance when the integral turbulent length scale is much larger than the cut off wavelength of the instability. The developed theory is used to analyse recent experiments on turbulent flames propagating in tubes. It is demonstrated that most of the flame velocity increase measured experimentally is provided by the large scale effects like the flame instability, and not by the small-scale external turbulence.

Vitaly Bychkov; Vyacheslav Akkerman; Arkady Petchenko

2012-10-19T23:59:59.000Z

60

Ionization chamber  

DOE Patents (OSTI)

An ionization chamber has separate drift and detection regions electrically isolated from each other by a fine wire grid. A relatively weak electric field can be maintained in the drift region when the grid and another electrode in the chamber are connected to a high voltage source. A much stronger electric field can be provided in the detection region by connecting wire electrodes therein to another high voltage source. The detection region can thus be operated in a proportional mode when a suitable gas is contained in the chamber. High resolution output pulse waveforms are provided across a resistor connected to the detection region anode, after ionizing radiation enters the drift region and ionize the gas.

Walenta, Albert H. (Port Jefferson Station, NY)

1981-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "flame ionization detector" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


61

Improved ion detector  

DOE Patents (OSTI)

An improved ion detector device of the ionization detection device chamber type comprises an ionization chamber having a central electrode therein surrounded by a cylindrical electrode member within the chamber with a collar frictionally fitted around at least one of the electrodes. The collar has electrical contact means carried in an annular groove in an inner bore of the collar to contact the outer surface of the electrode to provide electrical contact between an external terminal and the electrode without the need to solder leads to the electrode.

Tullis, A.M.

1986-01-30T23:59:59.000Z

62

IONIZATION CHAMBER  

DOE Patents (OSTI)

This patent describes a novel ionization chamber which is well suited to measuring the radioactivity of the various portions of a wire as the wire is moved at a uniform speed, in order to produce the neutron flux traverse pattern of a reactor in which the wire was previously exposed to neutron radiation. The ionization chamber of the present invention is characterized by the construction wherein the wire is passed through a tubular, straight electrode and radiation shielding material is disposed along the wire except at an intermediate, narrow area where the second electrode of the chamber is located.

Redman, W.C.; Shonka, F.R.

1958-02-18T23:59:59.000Z

63

A combustion-monitoring system with 3-D temperature reconstruction based on flame-image processing technique  

Science Conference Proceedings (OSTI)

Based on a flame-image processing technology, a real-time combustion-monitoring, system with 3-D temperature reconstruction and visualization installed in a coal-fired furnace of a power plant was reported. A dozen flame detectors with charge-couple-device cameras were mounted along the height of the furnace to capture multiple digital flame images. A radiation energy signal (RES) was obtained from the flame images according to Wien's law of radiation. A series of in situ experiments have been done, and the results showed that the flame temperature distribution and the RES are sensitive to change in the combustion of the boiler and can be used to improve the combustion control in practical application.

Luo, Z.X.; Zhou, H.C. [Huazhong University of Science & Technology, Wuhan (China). School of Energy & Power Engineering

2007-10-15T23:59:59.000Z

64

Flame spread Analysis using a Variable B-Number  

E-Print Network (OSTI)

for the Upward Laminar Spread of Flames Over Vertical FuelSurfaces," Combust. Flame, vol. 31, p. 135-148 P. J. PagniA. S. Rangwala, “A Theory of Flame Extinction based on Flame

Rangwala, Ali S.

2006-01-01T23:59:59.000Z

65

Effects of buoyancy on premixed flame stabilization  

SciTech Connect

The stabilization limits of v-flame and conical flames are investigated in normal gravity (+g) and reversed gravity (up-side-down burner, -g) to compare with observations of flame stabilization during microgravity experiments. The results show that buoyancy has most influence on the stabilization of laminar V-flames. Under turbulent conditions, the effects are less significant. For conical flames stabilized with a ring, the stabilization domain of the +g and -g cases are not significantly different. Under reversed gravity, both laminar v-flames and conical flames show flame behaviors that were also found in microgravity. The v-flames reattached to the rim and the conical flame assumed a top-hat shape. One of the special cases of -g conical flame is the buoyancy stabilized laminar flat flame that is detached from the burner. These flame implies a balance between the flow momentum and buoyant forces. The stretch rates of these flames are sufficiently low (< 20 s{sup -1}) such that the displacement speeds S{sub L} are almost equal to the laminar burning speed S{sub L}{sup 0}. An analysis based on evaluating the Richardson number is used to determine the relevant parameters that describe the buoyancy/momentum balance. A perfect balance i.e. Ri = l can be attained when the effect of heat loss from the flame zone is low. For the weaker lean cases, our assumption of adiabaticity tends to overestimate the real flame temperature. This interesting low stretch laminar flame configuration can be useful for fundamental studies of combustion chemistry.

Bedat, B.; Cheng, R.K.

1995-10-01T23:59:59.000Z

66

Effects of Magnetic Field on Micro Flames.  

E-Print Network (OSTI)

??The effect of a gradient magnetic field on a diffusion micro flame i.e. C3H8/air flame has been systematically studied to comprehend their interaction. A non-uniform… (more)

Swaminathan, Sumathi

2005-01-01T23:59:59.000Z

67

High-efficiency photoionization detector  

DOE Patents (OSTI)

A high efficiency photoionization detector using tetraaminoethylenes in a gaseous state having a low ionization potential and a relative photoionization cross section which closely matches the emission spectrum of xenon gas. Imaging proportional counters are also disclosed using the novel photoionization detector of the invention. The compound of greatest interest is TMAE which comprises tetrakis(dimethylamino)ethylene which has a measured ionization potential of 5.36 +- 0.02 eV, and a vapor pressure of 0.35 torr at 20/sup 0/C.

Anderson, D.F.

1981-05-12T23:59:59.000Z

68

Flame Inhibition by Ferrocene, Carbon Dioxide, and ...  

Science Conference Proceedings (OSTI)

Flame Inhibition by Ferrocene, Carbon Dioxide, and Trifluoromethane Blends: Synergistic ... a straight sided schlieren image which is captured by a ...

2012-10-23T23:59:59.000Z

69

Displacement speeds in turbulent premixed flame simulations  

SciTech Connect

The theory of turbulent premixed flames is based on acharacterization of the flame as a discontinuous surface propagatingthrough the fluid. The displacement speed, defined as the local speed ofthe flame front normal to itself, relative to the unburned fluid,provides one characterization of the burning velocity. In this paper, weintroduce a geometric approach to computing displacement speed anddiscuss the efficacy of the displacement speed for characterizing aturbulent flame.

Day, Marcus S.; Shepherd, Ian G.; Bell, J.; Grcar, Joseph F.; Lijewski, Michael J.

2007-07-01T23:59:59.000Z

70

Polyolefin-based flame retardant material  

Disclosure Number 200902239 Technology Summary ... Invention discloses a method to produce flame retardant fibers from neat and recycled ...

71

Production of fullerenic nanostructures in flames  

DOE Patents (OSTI)

A method for the production of fullerenic nanostructures is described in which unsaturated hydrocarbon fuel and oxygen are combusted in a burner chamber at a sub-atmospheric pressure, thereby establishing a flame. The condensibles of the flame are collected at a post-flame location. The condensibles contain fullerenic nanostructures, such as single and nested nanotubes, single and nested nanoparticles and giant fullerenes. The method of producing fullerenic soot from flames is also described.

Howard, Jack B. (Winchester, MA); Vander Sande, John B. (Newbury, MA); Chowdhury, K. Das (Cambridge, MA)

1999-01-01T23:59:59.000Z

72

Production Of Fullerenic Soot In Flames  

DOE Patents (OSTI)

A method for the production of fullerenic nanostructures is described in which unsaturated hydrocarbon fuel and oxygen are combusted in a burner chamber at a sub-atmospheric pressure, thereby establishing a flame. The condensibles of the flame are collected at a post-flame location. The condensibles contain fullerenic nanostructures, such as single and nested nanotubes, single and nested nanoparticles and giant fullerenes. The method of producing fullerenic soot from flames is also described.

Howard, Jack B. (Winchester, MA); Vander Sande, John B. (Newbury, MA); Chowdhury, K. Das (Cambridge, MA)

2000-12-19T23:59:59.000Z

73

Laser controlled flame stabilization  

DOE Patents (OSTI)

A method and apparatus is provided for initiating and stabilizing fuel combustion in applications such as gas turbine electrical power generating engines and jet turbine engines where it is desired to burn lean fuel/air mixtures which produce lower amounts of NO.sub.x. A laser induced spark is propagated at a distance from the fuel nozzle with the laser ignitor being remotely located from the high temperature environment of the combustion chamber. A laser initiating spark generated by focusing high peak power laser light to a sufficiently tight laser spot within the fuel to cause the ionization of air and fuel into a plasma is unobtrusive to the flow dynamics of the combustion chamber of a fuel injector, thereby facilitating whatever advantage can be taken of flow dynamics in the design of the fuel injector.

Early, James W. (Los Alamos, NM); Thomas, Matthew E. (Huntsville, AL)

2001-01-01T23:59:59.000Z

74

Long range alpha particle detector  

DOE Patents (OSTI)

An alpha particle detector capable of detecting alpha radiation from distant sources. In one embodiment, a high voltage is generated in a first electrically conductive mesh while a fan draws air containing air molecules ionized by alpha particles through an air passage and across a second electrically conductive mesh. The current in the second electrically conductive mesh can be detected and used for measurement or alarm. The detector can be used for area, personnel and equipment monitoring.

MacArthur, Duncan W. (Los Alamos, NM); Wolf, Michael A. (Los Alamos, NM); McAtee, James L. (Los Alamos, NM); Unruh, Wesley P. (Los Alamos, NM); Cucchiara, Alfred L. (Los Alamos, NM); Huchton, Roger L. (Los Alamos, NM)

1993-01-01T23:59:59.000Z

75

Long range alpha particle detector  

DOE Patents (OSTI)

An alpha particle detector capable of detecting alpha radiation from distant sources. In one embodiment, a high voltage is generated in a first electrically conductive mesh while a fan draws air containing air molecules ionized by alpha particles through an air passage and across a second electrically conductive mesh. The current in the second electrically conductive mesh can be detected and used for measurement or alarm. The detector can be used for area, personnel and equipment monitoring.

MacArthur, D.W.; Wolf, M.A.; McAtee, J.L.; Unruh, W.P.; Cucchiara, A.L.; Huchton, R.L.

1993-02-02T23:59:59.000Z

76

Flame stabilizer for stagnation flow reactor  

DOE Patents (OSTI)

A method of stabilizing a strained flame in a stagnation flow reactor. By causing a highly strained flame to be divided into a large number of equal size segments it is possible to stablize a highly strained flame that is on the verge of extinction, thereby providing for higher film growth rates. The flame stabilizer is an annular ring mounted coaxially and coplanar with the substrate upon which the film is growing and having a number of vertical pillars mounted on the top surface, thereby increasing the number of azimuthal nodes into which the flame is divided and preserving an axisymmetric structure necessary for stability.

Hahn, David W. (Dublin, CA); Edwards, Christopher F. (Sunnyvale, CA)

1999-01-01T23:59:59.000Z

77

Interferometric Visualization of Jet Flames  

Science Conference Proceedings (OSTI)

This paper presents visualizations of reacting, round jets of the premixed and nonpremixed type realized by using interferometry and, complementarily, direct photography. The available interferometer, proposed by Carlomagno (1986), employs low-cost components ... Keywords: coherent structures, combustion, destabilization, interferometry, jet flames

A. Stella; G. Guj; A. Mataloni

2000-01-01T23:59:59.000Z

78

Flame Doctor for Cyclone Boilers  

Science Conference Proceedings (OSTI)

NOx control and combustion optimization in cyclone boilers requires a monitoring technique that can assess the quality of combustion in the burner and barrel and provide guidance to the operator to make adjustments in the air distribution. This report describes the results through the end of 2008 of a beta demonstration of the Flame Doctor combustion diagnostic system at five working cyclone boilers.

2009-07-22T23:59:59.000Z

79

Flex-flame burner and combustion method  

DOE Patents (OSTI)

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.

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

80

Nonlinear effects in the extraction of laminar flame speeds from expanding spherical flames  

Science Conference Proceedings (OSTI)

Various factors affecting the determination of laminar flames speeds from outwardly propagating spherical flames in a constant-pressure combustion chamber were considered, with emphasis on the nonlinear variation of the stretched flame speed to the flame stretch rate, and the associated need to nonlinearly extrapolate the stretched flame speed to yield an accurate determination of the laminar flame speed and Markstein length. Experiments were conducted for lean and rich n-butane/air flames at 1atm initial pressure, demonstrating the complex and nonlinear nature of the dynamics of flame evolution, and the strong influences of the ignition transient and chamber confinement during the initial and final periods of the flame propagation, respectively. These experimental data were analyzed using the nonlinear relation between the stretched flame speed and stretch rate, yielding laminar flame speeds that agree well with data determined from alternate flame configurations. It is further suggested that the fidelity in the extraction of the laminar flame speed from expanding spherical flames can be facilitated by using small ignition energy and a large combustion chamber. (author)

Kelley, A.P.; Law, C.K. [Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, NJ 08544 (United States)

2009-09-15T23:59:59.000Z

Note: This page contains sample records for the topic "flame ionization detector" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


81

Syngas formation in methane flames and carbon monoxide release during quenching  

SciTech Connect

Following a recent investigation into chemi-ionization and chemiluminescence during gradual aeration of small, laminar methane flames, we proposed that partial oxidation products, or syngas constituents, formed in the pre-flame zone well below the luminous region, were responsible for the observed effects. We therefore map temperature, CO, and H{sub 2} for geometries and conditions relevant to burners in domestic boiler systems, to assess the potential hazard of CO release into the ambient atmosphere, should any partial quenching occur. CO concentrations peaks of 5.5 volume % are recorded in the core surrounding the axis. Appreciable CO concentrations are also found in the absence of added air. Experiments on various burner port geometries and temperatures suggest that this is not due to air entrainment at the flame base but to diffusion from zones closer to the flame. Next, quenching surfaces such as grids, perforated plates and flame trap matrices of different metals are progressively lowered into the flame. To avoid flow line distortion, suction aspirates the quenched products. The highest emission rate occurs with the quenching plane some 4 mm above the burner; further lowering of the quenching surface causes flame extinction. The maximum CO release is close to converting 10% of the CH{sub 4} feed, with some variation with quenching material. Expressing this potential release in terms of, e.g. boiler power, predicts a potentially serious hazard. Results of numerical simulations adequately parallel the experimental sampling profiles and provide insights into local concentrations, as well as the spatially resolved CO flux, which is calculated for a parabolic inlet flow profile. Integration across the stream implies, on the basis of the simulation, a possible tripling of the experimental CO release, were quenching simply to release the local gas composition into the atmosphere. Comparison with experiment suggests some chemical interaction with the quenching surface. (author)

Weinberg, Felix; Carleton, Fred; Houdmont, Raphael [Department of Chemical Engineering, Imperial College, London (United Kingdom); Dunn-Rankin, Derek; Karnani, Sunny [Department of Mechanical and Aerospace Engineering, University of California, Irvine (United States)

2011-02-15T23:59:59.000Z

82

Computational and experimental study of laminar flames  

Science Conference Proceedings (OSTI)

During fiscal year 1991 we have made substantial progress in both the computational and experimental portions of our research. In particular we have continued our study of non-premixed axisymmetric methane-air flames. Computer calculations of multidimensional elliptic flames with two carbon atom chemistry using a shared memory parallel computer are reported for the first time. Also laser spectroscopy of flames utilizing a neodymium laser are also reported. (GHH)

Smooke, M.; Long, M.

1991-01-01T23:59:59.000Z

83

RADIATION DETECTOR  

DOE Patents (OSTI)

A radiation detector of the type is described wherein a condenser is directly connected to the electrodes for the purpose of performing the dual function of a guard ring and to provide capacitance coupling for resetting the detector system.

Wilson, H.N.; Glass, F.M.

1960-05-10T23:59:59.000Z

84

Numerical Simulation of a Laboratory-Scale Turbulent Slot Flame  

E-Print Network (OSTI)

J. M. Don- bar, Combust. Flame 141 (2005) 1–21. [9] R. K.I. G. Shepherd, Combust. Flame 85 [10] M. J. Berger, P.Rosa- lik, Combustion and Flame 112 (1998) 342–358. [16] S.

Bell, John B.; Day, Marcus S.; Grcar, Joseph F.; Lijewski, Michael J.; Driscoll, James F.; Filatyev, Sergei A.

2006-01-01T23:59:59.000Z

85

NUMERICAL ANALYSIS OF FLOW FIELDS GENERATED BY ACCELERATING FLAMES  

E-Print Network (OSTI)

A.J. and Oppenheim, A.K. , "Initial Flame Acceleration in anGeneration of a Shock Wave by a Flame in an Explosive Gas",of Pressure Waves by Accelerating Flames", Tenth Symposium (

Kurylo, J.

2011-01-01T23:59:59.000Z

86

Circulating Flames: Sati, Bridget Cleary and the Fiery “Native Woman”  

E-Print Network (OSTI)

McIvor Circulating Flames: Sati, Bridget Cleary andwho dies in the burning flames with her husband also belongswho dies in the burning flames with her husband,” or sati,

McIvor, Charlotte A.

2008-01-01T23:59:59.000Z

87

Counterflow Extinction of Premixed and Nonpremixed Methanol and Ethanol Flames  

E-Print Network (OSTI)

of methanol. Combustion and Flame, 25:343, 1975. [6] A. Leeand nitrogen. Combustion and Flame, 33:197–215, 1978. [4] T.Methanol and Formaldehyde Flames. Ph.d thesis, University of

Seshadri, Kalyanasundaram

2005-01-01T23:59:59.000Z

88

Active Control for Statistically Stationary Turbulent Premixed Flame Simulations  

E-Print Network (OSTI)

of the Flames . . . . . . . . . . . . . . . . 4.2 GlobalControl Parameters . 3 Controlled Methane Flames 3.1 2-step10 4 Analysis of the GRI-Mech 3.0 Flames 4.1 Appearance

Bell, J.B.; Day, M.S.; Grcar, J.F.; Lijewski, M.J.

2005-01-01T23:59:59.000Z

89

Stochastic algorithms for the analysis of numerical flame simulations  

E-Print Network (OSTI)

methane/air ?ames. Combust. Flame, 123:522–546, 2000. [7] J.reactants. Combust. Flame, 121:395–417, [21] R. Hilbert, F.ame burning rate. Combust. Flame, [29] H. N. Najm and P. S.

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

2004-01-01T23:59:59.000Z

90

A COMPUTATIONAL STUDY OF PHYSICAL AND CHEMICAL FLAME INHIBITION  

E-Print Network (OSTI)

Prothero, A. , Comb. and Flame ll, Pratt, D.T. and Bowman,in a Stoichiometric Flame INHIBITOR CONCENTRATION (molein a 1.5 Equivalence Ratio Flame INHIBITOR CONCENTRATION (

Brown, N.J.

2011-01-01T23:59:59.000Z

91

Laser Extinction in Laminar Inverse Diffusion Flames  

E-Print Network (OSTI)

Diagnostics, Chapter 9: Laser-Induced Incandescence,Laser Extinction in Laminar Inverse Diffusion Flames WesternFoundation, Arlington, VA Laser Extinction in Laminar

Macko, Kevin; Mikofski, Mark A; Fernandez-Pello, Carlos; Blevins, Linda G; Davis, Ronald W.

2005-01-01T23:59:59.000Z

92

Diffusion Flame Measurements: Literature Citations B  

Science Conference Proceedings (OSTI)

... 2-D axisymmetric geometry: Steady and time-varying methane/air, ethylene/air and propane/air flames. 1. KC Smyth, JE ...

2012-10-17T23:59:59.000Z

93

Confined superadiabatic premixed flame-flow interaction  

Science Conference Proceedings (OSTI)

Laminar premixed unity-Lewis number flames are studied numerically, to examine flow-flame interaction in a two-dimensional closed domain. Two opposed planar flame fronts are perturbed sinusoidally and allowed to develop by consuming premixed reactants. Combustion heat release leads to global pressure and temperature rise in the domain, due to confinement. A superadiabatic condition, with products temperature rising with distance behind the flame front, is observed due to stagnation pressure rise. Variations in tangential strain rate behind the perturbed flame fronts, due to flame curvature and heat release, result in a modified local superadiabatic temperature gradient in the products. These variations in temperature gradients are shown to determine the net local confinement-heating rate in the products, leading to corresponding deviations in products temperature, and the local reaction rate along the flame front. These observations, which are not consistent with one-dimensional superadiabatic stagnation flame behavior, are a direct result of the unrestrained unsteady nature of two-dimensional flame-flow interaction.

Najm, H.N.

1995-12-31T23:59:59.000Z

94

Computational and experimental study of laminar flames  

Science Conference Proceedings (OSTI)

We have begun a computational study of nonpremixed tubular methane-air flames with detailed transport and finite rate chemistry. Our multidimensional computation research has been focused primarily on determining the structure of methane-air flames with C{sub 2} chemistry. Experimentally, we have continued our investigation of axisymmetric laminar flames using laser imaging techniques. We have investigated varying the fuel/diluent ratio. In methane flames,there is a broadband fluorescence that overlaps the Raman wavelengths used to measure the concentration of major species.

Smooke, M.D.

1990-01-01T23:59:59.000Z

95

Synthesis of Spinels by Thermal Spray Flame  

Science Conference Proceedings (OSTI)

Presentation Title, Synthesis of Spinels by Thermal Spray Flame. Author(s), Oscar Jaime Restrepo, Ernesto Román Baena Murillo. On-Site Speaker (Planned ) ...

96

Flame Doctor Test at Alabama Power's Plant Gaston  

Science Conference Proceedings (OSTI)

This report describes the results of an evaluation conducted by the Electric Power Research Institute (EPRI) on the Flame Doctor combustion diagnostic system, a hardware and software package designed to diagnose burner performance problems in order to improve overall combustion in the boiler. The Flame Doctor uses signals of existing flame scanners to rate the characteristics of individual boiler flames. The software generates several burner performance indicatorsincluding flame diagnostic number, flame ...

2010-04-22T23:59:59.000Z

97

Flame inhibition/suppression by water mist: Droplet size ...  

Science Conference Proceedings (OSTI)

... 1. Analysis of the flame structure and critical flame ... In the present work, the inhibition of a one ... sizes, the underlying reason for the breakdown in the ...

2012-07-27T23:59:59.000Z

98

Halogen Free Flame Retardant for ABS Composite with Oxides ...  

Science Conference Proceedings (OSTI)

The irrevocable finality from flame retardant is fires protection to help safeguard of ... the oxides particles on obtain the ABS with halogen free flame retardant.

99

INVESTIGATION OF STRETCH AND CURVATURE EFFECTS ON FLAMES.  

E-Print Network (OSTI)

??Flame response on curvature is very important for understanding and predicting of both laminar and turbulent combustion. In this work, curvature effects on flames are… (more)

Wang, Peiyong

2006-01-01T23:59:59.000Z

100

Analyzing and Tracking Burning Structures in Lean Premixed Hydrogen Flames  

E-Print Network (OSTI)

hydrogen ?ames. Combustion and Flame, 156:1035–1045, 2009. [in Lean Premixed Hydrogen Flames P. -T. Bremer 1 , G. Weber

Bremer, Peer-Timo

2010-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "flame ionization detector" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


101

The dependence of chemistry on the inlet equivalence ratio in vortex-flame interactions [Printed LBNL report with title: The effect of stoichiometry on vortex flame interactions  

E-Print Network (OSTI)

of stoichiometry on vortex flame interactions [31] Pember,Rosalik, M . E . , Combust. Flame, 112(3):342-358 (1998).of stoichiometry on vortex flame interactions [15] Mueller,

Tonse, Shaheen R.

2011-01-01T23:59:59.000Z

102

The dependence of chemistry on the inlet equivalence ratio in vortex-flame interactions [Printed LBNL report with title: The effect of stoichiometry on vortex flame interactions  

E-Print Network (OSTI)

of stoichiometry on vortex flame interactions [31] Pember,Rosalik, M . E . , Combust. Flame, 112(3):342-358 (1998).of stoichiometry on vortex flame interactions [15] Mueller,

Bell, John B.; Brown, Nancy J.; Day, Marcus S.; Frenklach, Michael; Grcar, Joseph F.; Tonse, Shaheen R.

1999-01-01T23:59:59.000Z

103

Gated strip proportional detector  

DOE Patents (OSTI)

A gated strip proportional detector includes a gas tight chamber which encloses a solid ground plane, a wire anode plane, a wire gating plane, and a multiconductor cathode plane. The anode plane amplifies the amount of charge deposited in the chamber by a factor of up to 10/sup 6/. The gating plane allows only charge within a narrow strip to reach the cathode. The cathode plane collects the charge allowed to pass through the gating plane on a set of conductors perpendicular to the open-gated region. By scanning the open-gated region across the chamber and reading out the charge collected on the cathode conductors after a suitable integration time for each location of the gate, a two-dimensional image of the intensity of the ionizing radiation incident on the detector can be made.

Morris, C.L.; Idzorek, G.C.; Atencio, L.G.

1985-02-19T23:59:59.000Z

104

Gated strip proportional detector  

DOE Patents (OSTI)

A gated strip proportional detector includes a gas tight chamber which encloses a solid ground plane, a wire anode plane, a wire gating plane, and a multiconductor cathode plane. The anode plane amplifies the amount of charge deposited in the chamber by a factor of up to 10.sup.6. The gating plane allows only charge within a narrow strip to reach the cathode. The cathode plane collects the charge allowed to pass through the gating plane on a set of conductors perpendicular to the open-gated region. By scanning the open-gated region across the chamber and reading out the charge collected on the cathode conductors after a suitable integration time for each location of the gate, a two-dimensional image of the intensity of the ionizing radiation incident on the detector can be made.

Morris, Christopher L. (Los Alamos, NM); Idzorek, George C. (Los Alamos, NM); Atencio, Leroy G. (Espanola, NM)

1987-01-01T23:59:59.000Z

105

Amorphous silicon radiation detectors  

DOE Patents (OSTI)

Hydrogenated amorphous silicon radiation detector devices having enhanced signal are disclosed. Specifically provided are transversely oriented electrode layers and layered detector configurations of amorphous silicon, the structure of which allow high electric fields upon application of a bias thereby beneficially resulting in a reduction in noise from contact injection and an increase in signal including avalanche multiplication and gain of the signal produced by incoming high energy radiation. These enhanced radiation sensitive devices can be used as measuring and detection means for visible light, low energy photons and high energy ionizing particles such as electrons, x-rays, alpha particles, beta particles and gamma radiation. Particular utility of the device is disclosed for precision powder crystallography and biological identification.

Street, Robert A. (Palo Alto, CA); Perez-Mendez, Victor (Berkeley, CA); Kaplan, Selig N. (El Cerrito, CA)

1992-01-01T23:59:59.000Z

106

Amorphous silicon radiation detectors  

DOE Patents (OSTI)

Hydrogenated amorphous silicon radiation detector devices having enhanced signal are disclosed. Specifically provided are transversely oriented electrode layers and layered detector configurations of amorphous silicon, the structure of which allow high electric fields upon application of a bias thereby beneficially resulting in a reduction in noise from contact injection and an increase in signal including avalanche multiplication and gain of the signal produced by incoming high energy radiation. These enhanced radiation sensitive devices can be used as measuring and detection means for visible light, low energy photons and high energy ionizing particles such as electrons, x-rays, alpha particles, beta particles and gamma radiation. Particular utility of the device is disclosed for precision powder crystallography and biological identification. 13 figs.

Street, R.A.; Perez-Mendez, V.; Kaplan, S.N.

1992-11-17T23:59:59.000Z

107

Active control for turbulent premixed flame simulations  

Science Conference Proceedings (OSTI)

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.

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

2004-03-26T23:59:59.000Z

108

Jet flames of a refuse derived fuel  

SciTech Connect

This paper is concerned with combustion of a refuse derived fuel in a small-scale flame. The objective is to provide a direct comparison of the RDF flame properties with properties of pulverized coal flames fired under similar boundary conditions. Measurements of temperature, gas composition (O{sub 2}, CO{sub 2}, CO, NO) and burnout have demonstrated fundamental differences between the coal flames and the RDF flames. The pulverized coals ignite in the close vicinity of the burner and most of the combustion is completed within the first 300 ms. Despite the high volatile content of the RDF, its combustion extends far into the furnace and after 1.8 s residence time only a 94% burnout has been achieved. This effect has been attributed not only to the larger particle size of fluffy RDF particles but also to differences in RDF volatiles if compared to coal volatiles. Substantial amounts of oily tars have been observed in the RDF flames even though the flame temperatures exceeded 1300 C. The presence of these tars has enhanced the slagging propensity of RDF flames and rapidly growing deposits of high carbon content have been observed. (author)

Weber, Roman; Kupka, Tomasz; Zajac, Krzysztof [Institute of Energy Process Engineering and Fuel Technology, Clausthal University of Technology, Agicolastrasse 4, 38 678 Clausthal-Zellerfeld (Germany)

2009-04-15T23:59:59.000Z

109

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

Science Conference Proceedings (OSTI)

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.

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

1997-11-01T23:59:59.000Z

110

DISTRIBUTED FLAMES IN TYPE Ia SUPERNOVAE  

Science Conference Proceedings (OSTI)

At a density near a few x10{sup 7} g cm{sup -3}, the subsonic burning in a Type Ia supernova (SN) enters the distributed regime (high Karlovitz number). In this regime, turbulence disrupts the internal structure of the flame, and so the idea of laminar burning propagated by conduction is no longer valid. The nature of the burning in this distributed regime depends on the turbulent Damkoehler number (Da{sub T}), which steadily declines from much greater than one to less than one as the density decreases to a few x10{sup 6} g cm{sup -3}. Classical scaling arguments predict that the turbulent flame speed s{sub T} , normalized by the turbulent intensity u-check, follows s{sub T}/u-check = Da{sub T}{sup 1/2} for Da{sub T} {approx}burns as a turbulently broadened effective unity Lewis number flame. This flame burns locally with speed s{sub l}ambda and width l{sub l}ambda, and we refer to this kind of flame as a lambda-flame. The burning becomes a collection of lambda-flames spread over a region approximately the size of the {integral} scale. While the total burning rate continues to have a well-defined average, s{sub T}{approx}u-check, the burning is unsteady. We present a theoretical framework, supported by both one-dimensional and three-dimensional numerical simulations, for the burning in these two regimes. Our results indicate that the average value of s{sub T} can actually be roughly twice u-check for Da{sub T} {approx}> 1, and that localized excursions to as much as 5 times u-check can occur. We also explore the properties of the individual flames, which could be sites for a transition to detonation when Da{sub T} {approx} 1. The lambda-flame speed and width can be predicted based on the turbulence in the star (specifically the energy dissipation rate epsilon*) and the turbulent nuclear burning timescale of the fuel tau {sup T}{sub nuc}. We propose a practical method for measuring s{sub l}ambda and l{sub l}ambda based on the scaling relations and small-scale computationally inexpensive simulations. This suggests that a simple turbulent flame model can be easily constructed suitable for large-scale distributed SNe flames. These results will be useful both for characterizing the deflagration speed in larger full-star simulations, where the flame cannot be resolved, and for predicting when detonation occurs.

Aspden, A. J.; Bell, J. B. [Lawrence Berkeley National Laboratory, 1 Cyclotron Road, MS 50A-1148, Berkeley, CA 94720 (United States); Woosley, S. E. [Department of Astronomy and Astrophysics, University of California at Santa Cruz, Santa Cruz, CA 95064 (United States)

2010-02-20T23:59:59.000Z

111

Ionizing Radiation Dosimetry  

Science Conference Proceedings (OSTI)

Ionizing Radiation Dosimetry. ... OH. US Air Force Radiation Dosimetry Laboratory, Wright-Patterson - Base, OH [100548- 0] PA. ...

2013-09-06T23:59:59.000Z

112

Theoretical studies in spiral edge-flame propagation and particle hydrodynamics  

E-Print Network (OSTI)

Diffusion-flame stand-off distance. . . . . . . . . .Summary of experimental flame patterns observed in theSpiral Edges of Diffusion Flames in Von K´ arm´ an Swirling

Urzay, Javier

2010-01-01T23:59:59.000Z

113

NVLAP Ionizing Radiation Dosimetry LAP  

Science Conference Proceedings (OSTI)

Ionizing Radiation Dosimetry LAP. ... This site has been established for applicants to the accreditation program for ionizing radiation dosimetry. ...

2013-07-23T23:59:59.000Z

114

NIST Ionizing Radiation Division - 2001  

Science Conference Proceedings (OSTI)

... The Ionizing Radiation Division of the Physics Laboratory supports the ... meaningful, and compatible measurements of ionizing radiations (x rays ...

115

Enol Intermediates Unexpectedly Found in Flames  

NLE Websites -- All DOE Office Websites (Extended Search)

Enol Intermediates Unexpectedly Found in Flames Print Enol Intermediates Unexpectedly Found in Flames Print For those studying flame chemistry and the properties of combustion intermediates by means of molecular beam mass spectrometry, the addition of tunable vacuum ultraviolet (VUV) from a synchrotron to photoionize the beam for mass spectrometry makes for a powerful technique capable of differentiating between isomers with the same molecular weight and composition. With the help of a unique experimental apparatus, an international team of American, Chinese, and German researchers has exploited this selectivity to identify chemical compounds known as enols as apparently ubiquitous intermediates in flames burning a variety of fuels. This surprising observation will require combustion modelers to revise their models to account for the presence of these compounds.

116

Enol Intermediates Unexpectedly Found in Flames  

NLE Websites -- All DOE Office Websites (Extended Search)

Enol Intermediates Unexpectedly Found in Flames Print Enol Intermediates Unexpectedly Found in Flames Print For those studying flame chemistry and the properties of combustion intermediates by means of molecular beam mass spectrometry, the addition of tunable vacuum ultraviolet (VUV) from a synchrotron to photoionize the beam for mass spectrometry makes for a powerful technique capable of differentiating between isomers with the same molecular weight and composition. With the help of a unique experimental apparatus, an international team of American, Chinese, and German researchers has exploited this selectivity to identify chemical compounds known as enols as apparently ubiquitous intermediates in flames burning a variety of fuels. This surprising observation will require combustion modelers to revise their models to account for the presence of these compounds.

117

Enol Intermediates Unexpectedly Found in Flames  

NLE Websites -- All DOE Office Websites (Extended Search)

Enol Intermediates Unexpectedly Found in Flames Print Enol Intermediates Unexpectedly Found in Flames Print For those studying flame chemistry and the properties of combustion intermediates by means of molecular beam mass spectrometry, the addition of tunable vacuum ultraviolet (VUV) from a synchrotron to photoionize the beam for mass spectrometry makes for a powerful technique capable of differentiating between isomers with the same molecular weight and composition. With the help of a unique experimental apparatus, an international team of American, Chinese, and German researchers has exploited this selectivity to identify chemical compounds known as enols as apparently ubiquitous intermediates in flames burning a variety of fuels. This surprising observation will require combustion modelers to revise their models to account for the presence of these compounds.

118

NETL: Releases & Briefs - A Fascination with Flame  

NLE Websites -- All DOE Office Websites (Extended Search)

image velocimetry to understand why and how flames oscillate as their fuel-to-air consumption ratio is decreased. When new fuel-flexible gas turbines are designed run at these...

119

Enol Intermediates Unexpectedly Found in Flames  

NLE Websites -- All DOE Office Websites (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...

120

Flame Spray Synthesis and Characterization of Nanocrystalline ...  

Science Conference Proceedings (OSTI)

The precursor solution was atomized by a jet nebulizer and allowed to pass through a co-flow diffusion burner in a reactor. A flame was generated by using LPG ...

Note: This page contains sample records for the topic "flame ionization detector" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


121

Transient Supersonic Methane-Air Flames  

E-Print Network (OSTI)

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. The combustor was designed following well-known principles of jet engine combustors. A flame holder and spark plug combination was used to encourage turbulent mixing and ignition of reactant gases, and to anchor the transient flame. Combustion created a high temperature and pressure environment which propelled a flame through a choked de Laval nozzle. The nozzle accelerated the products of combustion to a Mach number of 1.6, creating an underexpanded transient flame which burned for approximately 25 milliseconds. Qualitative information of the flame was gathered by two optical systems. An intensified charge-coupled device (ICCD) was constructed from constitutive components to amplify and capture the chemiluminescence generated by the transient flame, as well as the spatial structure of the flame at specific phases. To gather temporal data of a single transient event as it unfolded, a z-type schlieren optical system was constructed for use with a high speed camera. The system resolves the data in 1 millisecond increments, sufficient for capturing the transient phenomenon. The transient system was modeled computationally in Cantera using the GRI-3.0 reaction mechanism. Experimental conditions were simulated within the zero- dimensional computation by explicit control of the reacting gas mass flow rates within the system. Results from the computational model were used to describe the ignition process. The major limitation of the zero-dimensional reactor model is homogeneity and lack of spatial mixing. In this work a Lagrangian tracking model was used to describe the flame behavior and properties as it travels within the zero-dimensional reactor towards the nozzle. Following this, the flow expansion through the de Laval nozzle was calculated using one-dimensional isentropic relations. The computed reactor model data was then contrasted to experimental results from the ICCD and high speed schlieren images to fully describe the events in the transient supersonic flame.

Richards, John L.

2012-05-01T23:59:59.000Z

122

Aromatics oxidation and soot formation in flames  

SciTech Connect

Work during this contract period has been concerned with the mechanisms through which aromatics are formed and destroyed in flames, and the processes responsible for soot formation. Recent progress has been primarily in two areas: experiments and modeling of the soot nucleation process in low pressure benzene flames and preparation for experiments on the destruction mechanisms of benzene. In addition, we have incorporated weak collision'' formalisms into a fall-off computer code.

Howard, J.B.

1989-01-01T23:59:59.000Z

123

On the dynamics of flame edges in diffusion-flame/vortex interactions  

Science Conference Proceedings (OSTI)

We analyze the local flame extinction and reignition of a counterflow diffusion flame perturbed by a laminar vortex ring. Local flame extinction leads to the appearance of flame edges separating the burning and extinguished regions of the distorted mixing layer. The dynamics of these edges is modeled based on previous numerical results, with heat release effects fully taken into account, which provide the propagation velocity of triple and edge flames in terms of the upstream unperturbed value of the scalar dissipation. The temporal evolution of the mixing layer is determined using the classical mixture fraction approach, with both unsteady and curvature effects taken into account. Although variable density effects play an important role in exothermic reacting mixing layers, in this paper the description of the mixing layer is carried out using the constant density approximation, leading to a simplified analytical description of the flow field. The mathematical model reveals the relevant nondimensional parameters governing diffusion-flame/vortex interactions and provides the parameter range for the more relevant regime of local flame extinction followed by reignition via flame edges. Despite the simplicity of the model, the results show very good agreement with previously published experimental results. (author)

Hermanns, Miguel; Linan, Amable [Departamento de Motopropulsion y Termofluidodinamica, Universidad Politecnica de Madrid, Pza. Cardenal Cisneros 3, 28040 Madrid (Spain); Vera, Marcos [Area de Mecanica de Fluidos, Universidad Carlos III de Madrid, 28911 Leganes (Spain)

2007-04-15T23:59:59.000Z

124

Flames in Type Ia Supernova: Deflagration-Detonation Transition in the Oxygen Burning Flame  

E-Print Network (OSTI)

Flames in Type Ia Supernova: Deflagration-Detonation Transition in the Oxygen Burning Flame S. E structure which, de- pending on density, may involve separate regions of carbon, oxygen and silicon burning, all propagating in a self-similar, subsonic front. The separation between these three burning regions

125

Numerical Issues of Monte Carlo PDF for Large Eddy Simulations of Turbulent Flames  

E-Print Network (OSTI)

piloted methane jet flame (Sandia Flame D),” Presented atof a pure mixing jet and Sandia Flame D using a steady-stateon pure mixing jet and Sandia flame D with a steady-

Bisetti, Fabrizio; Chen, J Y

2005-01-01T23:59:59.000Z

126

Laminar flame speeds of moist syngas mixtures  

SciTech Connect

This work experimentally investigates the effect of the presence of water vapor on the laminar flame speeds of moist syngas/air mixtures using the counterflow twin-flame configuration. The experimental results presented here are for fuel lean syngas mixtures with molar percentage of hydrogen in the hydrogen and carbon monoxide mixture varying from 5% to 100%, for an unburned mixture temperature of 323 K, and under atmospheric pressure. At a given equivalence ratio, the effect of varying amount of water vapor addition on the measured laminar flame speed is demonstrated. The experimental laminar flame speeds are also compared with computed values using chemical kinetic mechanisms reported in the literature. It is found that laminar flame speed varies non-monotonically with addition of water for the carbon monoxide rich mixtures. It first increases with increasing amount of water addition, reaches a maximum value, and then decreases. An integrated reaction path analysis is further conducted to understand the controlling mechanism responsible for the non-monotonic variation in laminar flame speed due to water addition. On the other hand, for higher values of H{sub 2}/CO ratio the laminar flame speed monotonically decreases with increasing water addition. It is shown that the competition between the chemical and thermal effects of water addition leads to the observed response. Furthermore, reaction rate sensitivity analysis as well as binary diffusion coefficient sensitivity analysis are conducted to identify the possible sources of discrepancy between the experimental and predicted values. The sensitivity results indicate that the reaction rate constant of H{sub 2}+OH = H{sub 2}O+H is worth revisiting and refinement of binary diffusion coefficient data of N{sub 2}-H{sub 2}O, N{sub 2}-H{sub 2}, and H{sub 2}-H{sub 2}O pairs can be considered. (author)

Das, Apurba K. [Department of Mechanical and Aerospace Engineering, Case Western Reserve University, Cleveland, OH 44106 (United States); Kumar, Kamal; Sung, Chih-Jen [Department of Mechanical Engineering, University of Connecticut, Storrs, CT 06269 (United States)

2011-02-15T23:59:59.000Z

127

Ultraviolet imaging of hydrogen flames  

DOE Green Energy (OSTI)

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.

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

1988-01-01T23:59:59.000Z

128

Lean Premixed Flame Stability Investigations  

E-Print Network (OSTI)

Fellowship Experience Throughout my twelve-week fellowship at Pratt & Whitney I had the opportunity to interact with numerous engineers and managers as well as to be exposed to a variety of disciplines and areas of engineering. My mentor, Bill Proscia, is an expert in the field of combustion instability analysis and modeling. I gained valuable experience working on a combustion project under his guidance. The project involved studying combustor aerodynamics and static stability of lean-premixed flames for two combustor geometries as a function of swirl number and fuel type. Having an almost non-existent background in the field of combustion, this was a challenging, but very rewarding project to work on. The first few weeks consisted of meeting with engineers and managers to decide on what kind of study I could conduct that would be useful to Pratt & Whitney. During this time I also was able to learn about the business side of engineering and gain a small insight into the overall infrastructure of Pratt & Whitney. In addition to these meetings much of my time was spent reading published literature as well as textbooks on combustion, methods used for modeling combustion, combustion stability, and other

Jared Crosby

2005-01-01T23:59:59.000Z

129

Experimental study of premixed flames in intense isotropic turbulence  

SciTech Connect

A methodology for investigating premixed turbulent flames propagating in intense isotropic turbulence has been developed. The burner uses a turbulence generator developed by Videto and Santavicca and the flame is stabilized by weak-swirl generated by air injectors. This set-up produces stable premixed turbulent flames under a wide range of mixture conditions and turbulence intensities. The experiments are designed to investigate systematically the changes in flame structures for conditions which can be classified as wrinkled laminar flames, corrugated flames and flames with distributed reaction zones. Laser Doppler anemometry and Rayleigh scattering techniques are used to determine the turbulence and scalar statistics. In the intense turbulence, the flames are found to produce very little changes in the mean and rams velocities. Their flame speed increase linearly with turbulence intensity as for wrinkled laminar flames. The Rayleigh scattering pdfs for flames within the distributed reaction zone regime are distinctly bimodal. The probabilities of the reacting states (i.e. contributions from within the reaction zone) is not higher than those of wrinkled laminar flame. These results show that there is no drastic changes in flame structures at Karlovitz number close to unity. This suggest that the Klimov-Williams criterion under-predicts the resilience of wrinkled flamelets to intense turbulence.

Bedat, B.; Cheng, R.K.

1994-04-01T23:59:59.000Z

130

Field Ionization of Cold Atoms near the Wall of a Single Carbon Nanotube  

E-Print Network (OSTI)

We observe the capture and field ionization of individual atoms near the side wall of a single suspended nanotube. Extremely large cross sections for ionization from an atomic beam are observed at modest voltages due to the nanotube's small radius and extended length. The effects of the field strength on both the atomic capture and the ionization process are clearly distinguished in the data, as are prompt and delayed ionizations related to the locations at which they occur. Efficient and sensitive neutral atom detectors can be based on the nanotube capture and wall ionization processes.

Anne Goodsell; Trygve Ristroph; J. A. Golovchenko; Lene Vestergaard Hau

2010-04-15T23:59:59.000Z

131

PHASE DETECTOR  

DOE Patents (OSTI)

A phase detector circuit is described for use at very high frequencies of the order of 50 megacycles. The detector circuit includes a pair of rectifiers inverted relative to each other. One voltage to be compared is applied to the two rectifiers in phase opposition and the other voltage to be compared is commonly applied to the two rectifiers. The two result:ng d-c voltages derived from the rectifiers are combined in phase opposition to produce a single d-c voltage having amplitude and polarity characteristics dependent upon the phase relation between the signals to be compared. Principal novelty resides in the employment of a half-wave transmission line to derive the phase opposing signals from the first voltage to be compared for application to the two rectifiers in place of the transformer commonly utilized for such purpose in phase detector circuits for operation at lower frequency.

Kippenhan, D.O.

1959-09-01T23:59:59.000Z

132

Distributed Flames in Type Ia Supernovae  

E-Print Network (OSTI)

In the distributed burning regime, turbulence disrupts the internal structure of the flame, and so the idea of laminar burning propagated by conduction is no longer valid. The nature of the burning depends on the turbulent Damkohler number (Da), which steadily declines from much greater than one to less that one as the density decreases to a few 10^6 g/cc. Scaling arguments predict that the turbulent flame speed s, normalized by the turbulent intensity u, follows s/u=Da^1/2 for Da1, and that localized excursions to as much as five times u can occur. The lambda-flame speed and width can be predicted based on the turbulence in the star and the turbulent nuclear burning time scale of the fuel. We propose a practical method for measuring these based on the scaling relations and small-scale computationally-inexpensive simulations. This suggests that a simple turbulent flame model can be easily constructed suitable for large-scale distributed supernovae flames.

Aspden, A J; Woosley, S E; 10.1088/0004-637X/710/2/1654

2011-01-01T23:59:59.000Z

133

Chaotic radiation/turbulence interactions in flames  

SciTech Connect

In this paper, the authors present a review of their recent efforts to model chaotic radiation-turbulence interactions in flames. The main focus is to characterize soot volume fraction fluctuations in turbulent diffusion flames, as they strongly contribute to these interaction. The approach is based on the hypothesis that the fluctuations of properties in turbulent flames are deterministic in nature, rather than random. The authors first discuss the theoretical details and then they briefly outline the experiments conducted to measure the scattered light signals from fluctuating soot particles along the axis of an ethylene-air diffusion flame. They compare the power spectra and time series obtained from experiments against the ad-hoc and rigorous models derived using a series of logistic maps. These logistic maps can be used in simulation of the fluctuations in these type of flames, without extensive computational effort or sacrifice of physical detail. Availability of accurate models of these kinds allows investigation of radiation-turbulence interactions at a more fundamental level than it was previously possible.

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

1998-11-01T23:59:59.000Z

134

Microwave detector  

DOE Patents (OSTI)

A microwave detector is provided for measuring the envelope shape of a microwave pulse comprised of high-frequency oscillations. A biased ferrite produces a magnetization field flux that links a B-dot loop. The magnetic field of the microwave pulse participates in the formation of the magnetization field flux. High-frequency insensitive means are provided for measuring electric voltage or current induced in the B-dot loop. The recorded output of the detector is proportional to the time derivative of the square of the envelope shape of the microwave pulse.

Meldner, H.W.; Cusson, R.Y.; Johnson, R.M.

1985-02-08T23:59:59.000Z

135

Microwave detector  

SciTech Connect

A microwave detector (10) is provided for measuring the envelope shape of a microwave pulse comprised of high-frequency oscillations. A biased ferrite (26, 28) produces a magnetization field flux that links a B-dot loop (16, 20). The magnetic field of the microwave pulse participates in the formation of the magnetization field flux. High-frequency insensitive means (18, 22) are provided for measuring electric voltage or current induced in the B-dot loop. The recorded output of the detector is proportional to the time derivative of the square of the envelope shape of the microwave pulse.

Meldner, Heiner W. (Moss Beach, CA); Cusson, Ronald Y. (Chapel Hill, NC); Johnson, Ray M. (San Ramon, CA)

1986-01-01T23:59:59.000Z

136

Flame-vortex interaction and mixing behaviors of turbulent non-premixed jet flames under acoustic forcing  

SciTech Connect

This study examines the effect of acoustic excitation using forced coaxial air on the flame characteristics of turbulent hydrogen non-premixed flames. A resonance frequency was selected to acoustically excite the coaxial air jet due to its ability to effectively amplify the acoustic amplitude and reduce flame length and NO{sub x} emissions. Acoustic excitation causes the flame length to decrease by 15% and consequently, a 25% reduction in EINO{sub x} is achieved, compared to coaxial air flames without acoustic excitation at the same coaxial air to fuel velocity ratio. Moreover, acoustic excitation induces periodical fluctuation of the coaxial air velocity, thus resulting in slight fluctuation of the fuel velocity. From phase-lock PIV and OH PLIF measurement, the local flow properties at the flame surface were investigated under acoustic forcing. During flame-vortex interaction in the near field region, the entrainment velocity and the flame surface area increased locally near the vortex. This increase in flame surface area and entrainment velocity is believed to be a crucial factor in reducing flame length and NO{sub x} emission in coaxial jet flames with acoustic excitation. Local flame extinction occurred frequently when subjected to an excessive strain rate, indicating that intense mass transfer of fuel and air occurs radially inward at the flame surface. (author)

Kim, Munki; Choi, Youngil; Oh, Jeongseog; Yoon, Youngbin [School of Mechanical and Aerospace Engineering, Seoul National University, Seoul (Korea)

2009-12-15T23:59:59.000Z

137

Paper # A02 Topic: Laminar Flames US Combustion Meeting  

E-Print Network (OSTI)

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

Seitzman, Jerry M.

138

Molecular-Beam Mass-Spectrometric Analyses of Hydrocarbon Flames.  

E-Print Network (OSTI)

??Laminar flat flame combustion has been studied with molecular-beam mass-spectrometry (MBMS) for a fuel-rich cyclohexane (? = 2.003) flame, a fuel-lean toluene (? = 0.895),… (more)

Gon, Saugata

2008-01-01T23:59:59.000Z

139

Flame Temperature Field Measurement Using Improved Generalized Cross Validation Method  

Science Conference Proceedings (OSTI)

The image quality is a crucial factor for calculating flame temperature field based on the color CCD method. However, much unknown noise in flame images would prevent from obtaining the temperature with accuracy. To eliminate noise, the wavelet denoising ...

Yinghui Zhou; Dezhong Zheng

2007-10-01T23:59:59.000Z

140

Investigating the Flame Microstructure in Type Ia Supernovae  

E-Print Network (OSTI)

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.

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

2002-04-02T23:59:59.000Z

Note: This page contains sample records for the topic "flame ionization detector" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


141

Pentan isomers compound flame front structure  

DOE Green Energy (OSTI)

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.

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

142

Analyzing and Tracking Burning Structures in Lean Premixed Hydrogen Flames  

E-Print Network (OSTI)

Analyzing and Tracking Burning Structures in Lean Premixed Hydrogen Flames P.-T. Bremer1, G. Weber2 flames subject to different levels of tur- bulence. Due to their unstable nature, lean flames burn to quantitatively correlate the turbulence of the burning process with the distribution of burning regions, properly

143

An Inverted Co-Flow Diffusion Flame for Producing Soot  

E-Print Network (OSTI)

R. A. Dobbins, Combustion & Flame. v 92 n 3, 320-333 (1993).and W. Lee, Combust. and Flame, 109, 266- 6. D. X. Du, H.C. K. Law, Combust. and Flame, 113, 264-270 (1998). 7. B. R.

Stipe, Christopher B.; Higgins, Brian S.; Lucas, Donald; Koshland, Catherine P.; Sawyer, Robert F.

2005-01-01T23:59:59.000Z

144

FLAME DENITRATION AND REDUCTION OF URANIUM NITRATE TO URANIUM DIOXIDE  

DOE Patents (OSTI)

A process is given for converting uranyl nitrate solution to uranium dioxide. The process comprises spraying fine droplets of aqueous uranyl nitrate solution into a hightemperature hydrocarbon flame, said flame being deficient in oxygen approximately 30%, retaining the feed in the flame for a sufficient length of time to reduce the nitrate to the dioxide, and recovering uranium dioxide. (AEC)

Hedley, W.H.; Roehrs, R.J.; Henderson, C.M.

1962-06-26T23:59:59.000Z

145

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

E-Print Network (OSTI)

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

Zare, Richard N.

146

Detailed modeling and laser-induced fluorescence imaging of nitric oxide in a NH(i)-seeded non-premixed methane/air flame  

E-Print Network (OSTI)

an axisymmetric laminar diffusion flame. Proc. Comb. Inst. ,laminar diffusion flames. Combust. Sci. Tech. , [25] N .premixed ethylene/air flames. Combust. Flame, 127:2004-2022,

2001-01-01T23:59:59.000Z

147

Nanocomposite scintillator, detector, and method  

DOE Patents (OSTI)

A compact includes a mixture of a solid binder and at least one nanopowder phosphor chosen from yttrium oxide, yttrium tantalate, barium fluoride, cesium fluoride, bismuth germanate, zinc gallate, calcium magnesium pyrosilicate, calcium molybdate, calcium chlorovanadate, barium titanium pyrophosphate, a metal tungstate, a cerium doped nanophosphor, a bismuth doped nanophosphor, a lead doped nanophosphor, a thallium doped sodium iodide, a doped cesium iodide, a rare earth doped pyrosilicate, or a lanthanide halide. The compact can be used in a radiation detector for detecting ionizing radiation.

Cooke, D. Wayne (Santa Fe, NM); McKigney, Edward A. (Los Alamos, NM); Muenchausen, Ross E. (Los Alamos, NM); Bennett, Bryan L. (Los Alamos, NM)

2009-04-28T23:59:59.000Z

148

The effects of gravity on wrinkled laminar flames  

Science Conference Proceedings (OSTI)

Laminar and turbulent conical Bunsen type flames were used. The study compares results from normal gravity with the burner in an up-right orientation (+g), the burner inverted (-g), and in microgravity ({mu}g) by using the NASA Lewis drop tower facility. The primary diagnostic is a laser schlieren system and some LDA measurements were taken for the +g condition to measure the flow field. The +g laminar flame experiences a large amount of instabilities and results in an unsteady flame tip; cause is torroidal vortex rolling up between products and stagnate surrounding air. Comparison between LDA measurements in reactants and schlieren images shows that velocity fluctuation are induced at the same frequency as the roll up vortices are formed. This pumping of the reactant stream by the product/air interface instability in the +g case is also observed in the turbulent flames. In the -g arrangement the product/air interface is stable so there is no large pumping of the flame tip. At low flow rates the -g flames have flattened tips, but at higher flow rates they become conical in shape. When both flames. appear conical, the -g flames are longer for the same flow rate. In {mu}g the larger instabilities in the flame no longer exist as the product/air interface is believed to become stable. The laminar flames in {mu}g still show small instabilities over the entire flame.

Kostiuk, L.W.; Zhou, L.; Cheng, R.K.

1992-09-01T23:59:59.000Z

149

Freely propagating open premixed turbulent flames stabilized by swirl  

DOE Green Energy (OSTI)

A novel means has been developed for using weak swirl to stabilize freely propagating open premixed turbulent flames (swirl numbers between 0.05 to 0.3). By injecting a small amount of air tangentially into the co-flow of a concentric burner, stationary flames can be maintained above the burner exit for a large range of mixture, turbulence and flow conditions. The absence of physical surfaces in the vicinity of the flame provides free access to laser diagnostics. Laser Doppler anemometry and laser Mie scattering measurements of four flames with and without incident turbulence show that their features are typical of wrinkled laminar flames. The most distinct characteristics is that flame stabilization does not rely on flow recirculation. Centrifugal force induced by swirl causes flow divergence, and the flame is maintained at where the local mass flux balances the burning rate. The flame speeds can be estimated based on the centerline velocity vector, which is locally normal to the flame brush. This flame geometry is the closest approximation to the 1-D planar flame for determining fundamental properties to advance turbulent combustion theories. 18 refs.

Chan, C.K.; Lau, K.S.; Chin, W.K. (Hong Kong Polytechnic, Kowloon (Hong Kong)); Cheng, R.K. (Lawrence Berkeley Lab., CA (United States))

1991-12-01T23:59:59.000Z

150

The effects of gravity on wrinkled laminar flames  

Science Conference Proceedings (OSTI)

Laminar and turbulent conical Bunsen type flames were used. The study compares results from normal gravity with the burner in an up-right orientation (+g), the burner inverted (-g), and in microgravity ([mu]g) by using the NASA Lewis drop tower facility. The primary diagnostic is a laser schlieren system and some LDA measurements were taken for the +g condition to measure the flow field. The +g laminar flame experiences a large amount of instabilities and results in an unsteady flame tip; cause is torroidal vortex rolling up between products and stagnate surrounding air. Comparison between LDA measurements in reactants and schlieren images shows that velocity fluctuation are induced at the same frequency as the roll up vortices are formed. This pumping of the reactant stream by the product/air interface instability in the +g case is also observed in the turbulent flames. In the -g arrangement the product/air interface is stable so there is no large pumping of the flame tip. At low flow rates the -g flames have flattened tips, but at higher flow rates they become conical in shape. When both flames. appear conical, the -g flames are longer for the same flow rate. In [mu]g the larger instabilities in the flame no longer exist as the product/air interface is believed to become stable. The laminar flames in [mu]g still show small instabilities over the entire flame.

Kostiuk, L.W.; Zhou, L.; Cheng, R.K.

1992-09-01T23:59:59.000Z

151

Increased Cytotoxicity of Oxidized Flame Soot  

NLE Websites -- All DOE Office Websites (Extended Search)

Increased Cytotoxicity of Oxidized Flame Soot Increased Cytotoxicity of Oxidized Flame Soot Title Increased Cytotoxicity of Oxidized Flame Soot Publication Type Journal Article Year of Publication 2012 Authors Holder, Amara L., Brietta J. Carter, Regine Goth-Goldstein, Donald Lucas, and Catherine P. Koshland Journal Atmospheric Pollution Research Volume 3 Start Page 25 Issue 1 Pagination 25-31 Date Published 01/2012 Keywords health effects, ozone, soot, toxicity Abstract Combustion-generated particles released into the atmosphere undergo reactions with oxidants, which can change the particles' physiochemical characteristics. In this work, we compare the physical and chemical properties and cellular response of particles fresh from a flame with those oxidized by ozone and nitrogen dioxide. The reaction with ozone and nitrogen dioxide does not significantly modify the physical characteristics of the particles (primary particle size, fractal dimension, and surface area). However, oxidation affects the chemical characteristics of the particles, creating more oxygen and nitrogen containing functional groups, and increases their hydrophilicity. In addition, oxidized soot generates more reactive oxygen species, as measured by the dithiothreitol (DTT) assay. Furthermore, oxidized soot is 1.5-2 times more toxic than soot that was not reacted with ozone, but the inflammatory response, measured by interleukin-8 (IL-8) secretion, is unchanged. These results imply that combustion-generated particles released into the atmosphere will have an increased toxicity on or after high ozone days.

152

Spark Ignited Turbulent Flame Kernel Growth  

DOE Green Energy (OSTI)

An experimental study of the effects of spark power and of incomplete fuel-air mixing on spark-ignited flame kernel growth was conducted in turbulent propane-air mixtures at 1 atm, 300K conditions. The results showed that increased spark power resulted in an increased growth rate, where the effect of short duration breakdown sparks was found to persist for times of the order of milliseconds. The effectiveness of increased spark power was found to be less at high turbulence and high dilution conditions. Increased spark power had a greater effect on the 0-5 mm burn time than on the 5-13 mm burn time, in part because of the effect of breakdown energy on the initial size of the flame kernel. And finally, when spark power was increased by shortening the spark duration while keeping the effective energy the same there was a significant increase in the misfire rate, however when the spark power was further increased by increasing the breakdown energy the misfire rate dropped to zero. The results also showed that fluctuations in local mixture strength due to incomplete fuel-air mixing cause the flame kernel surface to become wrinkled and distorted; and that the amount of wrinkling increases as the degree of incomplete fuel-air mixing increases. Incomplete fuel-air mixing was also found to result in a significant increase in cyclic variations in the flame kernel growth. The average flame kernel growth rates for the premixed and the incompletely mixed cases were found to be within the experimental uncertainty except for the 33%-RMS-fluctuation case where the growth rate was significantly lower. The premixed and 6%-RMS-fluctuation cases had a 0% misfire rate. The misfire rates were 1% and 2% for the 13%-RMS-fluctuation and 24%-RMS-fluctuation cases, respectively; however, it drastically increased to 23% in the 33%-RMS-fluctuation case.

Santavicca, D.A.

1995-06-01T23:59:59.000Z

153

Ionization Energy Search  

Science Conference Proceedings (OSTI)

... SI calorie-based; Select the desired type(s) of ... search for species based on ionization energy values in ... Rules for data types (step 4) (Back to search). ...

2013-07-15T23:59:59.000Z

154

NIST Ionizing Radiation Division - 1998  

Science Conference Proceedings (OSTI)

TECHNICAL ACTIVITIES 1998 - NISTIR 6268 IONIZING RADIATION DIVISION. The Neutron Interferometer. The neutron ...

155

NIST Ionizing Radiation Division - 2000  

Science Conference Proceedings (OSTI)

"Technical Activities 2000" - Table of Contents, Division home page. Ionizing Radiation Division. ...

156

Flame quality monitor system for fixed firing rate oil burners  

DOE Patents (OSTI)

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.

Butcher, T.A.; Cerniglia, P.

1990-10-23T23:59:59.000Z

157

Flame quality monitor system for fixed firing rate oil burners  

DOE Patents (OSTI)

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.

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

1992-01-01T23:59:59.000Z

158

Visualization of Multiple Scalar and Velocity Fields in a Lifted Jet Flame  

Science Conference Proceedings (OSTI)

The stabilization of lifted jet diffusion flames has long been a topic of interest to combustion researchers. The flame and flow morphology, the role of partial premixing, and the effects of large scale structures on the flame can be visualized through ... Keywords: Rayleigh scattering, combustion, flame stabilization, jet diffusion flame, laser diagnostics, laser-induced fluorescence (LIF), particle image velocimetry (PIV)

K. A. Watson; K. M. Lyons; J. M. Donbar; C. D. Carter

2000-08-01T23:59:59.000Z

159

Device for calibrating a radiation detector system  

DOE Patents (OSTI)

A device for testing a radiation detector system that includes at least two arrays of radiation detectors that are movable with respect to each other. The device includes a "shield plate" or shell, and an opposing "source plate" containing a source of ionizing radiation. Guides are attached to the outer surface of the shell for engaging the forward ends of the detectors, thereby reproducibly positioning the detectors with respect to the source and with respect to each other, thereby ensuring that a predetermined portion of the radiation emitted by the source passes through the shell and reaches the detectors. The shell is made of an hydrogenous material having approximately the same radiological attenuation characteristics as composite human tissue. The source represents a human organ such as the lungs, heart, kidneys, heart, liver, spleen, pancreas, thyroid, testes, prostate, or ovaries. The source includes a source of ionizing radiation having a long half-life and an activity that is within the range typically searched for in human subjects.

Mc Fee, Matthew C. (New Ellenton, SC); Kirkham, Tim J. (Beech Island, SC); Johnson, Tippi H. (Aiken, SC)

1994-01-01T23:59:59.000Z

160

Device for calibrating a radiation detector system  

DOE Patents (OSTI)

A device is disclosed for testing a radiation detector system that includes at least two arrays of radiation detectors that are movable with respect to each other. The device includes a ''shield plate'' or shell, and an opposing ''source plate'' containing a source of ionizing radiation. Guides are attached to the outer surface of the shell for engaging the forward ends of the detectors, thereby reproducibly positioning the detectors with respect to the source and with respect to each other, thereby ensuring that a predetermined portion of the radiation emitted by the source passes through the shell and reaches the detectors. The shell is made of an hydrogenous material having approximately the same radiological attenuation characteristics as composite human tissue. The source represents a human organ such as the lungs, heart, kidneys, liver, spleen, pancreas, thyroid, testes, prostate, or ovaries. The source includes a source of ionizing radiation having a long half-life and an activity that is within the range typically searched for in human subjects. 3 figures.

McFee, M.C.; Kirkham, T.J.; Johnson, T.H.

1994-12-27T23:59:59.000Z

Note: This page contains sample records for the topic "flame ionization detector" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


161

Environmentally Benign Flame Retardant Nanocoatings for Fabric  

E-Print Network (OSTI)

A variety of materials were used to fabricate nanocoatings using layer-by-layer (LbL) assembly to reduce the flammability of cotton fabric. The most effective brominated flame retardants have raised concerns related to their toxicity and environmental impact, which has created a need for alternative flame retardant chemistries and approaches. Polymer nanocomposites typically exhibit reduced mass loss and heat release rates, along with anti-dripping behavior, all of which are believed to be due to the formation of a barrier surface layer. Despite these benefits, the viscosity and modulus of the final polymeric material is often altered, making industrial processing difficult. These challenges inspired the use of LbL assembly to create densely layered 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 mixtures. Both films can be grown linearly as a function of layers deposited, and they contained at least 70 wt percent of clay. When applying these films to cotton fabric, the individual fibers are uniformly coated and the fabric has significant char left after burning. MMT-coated fabric exhibits reduced total heat release, suggesting a protective ceramic surface layer is created. Small molecule, POSS-based LbL thin films were also successfully deposited on cotton fabric. With less than 8 wt percent added to the total fabric weight, more than 12 wt percent char remained after microscale combustion calorimetry. Furthermore, afterglow time was reduced and the fabric weave structure and shape of the individual fibers were highly preserved following vertical flame testing. A silica-like sheath was formed after burning that protected the fibers. Finally, the first intumescent LbL assembly was deposited on cotton fabric. SEM images show significant bubble formation on fibers, coated with a 0.5 wt percent PAAm/1 wt percent PSP coating after burning. In several instances, a direct flame on the fabric was extinguished. The peak HRR and THR of coated fabric has 30 percent and 65 percent reduction, respectively, compared to the uncoated control fabric. These anti-flammable nanocoatings provide a relatively environmentally-friendly alternative for protecting fabrics, such as cotton, and lay the groundwork for rendering many other complex substrates (e.g., foam) flame-retardant without altering their processing and desirable mechanical behavior.

Li, Yu-Chin

2011-05-01T23:59:59.000Z

162

Strained flamelets for turbulent premixed flames, I: Formulation and planar flame results  

SciTech Connect

A strained flamelet model is proposed for turbulent premixed flames using scalar dissipation rate as a parameter. The scalar dissipation rate of reaction progress variable is a suitable quantity to describe the flamelet structure since it is governed by convection-diffusion-reaction balance and it is defined at every location in the flamelets, which are represented by laminar flames in reactant-to-product opposed flow configuration. The mean reaction rate is obtained by using the flamelets reaction rate and the joint pdf of the progress variable and its dissipation rate. The marginal pdf of the progress variable is presumed to be {beta}-pdf and the pdf of the conditional dissipation rate is taken to be log-normal. The conditional mean dissipation rate is obtained from modelled mean dissipation rate. This reaction rate closure is assessed using RANS calculations of statistically planar flames in the corrugated flamelets and thin reaction zones regimes. The flame speeds calculated using this closure are close to the experimental data of Abdel-Gayed et al. (1987) for flames in both the regimes. Comparisons with other reaction rate closures showed the benefits of the strained flamelets approach. (author)

Kolla, H.; Swaminathan, N. [Department of Engineering, Cambridge University, Cambridge CB2 1PZ (United Kingdom)

2010-05-15T23:59:59.000Z

163

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

DOE Data Explorer (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.

None

164

The Soret Effect in Naturally Propagating, Premixed, Lean, Hydrogen-Air Flames  

E-Print Network (OSTI)

H. Markstein (Ed. ), Nonsteady Flame Propagation, PergamonHassan, G. M. Faeth, Combust. Flame 109 (1997) 1–24. [6] Y.P. Middha, H. Wang, Combus. Flame [7] F. N. Egolfopoulos, C.

Grcar, Joseph F

2008-01-01T23:59:59.000Z

165

STUDIES OF WALL FLAME QUENCHING AND HYDROCARBON EMISSIONS IN A MODEL SPARK IGNITION ENGINE  

E-Print Network (OSTI)

spark ignition . Particle velocity at a flame front Profileof apparent flame front approaching a position at a side warolled-up votex and CH4-air flame; equivalence ratio 0.6,

Ishikawa, Nobuhiko

2011-01-01T23:59:59.000Z

166

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

E-Print Network (OSTI)

along the centerline of a flame from the 7.5 mm ID nozzle,Oxide Nanoparticles in a Diffusion Flame Bing Guo and Ian M.in a hydrogen diffusion flame seeded with Cr(CO) 6 vapor.

Guo, B; Kennedy, Ian M

2004-01-01T23:59:59.000Z

167

MODELLING OF BURNING AND EXTINCTION CHARACTERISTICS OF A POLYMER DIFFUSION FLAME AND COMPARISON WITH EXPERIMENT  

E-Print Network (OSTI)

and Seshadri, K. : Combustion and Flame, 26, 363, 1976. ActaD.P. and Prahl, J.M. : and Flame 33, 55, 1978. Burke, S.P.OF A POLYMER DIFFUSION FLAME AND COMPARISON WITH EXPERIMENT

Pitz, W.J.

2012-01-01T23:59:59.000Z

168

Dynamics of the flame flowfields in a low-swirl burner  

E-Print Network (OSTI)

Cheng, R.K. , Combustion and Flame 127:2066 (2001). Chan,4 /air premixed turbulent flames at ? = 0.8 and U o = 5, 7.5Cheng, R.K. , Combustion and Flame 100:485 (1995). Cheng,

Johnson, Matthew R.

2003-01-01T23:59:59.000Z

169

Flow-Assisted Flame Propagation Through a Porous Combustible in Microgravity  

E-Print Network (OSTI)

P.J. Pagni and T.G. Peterson, “Flame Spread Through PorousT. Niioka, ”Flow-Assisted Flame Propagation Through a PorousMarch 2002 Flow-Assisted Flame Propagation Through a Porous

Bar-Ilan, Amnon; Rich, David B; Rein, Guillermo; Fernandez-Pello, Carlos; Hanai, H.; Niioka, T.

2002-01-01T23:59:59.000Z

170

Numerical simulation of a laboratory-scale turbulent V-flame  

E-Print Network (OSTI)

and P. S. Wyckoff. Combust. Flame, [13] H. N. Najm and P.S. Wyckoff. Combust. Flame, 110(1–2):92–112, 1997. [14] R.and J. M. Donbar. Combust. Flame, 2005. in press. [7] M.

2005-01-01T23:59:59.000Z

171

THE COMBUSTION OF SOLVENT REPINED COAL IN AN OPPOSED FLOW DIFFUSION FLAME  

E-Print Network (OSTI)

of counterflow diffusion flames above condensed fuels.IN AN OPPOSED FLOW DIFFUSION FLAME* W.K. Chin R.F. Sawyeropposed flow diffusion flame burner. An earlier experimental

Chin, W.K.

2011-01-01T23:59:59.000Z

172

Durable and Non-Toxic Topical Flame Retardants for Cotton and Cotton Blends.  

E-Print Network (OSTI)

??Flame retardant chemicals were used as topical finishes on cotton and cotton blended fabric. Comparison of flame resistance and durability of non-bromine/non-antimony flame retardants were… (more)

Mathews, Marc Christopher

2008-01-01T23:59:59.000Z

173

Scaling and efficiency of PRISM in adaptive simulations of turbulent premixed flames  

E-Print Network (OSTI)

one-dimensional premixed flames," Sandia National Labora-U. and Pope, S. B. , Combust. Flame, 88:239-264 (1992). [7]B. and Pope, S. B. , Combust. Flame, 112:85-112 (1998). [13

Tonse, Shaheen R.

2011-01-01T23:59:59.000Z

174

LES of Sandia Flame D with Eulerian PDF and Finite-Rate Chemistry  

E-Print Network (OSTI)

mixing models. Com- bust. Flame 136, 208–216. Subramaniam,Ald´ n, M. , Kaminski, C. , e 2000. Flame front tracking andspanning trees. Combust. Flame 115, 487–514. Tang, Q. , Xu,

Bisetti, Fabrizio; Chen, J Y

2005-01-01T23:59:59.000Z

175

Numerical Issues of Monte Carlo PDF for Large Eddy Simulations of Turbulent Flames  

E-Print Network (OSTI)

Carlo PDF Methods for Turbulent Diffusion Flames,” Combust.Flame 124:519-534 (2001). Muradoglu, M. , Jenny, P. Pope,Methane-Air Nonpremixed Jet Flames,” Combustion Science and

Bisetti, Fabrizio; Chen, J Y

2005-01-01T23:59:59.000Z

176

Flame Doctor for Cyclone Boilers: Beta Demonstration Program  

Science Conference Proceedings (OSTI)

This report describes the results of the beta demonstration of the Flame Doctor system as it is applied to cyclone boilers.

2012-07-10T23:59:59.000Z

177

Flashback, Blow out, Emissions and Turbulent Displacement Flame...  

NLE Websites -- All DOE Office Websites (Extended Search)

driving physics relating turbulent flame speeds to flashback at conditions relevant to gas turbine engines. Testing was conducted in an optically accessible single nozzle...

178

Influence of Different Parameters on Theoretical Flame Temperature ...  

Science Conference Proceedings (OSTI)

One of the main parameters to measure the thermal state in Corex melter gasifier is the theoretical flame temperature (TFT) before tuyere, which is important to ...

179

Boundary Layer Flame Spread over PMMA within the Initial ...  

Science Conference Proceedings (OSTI)

... INTRODUCTION Boundary layer-type flames are prevalent in wall fires, ceiling fires, and wind-driven fires on flat surfaces such as floors and roofs. ...

2011-11-03T23:59:59.000Z

180

Session Overview: Flame Synthesis Hai Wang, Session Chair Dept...  

NLE Websites -- All DOE Office Websites (Extended Search)

of gas-phase chemistry, heterogeneous reaction kinetics and materials thermodynamics and kinetics. A successful flame synthesis route to a particular material is often...

Note: This page contains sample records for the topic "flame ionization detector" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


181

Active Control for Statistically Stationary Turbulent PremixedFlame Simulations  

Science Conference Proceedings (OSTI)

The speed of propagation of a premixed turbulent flame correlates with the intensity of the turbulence encountered by the flame. One consequence of this property is that premixed flames in both laboratory experiments and practical combustors require some type of stabilization mechanism 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. Furthermore, the stabilization introduces additional fluid mechanical complexity into the overall combustion process that can complicate the analysis of fundamental flame properties. To circumvent these difficulties we introduce a feedback control algorithm that allows us to computationally stabilize a turbulent premixed flame in a simple geometric configuration. For the simulations, we specify turbulent inflow 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 on methane flames at various equivalence ratios in two dimensions. The simulation data are used to study the local variation in the speed of propagation due to flame surface curvature.

Bell, J.B.; Day, M.S.; Grcar, J.F.; Lijewski, M.J.

2005-08-30T23:59:59.000Z

182

Catalytic inhibition of laminar flames by transition metal ...  

Science Conference Proceedings (OSTI)

... measurements of OH concentration reduction in low-pressure counterflow diffusion flames inhibited by Fe(CO)5, using laser-induced fluorescence ...

2008-10-16T23:59:59.000Z

183

Influence of the Pulverized Coal Ash on Theoretical Flame ...  

Science Conference Proceedings (OSTI)

Moreover, the modified formula for calculating of theoretical flame temperature before tuyere is established. The effect of the ratio of reduced SiO2 in raceway ...

184

Flame Synthesized Metal Oxide Nanowires as Effective Photoanodes  

NLE Websites -- All DOE Office Websites (Extended Search)

Stanford, CA 94305, USA I will discuss an atmospheric, cost-effective and scalable flame synthesis method for the growth and doping of metal oxide nanowires and these...

185

Development and testing of flame retardant additives and polymers.  

E-Print Network (OSTI)

??The first chapter examines the non-halogenated flame retardant additives. The synthesis and blending of these various boron compounds are discussed and the blending of these… (more)

Jurs, Joshua Lewis

2004-01-01T23:59:59.000Z

186

Flame-capturing technique. 1: Adaptation to gas expansion  

E-Print Network (OSTI)

Various flame tracking techniques are often used in hydrodynamic simulations. Their use is indispensable when resolving actual scale of the flame is impossible. We show that parameters defining "artificial flame" propagation found from model systems may yield flame velocities several times distinct from the required ones, due to matter expansion being ignored in the models. Integral effect of material expansion due to burning is incorporated into flame capturing technique (FCT) [Khokhlov(1995)]. Interpolation formula is proposed for the parameters governing flame propagation yielding 0.2% accurate speed and width for any expansion (and at least 0.01% accurate for expansions typical in type Ia supernova explosions.) Several models with simple burning rates are studied with gas expansion included. Plausible performance of the technique in simulations is discussed. Its modification ensuring finite flame width is found. Implementation suggestions are summarized, main criterion being the scheme performance being insensitive to expansion parameter (thus absence of systematic errors when the burning progresses from inner to outer layers); in this direction promising realizations are found, leading to flame structure not changing while flame evolves through the whole range of densities in the white dwarf.

Andrey V. Zhiglo

2005-11-12T23:59:59.000Z

187

High Frequency Acoustic Wave Scattering From Turbulent Premixed Flames .  

E-Print Network (OSTI)

??This thesis describes an experimental investigation of high frequency acoustic wave scattering from turbulent premixed flames. The objective of this work was to characterize the… (more)

Narra, Venkateswarlu

2008-01-01T23:59:59.000Z

188

Particle Size Effects on the Morphology and Bioactivity of Flame ...  

Science Conference Proceedings (OSTI)

Flame spraying was used to manufacture coatings with different levels of porosity by altering both the deposition conditions and the feedstock particle size ...

189

Analysis of the Wave Scattering From Turbulent Premixed Flame .  

E-Print Network (OSTI)

??A theoretical investigation of acoustic wave interactions with turbulent premixed flames was performed. Such interactions affect the characteristic unsteadiness of combustion processes, e.g., combustion instabilities.… (more)

Cho, Ju Hyeong

2006-01-01T23:59:59.000Z

190

Mechanism of Sulfur-containing Aryl Polyphosphonate as Flame ...  

Science Conference Proceedings (OSTI)

Presentation Title, Mechanism of Sulfur-containing Aryl Polyphosphonate as Flame Retardant for PET. Author(s), Deng Yi. On-Site Speaker (Planned), Deng Yi.

191

FIELD TEST OF THE FLAME QUALITY INDICATOR  

Science Conference Proceedings (OSTI)

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.

Andrew M. Rudin; Thomas Butcher; Henry Troost

2003-02-04T23:59:59.000Z

192

CG-3 Detector Array  

NLE Websites -- All DOE Office Websites (Extended Search)

tanks for the SANS instruments at HFIR. The Bio-SANS detector is on the left. CG-3 Detector Array For more information, contact Instrument Scientist: Volker Urban,...

193

NIST Detector metrology  

Science Conference Proceedings (OSTI)

... Description: Improved detector technology in the past two decades has opened a new era in detector metrology of optical radiation measurements. ...

2013-08-22T23:59:59.000Z

194

Flame Response Mechanisms and their Interaction in a Lean Premixed Swirl-Stabilized Gas Turbine Combustor.  

E-Print Network (OSTI)

??To satisfy increasingly stringent environmental regulations, gas turbine engines are run in a lean premixed mode. Unfortunately, operating in this mode greatly increases the flame’s… (more)

Jones, Brian

2011-01-01T23:59:59.000Z

195

Measurement of gas temperature field in a flame spreading over solid fuel.  

E-Print Network (OSTI)

??An experimental measurement is developed to measure the gas temperature field in a flame spreading downward over thermally thin filter paper. A flame stabilizer apparatus… (more)

Alghamdi, Abdulaziz Othman

2012-01-01T23:59:59.000Z

196

Modeling of flame spread over thin fuels on downward configuration in the presence of forced convection.  

E-Print Network (OSTI)

??The purpose of this thesis is to simulate the downward flame spread over thin fuel (Cellulose and Polymethylmethacrylate) in a natural convection environment. Flame spread… (more)

Patel, Gaurav Rameshbhai

2013-01-01T23:59:59.000Z

197

Atomic ionization of germanium due to neutrino magnetic moments  

E-Print Network (OSTI)

An ab initio calculation of atomic ionization of germanium (Ge) by neutrinos was carried out in the framework of multiconfiguration relativistic random phase approximation. The main goal is to provide a more accurate cross section formula than the conventional one, which is based on the free electron approximation, for searches of neutrino magnetic moments with Ge detectors whose threshold is reaching down to the sub-keV regime. Limits derived with both methods are compared, using reactor neutrino data taken with low threshold germanium detectors.

Jiunn-Wei Chen; Hsin-Chang Chi; Keh-Ning Huang; C. -P. Liu; Hao-Tse Shiao; Lakhwinder Singh; Henry T. Wong; Chih-Liang Wu; Chih-Pan Wu

2013-11-21T23:59:59.000Z

198

Calculating thermal radiation fields from 3D flame reconstruction  

Science Conference Proceedings (OSTI)

Designing fire safety into a building requires a designer to think through issues that include fire ignition, growth and spread. Radiative heat transfer from flames is the dominant method of spread. It is, therefore, necessary to determine the thermal ... Keywords: configuration factor, flame geometry, heat flux, radial basis function, thermal radiation field

Paul Mason; Chris Rogers

2003-02-01T23:59:59.000Z

199

Measurements of Laminar Flame Velocity for Components of Natural Gas  

E-Print Network (OSTI)

Measurements of Laminar Flame Velocity for Components of Natural Gas Patricia Dirrenberger1 flame velocity of components of natural gas, methane, ethane, propane, and nbutane as well as of binary and tertiary mixtures of these compounds proposed as surrogates for natural gas. These measurements have been

200

High-speed Visualization of Flame Propagation in Explosions  

Science Conference Proceedings (OSTI)

Flow visualization data is presented to describe the structure of flames propagating in methane-air explosions in semi-confined enclosures. The role of turbulence is well established as a mechanism for increasing burning velocity by fragmenting the flame ... Keywords: combustion, explosions, high-speed, imaging, laser-sheet

G. K. Hargrave; T. C. Williams; S. Jarvis

2001-12-01T23:59:59.000Z

Note: This page contains sample records for the topic "flame ionization detector" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


201

Analyzing and Tracking Burning Structures in Lean Premixed Hydrogen Flames  

E-Print Network (OSTI)

Analyzing and Tracking Burning Structures in Lean Premixed Hydrogen Flames Peer-Timo Bremer, Member levels of turbulence. Due to their unstable nature, lean flames burn in cells separated by locally the turbulence of the burning process with the distribution of burning regions, properly segmented and selected

Pascucci, Valerio

202

Author's personal copy Combustion and Flame 151 (2007) 104119  

E-Print Network (OSTI)

May 2007 Available online 28 June 2007 Abstract Laminar flame speeds of lean H2/CO/CO2 (syngas) fuel Inc. All rights reserved. Keywords: Syngas; Laminar flame speed; CO2 dilution; Reactant preheat). emissions. Synthetic gas (syngas) fuels derived from coal are particularly promising in this regard. Syn

Lieuwen, Timothy C.

203

A Study of Premixed Propagating Flame Vortex Interaction  

Science Conference Proceedings (OSTI)

Experimental data is presented for the interaction between a propagating flame and a simple vortex flow field structure generated in the wake of solid obstacles. The interaction between gas movement and obstacles creates vortex shedding forming a simple ... Keywords: Combustion, Flame/Vortex, PIV, Visualization

G. K. Hargrave; S. Jarvis

2006-04-01T23:59:59.000Z

204

Flame Spectral Analysis for Boiler Control  

E-Print Network (OSTI)

An instrument has been developed by Tecogen, Inc., to determine the combustion characteristics of individual burners in multiburner installations. The technology is based on measuring the emissions in the ultraviolet (UV) and infrared (IR) spectral 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. These instruments provide data relating to the variations in the IR and UV spectrum with a change in the combustion condition in individuals burners. This paper describes the instruments operation and these tests.

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

1987-09-01T23:59:59.000Z

205

Turbulence-Flame Interactions in Type Ia Supernovae  

SciTech Connect

The large range of time and length scales involved in type Ia supernovae (SN Ia) requires the use of flame models. As a prelude to exploring various options for flame models, we consider, in this paper, high-resolution three-dimensional simulations of the small-scale dynamics of nuclear flames in the supernova environment in which the details of the flame structure are fully resolved. The range of densities examined, 1 to 8 x 107 g cm-3, spans the transition from the laminar flamelet regime to the distributed burning regime where small scale turbulence disrupts the flame. The use of a low Mach number algorithm facilitates the accurate resolution of the thermal structure of the flame and the inviscid turbulent kinetic energy cascade, while implicitly incorporating kinetic energy dissipation at the grid-scale cutoff. For an assumed background of isotropic Kolmogorov turbulence with an energy characteristic of SN Ia, we find a transition density between 1 and 3 x 107 g cm-3 where the nature of the burning changes ualitatively. By 1 x 107 g cm-3, energy diffusion by conduction and radiation is exceeded, on the flame scale, by turbulent advection. As a result, the effective Lewis Number approaches unity. That is, the flame resembles a laminar flame, but is turbulently broadened with an effective diffusion coefficient, D_T \\sim u' l, where u' is the turbulent intensity and l is the integral scale. For the larger integral scales characteristic of a real supernova, the flame structure is predicted to become complex and unsteady. Implications for a possible transition to detonation are discussed.

Lawrence Berkeley National Laboratory, 1 Cyclotron Road, MS 50A-1148, Berkeley, CA 94720 (Authors 1, 2& 3); Department of Astronomy and Astrophysics, University of California at Santa Cruz, Santa Cruz, CA 95064 (Author 4); Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY 11794 (Author 5); Aspden, Andrew J; Aspden, Andrew J.; Bell, John B.; Day, Marc S.; Woosley, Stan E.; Zingale, Mike

2008-05-27T23:59:59.000Z

206

Turbulence-Flame Interactions in Type Ia Supernovae  

E-Print Network (OSTI)

The large range of time and length scales involved in type Ia supernovae (SN Ia) requires the use of flame models. As a prelude to exploring various options for flame models, we consider, in this paper, high-resolution three-dimensional simulations of the small-scale dynamics of nuclear flames in the supernova environment in which the details of the flame structure are fully resolved. The range of densities examined, 1 to $8 \\times 10^7$ g cm$^{-3}$, spans the transition from the laminar flamelet regime to the distributed burning regime where small scale turbulence disrupts the flame. The use of a low Mach number algorithm facilitates the accurate resolution of the thermal structure of the flame and the inviscid turbulent kinetic energy cascade, while implicitly incorporating kinetic energy dissipation at the grid-scale cutoff. For an assumed background of isotropic Kolmogorov turbulence with an energy characteristic of SN Ia, we find a transition density between 1 and $3 \\times 10^7$ g cm$^{-3}$ where the nature of the burning changes qualitatively. By $1 \\times 10^7$ g cm$^{-3}$, energy diffusion by conduction and radiation is exceeded, on the flame scale, by turbulent advection. As a result, the effective Lewis Number approaches unity. That is, the flame resembles a laminar flame, but is turbulently broadened with an effective diffusion coefficient, $D_T \\sim u' l$, where $u'$ is the turbulent intensity and $l$ is the integral scale. For the larger integral scales characteristic of a real supernova, the flame structure is predicted to become complex and unsteady. Implications for a possible transition to detonation are discussed.

A. J. Aspden; J. B. Bell; M. S. Day; S. E. Woosley; M. Zingale

2008-11-17T23:59:59.000Z

207

Plastic neutron detectors.  

Science Conference Proceedings (OSTI)

This work demonstrated the feasibility and limitations of semiconducting {pi}-conjugated organic polymers for fast neutron detection via n-p elastic scattering. Charge collection in conjugated polymers in the family of substituted poly(p-phenylene vinylene)s (PPV) was evaluated using band-edge laser and proton beam ionization. These semiconducting materials can have high H/C ratio, wide bandgap, high resistivity and high dielectric strength, allowing high field operation with low leakage current and capacitance noise. The materials can also be solution cast, allowing possible low-cost radiation detector fabrication and scale-up. However, improvements in charge collection efficiency are necessary in order to achieve single particle detection with a reasonable sensitivity. The work examined processing variables, additives and environmental effects. Proton beam exposure was used to verify particle sensitivity and radiation hardness to a total exposure of approximately 1 MRAD. Conductivity exhibited sensitivity to temperature and humidity. The effects of molecular ordering were investigated in stretched films, and FTIR was used to quantify the order in films using the Hermans orientation function. The photoconductive response approximately doubled for stretch-aligned films with the stretch direction parallel to the electric field direction, when compared to as-cast films. The response was decreased when the stretch direction was orthogonal to the electric field. Stretch-aligned films also exhibited a significant sensitivity to the polarization of the laser excitation, whereas drop-cast films showed none, indicating improved mobility along the backbone, but poor {pi}-overlap in the orthogonal direction. Drop-cast composites of PPV with substituted fullerenes showed approximately a two order of magnitude increase in photoresponse, nearly independent of nanoparticle concentration. Interestingly, stretch-aligned composite films showed a substantial decrease in photoresponse with increasing stretch ratio. Other additives examined, including small molecules and cosolvents, did not cause any significant increase in photoresponse. Finally, we discovered an inverse-geometric particle track effect wherein increased track lengths created by tilting the detector off normal incidence resulted in decreased signal collection. This is interpreted as a trap-filling effect, leading to increased carrier mobility along the particle track direction. Estimated collection efficiency along the track direction was near 20 electrons/micron of track length, sufficient for particle counting in 50 micron thick films.

Wilson, Tiffany M.S; King, Michael J.; Doty, F. Patrick

2008-12-01T23:59:59.000Z

208

Photon Sciences Directorate | 2010 Annual Report | Detector R&D  

NLE Websites -- All DOE Office Websites (Extended Search)

Detector R&D Detector R&D ionization chamber A miniature four-channel ionization chamber that was developed at NSLS Detectors sit at the very end of the intricate systems that constitute light sources like NSLS and NSLS-II. Because detectors are where the science gets done, detector research and development can enable new science. For the user community, NSLS-II will offer a significantly higher degree of coherence in its beams than most other synchrotrons, so imaging techniques that take advantage of that superiority are at the forefront of detector R&D. The CHX beamline, one of six project beamlines being built for NSLS-II, uses photon correlation spectroscopy. The goal is to detect the arrival time of photons with the highest possible resolution over the largest

209

Modeling of NOx formation in circular laminar jet flames  

E-Print Network (OSTI)

Emissions of oxides of nitrogen (NOx) from combustion devices is a topic of tremendous current importance. The bulk of the review of NOx emissions has been in the field of turbulent jet flames. However laminar jet flames have provided much insight into the relative importance of NOx reaction pathways in non premixed combustion for various flame conditions. The existing models include detailed chemistry kinetics for various species involved in the flame. These detailed models involve very complex integration of hundreds of chemical reactions of various species and their intermediates. Hence such models are highly time consuming and also normally involve heavy computational costs. This work proposes a numerical model to compute the total production of NOx in a non-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 of air entrainment by jet depends upon the Sc number of fuel. The higher the Sc number, the higher is the air entrained which lowers the flame temperature and hence NOx formation. With increasing Sc number, flame volume increases which leads to an increase in the NOx formation. The effect of the Sc number variation on the net production of NOx and flame structure is also investigated. The effect of equilibrium chemistry for CO2 CO + 1/2 O2 and H2O H2 +1/2 O2 on total NOx emission is studied. Also the effect of both CO2 and H2O equilibrium is considered simultaneously and the net x NO formation for propane is 45 ppm. The split between pre-flame and post-flame regions is also investigated. For Propane, 96% of NO emissions occur in the pre-flame region and about 4% in the post-flame region. The model predictions are compared with experimental values of NOx missions reported elsewhere.

Siwatch, Vivek

2005-12-01T23:59:59.000Z

210

DETERMINATION OF LITHIUM BY FLAME EMISSION SPECTROMETRY Background Reading: Harris, 7th  

E-Print Network (OSTI)

DETERMINATION OF LITHIUM BY FLAME EMISSION SPECTROMETRY Background Reading: Harris, 7th ed., Chap of this experiment is to acquaint you with flame emission spectrometry. The determination of lithium, and all other. It uses a propane/air flame. #12;Lithium by Flame Emission, Page 2 Identify the burner with its nebulizer

Weston, Ken

211

Application of Flame Doctor to T-Fired Boilers: Feasibility Study  

Science Conference Proceedings (OSTI)

Flame Doctor, a burner diagnostic technology, is a packaged system consisting of hardware and software that ties into existing burner flame scanner systems of wall-fired, cyclone-fired, and turbo-fired boilers to provide real-time assessment of flame quality. This report describes feasibility tests to evaluate Flame Doctor for extension to tangentially fired (T-fired) boiler applications.

2007-03-22T23:59:59.000Z

212

Fire Emulator/Detector Evaluator  

Science Conference Proceedings (OSTI)

... Black smoke is generated by a propane diffusion flame burner with smoke concentration controlled by fuel flow and the damper control from the ...

2011-11-16T23:59:59.000Z

213

GRAVITATIONALLY UNSTABLE FLAMES: RAYLEIGH-TAYLOR STRETCHING VERSUS TURBULENT WRINKLING  

SciTech Connect

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.

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

214

Muon Collider Machine-Detector Interface  

SciTech Connect

In order to realize the high physics potential of a Muon Collider (MC) a high luminosity of {mu}{sup +}{mu}{sup -}-collisions at the Interaction Point (IP) in the TeV range must be achieved ({approx}10{sup 34} cm{sup -2}s{sup -1}). To reach this goal, a number of demanding requirements on the collider optics and the IR hardware - arising from the short muon lifetime and from relatively large values of the transverse emittance and momentum spread in muon beams that can realistically be obtained with ionization cooling should be satisfied. These requirements are aggravated by limitations on the quadrupole gradients as well as by the necessity to protect superconducting magnets and collider detectors from muon decay products. The overall detector performance in this domain is strongly dependent on the background particle rates in various sub-detectors. The deleterious effects of the background and radiation environment produced by the beam in the ring are very important issues in the Interaction Region (IR), detector and Machine-Detector Interface (MDI) designs. This report is based on studies presented very recently.

Mokhov, Nikolai V.; /Fermilab

2011-08-01T23:59:59.000Z

215

Program on Technology Innovation: Flame Structure Sensor for PC Combustion - Feasibility Study  

Science Conference Proceedings (OSTI)

The flame-scanner sensor technology incorporated in the Flame Doctor system to provide critical burner state information in pulverized-coal applications is inherently limited in its ability to provide the type of information needed to make very rapid control adjustments. This project investigated the feasibility of two new types of flame-structure sensors for providing supplemental information about flame state that can be used for Flame Doctor system calibration and also for advanced high-speed burner c...

2007-05-16T23:59:59.000Z

216

Building and Fire Publications  

Science Conference Proceedings (OSTI)

... flame chemistry, flame detectors, flame ... fundamental mechanistic experiments, furnace, furnaces, ... control guidelines, Moisture Control Handbook. ...

217

Modeling and experimental validation of unsteady impinging flames  

Science Conference Proceedings (OSTI)

This study reports on a joint experimental and analytical study of premixed laminar flames impinging onto a plate at controlled temperature, with special emphasis on the study of periodically oscillating flames. Six types of flame structures were found, based on parametric variations of nozzle-to-plate distance (H), jet velocity (U), and equivalence ratio (f). They were classified as conical, envelope, disc, cool central core, ring, and side-lifted flames. Of these, the disc, cool central core, and envelope flames were found to oscillate periodically, with frequency and sound pressure levels increasing with Re and decreasing with nozzle-to-plate distance. The unsteady behavior of these flames was modeled using the formulation derived by Durox et al. [D. Durox, T. Schuller, S. Candel, Proc. Combust. Inst. 29 (2002) 69-75] for the cool central core flames where the convergent burner acts as a Helmholtz resonator, driven by an external pressure fluctuation dependent on a velocity fluctuation at the burner mouth after a convective time delay {tau}. Based on this model, the present work shows that {tau} = [Re[2jtanh{sup -1}((2{delta}{omega}+(1+N)j{omega}{sup 2}-j{omega}{sub 0}{sup 2})/ (2{delta}{omega}+(1-N)j{omega}{sup 2}-j{omega}{sub 0}{sup 2}))]+2{pi}K]/{omega}, i.e., there is a relation between oscillation frequency ({omega}), burner acoustic characteristics ({omega}{sub 0},{delta}), and time delay {tau}, not explicitly dependent on N, the flame-flow normalized interaction coefficient [D. Durox, T. Schuller, S. Candel, Proc. Combust. Inst. 29 (2002) 69-75], because {partial_derivative}t/{partial_derivative}N = 0. Based on flame motion and noise analysis, K was found to physically represent the integer number of perturbations on flame surface or number of coherent structures on impinging jet. Additionally, assuming that {tau}={beta}H/U, where H is the nozzle-to-plate distance and U is the mean jet velocity, it is shown that {beta}{sub Disc}=1.8, {beta}{sub CCC}=1.03, and {beta}{sub Env}=1.0. A physical analysis of the proportionality constant {beta} showed that for the disc flames, {tau} corresponds to the ratio between H and the velocity of the coherent structures. In the case of envelope and cool central core flames, {tau} corresponds to the ratio between H and the mean jet velocity. The predicted frequency fits the experimental data, supporting the validity of the mathematical modeling, empirical formulation, and assumptions made. (author)

Fernandes, E.C.; Leandro, R.E. [Center for Innovation, Technology and Policy Research, Mechanical Engineering Department, Instituto Superior Tecnico, Av. Rovisco Pais, 1049-001 Lisboa Codex (Portugal)

2006-09-15T23:59:59.000Z

218

Counterflow diffusion flame synthesis of ceramic oxide powders  

DOE Patents (OSTI)

Ceramic oxide powders and methods for their preparation are revealed. Ceramic oxide powders are obtained using a flame process whereby one or more precursors of ceramic oxides are introduced into a counterflow diffusion flame burner wherein the precursors are converted into ceramic oxide powders. The nature of the ceramic oxide powder produced is determined by process conditions. The morphology, particle size, and crystalline form of the ceramic oxide powders may be varied by the temperature of the flame, the precursor concentration ratio, the gas stream and the gas velocity.

Katz, Joseph L. (Baltimore, MD); Miquel, Philippe F. (Towson, MD)

1997-01-01T23:59:59.000Z

219

Counterflow diffusion flame synthesis of ceramic oxide powders  

DOE Patents (OSTI)

Ceramic oxide powders and methods for their preparation are revealed. Ceramic oxide powders are obtained using a flame process whereby one or more precursors of ceramic oxides are introduced into a counterflow diffusion flame burner wherein the precursors are converted into ceramic oxide powders. The nature of the ceramic oxide powder produced is determined by process conditions. The morphology, particle size, and crystalline form of the ceramic oxide powders may be varied by the temperature of the flame, the precursor concentration ratio, the gas stream and the gas velocity. 24 figs.

Katz, J.L.; Miquel, P.F.

1997-07-22T23:59:59.000Z

220

FLAMES IN TYPE Ia SUPERNOVA: DEFLAGRATION-DETONATION TRANSITION IN THE OXYGEN-BURNING FLAME  

Science Conference Proceedings (OSTI)

The flame in a Type Ia supernova is a conglomerate structure that, depending on density, may involve separate regions of carbon, oxygen, and silicon burning, all propagating in a self-similar, subsonic front. The separation between these three burning regions increases as the density declines until eventually, below about 2 x 10{sup 7} g cm{sup -3}, only carbon burning remains active, the other two burning phases having 'frozen out' on stellar scales. Between 2 and 3 x 10{sup 7} g cm{sup -3}, however, there remains an energetic oxygen-burning region that trails the carbon burning by an amount that is sensitive to the turbulence intensity. As the carbon flame makes a transition to the distributed regime (Karlovitz number {approx}> 10), the characteristic separation between the carbon- and oxygen-burning regions increases dramatically, from a fraction of a meter to many kilometers. The oxygen-rich mixture between the two flames is created at a nearly constant temperature, and turbulence helps to maintain islands of well-mixed isothermal fuel as the temperature increases. The delayed burning of these regions can be supersonic and could initiate a detonation.

Woosley, S. E. [Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064 (United States); Kerstein, A. R. [Combustion Research Facility, Sandia National Laboratories, Livermore, CA 94551 (United States); Aspden, A. J., E-mail: woosley@ucolick.org, E-mail: arkerst@sandia.gov, E-mail: ajaspden@lbl.gov [Center for Computational Sciences and Engineering, Lawrence Berkeley National Laboratory, CA 94720 (United States)

2011-06-10T23:59:59.000Z

Note: This page contains sample records for the topic "flame ionization detector" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


221

Children's residential exposures to flame retardants, pesticides and pesticide degradation products, and the relationship of pesticides with autonomic nervous system functioning  

E-Print Network (OSTI)

diphenyl ethers: a flame-retardant additive in severaldiphenyl ether (PBDE) flame retardants. Neurotoxicology. 28,diphenyl ethers: a flame-retardant additive in several

Quiros Alcala, Lesliam

2010-01-01T23:59:59.000Z

222

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)

et al. : Combustion-derived flame generated ultrafine sootacute inhalation of diffusion flame soot particles: cellularAccess Combustion-derived flame generated ultrafine soot

2013-01-01T23:59:59.000Z

223

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

E-Print Network (OSTI)

Natural gas is the primary fuel used in industrial gas turbines for power generation. 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 of the physical characteristics such as the laminar flame speed is necessary, especially at elevated pressures to have the most relevance to the gas turbine industry. This thesis discusses the equations governing premixed laminar flames, historical methods used to measure the laminar flame speed, the experimental device used in this study, the procedure for converting the measured data into the flame speed, the results of the measurements, and a discussion of the results. The results presented in this thesis 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 comparison between the experimental measurements and four chemical kinetic models. The C4 mechanism, developed in part through collaboration between the National University of Ireland Galway and Texas A&M, was improved using the data presented herein, showing good agreement for all cases. The effect of blending ethane, propane, and dimethyl ether with methane in binary form is emphasized in this study, with the resulting Markstein length, Lewis number (Le), and flame stability characterized and discussed. It was noticed in this study, as well as in other studies, that the critical radius of the flame typically decreased as the Le decreased, and that the critical radius of the flame increased as the Le increased. Also, a rigorous uncertainty analysis has been performed, showing a range of 0.3 cm/s to 3.5 cm/s depending on equivalence ratio and initial pressure.

Lowry, William Baugh

2010-12-01T23:59:59.000Z

224

RHIC | STAR Detector  

NLE Websites -- All DOE Office Websites (Extended Search)

The STAR Detector The STAR detector specializes in tracking the thousands of particles produced by each ion collision at RHIC. Weighing 1,200 tons and as large as a house, STAR is...

225

Asynchronous Failure Detectors  

E-Print Network (OSTI)

Failure detectors -- oracles that provide information about process crashes -- are an important abstraction for crash tolerance in distributed systems. The generality of failure-detector theory, while providing great ...

Cornejo, Alejandro

2013-10-10T23:59:59.000Z

226

The Effects of Ionizing Irradiation  

Science Conference Proceedings (OSTI)

Page 1. The Effects of Ionizing Irradiation on Liquid, Dried, and Absorbed DNA Extracts ... Page 12. Study Shipped Land Carrier Irradiation ? ...

2012-02-29T23:59:59.000Z

227

Ionizing Radiation Division Quality Manual  

Science Conference Proceedings (OSTI)

... 08 47020C Low-energy Photon Brachytherapy Seeds, ... Calibrated for Surface Dose Rate 10 ... Sources Calibrated for Radiation Protection Ionization ...

2012-03-08T23:59:59.000Z

228

VUV Detector Calibrations - Overview  

Science Conference Proceedings (OSTI)

... In the magnesium fluoride window region (116 nm to 254 nm), standard detectors are cesium telluride photoemissive photodcathodes deposited ...

2012-01-26T23:59:59.000Z

229

Semantic point detector  

Science Conference Proceedings (OSTI)

Local features are the building blocks of many visual systems, and local point detector is usually the first component for local feature extraction. Existing local point detector are designed with target for matching and it may not perform well when ... Keywords: semantic point detector

Kuiyuan Yang; Lei Zhang; Meng Wang; Hong-Jiang Zhang

2011-11-01T23:59:59.000Z

230

Gamma ray detector shield  

DOE Patents (OSTI)

A gamma ray detector shield comprised of a rigid, lead, cylindrical-shaped vessel having upper and lower portions with an pneumatically driven, sliding top assembly. Disposed inside the lead shield is a gamma ray scintillation crystal detector. Access to the gamma detector is through the sliding top assembly.

Ohlinger, R.D.; Humphrey, H.W.

1985-08-26T23:59:59.000Z

231

NETL: Gasification Systems - Real Time Flame Monitoring of Gasifier...  

NLE Websites -- All DOE Office Websites (Extended Search)

Real Time Flame Monitoring of Gasifier Burner and Injectors Project No.: DE-FC26-02NT41585 Gas Technology Institute is developing a reliable, practical, and cost effective means to...

232

Adaptive low Mach number simulations of nuclear flame microphysics  

Science Conference Proceedings (OSTI)

We introduce a numerical model for the simulation of nuclear flames in Type Ia supernovae. This model is based on a low Mach number formulation that analytically removes acoustic wave propagation while retaining the compressibility effects resulting ...

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

2004-04-01T23:59:59.000Z

233

Surface wettability studies of PDMS using flame plasma treatment  

E-Print Network (OSTI)

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 ...

Wang, Xin C

2009-01-01T23:59:59.000Z

234

NETL: Investigation on Flame Characteristics and Burner Operability...  

NLE Websites -- All DOE Office Websites (Extended Search)

Oxy-Combustion CO2 Emissions Control Investigation on Flame Characteristics and Burner Operability Issues of Oxy-Fuel Combustion Project No.: DE-FE0002402 NETL has partnered with...

235

Flame size, heat release, and smoke points in materials ...  

Science Conference Proceedings (OSTI)

... to flame area was 0.25 cm for propane, ethylene, and ... means to insure a steady state condition (or ... Pergamon Press, New York, 1979, pp., 185–195. ...

2008-08-20T23:59:59.000Z

236

Scalar dissipation rate based flamelet modelling of turbulent premixed flames  

E-Print Network (OSTI)

closures . . . . . . . . . . . . . . . 98 7.2 RANS of planar one–dimensional flames . . . . . . . . . . . . . . 99 7.2.1 Computational details . . . . . . . . . . . . . . . . . . . . 99 7.2.2 Results and discussion... ). . . . . . . . . . . . . . . . . . . . . . 129 7.21 The contour plot of temperature (K) from the Bunsen flame calcu- lations for case F3. The plot for the entire computational domain (top) and the region close to the nozzle exit (bottom) are shown. 130 7.22 The mean progress variable, c, using...

Kolla, Hemanth

2010-03-16T23:59:59.000Z

237

Stability Regimes of Turbulent Nitrogen-Diluted Hydrogen Jet Flames  

SciTech Connect

One option for combustion in zero-emission Integrated Gasification Combined Cycle (IGCC) power plants is non-premixed combustion of nitrogen-diluted hydrogen in air. An important aspect to non-premixed combustion is flame stability or anchoring, though only a few fundamental stability studies of these flames have taken place to date. The following paper presents the results of experiments investigating the effects of nitrogen diluent fraction, jet diameter, and exit velocity on the static stability limits of a turbulent hydrogen jet flame issuing from a thin-lipped tube into a quiescent atmosphere. Four different stability limits are observed: detachment from the burner lip, reattachment to the burner lip, transition from a laminar lifted flame base to blowout or to a turbulent lifted flame, and transition from a turbulent lifted flame to blowout. The applicability of existing theories and correlations to the stability results is discussed. These results are an important step in assessing the viability of a non-premixed combustion approach using hydrogen diluted with nitrogen as a fuel.

Weiland, N.T.; Strakey, P.A.

2007-03-01T23:59:59.000Z

238

Coupling of diffusion flame structure to an unsteady vortical flowfield  

Science Conference Proceedings (OSTI)

A laminar methane-air diffusion flame is interacted with vortices of various sizes and strengths in order to better understand unsteady stretch and history effects on turbulent flames. The nitrogen-diluted fuel stream of a Wolfhard-Parker slot burner is acoustically forced, producing repeatable two-dimensional vortices that strain and curve the flame. Phase locked, planar laser-induced fluorescence (PLIF) diagnostics are used to quantify the response of the OH-radical to the vortex-induced stretch. Acetone PLIF images are used to clarify the relationship between the vortex structure and the flame. The results show that the vortex causes significant variations in the OH layer thickness. In particular, negative strain produces a doubling of the flame thickness. Such large increases in OH layer thickness are not predicted by the laminar flamelet model (LFM) because negative strain rates cannot be simulated using standard counterflow flamelet geometry. Local extinction of the OH layer due to high strain is observed near the flame base. Peak OH mole fraction levels vary considerably more than adiabatic LFM predictions. In particular, the peak OH decreases by a factor of two with downstream distance. This decrease is believed due to dilution of reactants by combustion products formed elsewhere in the flow. A simplified model is proposed, which shows the OH concentration is sensitive to product dilution through the scalar dissipation rate.

C. J. Mueller; R. W. Schefer

1998-08-02T23:59:59.000Z

239

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

E-Print Network (OSTI)

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...

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

2012-01-01T23:59:59.000Z

240

A comparative experimental and computational study of methanol, ethanol, and n-butanol flames  

Science Conference Proceedings (OSTI)

Laminar flame speeds and extinction strain rates of premixed methanol, ethanol, and n-butanol flames were determined experimentally in the counterflow configuration at atmospheric pressure and elevated unburned mixture temperatures. Additional measurements were conducted also to determine the laminar flame speeds of their n-alkane/air counterparts, namely methane, ethane, and n-butane in order to compare the effect of alkane and alcohol molecular structures on high-temperature flame kinetics. For both propagation and extinction experiments the flow velocities were determined using the digital particle image velocimetry method. Laminar flame speeds were derived through a non-linear extrapolation approach based on direct numerical simulations of the experiments. Two recently developed detailed kinetics models of n-butanol oxidation were used to simulate the experiments. The experimental results revealed that laminar flame speeds of ethanol/air and n-butanol/air flames are similar to those of their n-alkane/air counterparts, and that methane/air flames have consistently lower laminar flame speeds than methanol/air flames. The laminar flame speeds of methanol/air flames are considerably higher compared to both ethanol/air and n-butanol/air flames under fuel-rich conditions. Numerical simulations of n-butanol/air freely propagating flames, revealed discrepancies between the two kinetic models regarding the consumption pathways of n-butanol and its intermediates. (author)

Veloo, Peter S.; Wang, Yang L.; Egolfopoulos, Fokion N. [Department of Aerospace and Mechanical Engineering, University of Southern California, Los Angeles, CA 90089-1453 (United States); Westbrook, Charles K. [Lawrence Livermore National Laboratory, Livermore, CA 94550 (United States)

2010-10-15T23:59:59.000Z

Note: This page contains sample records for the topic "flame ionization detector" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


241

The BABAR Detector  

NLE Websites -- All DOE Office Websites (Extended Search)

BABAR Detector BABAR Detector This page provides background information on HEP detectors in general and the BaBar detector in particular. A Technical Introduction to Particle-Physics Experiments A particle physics experiment has two basic components: an accelerator and a detector. The particle accelerator's job is to produce the high-energy particles. It does this by taking a particle, speeding it up using electromagnetic fields, and crashing it into another particle. At first, only one or two high-energy particles are produced, but these soon decay to many more lower-energy particles, so you end up with lots of particles shooting out from the collision point. The detector's job is to record information about the particles. A typical particle detector consists of several subdetectors, each of which performs a different type of measurement. Particles from the collision pass through and interact with each subdetector, and the results are recorded.

242

High-energy detector  

SciTech Connect

The preferred embodiments are directed to a high-energy detector that is electrically shielded using an anode, a cathode, and a conducting shield to substantially reduce or eliminate electrically unshielded area. The anode and the cathode are disposed at opposite ends of the detector and the conducting shield substantially surrounds at least a portion of the longitudinal surface of the detector. The conducting shield extends longitudinally to the anode end of the detector and substantially surrounds at least a portion of the detector. Signals read from one or more of the anode, cathode, and conducting shield can be used to determine the number of electrons that are liberated as a result of high-energy particles impinge on the detector. A correction technique can be implemented to correct for liberated electron that become trapped to improve the energy resolution of the high-energy detectors disclosed herein.

Bolotnikov, Aleksey E. (South Setauket, NY); Camarda, Giuseppe (Farmingville, NY); Cui, Yonggang (Upton, NY); James, Ralph B. (Ridge, NY)

2011-11-22T23:59:59.000Z

243

Detection of Ionizing Radiation by Plasma-Panel Sensors: Cosmic Muons, Ion Beams, and Cancer Therapy  

Science Conference Proceedings (OSTI)

The plasma panel sensor is an ionizing photon and particle radiation detector derived from PDP technology with high gain and nanosecond response. Experimental results in detecting cosmic ray muons and beta particles from radioactive sources are described along with applications including high energy and nuclear physics, homeland security and cancer therapeutics.

Friedman, Dr. Peter S. [Integrated Sensors, LLC; Ferretti, Claudio [University of Michigan; Ball, Robert [University of Michigan; Beene, James R [ORNL; Ben Moshe, M. [Tel Aviv University; Benhammou, Yan [Tel Aviv University; Chapman, J. Wehrley [University of Michigan; Levin, Daniel S. [University of Michigan; Silver, Yiftah [Tel Aviv University; Weaverdyck, Curtis [University of Michigan; Zhou, Bing [University of Michigan; Etzion, E [Tel Aviv University; Moshe, M. [Tel Aviv University; Bentefour, E [Ion Beam Applications

2012-01-01T23:59:59.000Z

244

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

E-Print Network (OSTI)

Joulin, P. Ronney, Combust. Flame 84 (1991) 411–422. [9] I.R. A. Strehlow, Combust. Flame 49 (1983) 123–140. [11] B.F. A. Williams, Combust. Flame 33 (1978) 33–45. [12] T.

Grcar, Joseph F

2008-01-01T23:59:59.000Z

245

Dimensionality estimate of the manifold in chemical composition space for a turbulent premixed H2+air flame  

E-Print Network (OSTI)

W. H. ; Barton, P. I. Combust Flame 2002, 128, 270–291. [8]Maas, U. ; Pope, S. B. Combust Flame 1992, 88, 239–264. [11]B. ; Pope, S. B. Combust Flame 1998, 112, 85–112. [18] Bray,

Tonse, Shaheen R.; Brown, Nancy J.

2003-01-01T23:59:59.000Z

246

The stabilization of a methane-air edge flame within a mixing layer in a narrow channel  

SciTech Connect

The flame stabilization mechanism of a methane-air edge flame formulated in a narrow channel was experimentally investigated and compared with a simple analytical model. Non-premixed flames were classified into premixed flame modes and edge flame modes. The correlation between the propagation velocity and the fuel concentration gradient in a narrow channel was investigated and the applicability of ordinary edge-flame theory was appraised. (author)

Lee, Min Jung; Kim, Nam Il [School of Mechanical Engineering, Chung-Ang University, Dongjak, Seoul 156-76 (Korea)

2010-01-15T23:59:59.000Z

247

Lewis number effects on turbulent premixed flame structure  

DOE Green Energy (OSTI)

The influence of the Lewis number on turbulent flame front geometry is investigated in a premixed turbulent stagnation point flame. A laser tomography technique is used to obtain the flame shape, a fractal analysis of the multiscale flame edges is performed and the distribution of local flame front curvature is determined. Lean H[sub 2]/Air and C[sub 3]H[sub 8]/Air mixtures with similar burning rates were investigated with Lewis numbers of 0.33 and 1.85 respectively. At the conditions studied the laminar H[sub 2]/Air mixture is unstable and a cellular structure is observed. Turbulence in the reactant is generated by a perforated plate and the turbulent length scale (3mm) and intensity (7%) at the nozzle exit are fixed. The equivalence ratio is set so that the burning velocity is the same for all the cases. Results show clearly that the turbulent flame surface area is dependent on the Lewis number. For a Lewis number less than unity surface area production is observed. The shape of the flame front curvature distribution is not found to be very sensitive to the Lewis number. For the H[sub 2]/Air mixture the distribution is skewed toward the positive values indicating the presence of cusps while for the C[sub 3]H[sub 8]/Air mixture the distribution is more symmetrical. In both cases the average curvature is found to be zero, and if the local burning speed varies linearly with curvature, the local positive and negative burning velocity variations due to curvature will balance.

Goix, P.J. (Centre National de la Recherche Scientifique (CNRS), 230 - Mont-Saint-Aignan (France). URA CORIA); Shepherd, I.G. (Lawrence Berkeley Lab., CA (United States))

1992-09-01T23:59:59.000Z

248

Lewis number effects on turbulent premixed flame structure  

DOE Green Energy (OSTI)

The influence of the Lewis number on turbulent flame front geometry is investigated in a premixed turbulent stagnation point flame. A laser tomography technique is used to obtain the flame shape, a fractal analysis of the multiscale flame edges is performed and the distribution of local flame front curvature is determined. Lean H{sub 2}/Air and C{sub 3}H{sub 8}/Air mixtures with similar burning rates were investigated with Lewis numbers of 0.33 and 1.85 respectively. At the conditions studied the laminar H{sub 2}/Air mixture is unstable and a cellular structure is observed. Turbulence in the reactant is generated by a perforated plate and the turbulent length scale (3mm) and intensity (7%) at the nozzle exit are fixed. The equivalence ratio is set so that the burning velocity is the same for all the cases. Results show clearly that the turbulent flame surface area is dependent on the Lewis number. For a Lewis number less than unity surface area production is observed. The shape of the flame front curvature distribution is not found to be very sensitive to the Lewis number. For the H{sub 2}/Air mixture the distribution is skewed toward the positive values indicating the presence of cusps while for the C{sub 3}H{sub 8}/Air mixture the distribution is more symmetrical. In both cases the average curvature is found to be zero, and if the local burning speed varies linearly with curvature, the local positive and negative burning velocity variations due to curvature will balance.

Goix, P.J. [Centre National de la Recherche Scientifique (CNRS), 230 - Mont-Saint-Aignan (France). URA CORIA; Shepherd, I.G. [Lawrence Berkeley Lab., CA (United States)

1992-09-01T23:59:59.000Z

249

Aromatics Oxidation and Soot Formation in Flames  

SciTech Connect

This project is concerned with the kinetics and mechanisms of aromatics oxidation and the growth process to polycyclic aromatic hydrocarbons (PAH) of increasing size, soot and fullerenes formation in flames. The overall objective of the experimental aromatics oxidation work is to extend the set of available data by measuring concentration profiles for decomposition intermediates such as phenyl, cyclopentadienyl, phenoxy or indenyl radicals which could not be measured with molecular-beam mass spectrometry to permit further refinement and testing of benzene oxidation mechanisms. The focus includes PAH radicals which are thought to play a major role in the soot formation process while their concentrations are in many cases too low to permit measurement with conventional mass spectrometry. The radical species measurements are used in critical testing and improvement of a kinetic model describing benzene oxidation and PAH growth. Thermodynamic property data of selected species are determined computationally, for instance using density functional theory (DFT). Potential energy surfaces are explored in order to identify additional reaction pathways. The ultimate goal is to understand the conversion of high molecular weight compounds to nascent soot particles, to assess the roles of planar and curved PAH and relationships between soot and fullerenes formation. The specific aims are to characterize both the high molecular weight compounds involved in the nucleation of soot particles and the structure of soot including internal nanoscale features indicative of contributions of planar and/or curved PAH to particle inception.

Howard, J. B.; Richter, H.

2005-03-29T23:59:59.000Z

250

Soot profiles in boundary-layer flames  

DOE Green Energy (OSTI)

Carbon particulate volume fractions and approximate particle size distributions are measured in a free laminar combusting boundary layer for liquid hydrocarbon fuels (n-heptane, iso-octane, cyclohexane, cyclohexene, toluene) and polymethylmethacrylate (PMMA). A multiwavelength laser transmission technique determines a most probable radius and the total particle concentration, which are two parameters in an assumed form for the size distribution. In the combusting boundary layer, a sooting region exists between the pyrolyzing fuel surface and the flame zone. The liquid fuel soot volume fractions, f/sub v/, range from f/sub v/ approx. 10/sup -7/ for n-heptane, a paraffin, to f/sub v approx. 10/sup -5/ for toluene, an aromatic. The PMMA volume fractions, f/sub v/ approx. 5 X 10/sup -7/, are approximately the same as the values previously reported for pool fires. The soot volume fractions increase with height; convection of carbon particles downstream widens the soot region with height. For all fuels tested, the most probable radius is between 20 nm and 50 nm, and it changes only slightly with height and distance from the fuel surface.

Beier, R.A.; Pagni, P.J.

1981-12-01T23:59:59.000Z

251

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

Science Conference Proceedings (OSTI)

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.

Ahsan R. Choudhuri

2006-08-07T23:59:59.000Z

252

On the motion of the center of mass of a spherical turbulent premixed flame  

DOE Green Energy (OSTI)

The movement of the center of mass of a premixed statistically spherical flame in the wrinkled-laminar flame regime has been examined. When the flame is small (or comparable) to the integral scale of the turbulence, the flame ball is convected as a whole by the turbulent eddy. When the flame grows to a size large compared to the integral scale, the flame center of motion is not affected by the turbulence. This phenomenon has been explained in terms of the phase coherence of the local turbulent convection velocity at the flame front. When the flame is small, the turbulent velocity is coherent over the entire flame surface; as a result, the flame is convected as a whole by the turbulent eddy. When the flame is large, the velocity at the different area elements of the flame front is independent of each other. The center of mass velocity, which is an aggregate of the velocities at the different elements, therefore, tends to the mean velocity and is independent of the turbulence. A theory for predicting the variance of the flame center velocity has been developed. The prediction is in good agreement with the experimental results. 12 refs., 5 figs.

Cheng, W. K.; Hainsworth, E.

1988-01-01T23:59:59.000Z

253

Ionization of hydrogen and ionized helium by slow antiprotons  

E-Print Network (OSTI)

We study the ionization process involving antiproton and hydrogen in the energy range between 0.1 keV to 500 keV, using single center close coupling approximation. We construct the scattering wave function using B-spline bases. The results obtained for ionization of atomic hydrogen are compared with other existing theoretical calculations as well as with the available experimental data. The present results are found to be encouraging. We also employed this method to study the ionization of ionized helium in the energy range between 1 and 500 keV. On comparision, the present results are found to interpret well the cross section values calculated using other theories.

Sahoo, S; Walters, H R J

2004-01-01T23:59:59.000Z

254

Study of the response of low pressure ionization chambers  

E-Print Network (OSTI)

The Beam Loss Monitoring System (BLM) of the Large Hadron Collider (LHC) is based on parallel plate Ionization Chambers (IC) with active volume 1.5l and a nitrogen filling gas at 0.1 bar overpressure. At the largest loss locations, the ICs generate signals large enough to saturate the read-out electronics. A reduction of the active volume and filling pressure in the ICs would decrease the amount of charge collected in the electrodes, and so provide a higher saturation limit using the same electronics. This makes Little Ionization Chambers (LIC) with both reduced pressure and small active volume a good candidate for these high radiation areas. In this contribution we present measurements performed with several LIC monitors with reduced active volume and various filling pressures. These detectors were tested under various conditions with different beam setups, with standard LHC ICs used for calibration purposes

Nebot Del Busto, E; Effinger, E; Grishin, V; Herranz Alvarez, J

2012-01-01T23:59:59.000Z

255

Physics Out Loud - Detector  

NLE Websites -- All DOE Office Websites (Extended Search)

Cryomodule Previous Video (Cryomodule) Physics Out Loud Main Index Next Video (Electromagnetic Force) Electromagnetic Force Detector Elena Long, a graduate student at Kent State...

256

EUV Detector Radiometry Beamline  

Science Conference Proceedings (OSTI)

... The second grating is ruled with 300 lines per millimeter and is ... detector responsivity; filter transmission; uniformity of responsivity or transmission. ...

2011-10-03T23:59:59.000Z

257

Salty Water Cerenkov Detectors  

E-Print Network (OSTI)

The addition of certain solutes to a water Cerenkov detector will introduce new charge-current channels for the detection of $\

W. C. Haxton

1995-11-28T23:59:59.000Z

258

Large Dynamic Range Detector  

Typical radiation detectors used to search for radioactive sources or detect radiation hazards by many fire departments and other emergency responders ...

259

Phonon Quasidiffusion in Cryogenic Dark Matter Search Large Germanium Detectors  

SciTech Connect

We present results on quasidiffusion studies in large, 3 inch diameter, 1 inch thick [100] high purity germanium crystals, cooled to 50 mK in the vacuum of a dilution refrigerator, and exposed with 59.5 keV gamma-rays from an Am-241 calibration source. We compare data obtained in two different detector types, with different phonon sensor area coverage, with results from a Monte Carlo. The Monte Carlo includes phonon quasidiffusion and the generation of phonons created by charge carriers as they are drifted across the detector by ionization readout channels.

Leman, S.W.; /MIT, MKI; Cabrera, B.; /Stanford U., Phys. Dept.; McCarthy, K.A.; /MIT, MKI; Pyle, M.; /Stanford U., Phys. Dept.; Resch, R.; /SLAC; Sadoulet, B.; Sundqvist, K.M.; /LBL, Berkeley; Brink, P.L.; Cherry, M.; /Stanford U., Phys. Dept.; Do Couto E Silva, E.; /SLAC; Figueroa-Feliciano, E.; /MIT, MKI; Mirabolfathi, N.; Serfass, B.; /UC, Berkeley; Tomada, A.; /Stanford U., Phys. Dept.

2012-06-04T23:59:59.000Z

260

Single and double grid long-range alpha detectors  

DOE Patents (OSTI)

Alpha particle detectors capable of detecting alpha radiation from distant sources. In one embodiment, a voltage is generated in a single electrically conductive grid while a fan draws air containing air molecules ionized by alpha particles through an air passage and across the conductive grid. The current in the conductive grid can be detected and used for measurement or alarm. Another embodiment builds on this concept and provides an additional grid so that air ions of both polarities can be detected. The detector can be used in many applications, such as for pipe or duct, tank, or soil sample monitoring.

MacArthur, Duncan W. (Los Alamos, NM); Allander, Krag S. (Ojo Caliente, NM)

1993-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "flame ionization detector" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


261

Single and double grid long-range alpha detectors  

DOE Patents (OSTI)

Alpha particle detectors capable of detecting alpha radiation from distant sources. In one embodiment, a voltage is generated in a single electrically conductive grid while a fan draws air containing air molecules ionized by alpha particles through an air passage and across the conductive grid. The current in the conductive grid can be detected and used for measurement or alarm. Another embodiment builds on this concept and provides an additional grid so that air ions of both polarities can be detected. The detector can be used in many applications, such as for pipe or duct, tank, or soil sample monitoring.

MacArthur, D.W.; Allander, K.S.

1993-03-16T23:59:59.000Z

262

Lean premixed flames for low NO{sub x} combustors  

DOE Green Energy (OSTI)

The overall objectives of the research at Purdue are to: obtain a reduced mechanism description of high pressure NO formation chemistry using experiments and calculations for laminar lean premixed methane air flames, develop a statistical model of turbulence NO chemistry interactions using a Bunsen type jet flame, and utilize the high pressure chemistry and turbulence models in a commercial design code, then evaluate its predictions using data from an analog gas turbine combustor. Work to date has resulted in the following achievements: spatially resolved measurements of NO in high-pressure high-temperature flat flames, plus evaluation of the influence of flame radiation on the measured temperature profile; measurements of temperature and velocity PDFs for a turbulent methane/air flame were obtained for the first time, under operating conditions which allow their study in the distributed regimes, and the increase in EINO{sub x} with equivalence ratio predicted using a chemical kinetics model; and simulation of non-reacting combustor flow fields from ambient to elevated pressure and temperature conditions and comparison of those results with experimental velocity profiles.

Sojka, P.; Tseng, L.; Bryyjak, J. [Purdue Univ., Lafayette, IN (United States). Thermal Sciences and Propulsion Center] [and others

1995-12-31T23:59:59.000Z

263

LES of Sandia Flame D with Eulerian PDF and Finite-Rate Chemistry  

E-Print Network (OSTI)

Barlow, R. S. , 2003. Sandia piloted CH 4 /air ?ame D data -LES of Sandia Flame D with Eulerian PDF and Finite-RatePaper: 05F-33 LES of Sandia Flame D with Eulerian PDF and

Bisetti, Fabrizio; Chen, J Y

2005-01-01T23:59:59.000Z

264

Analysis of Reaction-Diffusion Systems for Flame Capturing in Type Ia Supernova Simulations  

E-Print Network (OSTI)

We present a study of numerical behavior of a thickened flame used in Flame Capturing (FC, Khokhlov (1995)) for tracking thin unresolved physical flames in deflagration simulations. We develop a steady-state procedure for calibrating the flame model used, and test it against analytical results. We observe numerical noises generated by original realization of the technique. Alternative artificial burning rates are discussed, which produce acceptably quiet flames. Two new quiet models are calibrated to yield required "flame" speed and width, and further studied in 2D and 3D setting. Landau-Darrieus type instabilities of the flames are observed. One model also shows significantly anisotropic propagation speed on the grid, both effects increasingly pronounced at larger matter expansion as a result of burning; this makes the model unacceptable for use in type Ia supernova simulations. Another model looks promising for use in flame capturing at fuel to ash density ratio of order 3 and below. That "Model B" yields f...

Zhiglo, Andrey V

2009-01-01T23:59:59.000Z

265

Effects of curvature and strain on a lean premixed methane-hydrogen-air flame  

E-Print Network (OSTI)

The elemental flame is a subgrid model for turbulent combustion, parameterized by time-varying strain rate and curvature. This thesis develops the unsteady one-dimensional governing equations for the elemental flame ...

Speth, Raymond L., 1981-

2006-01-01T23:59:59.000Z

266

STUDIES OF WALL FLAME QUENCHING AND HYDROCARBON EMISSIONS IN A MODEL SPARK IGNITION ENGINE  

E-Print Network (OSTI)

Cylinder Engine Study with Propane as a Fuel," SAE Paper No.Wall-Quenching of Laminar Propane Flames as a Function ofQuenching Distance of Propane-Air Flames in a Constant-

Ishikawa, Nobuhiko

2011-01-01T23:59:59.000Z

267

Flame transfer function measurements and mechanisms in a single-nozzle combustor.  

E-Print Network (OSTI)

??The response of a fully-premixed flame to velocity fluctuations was experimentally measured in a single-nozzle, swirl-stabilized, model gas turbine combustor. Flame response was quantified in… (more)

Bunce, Nicholas

2013-01-01T23:59:59.000Z

268

Flame Arrester Evaluation for E-Diesel Fuel Tanks: September 3, 2002 - May 28, 2003  

DOE Green Energy (OSTI)

An evaluation of various flame arresters for use with E-Diesel fuel was conducted on four diesel fuel tanks selected to represent typical fuel tank and fill neck designs. Multiple flame arresters were tested on each fuel tank.

Weyandt, N.; Janssens, M. L.

2003-06-01T23:59:59.000Z

269

Field ionization from carbon nanofibers  

E-Print Network (OSTI)

The Micro Gas Analyzer project aims to develop power-efficient, high resolution, high sensitivity, portable and real-time gas sensors. We developed a field ionizer array based on gated CNTs. Arrays of CNTs are used because ...

Adeoti, Bosun J

2008-01-01T23:59:59.000Z

270

Welding arc gap ionization device  

SciTech Connect

An alpha emitting isotope is positioned near the tip of a TIG welding electrode so that the alpha radiation can provide an ionized path between the electrode and the workpiece.

Schweikhardt, George M. (Richland, WA)

1976-01-01T23:59:59.000Z

271

Humidity effects in ionization chambers  

SciTech Connect

Capacitance variations due to humidity alterations have been suggested as the cause of ionization chamber current variations. The validity of the arguments is seriously questioned on several points. (auth)

Bengtsson, L.G.

1973-01-01T23:59:59.000Z

272

Ionizing Radiation Injury (South Carolina)  

Energy.gov (U.S. Department of Energy (DOE))

This legislation applies to employers that have more than one employee who engages in activities which involve the presence of ionizing radiation. Employers with less than three employees can...

273

Scaling and efficiency of PRISM in adaptive simulations of turbulent premixed flames  

E-Print Network (OSTI)

dimensional premixed flames," Sandia National Labora­ toriesand plasma kinetics," Sandia National Laboratories Reporttransport properties," Sandia National Laboratories Report

1999-01-01T23:59:59.000Z

274

Scaling and efficiency of PRISM in adaptive simulations of turbulent premixed flames  

E-Print Network (OSTI)

dimensional premixed flames," Sandia National Labora- toriesand plasma kinetics," Sandia National Laboratories Reporttransport properties," Sandia National Laboratories Report

Tonse, Shaheen R.

2011-01-01T23:59:59.000Z

275

Coordinate-free description of corrugated flames with realistic density drop at the front  

E-Print Network (OSTI)

The complete set of hydrodynamic equations for a corrugated flame front is reduced to a system of coordinate-free equations at the front using the fact that vorticity effects remain relatively weak even for corrugated flames. It is demonstrated how small but finite flame thickness may be taken into account in the equations. Similar equations are obtained for turbulent burning in the flamelet regime. The equations for a turbulent corrugated flame are consistent with the Taylor hypothesis of stationary external turbulence.

Vitaly Bychkov; Maxim Zaytsev; V'yacheslav Akkerman

2012-10-30T23:59:59.000Z

276

Protection Against Ionizing Radiation in Extreme Radiation ...  

Science Conference Proceedings (OSTI)

Protection Against Ionizing Radiation in Extreme Radiation-resistant Microorganisms. ... Elucidated radiation protection by intracellular halides. ...

2013-05-01T23:59:59.000Z

277

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

Science Conference Proceedings (OSTI)

Ultra-lean, hydrogen-air mixtures are found to support another kind of laminar flame that is steady and stable beside flat flames and flame balls. Direct numerical simulations are performed of flames that develop into steadily and stably propagating cells. These cells were the original meaning of the word"flamelet'' when they were observed in lean flammability studies conducted early in the development of combustion science. Several aspects of these two-dimensional flame cells are identified and are contrasted with the properties of one-dimensional flame balls and flat flames. Although lean hydrogen-air flames are subject to thermo-diffusive effects, in this case the result is to stabilize the flame rather than to render it unstable. The flame cells may be useful as basic components of engineering models for premixed combustion when the other types of idealized flames are inapplicable.

Grcar, Joseph F; Grcar, Joseph F

2008-06-30T23:59:59.000Z

278

Flame Synthesis of One-Dimensional Metal Oxide Nanomaterials  

NLE Websites -- All DOE Office Websites (Extended Search)

Synthesis of One-Dimensional Metal Oxide Nanomaterials Synthesis of One-Dimensional Metal Oxide Nanomaterials Alexei V. Saveliev Dept. of Mechanical and Aerospace Engineering, North Carolina State University, Raleigh, NC 27695, USA Robust, scalable, and energy efficient methods of nanomaterial synthesis are needed to meet the demands of current and potential applications. Flames have been successfully applied for the synthesis of metal oxide and ceramic nanopowders largely composed of spherical particles and their aggregates. In recent years, premixed and diffusion flames have been employed for the synthesis of 1-D carbon nanoforms such as carbon fibers and carbon nanotubes. The extension of flame methods to gas phase and solid support synthesis of 1-D inorganic nanoforms is of great interest and significance. This talk presents

279

Measurements of Laminar Flame Velocity for Components of Natural Gas  

E-Print Network (OSTI)

This paper presents new experimental measurements of the laminar flame velocity of components of natural gas, methane, ethane, propane, and n?butane as well as of binary and tertiary mixtures of these compounds proposed as surrogates for natural gas. These measurements have been performed by the heat flux method using a newly built flat flame adiabatic burner at atmospheric pressure. The composition of the investigated air/hydrocarbon mixtures covers a wide range of equivalence ratios, from 0.6 to 2.1, for which it is possible to sufficiently stabilize the flame. Other measurements involving the enrichment of methane by hydrogen (up to 68%) and the enrichment of air by oxygen (oxycombustion techniques) were also performed. Both empirical correlations and a detailed chemical mechanism have been proposed, the predictions being satisfactorily compared with the newly obtained experimental data under a wide range of conditions.

Patricia Dirrenberger; Hervé Le Gall; Roda Bounaceur; Olivier Herbinet; Re Glaude; Er Konnov

2013-01-01T23:59:59.000Z

280

The TESLA Detector  

E-Print Network (OSTI)

For the superconducting linear collider TESLA a multi purpose detector has been designed. This detector is optimised for the important physics processes expected at a next generation linear collider up to around 1 TeV and is designed for the specific environment of a superconducting collider.

Klaus Moenig

2001-11-05T23:59:59.000Z

Note: This page contains sample records for the topic "flame ionization detector" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


281

Arsenic activation neutron detector  

DOE Patents (OSTI)

A detector of bursts of neutrons from a deuterium-deuteron reaction includes a quantity of arsenic adjacent a gamma detector such as a scintillator and photomultiplier tube. The arsenic is activated by the 2.5-MeV neutrons to release gamma radiation which is detected to give a quantitative representation of detected neutrons.

Jacobs, E.L.

1980-01-28T23:59:59.000Z

282

SCINTILLATION EXPOSURE RATE DETECTOR  

DOE Patents (OSTI)

A radiation detector for gamma and x rays is described. The detector comprises a scintillation crystal disposed between a tantalum shield and the input of a photomultiplier tube, the crystal and the shield cooperating so that their combined response to a given quantity of radiation at various energy levels is substantially constant.

Spears, W.G.

1960-11-01T23:59:59.000Z

283

Effects of buoyancy on the flowfields of lean premixed turbulentv-flames  

SciTech Connect

Open laboratory turbulent flames used for investigating fundament flame turbulence interactions are greatly affected by buoyancy. Though much of our current knowledge is based on observations made in these open flames, the effects of buoyancy are usually not included in data interpretation, numerical analysis or theories. This inconsistency remains an obstacle to merging experimental observations and theoretical predictions. To better understanding the effects of buoyancy, our research focuses on steady lean premixed flames propagating in fully developed turbulence. We hypothesize that the most significant role of buoyancy forces on these flames is to influence their flowfields through a coupling with mean and fluctuating pressure fields. Changes in flow pattern alter the mean aerodynamic stretch and in turn affect turbulence fluctuation intensities both upstream and downstream of the flame zone. Consequently, flame stabilization, reaction rates, and turbulent flame processes are all affected. This coupling relates to the elliptical problem that emphasizes the importance of the upstream, wall and downstream boundary conditions in determining all aspects of flame propagation. Therefore, buoyancy has the same significance as other parameters such as flow configuration, flame geometry, means of flame stabilization, flame shape, enclosure size, mixture conditions, and flow conditions.

Cheng, R.K.; Bedat, B.; Yegian, D.T.; Greenberg, P.

2001-03-01T23:59:59.000Z

284

A lattice Boltzmann algorithm for calculation of the laminar jet diffusion flame  

Science Conference Proceedings (OSTI)

A new two-distribution lattice Boltzmann equation (LBE) algorithm is presented to solve the laminar diffusion flames within the context of Burke-Schumann flame sheet model. One distribution models the transport of the Schvab-Zeldovich coupling function, ... Keywords: TVD scheme, laminar diffusion flame, lattice Boltzmann equation, quasi-incompressible flow

Taehun Lee; Ching-Long Lin; Lea-Der Chen

2006-06-01T23:59:59.000Z

285

Wide-range radioactive-gas-concentration detector  

DOE Patents (OSTI)

A wide-range radioactive-gas-concentration detector and monitor capable of measuring radioactive-gas concentrations over a range of eight orders of magnitude is described. The device is designed to have an ionization chamber sufficiently small to give a fast response time for measuring radioactive gases but sufficiently large to provide accurate readings at low concentration levels. Closely spaced parallel-plate grids provide a uniform electric field in the active region to improve the accuracy of measurements and reduce ion migration time so as to virtually eliminate errors due to ion recombination. The parallel-plate grids are fabricated with a minimal surface area to reduce the effects of contamination resulting from absorption of contaminating materials on the surface of the grids. Additionally, the ionization-chamber wall is spaced a sufficient distance from the active region of the ionization chamber to minimize contamination effects.

Anderson, D.F.

1981-11-16T23:59:59.000Z

286

NO sub x destruction in diffusion flame environments  

Science Conference Proceedings (OSTI)

This research is concerned with reburning, which is an NO{sub x} abatement technique involving the injection of secondary fuel into the post flame of a furnace. The specific objectives of this research are to determine whether heterogeneities inherent in diffusion flame environments can be exploited to achieve greater reductions in NO than can be achieved in premixed systems. The research project described here is but a first step to explore this question, and should be viewed more as a screening study rather than as completed research, the results of which are completely understood. The problem was attacked through both experimentation and theoretical modeling. Experiments employed a bench scale, laminar, counter-flow, diffusion flame, which was designed to simulate the stretched diffusion flamelets that arise at the interface between turbulent fuel and oxidant jets. Data gathered were of two types. First, NO destruction from the integral system was investigated through parametric studies in which only inlet and outlet species and flows were measured. Three different experimental configurations were examined, under a wide range of operating conditions, with emphasis on reburning under overall fuel lean conditions. Second, in order to gain insight into the observed phenomena, detailed axial profiles of major and minor species were measured for one configurations. Theoretical modeling consisted of computer simulations which attempt to describe the experimental configuration as an infinitely wide flat flame. This yielded predictions of axial profiles but was not readily adaptable for (integral) predictions of total NO destroyed in our flame. The model employed detailed chemical reactions, and was also used to determine regimes in which ignition occurs under diffusion flame conditions. 30 refs., 31 figs., 19 tabs.

Wendt, J.O.L.; Lin, W.C.; Mwabe, P.

1991-07-31T23:59:59.000Z

287

Advanced far infrared detectors  

SciTech Connect

Recent advances in photoconductive and bolometric semiconductor detectors for wavelength 1 mm > {lambda} > 50 {mu}m are reviewed. Progress in detector performance in this photon energy range has been stimulated by new and stringent requirements for ground based, high altitude and space-borne telescopes for astronomical and astrophysical observations. The paper consists of chapters dealing with the various types of detectors: Be and Ga doped Ge photoconductors, stressed Ge:Ga devices and neutron transmutation doped Ge thermistors. Advances in the understanding of basic detector physics and the introduction of modern semiconductor device technology have led to predictable and reliable fabrication techniques. Integration of detectors into functional arrays has become feasible and is vigorously pursued by groups worldwide.

Haller, E.E.

1993-05-01T23:59:59.000Z

288

Nanomechanical resonance detector  

SciTech Connect

An embodiment of a nanomechanical frequency detector includes a support structure and a plurality of elongated nanostructures coupled to the support structure. Each of the elongated nanostructures has a particular resonant frequency. The plurality of elongated nanostructures has a range of resonant frequencies. An embodiment of a method of identifying an object includes introducing the object to the nanomechanical resonance detector. A resonant response by at least one of the elongated nanostructures of the nanomechanical resonance detector indicates a vibrational mode of the object. An embodiment of a method of identifying a molecular species of the present invention includes introducing the molecular species to the nanomechanical resonance detector. A resonant response by at least one of the elongated nanostructures of the nanomechanical resonance detector indicates a vibrational mode of the molecular species.

Grossman, Jeffrey C; Zettl, Alexander K

2013-10-29T23:59:59.000Z

289

Real Time Flame Monitoring of Gasifier Burner and Injectors  

NLE Websites -- All DOE Office Websites (Extended Search)

Real Time Flame Monitoring of Gasifier Real Time Flame Monitoring of Gasifier Burner and Injectors Background The Gasification Technologies Program at the National Energy Technology Laboratory (NETL) supports research and development (R&D) in the area of gasification-a process whereby carbon-based materials (feedstocks) such as coal are converted into synthesis gas (syngas), which is separated into hydrogen (H 2 ) and carbon dioxide (CO 2 ) gas streams in a combustion turbine-generator as a way to generate clean electricity while

290

Flame acceleration and transition to detonation in channels  

DOE Green Energy (OSTI)

Experimental results are reported for combustion of pre-mixed H/sub 2/-air mixtures in a 136 m/sup 3/ channel and a 1:12.6 linear scale model. Test variables include H/sub 2/-air equivalence ratio, obstacles and degree of transverse venting. The results show that flame acceleration is increased by sensitive mixtures, presence of obstacles, large scales, and insufficient venting. The results also support the hypothesis that deflagration to detonation transition (DDT) can occur if the ratio of detonation cell width to channel width is less than a critical value, provided that the flame speed prior to transition has approached the isobaric sound speed.

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

1987-01-01T23:59:59.000Z

291

Structure of Partially Premixed Flames Using Detailed Chemistry Simulations  

E-Print Network (OSTI)

State-of-the-art reacting-flow computations have to compromise either on the detail of chemical reactions or on the dimensionality of the solution, while experiments in flames are limited by the flow accessibility and provide at best a limited number of observables. In the present work, the partially premixed laminar flame structure is examined using a detailed-chemistry, one-dimensional simulation. The computational results are compared to unpublished single-point multiscalar measurements 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 to analyze the spatial and scalar flame structure under the overarching concept of flamelets. The computations are based on the Cantera open-source software package developed at CalTech by D. Goodwin, and incorporating the GRI 3.0 chemical kinetic mechanism utilizing 325 chemical reactions and 53 species for methane combustion. Cross-transport effects as well as an optically-thin radiation model are included in the calculations. Radiation changes the flame profiles due to its effect on temperature, and the attendant effects on a number of species. Using the detailed analysis of different reaction rates, the adiabatic and radiative nitric oxide concentrations are compared. The cross-transport effects, i.e. Soret and Dufour, were studied in detail. The Soret term has a small but important effect on the flame structure through a reduction of the hydrogen mass fraction, which changes the conserved scalar values. Based on the flamelet approach and a unique formulation of the conserved scalar, the flame thermochemistry can be analyzed and understood. A number of interesting effects on the flame thermochemistry can be discerned in both experiments and computations when the premixture strength is varied. An increase in premixing results in a counterintuitive decrease in intermediate species such as carbon monoxide and hydrogen, as well as an expected increase in nitric oxide concentrations. Good agreement is found between experiments and calculations in scalar space, while the difference in dimensionality between axisymmetric measurements and opposed jet computations makes comparison in physical space tentative.

Kluzek, Celine D.

2009-08-01T23:59:59.000Z

292

INVESTIGATION ON THE FLAME EXTINCTION LIMIT OF FUEL BLENDS  

SciTech Connect

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.

Ahsan R. Choudhuri

2005-02-01T23:59:59.000Z

293

Method of growing films by flame synthesis using a stagnation-flow reactor  

DOE Patents (OSTI)

A method of stabilizing a strained flame in a stagnation flow reactor. By causing a highly strained flame to be divided into a large number of equal size segments it is possible to stablize a highly strained flame that is on the verge of extinction, thereby providing for higher film growth rates. The flame stabilizer is an annular ring mounted coaxially and coplanar with the substrate upon which the film is growing and having a number of vertical pillars mounted on the top surface, thereby increasing the number of azimuthal nodes into which the flame is divided and preserving an axisymmetric structure necessary for stability.

Hahn, David W. (Dublin, CA); Edwards, Christopher F. (Sunnyvale, CA)

1998-01-01T23:59:59.000Z

294

Method of growing films by flame synthesis using a stagnation-flow reactor  

DOE Patents (OSTI)

A method is described for stabilizing a strained flame in a stagnation flow reactor. By causing a highly strained flame to be divided into a large number of equal size segments it is possible to stablize a highly strained flame that is on the verge of extinction, thereby providing for higher film growth rates. The flame stabilizer is an annular ring mounted coaxially and coplanar with the substrate upon which the film is growing and having a number of vertical pillars mounted on the top surface, thereby increasing the number of azimuthal nodes into which the flame is divided and preserving an axisymmetric structure necessary for stability. 5 figs.

Hahn, D.W.; Edwards, C.F.

1998-11-24T23:59:59.000Z

295

Effects of Soret diffusion on the laminar flame speed and Markstein length of syngas/air mixtures  

E-Print Network (OSTI)

Effects of Soret diffusion on the laminar flame speed and Markstein length of syngas/air mixtures, Beijing 100084, China Abstract The effects of Soret diffusion on premixed syngas/air flames at normal and stretched laminar flame speed and Markstein length of syngas/air mixtures. The laminar flame speed

Chen, Zheng

296

Effects of Soret diffusion on the laminar flame speed and Markstein length of syngas/air mixtures  

E-Print Network (OSTI)

Effects of Soret diffusion on the laminar flame speed and Markstein length of syngas/air mixtures, China Abstract The effects of Soret diffusion on premixed syngas/air flames at normal and elevated and stretched flame speed and Markstein length of syngas/air mixtures. The laminar flame speed and Markstein

Chen, Zheng

297

Layered semiconductor neutron detectors  

SciTech Connect

Room temperature operating solid state hand held neutron detectors integrate one or more relatively thin layers of a high neutron interaction cross-section element or materials with semiconductor detectors. The high neutron interaction cross-section element (e.g., Gd, B or Li) or materials comprising at least one high neutron interaction cross-section element can be in the form of unstructured layers or micro- or nano-structured arrays. Such architecture provides high efficiency neutron detector devices by capturing substantially more carriers produced from high energy .alpha.-particles or .gamma.-photons generated by neutron interaction.

Mao, Samuel S; Perry, Dale L

2013-12-10T23:59:59.000Z

298

A mechanistic study of Soret diffusion in hydrogen-air flames  

Science Conference Proceedings (OSTI)

The separate and combined effects of Soret diffusion of the hydrogen molecule (H{sub 2}) and radical (H) on the structure and propagation speed of the freely-propagating planar premixed flames, and the strain-induced extinction response of premixed and nonpremixed counterflow flames, were computationally studied for hydrogen-air mixtures using a detailed reaction mechanism and transport properties. Results show that, except for the conservative freely-propagating planar flame, Soret diffusion of H{sub 2} increases the fuel concentration entering the flame structure and as such modifies the mixture stoichiometry and flame temperature, which could lead to substantial increase (decrease) of the flame speed for the lean (rich) mixtures respectively. On the other hand, Soret diffusion of H actively modifies its concentration and distribution in the reaction zone, which in turn affects the individual reaction rates. In particular, the reaction rates of the symmetric, twin, counterflow premixed flames, especially at near-extinction states, can be increased for lean flames but decreased for rich flames, whose active reaction regions are respectively located at, and away from, the stagnation surface. However, such a difference is eliminated for the single counterflow flame stabilized by an opposing cold nitrogen stream, as the active reaction zone up to the state of extinction is always located away from the stagnation surface. Finally, the reaction rate is increased in general for diffusion flames because the bell-shaped temperature distribution localizes the H concentration to the reaction region which has the maximum temperature. (author)

Yang, F. [Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, NJ 08544 (United States); Department of Engineering Mechanics, Tsinghua University, Beijing (China); Law, C.K. [Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, NJ 08544 (United States); Sung, C.J. [Department of Mechanical Engineering, University of Connecticut, Storrs, CT 06269 (United States); Zhang, H.Q. [Department of Engineering Mechanics, Tsinghua University, Beijing (China)

2010-01-15T23:59:59.000Z

299

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

Science Conference Proceedings (OSTI)

An experimental study has been conducted in axisymmetric, co-flowing triple flames with different equivalence ratios of the inner and outer reactant streams (2propane/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)

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

300

NETL: Investigation on Flame Characteristics and Burner Operability Issues  

NLE Websites -- All DOE Office Websites (Extended Search)

Investigation on Flame Characteristics and Burner Operability Issues of Oxy-Fuel Combustion Investigation on Flame Characteristics and Burner Operability Issues of Oxy-Fuel Combustion Project No.: DE-FE0002402 NETL has partnered with the University of Texas at El Paso (UTEP) to investigate the characteristics of oxy-fuel flames and assess their impact on the operability of oxy-fuel combustion systems. The examination of fundamental flame characteristics data and related burner operability parameters are essential for designing and developing oxy-fuel combustion systems for new power plants and retrofitting existing power generation units. In an oxy-fuel system, coal is combusted in an enriched oxygen environment using pure oxygen diluted with recycled CO2 or water vapor (H2O), resulting in a flue stream consisting only of CO2 and H2O (no other co-contaminants) (Figure 1). Oxy-fuel combustion is promising for CCUS applications because water can be condensed out of the CO2/H2O flue stream to produce a relatively pure CO2 end product for capture. Oxy-fuel combustion and subsequent CO2 capture is currently being considered by the DOE's Innovations for Existing Plants Program as having the potential to meet the goal of 90 percent CO2 capture without increasing the cost of electricity more than 35 percent.

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301

Research on the Connection between FLAMES and RTI  

Science Conference Proceedings (OSTI)

HLA (High Level Architecture) based distributed simulation has become the mainstream in practice these days. During the development of a HLA federation, the main work is to develop models in each federate. However, it is common that unreasonable models ... Keywords: FLAMES, Model system, RTI, Connection, Client/Server

Xu Xie; Xiaocheng Liu; Kedi Huang

2012-08-01T23:59:59.000Z

302

Multiscalar measurements of turbulence-chemistry interactions in nonpremixed flames  

DOE Green Energy (OSTI)

Selected results from experiments conducted over the past several years involving simultaneous multiscalar point measurements in turbulent nonpremixed flames are reviewed in this paper. In these experiments, spontaneous Raman scattering and Rayleigh scattering measurements of the major species and temperature were combined with laser-induced fluorescence measurements of minor species. The most important feature of these experiments is that they provide detailed data on the instantaneous relationships among species concentration, temperature, and derived scalar quantities that reflect the state of mixing or the progress of reaction. The data allow quantitative comparisons of the thermochemical states in turbulent flames with those in idealized representations, such as steady strained laminar flames, perfectly stirred reactors, or adiabatic equilibrium. The data may also be compared with results (measured or calculated) from unsteady laminar flames and from direct numerical simulations (DNS) of turbulent reacting flows. such comparisons provide insights into the fundamental nature of turbulence-chemistry interactions, and they allow one to examine the validity of some of the basic assumptions that turbulent combustion models are built upon. Furthermore, these data allow quantitative evaluations of the predictive accuracy, strengths, and limitations of a wide variety of combustions models.

Barlow, R.S.

1995-12-01T23:59:59.000Z

303

Modeling of combustion noise spectrum from turbulent premixed flames  

E-Print Network (OSTI)

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

Paris-Sud XI, Université de

304

Formation mechanism for polycyclic aromatic hydrocarbons in methane flames  

E-Print Network (OSTI)

exhausts,7­17 coal-fired, electricity generating power plants,18,19 tobacco smoke,20 residential wood applications including heating systems and gas turbines for electric power generation.62­64 The combustion propane,57,58 butane,59 ethane,31,53,60 and other aliphatic61 flames. Methane is used as fuel in many

Sattler, Klaus

305

Flame Synthesis of Carbon Nanotubes Using Low Calorific Value Gases  

DOE Green Energy (OSTI)

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.

Jorge Camacho; Mahesh Subramanya; Ahsan R. Choudhuri

2007-03-31T23:59:59.000Z

306

Radiation intensity of lignite-fired oxy-fuel flames  

SciTech Connect

The radiative heat transfer in oxy-fuel flames is compared to corresponding conditions in air-fuel flames during combustion of lignite in the Chalmers 100 kW oxy-fuel test facility. In the oxy-fuel cases the flue-gas recycle rate was varied, so that, in principle, the same stoichiometry was kept in all cases, whereas the oxygen fraction in the recycled flue-gas mixture ranged from 25 to 29 vol.%. Radial profiles of gas concentration, temperature and total radiation intensity were measured in the furnace. The temperature, and thereby the total radiation intensity of the oxy-fuel flames, increases with decreasing flue-gas recycle rate. The ratio of gas and total radiation intensities increases under oxy-fuel conditions compared to air-firing. However, when radiation overlap between gas and particles is considered the ratios for air-firing and oxy-fuel conditions become more similar, since the gas-particle overlap is increased in the CO{sub 2}-rich atmosphere. A large fraction of the radiation in these lignite flames is emitted by particles whose radiation was not significantly influenced by oxy-fuel operation. Therefore, an increment of gas radiation due to higher CO{sub 2} concentration is not evident because of the background of particle radiation, and, the total radiation intensities are similar during oxy-fuel and air-fuel operation as long as the temperature distributions are similar. (author)

Andersson, Klas; Johansson, Robert; Hjaertstam, Stefan; Johnsson, Filip; Leckner, Bo [Department of Energy and Environment, Division of Energy Technology, Chalmers University of Technology, SE - 412 96 Goeteborg (Sweden)

2008-10-15T23:59:59.000Z

307

AIRBORNE RADIATION DETECTOR  

DOE Patents (OSTI)

An ionization chamber used for measuring the radioactivity of dust present in atmospheric air is described. More particularly. the patent describes a device comprising two concentric open ended, electrically connected cylinders between which is disposed a wire electrcde. A heating source is disposed inside of the cylinder to circulate air through the space between the two cylinders by convective flow. A high voltage electric field between the wire electrcde of the electrically connected cylinder will cause ionization of the air as it passes therethrough.

Cartmell, T.R.; Gifford, J.F.

1959-08-01T23:59:59.000Z

308

Real Time Flame Monitoring of Gasifier and Injectors  

SciTech Connect

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.

Zelepouga, Serguei; Saveliev, Alexei

2011-12-31T23:59:59.000Z

309

Pendulum detector testing device  

DOE Patents (OSTI)

A detector testing device is described which provides consistent, cost-effective, repeatable results. The testing device is primarily constructed of PVC plastic and other non-metallic materials. Sensitivity of a walk-through detector system can be checked by: (1) providing a standard test object simulating the mass, size and material content of a weapon or other contraband, (2) suspending the test object in successive positions, such as head, waist and ankle levels, simulating where the contraband might be concealed on a person walking through the detector system; and (3) swinging the suspended object through each of the positions, while operating the detector system and observing its response. The test object is retained in a holder in which the orientation of the test device or target can be readily changed, to properly complete the testing requirements. 5 figs.

Gonsalves, J.M.

1997-09-30T23:59:59.000Z

310

Flexible Composite Radiation Detector  

NLE Websites -- All DOE Office Websites (Extended Search)

Flexible Composite Radiation Detector Flexible Composite Radiation Detector Flexible Composite Radiation Detector A flexible composite scintillator was prepared by mixing fast, bright, dense rare-earth doped powdered oxyorthosilicate (such as LSO:Ce, LSO:Sm, and GSO:Ce) scintillator with a polymer binder. Available for thumbnail of Feynman Center (505) 665-9090 Email Flexible Composite Radiation Detector A flexible composite scintillator was prepared by mixing fast, bright, dense rare-earth doped powdered oxyorthosilicate (such as LSO:Ce, LSO:Sm, and GSO:Ce) scintillator with a polymer binder. The binder is transparent to the scintillator emission. The composite is seamless and can be made large and in a wide variety of shapes. Importantly, the composite can be tailored to emit light in a spectral region that matches the optimum

311

Ultrafast neutron detector  

DOE Patents (OSTI)

A neutron detector of very high temporal resolution is described. It may be used to measure distributions of neutrons produced by fusion reactions that persist for times as short as about 50 picoseconds.

Wang, C.L.

1985-06-19T23:59:59.000Z

312

Pocked surface neutron detector  

DOE Patents (OSTI)

The detection efficiency, or sensitivity, of a neutron detector material such as of Si, SiC, amorphous Si, GaAs, or diamond is substantially increased by forming one or more cavities, or holes, in its surface. A neutron reactive material such as of elemental, or any compound of, .sup.10 B, .sup.6 Li, .sup.6 LiF, U, or Gd is deposited on the surface of the detector material so as to be disposed within the cavities therein. The portions of the neutron reactive material extending into the detector material substantially increase the probability of an energetic neutron reaction product in the form of a charged particle being directed into and detected by the neutron detector material.

McGregor, Douglas (Whitmore Lake, MI); Klann, Raymond (Bolingbrook, IL)

2003-04-08T23:59:59.000Z

313

Pendulum detector testing device  

DOE Patents (OSTI)

A detector testing device which provides consistent, cost-effective, repeatable results. The testing device is primarily constructed of PVC plastic and other non-metallic materials. Sensitivity of a walk-through detector system can be checked by: 1) providing a standard test object simulating the mass, size and material content of a weapon or other contraband, 2) suspending the test object in successive positions, such as head, waist and ankle levels, simulating where the contraband might be concealed on a person walking through the detector system; and 3) swinging the suspended object through each of the positions, while operating the detector system and observing its response. The test object is retained in a holder in which the orientation of the test device or target can be readily changed, to properly complete the testing requirements.

Gonsalves, John M. (Modesto, CA)

1997-01-01T23:59:59.000Z

314

Fiber optic detector  

DOE Patents (OSTI)

This invention is comprised of a portable fiber optic detector that senses the presence of specific target chemicals by exchanging the target chemical for a fluorescently-tagged antigen that is bound to an antibody which is in turn attached to an optical fiber. Replacing the fluorescently-tagged antigen reduces the fluorescence so that a photon sensing detector records the reduced light level and activates an appropriate alarm or indicator.

Partin, J.K.; Ward, T.E.; Grey, A.E.

1990-12-31T23:59:59.000Z

315

Measurements of the flame emissivity and radiative properties of particulate medium in pulverized-coal-fired boiler furnaces by image processing of visible radiation  

SciTech Connect

Due to the complicated processes for coal particles burning in industrial furnaces, their radiative properties, such as the absorption and scattering coefficients, which are essential to make reliable calculation of radiative transfer in combustion computation, are hard to be given exactly by the existing methods. In this paper, multiple color image detectors were used to capture approximately red, green, and blue monochromatic radiative intensity images in the visible wavelength region, and the flame emissivity and the radiative properties of the particulate media in three pulverized-coal-fired boiler furnaces were got from the flame images. It was shown that as the load increased, the flame emissivity and the radiative properties increased too; these radiative parameters had the largest values near the burner zone, and decreased along the combustion process. Compared with the combustion medium with a low-volatile anthracite coal burning in a 670 t/h boiler, the emissivity and the absorption coefficient of the medium with a high-volatile bituminous coal burning in a 1025 t/h boiler were smaller near the outlet zone, but were larger near the burner zone of the furnace, due to the significant contribution of soot to the radiation. This work will be of practical importance in modeling and calculating the radiative heat transfer in combustion processes, and improving the technology for in situ, multi-dimensional visualization of large-scale combustion processes in coal-fired furnaces of power plants. 18 refs., 10 figs., 8 tabs.

Chun Lou; Huai-Chun Zhou; Peng-Feng Yu; Zhi-Wei Jiang [Huazhong University of Science and Technology, Wuhan (China). State Key Laboratory of Coal Combustion

2007-07-01T23:59:59.000Z

316

Carbon nanotube-based field ionization vacuum  

E-Print Network (OSTI)

We report the development of a novel micropump architecture that uses arrays of isolated vertical carbon nanotubes (CNT) to field ionize gas particles. The ionized gas molecules are accelerated to and implanted into a ...

Jang, Daniel, M. Eng. Massachusetts Institute of Technology

2012-01-01T23:59:59.000Z

317

MUCOOL: Ionization Cooling R&D  

NLE Websites -- All DOE Office Websites (Extended Search)

Laboratory MUCOOL Muon Ionization Cooling R&D Welcome to the muon ionization cooling experimental R&D page. The MuCool collaboration has been formed to pursue the development of a...

318

Ionization of hydrogen by neutrino magnetic moment, relativistic muon, and WIMP  

E-Print Network (OSTI)

We studied the ionization of hydrogen by scattering of neutrino magnetic moment, relativistic muon, and weakly-interacting massive particle with a QED-like interaction. Analytic results were obtained and compared with several approximation schemes often used in atomic physics. As current searches for neutrino magnetic moment and dark matter have lowered the detector threshold down to the sub-keV regime, we tried to deduce from this simple case study the influence of atomic structure on the the cross sections and the applicabilities of various approximations. The general features being found will be useful for cases where practical detector atoms are considered.

Jiunn-Wei Chen; C. -P. Liu; Chien-Fu Liu; Chih-Liang Wu

2013-07-10T23:59:59.000Z

319

Liftoff and blowoff of a diffusion flame between parallel streams of fuel and air  

SciTech Connect

A numerical analysis is presented to describe the liftoff and blowoff of a diffusion flame in the mixing layer between two parallel streams of fuel (mainly methane diluted with nitrogen) and air emerging from porous walls. The analysis, which takes into account the effects of thermal expansion, assumes a one-step overall Arrhenius reaction, where the activation energy E is allowed to vary to reproduce the variations of the planar flame propagation velocity with the equivalence ratio. First, we describe the steady flame-front structure when stabilized close to the porous wall (attached flame regime). Then, we analyze the case where the flame front is located far away from the porous wall, at a distance x{sub f}' such that, upstream of the flame front, the mixing layer has a self-similar structure (lifted flame regime). For steady lifted flames, the results, given here in the case when the fuel and air streams are injected with the same velocity, relate U{sub f}'/S{sub L}, the front velocity (relative to the upstream flow) measured with the planar stoichiometric flame velocity, with the Damkohler number D{sub m}=({delta}{sub m}/{delta}{sub L}){sup 2}, based on the thickness, {delta}{sub m}, of the nonreacting mixing layer at the flame-front position and the laminar flame thickness, {delta}{sub L}. For large values of D{sub m}, the results, presented here for a wide range of dilutions of the fuel stream, provide values of the front propagation velocity that are in good agreement with previous experimental results, yielding well-defined conditions for blowoff. The calculated flame-front velocity can also be used to describe the transient flame-front dynamics after ignition by an external energy source.

Fernandez-Tarrazo, Eduardo [I.N.T.A. Area de Propulsion-Edificio R02, Ctra. Ajalvir, km 4, 28850 Torrejon de Ardoz, Madrid (Spain); Vera, Marcos [Area de Mecanica de Fluidos, Universidad Carlos III de Madrid, 28911 Leganes (Spain); Linan, Amable [Departamento de Motopropulsion y Termofluidodinamica, Universidad Politecnica de Madrid, Pza. Cardenal Cisneros 3, 28040 Madrid (Spain)

2006-01-01T23:59:59.000Z

320

Variation of equivalence ratio and element ratios in low-pressure premixed flames of aliphatic fuels  

DOE Green Energy (OSTI)

In previously published work it was found that the element ratios (such as C/O, H/O, H/C) and the equivalence ratio all varied in the flame zone of a low-pressure premixed fuel-rich benzene/oxygen/argon laminar flat flame. These variations were seen from analyses of both the data and detailed kinetic modeling. In the present work, seven additional flames were analyzed in the same manner, including five flames with a single hydrocarbon fuel (methane, acetylene, ethylene, allene, and propene) and two flames with a mixture of fuels (acetylene/allene, hydrogen/allene). All the flames had argon as the diluent, with pressures between 20 and 37.5 Torr, equivalence ratios between 1.6 and 2.5, cold gas velocities between 42 and 126 cm/sec. All of these flames showed variations in the element ratios and equivalence ratios. Furthermore, these variations changed in a consistent pattern with respect to the molecular weight of the fuel. In the flame zone, the percent change in the H/O, C/O and equivalence ratios increased with increasing molecular weight of the fuel, except for the hydrogen/allene flame in which the C/O ratio first increases, then decreases in the flame zone. Also, unlike all the other hydrocarbon flames, the C/O ratio decreases below its inlet value for the methane flame. The H/O and equivalence ratios decrease below their inlet values for the hydrogen/allene flame. These results are explained in terms of differential diffusion effects between the products and the reactants, which increase as the fuel becomes increasingly heavier than the major carbon- and hydrogen-containing products.

C. J. Pope; J. A. Miller

2000-03-14T23:59:59.000Z

Note: This page contains sample records for the topic "flame ionization detector" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


321

Partially-Premixed Flames in Internal Combustion Engines  

DOE Green Energy (OSTI)

This was a joint university-industry research program funded by the Partnerships for the Academic-Industrial Research Program (PAIR). The research examined partially premixed flames in laboratory and internal combustion engine environments at Vanderbilt University, University of Michigan, and General Motors Research and Development. At Vanderbilt University, stretched and curved ''tubular'' premixed flames were measured in a unique optically accessible burner with laser-induced spontaneous Raman scattering. Comparisons of optically measured temperature and species concentration profiles to detailed transport, complex chemistry simulations showed good correspondence at low-stretch conditions in the tubular flame. However, there were significant discrepancies at high-stretch conditions near flame extinction. The tubular flame predictions were found to be very sensitive to the specific hydrogen-air chemical kinetic mechanism and four different mechanisms were compared. In addition, the thermo-diffusive properties of the deficient reactant, H2, strongly affected the tubular flame structure. The poor prediction near extinction is most likely due to deficiencies in the chemical kinetic mechanisms near extinction. At the University of Michigan, an optical direct-injected engine was built up for laser-induced fluorescence imaging experiments on mixing and combustion under stratified charge combustion conditions with the assistance of General Motors. Laser attenuation effects were characterized both experimentally and numerically to improve laser imaging during the initial phase of the gasoline-air mixture development. Toluene was added to the isooctane fuel to image the fuel-air equivalence ratio in an optically accessible direct-injected gasoline engine. Temperature effects on the toluene imaging of fuel-air equivalence ratio were characterized. For the first time, oxygen imaging was accomplished in an internal combustion engine by combination of two fluorescence trackers, toluene and 3-pentanone. With this method, oxygen, fuel and equivalence ratio were measured in the cylinder. At General Motors, graduate students from the University of Michigan and Vanderbilt University worked with GM researchers to develop high-speed imaging methods for optically accessible direct-injection engines. Spark-emission spectroscopy was combined with high-speed spectrally-resolved combustion imaging in a direct-injected engine.

Robert W. Pitz; Michael C. Drake; Todd D. Fansler; Volker Sick

2003-11-05T23:59:59.000Z

322

Real Time Flame Monitoring of Gasifier Burner and Injectors  

NLE Websites -- All DOE Office Websites (Extended Search)

8 8 Gasification Technologies contacts Gary J. stiegel Gasification Technology Manager National Energy Technology Laboratory 626 Cochrans Mill Road P.O. Box 10940 Pittsburgh, PA 15236 412-386-4499 gary.stiegel@netl.doe.gov Jenny tennant Project Manager National Energy Technology Laboratory 3610 Collins Ferry Road P.O. Box 880 Morgantown, WV 26507 304-285-4830 jenny.tennant@netl.doe.gov David Rue Principal Investigator Gas Technology Institute 1700 South Mount Prospect Road Des Plaines, IL 60018 847-768-0508 david.rue@gastechnology.org Real Time Flame moniToRing oF gasiFieR BuRneR and injecToRs Description Combustion scientists and engineers have studied radiant emissions of various flames for many years. For some time, technologists have understood the rich potential for

323

Microwave remote sensing of ionized air.  

SciTech Connect

We present observations of microwave scattering from ambient room air ionized with a negative ion generator. The frequency dependence of the radar cross section of ionized air was measured from 26.5 to 40 GHz (Ka-band) in a bistatic mode with an Agilent PNA-X series (model N5245A) vector network analyzer. A detailed calibration scheme is provided to minimize the effect of the stray background field and system frequency response on the target reflection. The feasibility of detecting the microwave reflection from ionized air portends many potential applications such as remote sensing of atmospheric ionization and remote detection of radioactive ionization of air.

Liao, S.; Gopalsami, N.; Heifetz, A.; Elmer, T.; Fiflis, P.; Koehl, E. R.; Chien, H. T.; Raptis, A. C. (Nuclear Engineering Division)

2011-07-01T23:59:59.000Z

324

N d'ordre : D. U 1843 E D S P I C : 404  

E-Print Network (OSTI)

Fluidized Bed Reactor GAC Granular Activated Charcoal GC/FID Gas Chromatography / Flame Ionization Detector Chromatography HRT Hydraulic Retention Time LAS Linear Alkylbenzene Sulfonate MBBR Moving Bed Biological Reactor

325

Speciated Engine-Out Organic Gas Emissions from a PFI-SI Engine Operating on Ethanol/Gasoline Mixtures  

E-Print Network (OSTI)

Engine-out HC emissions from a PFI spark ignition engine were measured using a gas chromatograph and a flame ionization detector (FID). Two port fuel injectors were used respectively for ethanol and gasoline so that the ...

Kar, Kenneth

326

Effect of the Darrieus-Landau instability on turbulent flame velocity  

E-Print Network (OSTI)

Propagation of turbulent premixed flames influenced by the intrinsic hydrodynamic flame instability (the Darrieus-Landau instability) is considered in a two-dimensional case using the model nonlinear equation proposed recently. The nonlinear equation takes into account both influence of external turbulence and intrinsic properties of a flame front, such as small but finite flame thickness and realistically large density variations across the flame front. Dependence of the flame velocity on the turbulent length scale, on the turbulent intensity and on the density variations is investigated in the case of weak non-linearity and weak external turbulence. It is shown that the Darrieus-Landau instability influences the flamelet velocity considerably. The obtained results are in agreement with experimental data on turbulent burning of moderate values of the Reynolds number.

Maxim Zaytsev; Vitaliy Bychkov

2012-11-26T23:59:59.000Z

327

Manufacturing cost of flame heated thermionic converters. Topical report  

DOE Green Energy (OSTI)

The cost of thermionic converters has been estimated in support of the cost calculations for thermionic topping of central station powerplants. These calculations supersede the previous calculations made in 1975 and use a design concept similar to the current configuration of flame-heated converters. The cost of converters was estimated by obtaining quotations from manufactureres whenever possible. The selling cost was found to be $110 per kilowatt.

LaRue, G.; Miskolczy, G.

1979-04-01T23:59:59.000Z

328

Noise in non?premixed turbulent syngas flames  

Science Conference Proceedings (OSTI)

A turbulentsyngasflame may generateacoustic noise of high acoustic intensity in a combustion chamber. This may lead to the failure of construction components in a gas turbine engine in periods of the order of 1–100 hours. The research as described in the literature has almost exclusively been performed on the generation of noise in premixed methane or propane flames.Syngas fuel is a mixture of hydrogen and carbon monoxide

Sikke A. Klein; Jim B. W. Kok

1998-01-01T23:59:59.000Z

329

The Flame Doctor® Combustion Diagnostic System: Beta Test Program  

Science Conference Proceedings (OSTI)

Accurate knowledge of individual burner flame quality is essential to advanced boiler management. This is particularly important for advanced low-NOx burners, which are more sensitive to changes in operation and fuel quality than conventional burners. While global emissions monitoring is certainly important for boiler control, such monitoring can only provide information that has been averaged over many burners and long time scales. Because individual burners can exhibit large differences in emissions an...

2004-11-24T23:59:59.000Z

330

Dose rate dependence for different dosimeters and detectors: TLD, OSL, EBT films, and diamond detectors  

Science Conference Proceedings (OSTI)

Purpose: The use of laser accelerators in radiation therapy can perhaps increase the low number of proton and ion therapy facilities in some years due to the low investment costs and small size. The laser-based acceleration technology leads to a very high peak dose rate of about 10{sup 11} Gy/s. A first dosimetric task is the evaluation of dose rate dependence of clinical dosimeters and other detectors. Methods: The measurements were done at ELBE, a superconductive linear electron accelerator which generates electron pulses with 5 ps length at 20 MeV. The different dose rates are reached by adjusting the number of electrons in one beam pulse. Three clinical dosimeters (TLD, OSL, and EBT radiochromic films) were irradiated with four different dose rates and nearly the same dose. A faraday cup, an integrating current transformer, and an ionization chamber were used to control the particle flux on the dosimeters. Furthermore two diamond detectors were tested. Results: The dosimeters are dose rate independent up to 410{sup 9} Gy/s within 2% (OSL and TLD) and up to 1510{sup 9} Gy/s within 5% (EBT films). The diamond detectors show strong dose rate dependence. Conclusions: TLD, OSL dosimeters, and EBT films are suitable for pulsed beams with a very high pulse dose rate like laser accelerated particle beams.

Karsch, L.; Beyreuther, E.; Burris-Mog, T.; Kraft, S.; Richter, C.; Zeil, K.; Pawelke, J. [OncoRay-National Center for Radiation Research in Oncology, Technische Universitaet Dresden, Fetscherstr, 74, 01307 Dresden (Germany); Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiation Physics, P.O. Box 510119, 01314 Dresden (Germany); OncoRay-National Center for Radiation Research in Oncology, Technische Universitaet Dresden, Fetscherstr, 74, 01307 Dresden (Germany) and Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiation Physics, P.O. Box 510119, 01314 Dresden (Germany)

2012-05-15T23:59:59.000Z

331

The Upgraded D0 detector  

Science Conference Proceedings (OSTI)

The D0 experiment enjoyed a very successful data-collection run at the Fermilab Tevatron collider between 1992 and 1996. Since then, the detector has been upgraded to take advantage of improvements to the Tevatron and to enhance its physics capabilities. We describe the new elements of the detector, including the silicon microstrip tracker, central fiber tracker, solenoidal magnet, preshower detectors, forward muon detector, and forward proton detector. The uranium/liquid-argon calorimeters and central muon detector, remaining from Run I, are discussed briefly. We also present the associated electronics, triggering, and data acquisition systems, along with the design and implementation of software specific to D0.

Abazov, V.M.; Abbott, B.; Abolins, M.; Acharya, B.S.; Adams, D.L.; Adams, M.; Adams, T.; Agelou, M.; Agram, J.-L.; Ahmed, S.N.; Ahn, S.H.; Ahsan, M.; Alexeev, G.D.; Alkhazov, G.; Alton, A.; Alverson, G.; Alves, G.A.; Anastasoaie, M.; Andeen, T.; Anderson, J.T.; Anderson, S.; /Buenos Aires U. /Rio de Janeiro, CBPF /Sao Paulo, IFT /Alberta U. /Simon Fraser U. /York U., Canada /McGill U. /Beijing, Inst. High Energy Phys. /Hefei, CUST /Andes U., Bogota /Charles U. /Prague, Tech. U. /Prague, Inst. Phys. /San Francisco de Quito U. /Clermont-Ferrand U. /LPSC, Grenoble /Marseille, CPPM /Orsay, LAL /Paris U., VI-VII /DAPNIA, Saclay /Strasbourg, IReS

2005-07-01T23:59:59.000Z

332

RADIATIVE PROPERTY MEASUREMENTS OF OXY-FUEL FLAMES  

Science Conference Proceedings (OSTI)

As part of the DOE Existing Plants, Emissions and Capture (EPEC) program, oxy-combustion is being investigated as a method to simplify carbon capture and reduce the parasitic energy penalties associated with separating CO2 from a dilute flue gas. Gas-phase radiation heat transfer in boilers becomes significant when shifting from air-firing to oxycombustion, and must be accurately represented in models. Currently, radiative property data are not widely available in the literature for conditions appropriate to this environment. In order to facilitate the development and validation of accurate oxy-combustion models, NETL conducted a series of studies to measure radiation properties of oxy-fuel flames at adiabatic flame temperatures of 1750 - 1950K, and product molar concentrations ranging from 95% CO2 to 100% steam, determined by equilibrium calculations. Transmission coefficients were measured as a function of wavelength using a mid-IR imaging spectrometer and a blackbody radiation source. Additionally, flame temperatures were calculated using data collected within CO2 and H2O absorption bands. Experimental results were compared to two statistical narrowband models and experimental data from literature sources. These comparisons showed good overall agreement, although differences between the models and experimental results were noted, particularly for the R branch of the 2.7 ?m H2O band.

Clinton R. Bedick; Stephen K. Beer; Kent H. Casleton; Benjamin T. Chorpening; David W. Shaw; M. Joseph Yip

2011-03-01T23:59:59.000Z

333

Fuel control for gas turbine with continuous pilot flame  

SciTech Connect

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.

Swick, Robert M. (Indianapolis, IN)

1983-01-01T23:59:59.000Z

334

Fuel effects on flame lift-off under diesel conditions  

SciTech Connect

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)

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

2011-01-15T23:59:59.000Z

335

Lesson 4 - Ionizing Radiation | Department of Energy  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

4 - Ionizing Radiation 4 - Ionizing Radiation Lesson 4 - Ionizing Radiation Lesson Three showed that unstable isotopes emit energy as they become more stable. This energy is known as radiation. This lesson explores forms of radiation, where radiation is found, how we detect and measure radiation, what sources of radiation people are exposed to, whether radiation is harmful, and how we can limit our exposure. Specific topics covered in this lesson include: Types of radiation Non-ionizing Ionizing Forms of ionizing radiation Alpha particles Beta particles Gamma rays Radiation Decay chain Half-life Dose Radiation measurements Sources of radiation Average annual exposure Lesson 4 - Ionizing Radiation.pptx More Documents & Publications DOE-HDBK-1130-2008 DOE-HDBK-1130-2008 DOE-HDBK-1130-2007

336

Computational and experimental study of laminar flames. Progress report, September 1, 1990--October 31, 1991  

SciTech Connect

During fiscal year 1991 we have made substantial progress in both the computational and experimental portions of our research. In particular we have continued our study of non-premixed axisymmetric methane-air flames. Computer calculations of multidimensional elliptic flames with two carbon atom chemistry using a shared memory parallel computer are reported for the first time. Also laser spectroscopy of flames utilizing a neodymium laser are also reported. (GHH)

Smooke, M.; Long, M.

1991-12-31T23:59:59.000Z

337

Fast Detector Simulation Using Lelaps, Detector Descriptions in GODL  

SciTech Connect

Lelaps is a fast detector simulation program which reads StdHep generator files and produces SIO or LCIO output files. It swims particles through detectors taking into account magnetic fields, multiple scattering and dE/dx energy loss. It simulates parameterized showers in EM and hadronic calorimeters and supports gamma conversions and decays. In addition to three built-in detector configurations, detector descriptions can also be read from files in the new GODL file format.

Langeveld, Willy; /SLAC

2005-07-06T23:59:59.000Z

338

Comparison of CDMS [100] and [111] Oriented Germanium Detectors  

Science Conference Proceedings (OSTI)

The Cryogenic Dark Matter Search (CDMS) utilizes large mass, 3-inch diameter x 1-inch thick target masses as particle detectors. The target is instrumented with both phonon and ionization sensors and comparison of energy in each channel provides event-by-event classification of electron and nuclear recoils. Fiducial volume is determined by the ability to obtain good phonon and ionization signal at a particular location. Due to electronic band structure in germanium, electron mass is described by an anisotropic tensor with heavy mass aligned along the symmetry axis defined by the [111] Miller index (L valley), resulting in large lateral component to the transport. The spatial distribution of electrons varies significantly for detectors which have their longitudinal axis orientations described by either the [100] or [111] Miller indices. Electric fields with large fringing component at high detector radius also affect the spatial distribution of electrons and holes. Both effects are studied in a 3 dimensional Monte Carlo and the impact on fiducial volume is discussed.

Leman, S.W.; Hertel, S.A.; /MIT, MKI; Kim, P.; /SLAC; Cabrera, B.; /Stanford U., Phys. Dept.; Do Couto E.Silva, E.; /SLAC; Figueroa-Feliciano, E.; McCarthy, K.A.; /MIT, MKI; Resch, R.; /SLAC; Sadoulet, B.; Sundqvist, K.M.; /UC, Berkeley

2012-09-14T23:59:59.000Z

339

Photovoltaic radiation detector element  

DOE Patents (OSTI)

A radiation detector element is formed of a body of semiconductor material, a coating on the body which forms a photovoltaic junction therewith, and a current collector consisting of narrow metallic strips, the aforesaid coating having an opening therein the edge of which closely approaches but is spaced from the current collector strips.

Agouridis, Dimitrios C. (Oak Ridge, TN)

1983-01-01T23:59:59.000Z

340

Photovoltaic radiation detector element  

DOE Patents (OSTI)

A radiation detector element is formed of a body of semiconductor material, a coating on the body which forms a photovoltaic junction therewith, and a current collector consisting of narrow metallic strips, the aforesaid coating having an opening therein in the edge of which closely approaches but is spaced from the current collector strips.

Agouridis, D.C.

1980-12-17T23:59:59.000Z

Note: This page contains sample records for the topic "flame ionization detector" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


341

Sensitive hydrogen leak detector  

DOE Patents (OSTI)

A sensitive hydrogen leak detector system using passivation of a stainless steel vacuum chamber for low hydrogen outgassing, a high compression ratio vacuum system, a getter operating at 77.5 K and a residual gas analyzer as a quantitative hydrogen sensor.

Myneni, Ganapati Rao (Yorktown, VA)

1999-01-01T23:59:59.000Z

342

Electromagnetic radiation detector  

DOE Patents (OSTI)

An electromagnetic radiation detector including a collimating window, a cathode member having a photoelectric emissive material surface angularly disposed to said window whereby radiation is impinged thereon at acute angles, an anode, separated from the cathode member by an evacuated space, for collecting photoelectrons emitted from the emissive cathode surface, and a negatively biased, high transmissive grid disposed between the cathode member and anode.

Benson, Jay L. (Albuquerque, NM); Hansen, Gordon J. (Albuquerque, NM)

1976-01-01T23:59:59.000Z

343

Directional gamma detector  

DOE Patents (OSTI)

An improved directional gamma radiation detector has a collector sandwiched etween two layers of insulation of varying thicknesses. The collector and insulation layers are contained within an evacuated casing, or emitter, which releases electrons upon exposure to gamma radiation. Delayed electrons and electrons entering the collector at oblique angles are attenuated as they pass through the insulation layers on route to the collector.

LeVert, Francis E. (Downers Grove, Knoxville, TN); Cox, Samson A. (Downers Grove, IL)

1981-01-01T23:59:59.000Z

344

Inhibition ofPremixed Methane-Air Flames by Water Mist  

Science Conference Proceedings (OSTI)

Fuss, SP, Dye, DJ, Williams, BA, and Fleming, JW, "Inhibition of Premixed Methane-Air Flames by Water Mist," Proceedings of the Fall Technical ...

2013-10-29T23:59:59.000Z

345

The Soret Effect in Naturally Propagating, Premixed, Lean, Hydrogen-Air Flames  

SciTech Connect

Comparatively little attention has been given to multicomponent diffusion effects in lean hydrogen-air flames, in spite of the importance of these flames in safety and their potential importance to future energy technologies. Prior direct numerical simulations either have considered only the mixture-averaged transport model, or have been limited to stabilized flames that do not exhibit the thermo-diffusive instability. The so-called full, multicomponent transport model with cross-diffusion is found to predict hotter, significantly faster flames with much faster extinction and division of cellular structures.

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

2008-06-30T23:59:59.000Z

346

Self-induced unstable behaviors of CH4 and H2/CH4 flames in a...  

NLE Websites -- All DOE Office Websites (Extended Search)

Portillo, David Littlejohn, Scott M. Martin, and Robert K. Cheng Journal Combustion and Flame Volume 160 Issue 2 Pagination 307 - 321 Date Published 022013 ISSN 00102180 DOI...

347

A model for the (QUASI) steady flame spread on vertical and horizontal surface.  

E-Print Network (OSTI)

??Initial fire spread is composed of the processes of ignition, flame spread, and burning rate. The effects of a material's thermal characteristics and burning behaviors… (more)

Shi, Yan

2008-01-01T23:59:59.000Z

348

Numerical Simulation of Flame-Vortex Interactions in Natural and Synthetic Gas Mixtures .  

E-Print Network (OSTI)

??The interactions between laminar premixed flames and counter-rotating vortex pairs in natural and synthetic gas mixtures have been computationally investigated through the use of Direct… (more)

Weiler, Justin D.

2004-01-01T23:59:59.000Z

349

Flame stabilization by a plasma driven radical jet in a high speed flow .  

E-Print Network (OSTI)

??In current afterburners combustion is stabilized by the high temperature, recirculating region behind bluff body flame holders, such as V-gutters. Blocking the high speed flow… (more)

Choi, Woong-Sik

2009-01-01T23:59:59.000Z

350

Flame retardant finishing for cotton using a hydroxy-functional organophosphorus oligomer.  

E-Print Network (OSTI)

??New durable flame retardant finishing systems based on a hydroxy-functional organophosphorus oligomer (HFPO) and a bonding agent have been developed for cotton. In this research,… (more)

Wu, Weidong

2004-01-01T23:59:59.000Z

351

An integral model for turbulent flame radial lengths under a ceiling.  

E-Print Network (OSTI)

?? An analytical study using an integral model for turbulent flame radial lengths under a ceiling is presented. Dimensionless equations give results in terms of… (more)

Ding, Haiwen

2010-01-01T23:59:59.000Z

352

Optimization of Global Reaction Mechanisms Evaluated on The Sandia Flame D.  

E-Print Network (OSTI)

??The main goal is to develop and evaluate global reaction mechanisms. The optimization is done using two methods; Laminar Flame Speed and Perfectly Stirred Reactor.… (more)

Mohseni, Seyedmohammad

2012-01-01T23:59:59.000Z

353

Detectors (XSD) | Advanced Photon Source  

NLE Websites -- All DOE Office Websites (Extended Search)

APS Detector Pool (X-ray Science Division) The Detector Pool provides many different types of x-ray detectors to beamline scientists at the Advanced Photon Source. These detectors are made available for short term loans (typically several days to a week or two, but this is flexible). The detector pool also coordinates loans between sectors, helps sectors repair equipment, and coordinates group purchases. Depending on budgets, we purchase new equipment, based largely on suggestions from the beamline scientists. Requests for detectors are submitted by beamline scientists at the sectors on behalf of general users. General Users are free to contact us regarding detector capabilities and other questions. The Detector Pool is staffed during normal working hours,

354

Detectors (XSD) | Advanced Photon Source  

NLE Websites -- All DOE Office Websites (Extended Search)

The Detectors Group is engaged in multiple activities in support of user science at the APS. The group manages the operation of the APS Detector Pool; conducts R&D in x-ray...

355

Experimental investigation into the effect of reformer gas addition on flame speed and flame front propagation in premixed, homogeneous charge gasoline engines  

SciTech Connect

The effect of reformer gas addition to gasoline in internal combustion engines is assessed based on in-cylinder measurement techniques. These include ion sensors, an optical spark plug and heat release analysis from the cylinder pressure. A detailed analysis of these measurements is presented, giving insight into the combustion process and into the energy release. The flame front shape and propagation in the combustion chamber are reconstructed and the flame speed is estimated. The laminar flame speed has been observed to increase linearly with the energy fraction of reformer gas in the fuel blend. From pure gasoline to pure reformer gas the laminar flame speed increases by a factor of 4.4. The relative increase in the turbulent flame speed is lower. These results confirm what can be observed from the heat release analysis, that reformer gas addition mainly shortens the first phase of the combustion process. Different reformer gas compositions were tested, varying the ratio of hydrogen to inert species. Finally, flame propagation and flame speed at EGR-burn limit and at lean-burn limit are investigated. (author)

Conte, Enrico; Boulouchos, Konstantinos [Aerothermochemistry and Combustion Systems Laboratory (LAV), ETH Zurich, CH-8092 (Switzerland)

2006-07-15T23:59:59.000Z

356

Autoignited laminar lifted flames of methane, ethylene, ethane, and n-butane jets in coflow air with elevated temperature  

Science Conference Proceedings (OSTI)

The autoignition characteristics of laminar lifted flames of methane, ethylene, ethane, and n-butane fuels have been investigated experimentally in coflow air with elevated temperature over 800 K. The lifted flames were categorized into three regimes depending on the initial temperature and fuel mole fraction: (1) non-autoignited lifted flame, (2) autoignited lifted flame with tribrachial (or triple) edge, and (3) autoignited lifted flame with mild combustion. For the non-autoignited lifted flames at relatively low temperature, the existence of lifted flame depended on the Schmidt number of fuel, such that only the fuels with Sc > 1 exhibited stationary lifted flames. The balance mechanism between the propagation speed of tribrachial flame and local flow velocity stabilized the lifted flames. At relatively high initial temperatures, either autoignited lifted flames having tribrachial edge or autoignited lifted flames with mild combustion existed regardless of the Schmidt number of fuel. The adiabatic ignition delay time played a crucial role for the stabilization of autoignited flames. Especially, heat loss during the ignition process should be accounted for, such that the characteristic convection time, defined by the autoignition height divided by jet velocity was correlated well with the square of the adiabatic ignition delay time for the critical autoignition conditions. The liftoff height was also correlated well with the square of the adiabatic ignition delay time. (author)

Choi, B.C.; Chung, S.H. [Clean Combustion Research Center, King Abdullah University of Science and Technology, Thuwal (Saudi Arabia)

2010-12-15T23:59:59.000Z

357

Effects of Combustor Geometry on the Flowfields and Flame Properties of A  

NLE Websites -- All DOE Office Websites (Extended Search)

Effects of Combustor Geometry on the Flowfields and Flame Properties of A Effects of Combustor Geometry on the Flowfields and Flame Properties of A Low-Swirl Injector Title Effects of Combustor Geometry on the Flowfields and Flame Properties of A Low-Swirl Injector Publication Type Journal Article Year of Publication 2008 Authors Cheng, Robert K., and David Littlejohn Journal Proceedings of the Combustion Institute Type of Article Conference Paper Abstract The Low-swirl injector (LSI) is a novel dry-low NOx combustion method that is being developed for gas turbines to burn a variety of gaseous fuels including natural gas, low-Btu fuels, syngases and hydrogen. Its basic principle is described by a top level analytical model that relates the flame position to the flowfield similarity parameters and the turbulent flame speed correlation. The model was based on experimental measurements in open laboratory flames. It has been useful for guiding hardware development. As the LSI is being adapted to different engine configurations, one open question is how the combustor geometry and size affect its basic operating principle. The objective of this paper is to investigate these effects by conducting Particle Image Velocimetry (PIV) measurements in open and enclosed flames produced by a 6.35 cm diameter LSI using two quartz cylinders of 15.5 and 20 cm diameter to simulate the combustor casing. Results from 18 methane-air flames show that the enclosures do not alter the flame properties or the nearfield flow structures. The differences occur mostly in the farfield where the tighter enclosure deters the formation of a weak recirculation zone. The enclosure effects on hydrogen and hydrogen-methane flames were studies using the 20 cm cylinder. The results show that the outer recirculation zone generated at the corner of the dump plane promotes the formation of attached flames. However, the properties and nearfield flow features of the attached flames are similar to those of the lifted flames. At higher stoichiometries, the attached flame collapses to form a compact disc shaped flame that has very different flowfield structures. These results show that the enclosure effects on the LSI are strongly coupled to the fuel type and dump plane geometry but are less dependent on the enclosure size. These observations will provide the basis for developing computational methods that can be used as design tools for LSI adaptation

358

Mechanisms of Flame Stabilization and Blowout in a Reacting Turbulent Hydrogen Jet in Cross-Flow  

SciTech Connect

The mechanisms contributing to flame stabilization and blowout in a nitrogen-diluted hydrogen transverse jet in a turbulent boundary layer cross-flow (JICF) are investigated using three-dimensional direct numerical simulation (DNS) with detailed chemistry. Non-reacting JICF DNS were performed to understand the relative magnitude and physical location of low velocity regions on the leeward side of the fuel jet where a flame can potentially anchor. As the injection angle is reduced from 90{sup o} to 70{sup o}, the low velocity region was found to diminish significantly, both in terms of physical extent and magnitude, and hence, its ability to provide favorable conditions for flame anchoring and stabilization are greatly reduced. In the reacting JICF DNS a stable flame is observed for 90{sup o} injection angle and, on average, the flame root is in the vicinity of low velocity magnitude and stoichiometric mixture. When the injection angle is smoothly transitioned to 75{sup o} a transient flame blowout is observed. Ensemble averaged quantities on the flame base reveal two phases of the blowout characterized by a kinematic imbalance between flame propagation speed and flow normal velocity. In the first phase dominant flow structures repeatedly draw the flame base closer to the jet centerline resulting in richer-than-stoichiometric mixtures and high velocity magnitudes. In the second phase, in spite of low velocity magnitudes and a return to stoichiometry, due to jet bending and flame alignment normal to the cross-flow, the flow velocity normal to the flame base increases dramatically perpetuating the blowout.

Kolla, H.; Grout, R. W.; Gruber, A.; Chen, J. H.

2012-08-01T23:59:59.000Z

359

Pulse mode readout techniques for use with non-gridded industrial ionization chambers  

SciTech Connect

Highly sensitive readout technique for precision long-term radiation measurements has been developed and tested in the Radiation Control Department at Jefferson Lab. The new electronics design is used to retrieve ionization data in a pulse mode. The dedicated data acquisition system works with M=Audio Audiophile 192 High-Definition 24-bit/192 kHz audio cards, taking data in continuous waveform recording mode. The on-line data processing algorithms extract signals of the ionization events from the data flow and measure the ionization value for each event. Two different ion chambers are evaluated. The first is a Reuter-Stokes Argon-filled (at 25 atm) High Pressure Ionization Chamber (HPIC), commonly used as a detector part in many GE Reuter-Stokes instruments of the RSS series. The second is a VacuTec Model 70181, 5 atm Xenon-filled ionization chamber. Results for both chambers indicate that the techniques allow using industrial ICs for high sensitivity and precision long-term radiation measurements, while at the same time providing information about spectral characteristics of the radiation fields.

Popov, Vladimir E. [JLAB; Degtiarenko, Pavel V. [JLAB

2011-10-01T23:59:59.000Z

360

Sample Desorption/Ionization From Mesoporous Silica  

NLE Websites -- All DOE Office Websites (Extended Search)

Sample Desorption/Ionization From Mesoporous Silica Sample Desorption/Ionization From Mesoporous Silica Sample Desorption/Ionization From Mesoporous Silica Mesoporous silica is shown to be a sample holder for laser desorption/ionization of mass spectrometry. Available for thumbnail of Feynman Center (505) 665-9090 Email Sample Desorption/Ionization From Mesoporous Silica Mesoporous silica is shown to be a sample holder for laser desorption/ionization of mass spectrometry. Supported mesoporous silica was prepared by coating an ethanolic silicate solution having a removable surfactant onto a substrate to produce a self-assembled, ordered, nanocomposite silica thin film. The surfactant was chosen to provide a desired pore size between about 1 nanometer diameter and 50 nanometers diameter. Removal of the surfactant resulted in a mesoporous silica thin

Note: This page contains sample records for the topic "flame ionization detector" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


361

Ultrafast neutron detector  

DOE Patents (OSTI)

The invention comprises a neutron detector (50) of very high temporal resolution that is particularly well suited for measuring the fusion reaction neutrons produced by laser-driven inertial confinement fusion targets. The detector comprises a biased two-conductor traveling-wave transmission line (54, 56, 58, 68) having a uranium cathode (60) and a phosphor anode (62) as respective parts of the two conductors. A charge line and Auston switch assembly (70, 72, 74) launch an electric field pulse along the transmission line. Neutrons striking the uranium cathode at a location where the field pulse is passing, are enabled to strike the phosphor anode and produce light that is recorded on photographic film (64). The transmission line may be variously configured to achieve specific experimental goals.

Wang, Ching L. (Livermore, CA)

1987-01-01T23:59:59.000Z

362

Underwater radiation detector  

DOE Patents (OSTI)

A detector apparatus for differentiating between gamma and neutron radiation is provided. The detector includes a pair of differentially shielded Geiger-Mueller tubes. The first tube is wrapped in silver foil and the second tube is wrapped in lead foil. Both the silver and lead foils allow the passage of gamma rays at a constant rate in a gamma ray only field. When neutrons are present, however, the silver activates and emits beta radiation that is also detected by the silver wrapped Geiger-Mueller tube while the radiation detected by the lead wrapped Geiger-Mueller tube remains constant. The amount of radiation impinging on the separate Geiger-Mueller tubes is then correlated in order to distinguish between the neutron and gamma radiations.

Kruse, Lyle W. (Albuquerque, NM); McKnight, Richard P. (Albuquerque, NM)

1986-01-01T23:59:59.000Z

363

Liquid level detector  

DOE Patents (OSTI)

A liquid level detector for conductive liquids for vertical installation in a tank, the detector having a probe positioned within a sheath and insulated therefrom by a seal so that the tip of the probe extends proximate to but not below the lower end of the sheath, the lower end terminating in a rim that is provided with notches, said lower end being tapered, the taper and notches preventing debris collection and bubble formation, said lower end when contacting liquid as it rises will form an airtight cavity defined by the liquid, the interior sheath wall, and the seal, the compression of air in the cavity preventing liquid from further entry into the sheath and contact with the seal. As a result, the liquid cannot deposit a film to form an electrical bridge across the seal.

Tshishiku, Eugene M. (Augusta, GA)

2011-08-09T23:59:59.000Z

364

Microwave hemorrhagic stroke detector  

DOE Patents (OSTI)

The microwave hemorrhagic stroke detector includes a low power pulsed microwave transmitter with a broad-band antenna for producing a directional beam of microwaves, an index of refraction matching cap placed over the patients head, and an array of broad-band microwave receivers with collection antennae. The system of microwave transmitter and receivers are scanned around, and can also be positioned up and down the axis of the patients head. The microwave hemorrhagic stroke detector is a completely non-invasive device designed to detect and localize blood pooling and clots or to measure blood flow within the head or body. The device is based on low power pulsed microwave technology combined with specialized antennas and tomographic methods. The system can be used for rapid, non-invasive detection of blood pooling such as occurs with hemorrhagic stoke in human or animal patients as well as for the detection of hemorrhage within a patient's body.

Haddad, Waleed S. (Dublin, CA); Trebes, James E. (Livermore, CA)

2007-06-05T23:59:59.000Z

365

Pulsed neutron detector  

DOE Patents (OSTI)

A pulsed neutron detector and system for detecting low intensity fast neutron pulses has a body of beryllium adjacent a body of hydrogenous material the latter of which acts as a beta particle detector, scintillator, and moderator. The fast neutrons (defined as having En>1.5 MeV) react in the beryllium and the hydrogenous material to produce larger numbers of slow neutrons than would be generated in the beryllium itself and which in the beryllium generate hellium-6 which decays and yields beta particles. The beta particles reach the hydrogenous material which scintillates to yield light of intensity related to the number of fast neutrons. A photomultiplier adjacent the hydrogenous material (scintillator) senses the light emission from the scintillator. Utilization means, such as a summing device, sums the pulses from the photo-multiplier for monitoring or other purposes.

Robertson, deceased, J. Craig (late of Albuquerque, NM); Rowland, Mark S. (Livermore, CA)

1989-03-21T23:59:59.000Z

366

Detector limitations, STAR  

Science Conference Proceedings (OSTI)

Every detector has limitations in terms of solid angle, particular technologies chosen, cracks due to mechanical structure, etc. If all of the presently planned parts of STAR [Solenoidal Tracker At RHIC] were in place, these factors would not seriously limit our ability to exploit the spin physics possible in RHIC. What is of greater concern at the moment is the construction schedule for components such as the Electromagnetic Calorimeters, and the limited funding for various levels of triggers.

Underwood, D. G.

1998-07-13T23:59:59.000Z

367

Biological detector and method  

DOE Patents (OSTI)

A biological detector includes a conduit for receiving a fluid containing one or more magnetic nanoparticle-labeled, biological objects to be detected and one or more permanent magnets or electromagnet for establishing a low magnetic field in which the conduit is disposed. A microcoil is disposed proximate the conduit for energization at a frequency that permits detection by NMR spectroscopy of whether the one or more magnetically-labeled biological objects is/are present in the fluid.

Sillerud, Laurel; Alam, Todd M; McDowell, Andrew F

2013-02-26T23:59:59.000Z

368

Sensor readout detector circuit  

DOE Patents (OSTI)

A sensor readout detector circuit is disclosed that is capable of detecting sensor signals down to a few nanoamperes or less in a high (microampere) background noise level. The circuit operates at a very low standby power level and is triggerable by a sensor event signal that is above a predetermined threshold level. A plurality of sensor readout detector circuits can be formed on a substrate as an integrated circuit (IC). These circuits can operate to process data from an array of sensors in parallel, with only data from active sensors being processed for digitization and analysis. This allows the IC to operate at a low power level with a high data throughput for the active sensors. The circuit may be used with many different types of sensors, including photodetectors, capacitance sensors, chemically-sensitive sensors or combinations thereof to provide a capability for recording transient events or for recording data for a predetermined period of time following an event trigger. The sensor readout detector circuit has applications for portable or satellite-based sensor systems. 6 figs.

Chu, D.D.; Thelen, D.C. Jr.

1998-08-11T23:59:59.000Z

369

Sensor readout detector circuit  

DOE Patents (OSTI)

A sensor readout detector circuit is disclosed that is capable of detecting sensor signals down to a few nanoamperes or less in a high (microampere) background noise level. The circuit operates at a very low standby power level and is triggerable by a sensor event signal that is above a predetermined threshold level. A plurality of sensor readout detector circuits can be formed on a substrate as an integrated circuit (IC). These circuits can operate to process data from an array of sensors in parallel, with only data from active sensors being processed for digitization and analysis. This allows the IC to operate at a low power level with a high data throughput for the active sensors. The circuit may be used with many different types of sensors, including photodetectors, capacitance sensors, chemically-sensitive sensors or combinations thereof to provide a capability for recording transient events or for recording data for a predetermined period of time following an event trigger. The sensor readout detector circuit has applications for portable or satellite-based sensor systems.

Chu, Dahlon D. (Albuquerque, NM); Thelen, Jr., Donald C. (Bozeman, MT)

1998-01-01T23:59:59.000Z

370

Ionization Energies, Electron Affinities and Electronegativies ... - TMS  

Science Conference Proceedings (OSTI)

Jun 28, 2007 ... Periodic table of the elements containing ionization energies, electron affinities, and electronegativities. CITATION: : R.E. Dickerson, H.B. Gray ...

371

Hall Magnetohydrodynamics of weakly-ionized plasma  

E-Print Network (OSTI)

We show that the Hall scale in a weakly ionized plasma depends on the fractional ionization of the medium and, Hall MHD description becomes important whenever the ion-neutral collision frequency is comparable to the ion-gyration frequency, or, the ion-neutral collisional mean free path is smaller than the ion gyro-radius. Wave properties of a weakly-ionized plasma also depends on the fractional ionization and plasma Hall parameters, and whistler mode is the most dominant mode in such a medium. Thus Hall MHD description will be important in astrophysical disks, dark molecular clouds, neutron star crusts, and, solar and planetary atmosphere.

B. P. Pandey; Mark Wardle

2006-08-01T23:59:59.000Z

372

NIST Ionizing Radiation Division 2000 - Future Directions  

Science Conference Proceedings (OSTI)

... will enable dose-reconstruction studies for populations exposed at the natural background levels of ionizing radiation. Calibrations of Low-Energy ...

373

Research on Stability Criterion of Furnace Flame Combustion Based on Image Processing  

Science Conference Proceedings (OSTI)

This paper proposes and analyzes the stability criterion of furnace flame combustion based on image processing, which uses the maximum criterion of gray scale difference, the distance criterion of gravity center and mass center in the high temperature ... Keywords: image processing, stability, flame detection, boiler safety

Rongbao Chen, Wuting Fan, Jingci Bian, Fanhui Meng

2012-12-01T23:59:59.000Z

374

Effects of Coaxial Air on Nitrogen-Diluted Hydrogen Jet Diffusion Flame Length and NOx Emission  

DOE Green Energy (OSTI)

Turbulent nitrogen-diluted hydrogen jet diffusion flames with high velocity coaxial air flows are investigated for their NOx emission levels. This study is motivated by the DOE turbine program’s goal of achieving 2 ppm dry low NOx from turbine combustors running on nitrogen-diluted high-hydrogen fuels. In this study, effects of coaxial air velocity and momentum are varied while maintaining low overall equivalence ratios to eliminate the effects of recirculation of combustion products on flame lengths, flame temperatures, and resulting NOx emission levels. The nature of flame length and NOx emission scaling relationships are found to vary, depending on whether the combined fuel and coaxial air jet is fuel-rich or fuel-lean. In the absence of differential diffusion effects, flame lengths agree well with predicted trends, and NOx emissions levels are shown to decrease with increasing coaxial air velocity, as expected. Normalizing the NOx emission index with a flame residence time reveals some interesting trends, and indicates that a global flame strain based on the difference between the fuel and coaxial air velocities, as is traditionally used, is not a viable parameter for scaling the normalized NOx emissions of coaxial air jet diffusion flames.

Weiland, N.T.; Chen, R.-H.; Strakey, P.A.

2007-10-01T23:59:59.000Z

375

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

E-Print Network (OSTI)

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

Dandy, David

376

Laboratory Study of Premixed H2-Air and H2-N2-Air Flames in a...  

NLE Websites -- All DOE Office Websites (Extended Search)

of Premixed H2-Air and H2-N2-Air Flames in a Low-Swirl Injector for Ultra-Low Emissions Gas Turbines Title Laboratory Study of Premixed H2-Air and H2-N2-Air Flames in a Low-Swirl...

377

Molecular diffusion effects in LES of a piloted methaneair flame Konstantin A. Kemenov  

E-Print Network (OSTI)

Molecular diffusion effects in LES of a piloted methane­air flame Konstantin A. Kemenov , Stephen-premixed turbulent combustion Large-eddy simulation Molecular diffusion Sandia flame D a b s t r a c t Molecular splines relationships are employed to represent thermochemical variables. The role of molecular

Pope, Stephen B.

378

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

E-Print Network (OSTI)

in a laminar premixed n-butane flame", Combustion and Flame,1.5 atm; T=1431-1680 K; (b) n-butane [22], ?=1.0; 2.5% C 4 Hof the parameters for n- butane were obtained from Marinov

Saxena, Priyank

2007-01-01T23:59:59.000Z

379

2008 Special Issue: An adaptive method for industrial hydrocarbon flame detection  

Science Conference Proceedings (OSTI)

An adaptive method for an infrared (IR) hydrocarbon flame detection system is presented. The model makes use of joint time-frequency analysis (JTFA) for feature extraction and the artificial neural networks (ANN) for training and classification. Multiple ... Keywords: Artificial neural networks, Flame detection, Signal processing

Javid J. Huseynov; Shankar B. Baliga; Alan Widmer; Zvi Boger

2008-03-01T23:59:59.000Z

380

Global NOx Measurements in Turbulent Nitrogen-Diluted Hydrogen Jet Flames  

DOE Green Energy (OSTI)

Turbulent hydrogen diffusion flames diluted with nitrogen are currently being studied to assess their ability to achieve the DOE Turbine Program’s aggressive emissions goal of 2 ppm NOx in a hydrogen-fueled IGCC gas turbine combustor. Since the unstrained adiabatic flame temperatures of these diluted flames are not low enough to eliminate thermal NOx formation the focus of the current work is to study how the effects of flame residence time and global flame strain can be used to help achieve the stated NOx emissions goal. Dry NOx measurements are presented as a function of jet diameter nitrogen dilution and jet velocity for a turbulent hydrogen/nitrogen jet issuing from a thin-lipped tube in an atmospheric pressure combustor. The NOx emission indices from these experiments are normalized by the flame residence time to ascertain the effects of global flame strain and fuel Lewis Number on the NOx emissions. In addition dilute hydrogen diffusion flame experiments were performed in a high-pressure combustor at 2 4 and 8 atm. The NOx emission data from these experiments are discussed as well as the results from a Computational Fluid Dynamics modeling effort currently underway to help explain the experimental data.

Weiland, N.T.; Strakey, P.A.

2007-03-01T23:59:59.000Z

Note: This page contains sample records for the topic "flame ionization detector" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


381

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

E-Print Network (OSTI)

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.

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

2003-12-03T23:59:59.000Z

382

Imaging and Diagnostics of Turbulent Methane-Air Premixed Flames by Acetone-OH Simultaneous PLIF  

Science Conference Proceedings (OSTI)

A strategy of diagnostics of ultra-lean combustion based on acetone-OH simultaneous PLIF is presented. Acetone seeded in the fuel flow and combustion-generated OH work for a marker of "unburned" and "burnt" zones, respectively. Since acetone and OH does ... Keywords: Acetone, Flame imaging, OH, PLIF, Turbulent flame

Y. Nakamura; S. Manome; H. Yamashita

2008-01-01T23:59:59.000Z

383

Analyzing and Tracking Burning Structures in Lean Premixed Hydrogen Flames  

DOE Green Energy (OSTI)

This paper presents topology-based methods to robustly extract, analyze, and track features defined as subsets of isosurfaces. First, we demonstrate how features identified by thresholding isosurfaces can be defined in terms of the Morse complex. Second, we present a specialized hierarchy that encodes the feature segmentation independent of the threshold while still providing a flexible multi-resolution representation. Third, for a given parameter selection we create detailed tracking graphs representing the complete evolution of all features in a combustion simulation over several hundred time steps. Finally, we discuss a user interface that correlates the tracking information with interactive rendering of the segmented isosurfaces enabling an in-depth analysis of the temporal behavior. We demonstrate our approach by analyzing three numerical simulations of lean hydrogen flames subject to different levels of turbulence. Due to their unstable nature, lean flames burn in cells separated by locally extinguished regions. The number, area, and evolution over time of these cells provide important insights into the impact of turbulence on the combustion process. Utilizing the hierarchy we can perform an extensive parameter study without re-processing the data for each set of parameters. The resulting statistics enable scientist to select appropriate parameters and provide insight into the sensitivity of the results wrt. to the choice of parameters. Our method allows for the first time to quantitatively correlate the turbulence of the burning process with the distribution of burning regions, properly segmented and selected. In particular, our analysis shows that counter-intuitively stronger turbulence leads to larger cell structures, which burn more intensely than expected. This behavior suggests that flames could be stabilized under much leaner conditions than previously anticipated.

Bremer, Peer-Timo; Weber, Gunther; Pascucci, Valerio; Day, Marc; Bell, John

2009-06-01T23:59:59.000Z

384

The dependence of chemistry on the inlet equivalence ratio in vortex-flame interactions [Printed LBNL report with title: The effect of stoichiometry on vortex flame interactions  

E-Print Network (OSTI)

premixed flames," Sandia N a t i o n a l Laboratories Reporttransport properties," Sandia N a t i o n a l LaboratoriesU C Berkeley, Berkeley, C A Sandia National Laboratories,

Tonse, Shaheen R.

2011-01-01T23:59:59.000Z

385

The dependence of chemistry on the inlet equivalence ratio in vortex-flame interactions [Printed LBNL report with title: The effect of stoichiometry on vortex flame interactions  

E-Print Network (OSTI)

premixed flames," Sandia N a t i o n a l Laboratories Reporttransport properties," Sandia N a t i o n a l LaboratoriesU C Berkeley, Berkeley, C A Sandia National Laboratories,

Bell, John B.; Brown, Nancy J.; Day, Marcus S.; Frenklach, Michael; Grcar, Joseph F.; Tonse, Shaheen R.

1999-01-01T23:59:59.000Z

386

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

E-Print Network (OSTI)

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

Geddes, Cameron Guy Robinson

387

Effects of Soret diffusion on the laminar flame speed and Markstein length of syngas/air mixtures  

E-Print Network (OSTI)

Effects of Soret diffusion on the laminar flame speed and Markstein length of syngas/air mixtures syngas/air flames at normal and elevated temperatures and pressures are investigated numerically of syngas/air mixtures. The laminar flame speed and Markstein length are obtained by simulating

Chen, Zheng

388

Development of a New Flame Speed Vessel to Measure the Effect of Steam Dilution on Laminar Flame Speeds of Syngas Fuel Blends at Elevated Pressures and Temperatures  

E-Print Network (OSTI)

Synthetic gas, syngas, is a popular alternative fuel for the gas turbine industry, but the composition of syngas can contain different types and amounts of contaminants, such as carbon dioxide, methane, moisture, and nitrogen, depending on the industrial process involved in its manufacturing. The presence of steam in syngas blends is of particular interest from a thermo-chemical perspective as there is limited information available in the literature. This study investigates the effect of moisture content (0 ? 15% by volume), temperature (323 ? 423 K), and pressure (1 ? 10 atm) on syngas mixtures by measuring the laminar flame speed in a newly developed constant-volume, heated experimental facility. This heated vessel also broadens the experimental field of study in the authors? laboratory to low vapor pressure fuels and other vaporized liquids. The new facility is capable of performing flame speed experiments at an initial pressure as high as 30 atm and an initial temperature up to 600 K. Several validation experiments were performed to demonstrate the complete functionality of the flame speed facility. Additionally, a design-of-experiments methodology was used to study the mentioned syngas conditions that are relevant to the gas turbine industry. The design-of-experiments methodology provided the capability to identify the most influential factor on the laminar flame speed of the conditions studied. The experimental flame speed data are compared to the most up-to-date C4 mechanism developed through collaboration between Texas A&M and the National University of Ireland Galway. Along with good model agreement shown with all presented data, a rigorous uncertainty analysis of the flame speed has been performed showing an extensive range of values from 4.0 cm/s to 16.7 cm/s. The amount of carbon monoxide dilution in the fuel was shown to be the most influential factor on the laminar flame speed from fuel lean to fuel rich. This is verified by comparing the laminar flame speed of the atmospheric mixtures. Also, the measured Markstein lengths of the atmospheric mixtures are compared and do not demonstrate a strong impact from any one factor but the ratio of hydrogen and carbon monoxide plays a key role. Mixtures with high levels of CO appear to stabilize the flame structure of thermal-diffusive instability. The increase of steam dilution has only a small effect on the laminar flame speed of high-CO mixtures, while more hydrogen-dominated mixtures demonstrate a much larger and negative effect of increasing water content on the laminar flame speed.

Krejci, Michael

2012-05-01T23:59:59.000Z

389

Critical radius for sustained propagation of spark-ignited spherical flames  

Science Conference Proceedings (OSTI)

An experimental study was performed to determine the requirements for sustained propagation of spark-ignited hydrogen-air and butane-air flames at atmospheric and elevated pressures. Results show that sustained propagation is always possible for mixtures whose Lewis number is less than unity, as long as a flame can be initially established. However, for mixtures whose Lewis number is greater than unity, sustained propagation depends on whether the initially ignited flame can attain a minimum radius. This minimum radius was determined for mixtures of different equivalence ratios and pressures, and was found to agree moderately well with the theoretically predicted critical radius beyond which there is no solution for the adiabatic, quasi-steady propagation of the spherical flame. The essential roles of pressure, detailed chemistry, and the need to use local values in the quantitative evaluation of the flame response parameters are emphasized. (author)

Kelley, Andrew P.; Jomaas, Grunde; Law, Chung K. [Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, NJ 08544 (United States)

2009-05-15T23:59:59.000Z

390

Analysis of the flamelet concept in the numerical simulation of laminar partially premixed flames  

Science Conference Proceedings (OSTI)

The aim of this work is to analyze the application of flamelet models based on the mixture fraction variable and its dissipation rate to the numerical simulation of partially premixed flames. Although the main application of these models is the computation of turbulent flames, this work focuses on the performance of flamelet concept in laminar flame simulations removing, in this way, turbulence closure interactions. A well-known coflow methane/air laminar flame is selected. Five levels of premixing are taken into account from an equivalence ratio {phi}={infinity} (nonpremixed) to {phi}=2.464. Results obtained using the flamelet approaches are compared to data obtained from the detailed solution of the complete transport equations using primitive variables. Numerical simulations of a counterflow flame are also presented to support the discussion of the results. Special emphasis is given to the analysis of the scalar dissipation rate modeling. (author)

Consul, R.; Oliva, A.; Perez-Segarra, C.D.; Carbonell, D. [Centre Tecnologic de Transferencia de Calor (CTTC), Universitat Politecnica de Catalunya (UPC), Colom 11, E-08222, Terrassa, Barcelona (Spain); de Goey, L.P.H. [Eindhoven University of Technology, Department of Mechanical Engineering, P.O. Box 513, 5600 MB Eindhoven (Netherlands)

2008-04-15T23:59:59.000Z

391

New flamelet combustion model combining premixed and non-premixed turbulent flames  

SciTech Connect

Flamelet models are now used in many turbulent combustion studies. The reaction zone is described as a collection of laminar flame elements imbedded in the turbulent flow. This approach decouples the detailed modeling of chemistry features of flamelets from the computation of the entire flow field. Most flamelet models consider only premixed or nonpremixed flame elements. But, in some situations, such as ignition of a diffusion flame or combustion in a Diesel engine, premixed and nonpremixed flames may be present in the same flow. The aim of the study is to propose a description, extending the basic ideas of the coherent flame model of Marble and Broadwell (1977) including premixed and nonpremixed flamelets. 19 references.

Veynante, D.; Lacas, F.; Candel, S.M.

1989-01-01T23:59:59.000Z

392

The role of in situ reforming in plasma enhanced ultra lean premixed methane/air flames  

Science Conference Proceedings (OSTI)

This paper describes a mechanism for the stabilization of ultra lean premixed methane/air flames by pulsed nonequilibrium plasma enhancement. It is shown that the pulsed discharge plasma produces a cool ({proportional_to}500-600 K) stream of relatively stable intermediate species including hydrogen (H{sub 2}) and carbon monoxide (CO), which play a central role in enhancing flame stability. This stream is readily visualized by ultraviolet emission from electronically excited hydroxyl (OH) radicals. The rotational and vibrational temperature of this ''preflame'' are determined from its emission spectrum. Qualitative imaging of the overall flame structure is obtained by planar laser-induced fluorescence measurements of OH. Preflame nitric oxide (NO) concentrations are determined by gas sampling chromatography. A simple numerical model of this plasma enhanced premixed flame is proposed that includes the generation of the preflame through plasma activation, and predicts the formation of a dual flame structure that arises when the preflame serves to pilot the combustion of the surrounding non-activated premixed flow. The calculation represents the plasma through its ability to produce an initial radical yield, which serves as a boundary condition for conventional flame simulations. The simulations also capture the presence of the preflame and the dual flame structure, and predict preflame levels of NO comparable to those measured. A subsequent pseudo-sensitivity analysis of the preflame shows that flame stability is most sensitive to the concentrations of H{sub 2} and CO in the preflame. As a consequence of the role of H{sub 2} and CO in enhancing the flame stability, the blowout limit extensions of methane/air and hydrogen/air mixtures in the absence/presence of a discharge are investigated experimentally. For methane/air mixtures, the blowout limit of the current burner is extended by {proportional_to}10% in the presence of a discharge while comparable studies carried out in lean hydrogen/air flames fail to extend this limit. (author)

Kim, Wookyung; Godfrey Mungal, M.; Cappelli, Mark A. [Mechanical Engineering Department, Stanford University, Bldg. 520, Stanford, CA 94305-3032 (United States)

2010-02-15T23:59:59.000Z

393

MICRO PIN ARRAY DETECTOR (MIPA): FIRST TEST RESULTS.  

DOE Green Energy (OSTI)

A novel gas proportional detector, consisting of an array of pins immersed into a cathode made out of closely packed hexagonals has been developed. The resulting geometry of the detector is 3 dimensional. Electron multiplication is limited to a region in close proximity to the tip of each pin, where the electric field decreases with distance from the pin at a rate faster than l/r, the rate that exists in a traditional wire chamber. The multiplication region is limited to a small part of the detector volume leading to stability of operation up to high charge gas gains. The amplification region is located far enough from any dielectric surface that the gas gain is insensitive to the charge state of the surface, a significant benefit compared with many other micro-pattern detectors. The microscopic dimensions of the individual pins of the array result in signals whose total duration is about a microsecond. Two identical, but opposite polarity signals are detected, one on the pin and one on the cathode. Both signals can be used by two independent, charge division, read-out systems to obtain unambiguous x-y position information of the primary ionization.

REHAK,P.; SMITH,G.C.; WARREN,J.B.; YU,B.

1999-06-28T23:59:59.000Z

394

MICRO PIN ARRAY DETECTOR (MIPA): FIRST TEST RESULTS.  

DOE Green Energy (OSTI)

A novel gas proportional detector, consisting of an array of pins immersed into a cathode made out of closely packed hexagonals has been developed. The resulting geometry of the detector is 3 dimensional. Electron multiplication is limited to a region in close proximity to the tip of each pin, where the electric field decreases with distance from the pin at a rate faster than 1/r, the rate that exists in a traditional wire chamber. The multiplication region is limited to a small part of the detector volume leading to stability of operation up to high charge gas gains. The amplification region is located far enough from any dielectric surface that the gas gain is insensitive to the charge state of the surface, a significant benefit compared with many other micro-pattern detectors. The microscopic dimensions of the individual pins of the array result in signals whose total duration is about a microsecond. Two identical, but opposite polarity signals are detected, one on the pin and one on the cathode. Both signals can be used by two independent, charge division, read-out systems to obtain unambiguous x-y position information of the primary ionization.

REHAK,P.; SMITH,G.C.; WARREN,J.B.; YU,B.

1999-06-28T23:59:59.000Z

395

R&D for Future 100 kton Scale Liquid Argon Detectors  

E-Print Network (OSTI)

Large liquid argon (LAr) detectors, up to 100 kton scale, are presently being considered for proton decay searches and neutrino astrophysics as well as far detectors for the next generation of long baseline neutrino oscillation experiments, aiming at neutrino mass hierarchy determination and CP violation searches in the leptonic sector. These detectors rely on the possibility of maintaining large LAr masses stably at cryogenic conditions with low thermal losses and of achieving long drifts of the ionization charge, so to minimize the number of readout channels per unit volume. Many R&D initiatives are being undertaken throughout the world, following somewhat different concepts for the final detector design, but with many common basic R&D issues.

A. Marchionni

2009-12-22T23:59:59.000Z

396

Background studies for a ton-scale argon dark matter detector (ArDM)  

E-Print Network (OSTI)

The ArDM project aims at operating a large noble liquid detector to search for direct evidence of Weakly Interacting Massive Particles (WIMP) as Dark Matter in the universe. Background sources relevant to ton-scale liquid and gaseous argon detectors, such as neutrons from detector components, muon-induced neutrons and neutrons caused by radioactivity of rock, as well as the internal $^{39}Ar$ background, are studied with simulations. These background radiations are addressed with the design of an appropriate shielding as well as with different background rejection potentialities. Among them the project relies on event topology recognition, event localization, density ionization discrimination and pulse shape discrimination. Background rates, energy spectra, characteristics of the background-induced nuclear recoils in liquid argon, as well as the shielding performance and rejection performance of the detector are described.

L. Kaufmann; A. Rubbia

2006-12-05T23:59:59.000Z

397

Liquid level detector  

DOE Patents (OSTI)

A liquid level detector for low pressure boilers. A boiler tank, from which apor, such as steam, normally exits via a main vent, is provided with a vertical side tube connected to the tank at the desired low liquid level. When the liquid level falls to the level of the side tube vapor escapes therethrough causing heating of a temperature sensitive device located in the side tube, which, for example, may activate a liquid supply means for adding liquid to the boiler tank. High liquid level in the boiler tank blocks entry of vapor into the side tube, allowing the temperature sensitive device to cool, for example, to ambient temperature.

Grasso, Albert P. (Vernon, CT)

1986-01-01T23:59:59.000Z

398

Liquid level detector  

DOE Patents (OSTI)

A liquid level detector for low pressure boilers. A boiler tank, from which vapor, such as steam, normally exits via a main vent, is provided with a vertical side tube connected to the tank at the desired low liquid level. When the liquid level falls to the level of the side tube vapor escapes therethrough causing heating of a temperature sensitive device located in the side tube, which, for example, may activate a liquid supply means for adding liquid to the boiler tank. High liquid level in the boiler tank blocks entry of vapor into the side tube, allowing the temperature sensitive device to cool, for example, to ambient temperature.

Grasso, A.P.

1984-02-21T23:59:59.000Z

399

Wire-inhomogeneity detector  

DOE Patents (OSTI)

A device for uncovering imperfections in electrical conducting wire, particularly superconducting wire, by detecting variations in eddy currents. Eddy currents effect the magnetic field in a gap of an inductor, contained in a modified commercial ferrite core, through which the wire being tested is passed. A small increase or decrease in the amount of conductive material, such as copper, in a fixed cross section of wire will unbalance a bridge used to measure the impedance of the inductor, tripping a detector and sounding an alarm.

Gibson, G.H.; Smits, R.G.; Eberhard, P.H.

1982-08-31T23:59:59.000Z

400

Pyroelectric demodulating detector  

DOE Patents (OSTI)

A pyroelectric demodulating detector (also termed a pyroelectric demodulator) is disclosed which utilizes an electrical resistor stacked upon a pyroelectric element to demodulate an rf or microwave electrical input signal which is amplitude-modulated (AM). The pyroelectric demodulator, which can be formed as a hybrid or a monolithic device, has applications for use in AM radio receivers. Demodulation is performed by feeding the AM input signal into the resistor and converting the AM input signal into an AM heat signal which is conducted through the pyroelectric element and used to generate an electrical output signal containing AM information from the AM input signal.

Brocato, Robert W. (Sandia Park, NM)

2008-07-08T23:59:59.000Z

Note: This page contains sample records for the topic "flame ionization detector" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


401

RADIATION DETECTOR SYSTEM  

DOE Patents (OSTI)

This patent relates to radiation detection devices and presents a unique detection system especialiy desirable for portable type instruments using a Geiger-Mueller for a high voltage battery, thereby reducing the size and weight of the instrument, by arranging a one-shot multivibrator to recharge a capacitance applying operating potential to tho Geiger-Mueller tube each time a nuclear particle is detected. When detection occurs, the multivibrator further delivers a pulse to an appropriate indicator doing away with the necessity for the pulse amplifier conventionally intermediate between the detector and indicator in pulse detection systems.

Gundlach, J.C.; Kelley, G.G.

1958-02-25T23:59:59.000Z

402

A model of particle nucleation in premixed ethylene flames  

SciTech Connect

A detailed model of particle inception is proposed to delve into the physical structure and chemistry of combustion-formed particles. A sectional method is used, from a previously developed kinetic mechanism of particle formation with a double discretization of the particle phase in terms of C and H atom number. The present model also distinguishes between different particle structures based on their state of aggregation; single high molecular mass molecules, cluster of molecules and aggregates of clusters. The model predicts the mass of particles, hydrogen content and internal structure. It represents a first approach in following the chemical evolution and internal structure of the particles formed in flames, coupled with the main pyrolysis and oxidation of the fuel. The model is tested in atmospheric premixed flat flames of ethylene and the effect of fuel equivalence ratio on particle morphology is analyzed. Molecular weight growth of aromatic compounds and the inception of particles are predicted. The morphology of the particles and the number of molecules in the clusters at particle inception are also indicated. (author)

D'Anna, Andrea; Sirignano, Mariano [Dipartimento di Ingegneria Chimica, Universita di Napoli ''Federico II'', Napoli (Italy); Kent, John [School of Aerospace, Mechanical and Mechatronic Engineering, University of Sydney (Australia)

2010-11-15T23:59:59.000Z

403

Adaptive low Mach number simulations of nuclear flame microphysics  

SciTech Connect

We introduce a numerical model for the simulation of nuclear flames in Type Ia supernovae. This model is based on a low Mach number formulation that analytically removes acoustic wave propagation while retaining the compressibility effects resulting from nuclear burning. The formulation presented here generalizes low Mach number models used in combustion that are based on an ideal gas approximation to the arbitrary equations of state such as those describing the degenerate matter found in stellar material. The low Mach number formulation permits time steps that are controlled by the advective time scales resulting in a substantial improvement in computational efficiency compared to a compressible formulation. We briefly discuss the basic discretization methodology for the low Mach number equations and their implementation in an adaptive projection framework. We present validation computations in which the computational results from the low Mach number model are compared to a compressible code and present an application of the methodology to the Landau-Darrieus instability of a carbon flame.

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

2003-03-20T23:59:59.000Z

404

Multi-anode ionization chamber  

DOE Patents (OSTI)

The present invention includes a high-energy detector having a cathode chamber, a support member, and anode segments. The cathode chamber extends along a longitudinal axis. The support member is fixed within the cathode chamber and extends from the first end of the cathode chamber to the second end of the cathode chamber. The anode segments are supported by the support member and are spaced along the longitudinal surface of the support member. The anode segments are configured to generate at least a first electrical signal in response to electrons impinging thereon.

Bolotnikov, Aleksey E. (South Setauket, NY); Smith, Graham (Port Jefferson, NY); Mahler, George J. (Rocky Point, NY); Vanier, Peter E. (Setauket, NY)

2010-12-28T23:59:59.000Z

405

Ionization tube simmer current circuit  

DOE Patents (OSTI)

A highly efficient flash lamp simmer current circuit utilizes a fifty percent duty cycle square wave pulse generator to pass a current over a current limiting inductor to a full wave rectifier. The DC output of the rectifier is then passed over a voltage smoothing capacitor through a reverse current blocking diode to a flash lamp tube to sustain ionization in the tube between discharges via a small simmer current. An alternate embodiment of the circuit combines the pulse generator and inductor in the form of an FET off line square wave generator with an impedance limited step up output transformer which is then applied to the full wave rectifier as before to yield a similar simmer current.

Steinkraus, Jr., Robert F. (Livermore, CA)

1994-01-01T23:59:59.000Z

406

Ionization tube simmer current circuit  

DOE Patents (OSTI)

A highly efficient flash lamp simmer current circuit utilizes a fifty percent duty cycle square wave pulse generator to pass a current over a current limiting inductor to a full wave rectifier. The DC output of the rectifier is then passed over a voltage smoothing capacitor through a reverse current blocking diode to a flash lamp tube to sustain ionization in the tube between discharges via a small simmer current. An alternate embodiment of the circuit combines the pulse generator and inductor in the form of an FET off line square wave generator with an impedance limited step up output transformer which is then applied to the full wave rectifier as before to yield a similar simmer current. 6 figures.

Steinkraus, R.F. Jr.

1994-12-13T23:59:59.000Z

407

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

DOE Green Energy (OSTI)

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.

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

408

Effects of flow transients on the burning velocity of hydrogen-air premixed flames  

DOE Green Energy (OSTI)

The effects of unsteady strain rate on the burning velocity of hydrogen-air premixed flames are studied in an opposed nozzle configuration. The numerical method employs adaptive time integration of a system of differential-algebraic equations. Detailed hydrogen-air kinetic mechanism and transport properties are considered. The equivalence ratio is varied from lean to rich premixtures in order to change the effective Lewis number. Steady Markstein numbers for small strain rate are computed and compared with experiment. Different definitions of flame burning velocity are examined under steady and unsteady flow conditions. It is found that, as the unsteady frequency increases, large deviations between different flame speeds are noted depending on the location of the flame speed evaluation. Unsteady flame response is investigated in terms of the Markstein transfer function which depends on the frequency of oscillation. In most cases, the flame speed variation attenuates at higher frequencies, as the unsteady frequency becomes comparable to the inverse of the characteristic flame time. Furthermore, unique resonance-like behavior is observed for a range of rich mixture conditions, consistent with previous studies with linearized theory.

H. G. Im; J. H. Chen

2000-07-30T23:59:59.000Z

409

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

E-Print Network (OSTI)

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.

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

2003-12-08T23:59:59.000Z

410

NIST Ground Levels and Ionization Energies for the Neutral ...  

Science Conference Proceedings (OSTI)

The ionization energies in the table are based on a recent survey of ... cited compilation gives the reference(s) for the original ionization-energy data. ...

2013-09-16T23:59:59.000Z

411

Modeling of 1,3-hexadiene, 2,4-hexadiene and 1,4-hexadiene-doped methane flames: Flame modeling, benzene and styrene formation  

Science Conference Proceedings (OSTI)

In this work, we have developed a detailed chemical kinetic model and reacting flow simulation for the hexadiene-doped 2-d methane diffusion flames studied experimentally by McEnally and Pfefferle. The GRI-Mech 2.11 methane oxidation and Lawrence Livermore butane oxidation mechanisms were used as the base mechanism to which hexadiene chemistry generated by Reaction Mechanism Generator (RMG) was added. Some important chemically activated pathways leading to aromatic species formation, including the reactions on C{sub 5}H{sub 7}, C{sub 6}H{sub 10}, C{sub 6}H{sub 9}, C{sub 6}H{sub 7}, C{sub 8}H{sub 8} and C{sub 8}H{sub 9} potential energy surfaces, are examined in great detail using quantum chemistry (CBS-QB3) and master equation analysis as implemented in Variflex. An efficient program to solve the doped methane diffusion flame was developed. The solver uses the method of lines to solve the species mass balance equation arising in the diffusion flame. It assumes that the temperature and velocity profiles of the doped flame are the same as those of the undoped flame. The mole fractions of various species as predicted by our model are compared to the experimentally measured mole fractions. The agreement between theory and experiments is quite good for most molecules. The added hexadiene dopants to the flame decompose to produce significant amount of cyclopentadienyl radical, which combines with methyl radical to produce benzene. We also show that styrene is formed primarily by recombination of cyclopentadienyl and propargyl radicals, a pathway which to our knowledge, has not been included in prior flame simulations. (author)

Sharma, Sandeep; Harper, Michael R.; Green, William H. [Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States)

2010-07-15T23:59:59.000Z

412

Three-dimensional numerical simulations of Rayleigh-Taylorunstable flames in type Ia supernovae  

SciTech Connect

Flame instabilities play a dominant role in accelerating the burning front to a large fraction of the speed of sound in a Type Ia supernova. We present a three-dimensional numerical simulation of a Rayleigh-Taylor unstable carbon flame, following its evolution through the transition to turbulence. A low Mach number hydrodynamics method is used, freeing us from the harsh time step restrictions imposed by sound waves. We fully resolve the thermal structure of the flame and its reaction zone, eliminating the need for a flame model. A single density is considered, 1.5x107 gm/cc, and half carbon/half oxygen fuel--conditions under which the flame propagated in the flamelet regime in our related two-dimensional study. We compare to a corresponding two-dimensional simulation, and show that while fire-polishing keeps the small features suppressed in two dimensions, turbulence wrinkles the flame on far smaller scales in the three-dimensional case, suggesting that the transition to the distributed burning regime occurs at higher densities in three dimensions. Detailed turbulence diagnostics are provided. We show that the turbulence follows a Kolmogorov spectrum and is highly anisotropic on the large scales, with a much larger integral scale in the direction of gravity. Furthermore, we demonstrate that it becomes more isotropic as it cascades down to small scales. Based on the turbulent statistics and the flame properties of our simulation, we compute the Gibson scale. We show the progress of the turbulent flame through a classic combustion regime diagram, indicating that the flame just enters the distributed burning regime near the end of our simulation.

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

2005-01-28T23:59:59.000Z

413

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

Science Conference Proceedings (OSTI)

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.

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

414

Detectors - Instrument Support | ORNL Neutron Sciences  

NLE Websites -- All DOE Office Websites (Extended Search)

Detectors Detectors Detectors The detector design group, led by Yacouba Diawara is responsible for supporting the design of HFIR and SNS instruments by developing the necessary infrastructure and acquiring detector components that will be used to complete the functionality of the instruments. The group's mission also includes supporting detector research and development (R&D) for the various instruments and their different needs. The support effort for instrument design entails monitoring detector development worldwide as neutron facilities around the globe are getting upgraded and adopting the newest technologies. Detector group technician Ted Visscher inspects a parahedreal lens on an Anger camera Detector group technician Ted Visscher inspects a parahedreal lens on an

415

Structure of the mean velocity and turbulence in premixed axisymmetric acetylene flames  

Science Conference Proceedings (OSTI)

Laser-Doppler measurements of axial mean velocities and the corresponding rms values of turbulent velocity fluctuations are reported for premixed, axisymmetric, acetylene flames together with the probability density distributions of the turbulent velocity fluctuations. All this information provides an insight into the structure of the flow field. Characteristic zones of the flow field are defined that show common features for all acetylene flames studied by the authors. These features are discussed in the paper and are suggested to characterize, in general, interesting parts of the flames.

Matovic, M.; Oka, S. (Inst. for Thermal Engineering and Energy Research, Beograd (Yugoslavia)); Durst, F. (Univ. Erlangen-Nuernberg, Erlangen (Germany). Lehrstuhl fuer Stroemungsmechanik)

1994-09-01T23:59:59.000Z

416

Particle detector spatial resolution  

DOE Patents (OSTI)

Method and apparatus for producing separated columns of scintillation layer material, for use in detection of X-rays and high energy charged particles with improved spatial resolution is disclosed. A pattern of ridges or projections is formed on one surface of a substrate layer or in a thin polyimide layer, and the scintillation layer is grown at controlled temperature and growth rate on the ridge-containing material. The scintillation material preferentially forms cylinders or columns, separated by gaps conforming to the pattern of ridges, and these columns direct most of the light produced in the scintillation layer along individual columns for subsequent detection in a photodiode layer. The gaps may be filled with a light-absorbing material to further enhance the spatial resolution of the particle detector. 12 figs.

Perez-Mendez, V.

1992-12-15T23:59:59.000Z

417

Alpine Pixel Detector Layout  

E-Print Network (OSTI)

A description of an optimized layout of pixel sensors based on a stave that combines both barrel and endcap module orientations. The mechanical stiffness of the structure is provided by carbon fiber shells spaced by carbon foam. The cooling of the modules is provided by two-phase $CO_{2}$ flowing in a thin titanium pipe glued inside the carbon fiber foam. The electrical services of all modules are provided by a single stave flex. This layout eliminates the need for separate barrel and endcap detector structures, and therefore the barrel services material in front of the endcap. The transition from barrel to endcap module orientation is optimized separately for each layer in order to minimize the active pixel area and the traversed material. The sparse module spacing in the endcap part of the stave allows for multiple fixation points, and for a stiff overall structure composed only of staves interconnected by stiff disks.

Delebecque, P; The ATLAS collaboration; Geffroy, N; Massol, N; Rambure, T; Todorov, T

2013-01-01T23:59:59.000Z

418

Imaging alpha particle detector  

DOE Patents (OSTI)

A method and apparatus for detecting and imaging alpha particles sources is described. A conducting coated high voltage electrode (1) and a tungsten wire grid (2) constitute a diode configuration discharge generator for electrons dislodged from atoms or molecules located in between these electrodes when struck by alpha particles from a source (3) to be quantitatively or qualitatively analyzed. A thin polyester film window (4) allows the alpha particles to pass into the gas enclosure and the combination of the glass electrode, grid and window is light transparent such that the details of the source which is imaged with high resolution and sensitivity by the sparks produced can be observed visually as well. The source can be viewed directly, electronically counted or integrated over time using photographic methods. A significant increase in sensitivity over other alpha particle detectors is observed, and the device has very low sensitivity to gamma or beta emissions which might otherwise appear as noise on the alpha particle signal.

Anderson, David F. (Los Alamos, NM)

1985-01-01T23:59:59.000Z

419

Charged-Particle Impact Ionization of Atoms  

Science Conference Proceedings (OSTI)

We have developed a hybrid method to treat charged-particle impact ionization of complex atoms and ions. The essential idea is to describe the interaction between a fast projectile and the target perturbatively, up to second order, while the initial bound state and the ejected-electron--residual-ion interaction can be handled via a convergent R-matrix with pseudo-states (close-coupling) expansion. Example results for ionization of the heavy noble gases (Ne-Xe) by positron and electron impact are presented. The general scheme for a distorted-wave treatment of ionization by heavy-particle impact is described.

Bartschat, Klaus; Guan Xiaoxu [Department of Physics and Astronomy, Drake University, Des Moines, IA 50311 (United States)

2008-08-08T23:59:59.000Z

420

Position Reconstruction in Scintillation Detectors  

E-Print Network (OSTI)

noble gas detector, the scintillator time dispersion is very broad due to the amount of internal to some basic properties of the detector: the linear dimension, the time dispersion of the photon emission.2.2 Scintillator dispersion time at the emission point The first non-trivial factor in the expression

Note: This page contains sample records for the topic "flame ionization detector" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


421

FLAME-SAMPLING PHOTOIONIZATION MASS SPECTROSCOPY - FINAL TECHNICAL REPORT  

SciTech Connect

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.

Hansen, Nils

2013-02-12T23:59:59.000Z

422

Multiple mapping conditioning of velocity in turbulent jet flames  

Science Conference Proceedings (OSTI)

Multiple mapping conditioning (MMC) has emerged as a new approach to model turbulent reacting flows. This study revises the standard MMC closure for velocity in turbulent jet flows from linearity in the reference space to linearity in the composition space. This modeling amendment ensures that the standard velocity model in conditional moment closure studies can now be used for MMC computation as well. A simplified model for the velocity-dependence of MMC drift coefficients is derived without loss of generality and is implemented for the revised velocity closure. Modeling results have been corroborated against the Direct Numerical Simulation database of a spatially evolving, planar turbulent jet flame. The revised model shows marked improvement over standard MMC closure in predicting velocity statistics close to the nozzle. (author)

Vaishnavi, P. [Mechanical Engineering Department, Imperial College, London SW7 2AZ (United Kingdom); Kronenburg, A. [Institut fuer Technische Verbrennung, Universitaet Stuttgart, 70174 Stuttgart (Germany)

2010-10-15T23:59:59.000Z

423

Experimental study of flame propagation in semiconfined geometries with obstacles  

DOE Green Energy (OSTI)

Accidents in which large quantities of liquefied natural gas (LNG) or other combustible materials are spilled can potentially lead to disastrous consequences, especially if the dispersing combustible cloud finds a suitable ignition source. So far, very little is known about the detailed behavior of a large burning cloud. Full-scale experiments are economically prohibitive, and therefore one must rely on laboratory and field experiments of smaller size, scaling up the results to make predictions about larger spill accidents. In this paper we describe our laboratory-scale experiments with a combustible propane/air mixture in various partially confined geometries. We summarize the experimental results and compare them with calculated results based on numerical simulations of the experiments. Our observations suggest that the geometry of the partial confinement is of primary importance; turbulence-producing obstacles can cause acceleration in the flame front and, more important, can cause a faster burnout of the combustible vapor.

Urtiew, P.A.; Brandeis, J.; Hogan, W.J.

1982-02-08T23:59:59.000Z

424

The D0 detector upgrade  

SciTech Connect

The Fermilab collider program is undergoing a major upgrade of both the accelerator complex and the two detectors. Operation of the Tevatron at luminosities upwards of ten time that currently provided will occur in early 1999 after the commissioning of the new Fermilab Main Injector. The D0 upgrade program has been established to deliver a detector that will meet the challenges of this environment. A new magnetic tracker consisting of a superconducting solenoid, a silicon vertex detector, a scintillating fiber central tracker, and a central preshower detector will replace the current central tracking and transition radiation chambers. We present the design and performance capabilities of these new systems and describe results from physics simulations that demonstrate the physics reach of the upgraded detector.

Bross, A.D.

1995-02-01T23:59:59.000Z

425

Ionization Yield from Nuclear Recoils in Liquid-Xenon Dark Matter Detection  

E-Print Network (OSTI)

The ionization yield in the two-phase liquid xenon dark-matter detector has been studied in keV nuclear-recoil energy region. The newly-obtained nuclear quenching as well as the recently-measured average energy required to produce an electron-ion pair are used to calculate the total electric charges produced. To estimate the fraction of the electron charges collected, the Thomas-Imel model is generalized to describing the field dependence for nuclear recoils in liquid xenon. With free parameters fitted to experiment measured 56.5 keV nuclear recoils, the energy dependence of ionization yield for nuclear recoils is predicted, which increases with the decreasing of the recoiling energy and reaches the maximum value at 2~3 keV. This prediction agrees well with existing data and may help to lower the energy detection threshold for nuclear recoils to ~1 keV.

Mu, Wei

2013-01-01T23:59:59.000Z

426

A numerical scheme for ionizing shock waves  

Science Conference Proceedings (OSTI)

A two-dimensional (2D) visual computer code to solve the steady state (SS) or transient shock problems including partially ionizing plasma is presented. Since the flows considered are hypersonic and the resulting temperatures are high, the plasma is ...

Necdet Aslan; Michael Mond

2005-12-01T23:59:59.000Z

427

Theory of electron transfer and ionization  

DOE Green Energy (OSTI)

The main effort reported is directed toward charge transfer and ionization in high energy atomic collisions. The research may be divided into classical trajectory calculations, quantum - mechanical collision theory, and phenomenological treatments of quantal interference effects in heavy ion collisions.

Becker, R.L.

1979-01-01T23:59:59.000Z

428

A DNS study on the stabilization mechanism of a turbulent lifted ethylene jet flame in highly-heated coflow  

SciTech Connect

Direct numerical simulation (DNS) of the near-field of a three-dimensional spatially-developing turbulent ethylene jet flame in highly-heated coflow is performed with a reduced mechanism to determine the stabilization mechanism. The DNS was performed at a jet Reynolds number of 10,000 with over 1.29 billion grid points. The results show that auto-ignition in a fuel-lean mixture at the flame base is the main source of stabilization of the lifted jet flame. The Damkoehler number and chemical explosive mode (CEM) analysis also verify that auto-ignition occurs at the flame base. In addition to auto-ignition, Lagrangian tracking of the flame base reveals the passage of large-scale flow structures and their correlation with the fluctuations of the flame base similar to a previous study (Yoo et al., J. Fluid Mech. 640 (2009) 453-481) with hydrogen/air jet flames. It is also observed that the present lifted flame base exhibits a cyclic 'saw-tooth' shaped movement marked by rapid movement upstream and slower movement downstream. This is a consequence of the lifted flame being stabilized by a balance between consecutive auto-ignition events in hot fuel-lean mixtures and convection induced by the high-speed jet and coflow velocities. This is confirmed by Lagrangian tracking of key variables including the flame-normal velocity, displacement speed, scalar dissipation rate, and mixture fraction at the stabilization point.

Yoo, Chun S [Sandia National Laboratories (SNL)

2011-01-01T23:59:59.000Z

429

On The Toxicity of Flame Retardants in Buildings and What Can Be Done About  

NLE Websites -- All DOE Office Websites (Extended Search)

On The Toxicity of Flame Retardants in Buildings and What Can Be Done About On The Toxicity of Flame Retardants in Buildings and What Can Be Done About It Speaker(s): Arlene Blum Date: November 3, 2010 - 12:00pm Location: 90-3122 Seminar Host/Point of Contact: William Fisk Polystyrene, polyisocyanurate, and polyurethane are insulation materials that increase energy efficiency and whose use in buildings, especially energy efficient buildings, is growing rapidly. At the same time, the flame retardants currently in use with these materials are often chemicals that are known to be toxic or have not been adequately evaluated for their impact on human health and the environment. For example, all polystyrene foam insulation used in buildings is treated with HBCD, a persistent, bioaccumulative, and toxic flame retardant. The impacts of exposure to

430

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

Science Conference Proceedings (OSTI)

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.

Kong, Peter C

2013-11-26T23:59:59.000Z

431

Multifractal detrended fluctuation analysis of combustion flames in four-burner impinging entrained-flow gasifier  

E-Print Network (OSTI)

On a laboratory-scale testing platform of impinging entrained-flow gasifier with four opposed burners, the flame images for diesel combustion and gasification process were measured with a single charge coupled device (CCD) camera. The two-dimensional multifractal detrended fluctuation analysis was employed to investigate the multifractal nature of the flame images. Sound power-law scaling in the annealed average of detrended fluctuations was unveiled when the order $q>0$ and the multifractal feature of flame images were confirmed. Further analyses identified two multifractal parameters, the minimum and maximum singularity $\\alpha_{\\min}$ and $\\alpha_{\\max}$, serving as characteristic parameters of the multifractal flames. These two characteristic multifractal parameters vary with respect to different experimental conditions.

Niu, Miao-Ren; Yan, Zhuo-Yong; Guo, Qing-Hua; Liang, Qin-Feng; Wang, Fu-Chen; Yu, Zun-Hong

2007-01-01T23:59:59.000Z

432

The Soret Effect in Naturally Propagating, Premixed, Lean, Hydrogen-Air Flames  

E-Print Network (OSTI)

3] R. W. Shefer, Int. J. Hydrogen Energ. 28 (2003) 1131–Propagating, Premixed, Lean, Hydrogen-Air Flames Joseph F.diffusion effects in lean hydrogen-air ?ames, in spite of

Grcar, Joseph F

2008-01-01T23:59:59.000Z

433

THE COMBUSTION OF SOLVENT REPINED COAL IN AN OPPOSED FLOW DIFFUSION FLAME  

E-Print Network (OSTI)

R.F. (1977). Combustion of coal in an opposed flow diffusionpulverized, solvent-refined coal. ASME Paper No. 76-WA/FU-6.OF SOLVENT REFINED COAL IN AN OPPOSED FLOW DIFFUSION FLAME*

Chin, W.K.

2011-01-01T23:59:59.000Z

434

Multigrid Solution Of Flame Sheet Problems On Serial And Parallel Computers  

E-Print Network (OSTI)

. Flame sheet problems are on the natural route to the numerical solution of detailed chemistry, laminar diffusion flames, which, in turn, are important in many engineering applications. In order to model the flame structure more accurately, we use the vorticity-velocity formulation of the fluid flow equations instead of the more traditional stream function-vorticity approach. The numerical solution of the resulting nonlinear coupled elliptic partial differential equations involves damped Newton iterations, adaptive grid procedures, and multigrid methods. We focus on nonlinear damped Newton multigrid, using either one way or correction schemes. Results on serial and parallel processors are presented. Key words. multigrid, combustion, flame sheet, Navier-Stokes, vorticity-velocity, nonlinear methods, iterative methods, parallel computing. AMS(MOS) subject classifications. 80A32, 80-08, 65C20, 65N20, 65F10. 1. Introduction. The difficulties associated with solving high heat release co...

Craig Douglas; Alexandre Ern; Mitchell; D. Smooke

1994-01-01T23:59:59.000Z

435

Numerical simulations of perforated plate stabilized premixed flames with detailed chemistry  

E-Print Network (OSTI)

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 ...

Kedia, Kushal Sharad

2010-01-01T23:59:59.000Z

436

Numerical simulation of a laboratory-scale turbulent V-flame  

SciTech Connect

We present a three-dimensional, time-dependent simulation of a laboratory-scale rod-stabilized premixed turbulent V-flame. The simulations are performed using an adaptive time-dependent low Mach number model with detailed chemical kinetics and a mixture model for differential species diffusion. The algorithm is based on a second-order projection formulation and does not require an explicit subgrid model for turbulence or turbulence chemistry interaction. Adaptive mesh refinement is used to dynamically resolve the flame and turbulent structures. Here, we briefly discuss the numerical procedure and present detailed comparisons with experimental measurements showing that the computation is able to accurately capture the basic flame morphology and associated mean velocity field. Finally, we discuss key issues that arise in performing these types of simulations and the implications of these issues for using computation to form a bridge between turbulent flame experiments and basic combustion chemistry.

Bell, J.B.; Day, M.S.; Shepherd, I.G.; Johnson, M.; Cheng, R.K.; Grcar,J.F.; Beckner, V.E.; Lijewski, M.J.

2005-02-07T23:59:59.000Z

437

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

E-Print Network (OSTI)

??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… (more)

Kedia, Kushal Sharad

2010-01-01T23:59:59.000Z

438

An Experimental Study of Flame Response Mechanisms in a Lean-premixed Gas Turbine Combustor.  

E-Print Network (OSTI)

??The heat release rate response of a swirl-stabilized, turbulent, lean-premixed natural gas-air flame to velocity oscillations was investigated in an atmospheric variable length research combustor… (more)

Peluso, Stephen

2012-01-01T23:59:59.000Z

439

Ionization of Rydberg atoms by blackbody radiation  

E-Print Network (OSTI)

We have studied an ionization of alkali-metal Rydberg atoms by blackbody radiation (BBR). The results of the theoretical calculations of ionization rates of Li, Na, K, Rb and Cs Rydberg atoms are presented. Calculations have been performed for nS, nP and nD states which are commonly used in a variety of experiments, at principal quantum numbers n=8-65 and at the three ambient temperatures of 77, 300 and 600 K. A peculiarity of our calculations is that we take into account the contributions of BBR-induced redistribution of population between Rydberg states prior to photoionization and field ionization by extraction electric field pulses. The obtained results show that these phenomena affect both the magnitude of measured ionization rates and shapes of their dependences on n. A Cooper minimum for BBR-induced transitions between bound Rydberg states of Li has been found. The calculated ionization rates are compared with our earlier measurements of BBR-induced ionization rates of Na nS and nD Rydberg states with ...

Beterov, I I; Ryabtsev, I I; Entin, V M; Ekers, A; Bezuglov, N N

2008-01-01T23:59:59.000Z

440

Spark ignited turbulent flame kernel growth. Annual report, January--December, 1992  

DOE Green Energy (OSTI)

Cyclic combustion variations in spark-ignition engines limit the use of dilute charge strategies for achieving low NO{sub x} emissions and improved fuel economy. Results from an experimental study of the effect of incomplete fuel-air mixing (ifam) on spark-ignited flame kernel growth in turbulent propane-air mixtures are presented. The experiments were conducted in a turbulent flow system that allows for independent variation of flow parameters, ignition system parameters, and the degree of fuel-air mixing. Measurements were made at 1 atm and 300 K conditions. Five cases were studied; a premixed and four incompletely mixed cases with 6%, 13%, 24% and 33% RMS (root-mean-square) fluctuations in the fuel/air equivalence ratio. High speed laser shadowgraphy at 4,000 frames-per-second was used to record flame kernel growth following spark ignition, from which the equivalent flame kernel radius as a function of time was determined. The effect of ifam was evaluated in terms of the flame kernel growth rate, cyclic variations in the flame kernel growth, and the rate of misfire. The results show that fluctuations in local mixture strength due to ifam cause the flame kernel surface to become wrinkled and distorted; and that the amount of wrinkling increases as the degree of ifam. Ifam was also found to result in a significant increase in cyclic variations in the flame kernel growth. The average flame kernel growth rates for the premixed and the incompletely mixed cases were found to be within the experimental uncertainty except for the 33%-RMS-fluctuation case where the growth rate is significantly lower. The premixed and 6%-RMS-fluctuation cases had a 0% misfire rate. The misfire rates were 1% and 2% for the 13%-RMS-fluctuation and 24%-RMS-fluctuation cases, respectively; however, it drastically increased to 23% in the 33%-RMS-fluctuation case.

Santavicca, D.A.

1994-06-01T23:59:59.000Z

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441

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

DOE Green Energy (OSTI)

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.

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

1996-03-01T23:59:59.000Z

442

Aromatics oxidation and soot formation in flames. Progress report for year beginning 15 August 1988  

SciTech Connect

Work during this contract period has been concerned with the mechanisms through which aromatics are formed and destroyed in flames, and the processes responsible for soot formation. Recent progress has been primarily in two areas: experiments and modeling of the soot nucleation process in low pressure benzene flames and preparation for experiments on the destruction mechanisms of benzene. In addition, we have incorporated ``weak collision`` formalisms into a fall-off computer code.

Howard, J.B.

1989-12-31T23:59:59.000Z

443

The FLAME DOCTOR Burner Monitoring System: Demonstration Tests at Alliant Energy's Edgewater 5  

Science Conference Proceedings (OSTI)

Accurate knowledge of the quality of the flames of individual burners is essential to advanced boiler management, especially in low-NOx burners, which are more sensitive to changes in operation and fuel quality than conventional burners. New technology is needed that permits direct, continuous monitoring of each burner in a boiler. One promising technology that addresses these needs is the FLAME DOCTOR® system developed under EPRI sponsorship. This report summarizes the results from the second full-s...

2004-11-23T23:59:59.000Z

444

Direct Detector for Terahertz Radiation - Energy ...  

Patent 7,420,225: Direct detector for terahertz radiation A direct detector for terahertz radiation comprises a grating-gated field-effect transistor ...

445

AN IONIZATION CHAMBER LAUNDRY MONITOR  

SciTech Connect

The determination of the amount of contamination remaining on a garment after it has been washed is an important part of hot laundry operations. In the past garments were monitored by measuring the contamination concentrated in the crotch with a GM tube probe. This type of spot check does not detect any isolated hot spots on other pants of the garment. To monitor the entire garment with a GM tube instrument is excessively time consuming for a large number of garments. To overcome these difficulties a sensitive, large-volume ionization chamber was constructed. It is rectangular in shape, 5 ft high by 2 1/2 ft wide by 4 in. deep. The center electrode is of a grid type and is mounted halfway between the front window and the back of the chamber. In a 0.5-mr/hr field, 180 v is sufficient to saturate toe chamber. In order to insure beta sensitivity, the front window has an equivalent thickness of approximately 7 mg/cm/sup 2/. The measuring device is a line-operated electrometer circuit equipped with an alarm that may be set at the rejection limit for the type of garment being monitored. A fullscale deflection on the most sensitive range is given by 2 to 3 mu C of liquid mixed fission products deposited on a garment. Since the chamber monitors the entire garment, the results are independent of the location of the contarnination. In practice, garments may be monitored at the rate of 7 per min, while only 3 per min may be completely checked with a GM tube probs. Field tests indicate that this instrument is stable and trouble free. Background causes a meter deflection of about 20 divisions, which is low enough to give reliable accuracy for monitoring garments. (auth)

Chester, J.D.; Handloser, J.S.

1958-06-01T23:59:59.000Z

446

Interaction of Plasma Discharges with a Flame: Experimental and Numerical Study  

Science Conference Proceedings (OSTI)

This paper presents experimental results and numerical simulations of methane/air non-premixed flame under plasma assistance. Without plasma assistance, the flame blows off at a 28-30 m{center_dot}s{sup -1} bulk velocity (power around 3 kW). When the discharge is on, the flame can be maintained up to a bulk velocity of 53 m{center_dot}s{sup -1}(power around 6 kW), corresponding to +90% gain in power with only a few watt of plasma power. The plasma discharges present short duration current pulses (between 100 ns and 200 ns) and occur non-monotonically (delay between two pulses from 6x10{sup -5} s to 0.1 s). The probability density function of this occurrence is significantly influenced by the mass flow rate or the absence of flame, revealing the strong coupling of the plasma with hydrodynamic and combustion. For the numerical section of this work, we simulated the flame using a Computational Fluid Dynamics code based on Direct Numerical Simulation (direct solving of Navier-Stokes equations), and investigated the thermal and/or chemical effects of discharges on the flame stability.

Vincent-Randonnier, Axel [ONERA, French Aerospace Lab, Palaiseau, F-91761 (France); Teixeira, David [IFP, Rueil-Malmaison, F-92852 (France)

2010-10-13T23:59:59.000Z

447

Composition PDF/photon Monte Carlo modeling of moderately sooting turbulent jet flames  

SciTech Connect

A comprehensive model for luminous turbulent flames is presented. The model features detailed chemistry, radiation and soot models and state-of-the-art closures for turbulence-chemistry interactions and turbulence-radiation interactions. A transported probability density function (PDF) method is used to capture the effects of turbulent fluctuations in composition and temperature. The PDF method is extended to include soot formation. Spectral gas and soot radiation is modeled using a (particle-based) photon Monte Carlo method coupled with the PDF method, thereby capturing both emission and absorption turbulence-radiation interactions. An important element of this work is that the gas-phase chemistry and soot models that have been thoroughly validated across a wide range of laminar flames are used in turbulent flame simulations without modification. Six turbulent jet flames are simulated with Reynolds numbers varying from 6700 to 15,000, two fuel types (pure ethylene, 90% methane-10% ethylene blend) and different oxygen concentrations in the oxidizer stream (from 21% O{sub 2} to 55% O{sub 2}). All simulations are carried out with a single set of physical and numerical parameters (model constants). Uniformly good agreement between measured and computed mean temperatures, mean soot volume fractions and (where available) radiative fluxes is found across all flames. This demonstrates that with the combination of a systematic approach and state-of-the-art physical models and numerical algorithms, it is possible to simulate a broad range of luminous turbulent flames with a single model. (author)

Mehta, R.S.; Haworth, D.C.; Modest, M.F. [Department of Mechanical and Nuclear Engineering, The Pennsylvania State University, University Park, PA 16802 (United States)

2010-05-15T23:59:59.000Z

448

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

SciTech Connect

Planar flames are intrinsically unstable in open domains due to the thermal expansion across the burning front--the Landau-Darrieus instability. This instability leads to wrinkling and growth of the flame surface, and corresponding acceleration of the flame, until it is stabilized by cusp formation. We look at the Landau-Darrieus in stability for C/O thermonuclear flames at conditions relevant to the late stages of a Type Ia supernova explosion. Two-dimensional direct numerical simulations of both single-mode and multi-mode perturbations using a low Mach number hydrodynamics code are presented. We show the effect of the instability on the flame speed as a function of both the density and domain size, demonstrate the existence of the small scale cutoff to the growth of the instability, and look for the proposed breakdown of the non-linear stabilization at low densities. The effects of curvature on the flame as quantified through measurements of the growth rate and computation of the corresponding Markstein number. While accelerations of a few percent are observed, they are too small to have any direct outcome on the supernova explosion.

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

2003-11-24T23:59:59.000Z

449

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

Science Conference Proceedings (OSTI)

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)

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

450

Effects of inclined jets on turbulent oxy-flame characteristics in a triple jet burner  

Science Conference Proceedings (OSTI)

The reactants are generally injected into the industrial furnaces by jets. An effective method to act on combustion in such systems is to control the way injection jets. The present study concerns the control of turbulent flames by the jets deflection in a natural gas-oxygen burner with separated jets. The burner of 25 kW power is constituted with three aligned jets, one central natural gas jet surrounded by two oxygen jets. The principal idea is to confine the fuel jet by oxygen jets to favour the mixing in order to improve the flame stability and consequently to reduce the pollutant emissions like NO{sub x}. The flame stability and its structural properties are analyzed by the OH chemiluminescence. The Particle Image Velocimetry technique has been used to characterize the dynamic field. Results show that the control by inclined jets has a considerable effect on the dynamic behaviour and flame topology. Indeed, the control by incline of oxygen jets towards fuel jet showed a double interest: a better stabilization of flame and a significant reduction of nitrogen oxides. Measurements showed that the deflection favours the mixing and accelerates the fusion of jets allowing the flame stabilization. (author)

Boushaki, T.; Mergheni, M.A.; Sautet, J.C. [CORIA UMR 6614 CNRS-Universite et INSA de ROUEN, Avenue de l'Universite, 76 801 Saint Etienne du Rouvray, Cedex (France); Labegorre, B. [Air Liquide CRCD, Les Loges en Josas, BP 126, 78350 Jouy en Josas (France)

2008-07-15T23:59:59.000Z

451

Control of flames by tangential jet actuators in oxy-fuel burners  

Science Conference Proceedings (OSTI)

The active control of oxy-fuel flames from burners with separated jets is investigated. The control system consists of four small jet actuators, placed tangential to the exit of the main jets to generate a swirling flow. These actuators are able to modify the flow structure and to act on mixing between the reactants and consequently on the flame behavior. The burner (25 kW) is composed of separated jets, one jet of natural gas and one or two jets of pure oxygen. Experiments are conducted with three burner configurations, according to the number of jets, the jet exit velocities, and the separation distance between the jets. OH chemiluminescence measurements, particle image velocimetry, and measurements of NO{sub x} emissions are used to characterize the flow and the flame structure. Results show that the small jet actuators have a significant influence on the behavior of jets and the flame characteristics, particularly in the stabilization zone. It is shown that the control leads to a decrease in lift-off heights and to better stability of the flame. The use of jet actuators induces high jet spreading and an increase in turbulence intensity, which improves the mixing between the reactants and the surrounding fluid. Pollutant measurements show important results in terms of NO{sub x} reductions (up to 60%), in particular for low swirl intensity. The burner parameters, such as the number of jets and the spacing between the jets, also impact the flame behavior and NO{sub x} formation. (author)

Boushaki, Toufik [CORIA UMR 6614 CNRS-Universite et INSA de ROUEN, Site Universitaire du Madrillet, 76801 Saint Etienne du Rouvray, Cedex (France); Universite de Toulouse-INPT-UPS, IMFT (Institut de Mecanique des Fluides de Toulouse), Allee Camille Soula, F-31400 Toulouse, Cedex (France); Sautet, Jean-Charles [CORIA UMR 6614 CNRS-Universite et INSA de ROUEN, Site Universitaire du Madrillet, 76801 Saint Etienne du Rouvray, Cedex (France); Labegorre, Bernard [Air Liquide, Centre de Recherche Claude-Delorme, Les Loges-en-Josas, B.P. 126 78354 Jouy-en-Josas, Cedex (France)

2009-11-15T23:59:59.000Z

452

Capturing the Fire: Flame Energetics and Neutronizaton for Type Ia Supernova Simulations  

E-Print Network (OSTI)

We develop and calibrate a realistic model flame for hydrodynamical simulations of deflagrations in white dwarf (Type Ia) supernovae. Our flame model builds on the advection-diffusion-reaction model of Khokhlov and includes electron screening and Coulomb corrections to the equation of state in a self-consistent way. We calibrate this model flame--its energetics and timescales for energy release and neutronization--with self-heating reaction network calculations that include both these Coulomb effects and up-to-date weak interactions. The burned material evolves post-flame due to both weak interactions and hydrodynamic changes in density and temperature. We develop a scheme to follow the evolution, including neutronization, of the NSE state subsequent to the passage of the flame front. As a result, our model flame is suitable for deflagration simulations over a wide range of initial central densities and can track the temperature and electron fraction of the burned material through the explosion and into the expansion of the ejecta.

A. C. Calder; D. M. Townsley; I. R. Seitenzahl; F. Peng; O. E. B. Messer; N. Vladimirova; E. F. Brown; J. W. Truran; D. Q. Lamb

2006-11-01T23:59:59.000Z

453

Relationships among nitric oxide, temperature and mixture fraction in hydrogen jet flames  

DOE Green Energy (OSTI)

Simultaneous point measurements of NO, the major species, mixture fraction, temperature, and OH are obtained in nonpremixed turbulent hydrogen jet flames, using the combination of spontaneous Raman scattering, Rayleigh scattering, and laser-induced fluorescence. Results are presented for an undiluted hydrogen flame at Reynolds number 10,000 and for flames with 20% and 40% helium dilution. Radial dependence of conditional mean NO mole fraction (conditional on mixture fraction) is shown to be small at upstream locations and negligible at the downstream locations that contribute most to the overall NO emission. Near the flame base, where NO formation rates and concentrations are sensitive to local strain, fluctuations of the NO mole fraction conditional on mixture fraction are 40 to 50% of conditional mean. When average NO levels are calculated conditional on both mixture fraction and temperature, a significant temperature dependence is found. However, this double conditioning does not substantially reduce NO fluctuations relative to the mean values. These results combined with previously reported data on the present hydrogen flames provide a detailed basis for evaluation and refinement of turbulent combustion models for thermal NO{sub x} formation in jet flames.

Barlow, R.S. [Sandia National Labs., Livermore, CA (United States); Carter, C.D. [Systems Research Labs., Inc., Dayton, OH (United States)

1994-01-01T23:59:59.000Z

454

Optical transcutaneous bilirubin detector  

DOE Patents (OSTI)

This invention consists of a transcutaneous bilirubin detector comprising a source of light having spectral components absorbable and not absorbable by bilirubin, a handle assembly, electronic circuitry and a fiber optic bundle connecting the assembly to the light source and circuitry. Inside the assembly is a prism that receives the light from one end of the fiber optic bundle and directs it onto the skin and directs the reflected light back into the bundle. The other end of the bundle is trifucated, with one end going to the light source and the other two ends going to circuitry that determines how much light of each kind has been reflected. A relatively greater amount absorbed by the skin from the portion of the spectrum absorbable by bilirubin may indicate the presence of the illness. Preferably, two measurements are made, one on the kneecap and one on the forehead, and compared to determine the presence of bilirubin. To reduce the impact of light absorption by hemoglobin in the blood carried by the skin, pressure is applied with a plunger and spring in the handle assembly, the pressure limited by points of a button slidably carried in the assembly that are perceived by touch when the pressure applied is sufficient.

Kronberg, J.W.

1991-03-04T23:59:59.000Z

455

Triple Coincidence Radioxenon Detector  

Science Conference Proceedings (OSTI)

The Automated Radioxenon Sampler/Analyzer (ARSA) built by Pacific Northwest National Laboratory (PNNL) is on e of the world’s most sensitive systems for monitoring the four radioxenon isotopes 133Xe, 133mXE, 131mXe and 135Xe. However, due to size, weight and power specifications appropriate to meet treaty-monitoring requirements; the ARSA is unsuitable for rapid deployment using modest transportation means. To transition this technology to a portable unit can be easily and rapidly deployed can be achieved by significant reductions in size, weight and power consumption if concentration were not required. As part of an exploratory effort to reduce both the size of the air sample and the gas processing requirement PNNL has developed an experimental nuclear detector to test and qualify the use of triple coincidence signatures (beta, conversion electron, x-ray) from two of the radioxenon isotopes (135Xe and 133Xe) as well as the more traditional beta-gamma coincidence signatures used by the ARSA system. The additional coincidence requirement allows for reduced passive shielding, and makes it possible for unambiguous detection of 133Xe and 153Xe in the presence of high 222Rn backgrounds. This paper will discuss the experimental setup and the results obtained for a 133Xe sample with and without 222Rn as an interference signature.

McIntyre, Justin I.; Aalseth, Craig E.; Bowyer, Ted W.; Hayes, James C.; Heimbigner, Tom R.; Morris, Scott J.; Reeder, Paul L.

2004-09-22T23:59:59.000Z

456

Seal system with integral detector  

DOE Patents (OSTI)

There is disclosed a seal system for materials where security is of the essence, such as nuclear materials, which is tamper-indicating, which indicates changes in environmental conditions that evidence attempts to by-pass the seal, which is unique and cost effective, said seal system comprised of a seal where an optical signal is transmitted through a loop, with a detector to read said signal, and one or more additional detectors designed to detect environmental changes, these detectors being operatively associated with the seal so that detection of a break in the optical signal or detection of environmental changes will cause an observable change in the seal.

Fiarman, Sidney (Port Jefferson, NY)

1985-01-01T23:59:59.000Z

457

The CDF Silicon Vertex Detector  

Science Conference Proceedings (OSTI)

A silicon strip vertex detector was designed, constructed and commissioned at the CDF experiment at the Tevatron collider at Fermilab. The mechanical design of the detector, its cooling and monitoring are presented. The front end electronics employing a custom VLSI chip, the readout electronics and various components of the SVX system are described. The system performance and the experience with the operation of the detector in the radiation environment are discussed. The device has been taking colliding beams data since May of 1992, performing at its best design specifications and enhancing the physics program of CDF.

Tkaczyk, S.; Carter, H.; Flaugher, B. [and others

1993-09-01T23:59:59.000Z

458

Seal system with integral detector  

DOE Patents (OSTI)

A seal system is disclosed for materials where security is of the essence, such as nuclear materials. The seal is tamper-indicating, indicates changes in environmental conditions that evidence attempts to bypass the seal, is unique and cost effective. The seal system is comprised of a seal where an optical signal is transmitted through a loop, with a detector to read said signal, and one or more additional detectors designed to detect environmental changes, these detectors being operatively associated with the seal so that detection of a break in the optical signal or detection of environmental changes will cause an observable change in the seal.

Fiarman, S.

1982-08-12T23:59:59.000Z

459

Detector Advisory Panel (DAP) Report  

NLE Websites -- All DOE Office Websites (Extended Search)

ATLAS Project Manager's Review ATLAS Project Manager's Review 1-2 April 2010 Panel Members Lothar Bauerdick, FNAL Ray Larsen, SLAC Ronald Lipton, FNAL David Morrison, BNL Robert Roser, FNAL Steve Wolbers, FNAL Brookhaven National Laboratory Upton, New York 10 May 2010 Executive Summary The Detector and Computing Advisory Panels (DAP and CAP) reviewed the status and plans of the US-ATLAS Program at Brookhaven National Laboratory on April 1-2, 2010. The Panel was extremely pleased to hear of the highly successful commissioning of the ATLAS detector during early LHC collisions. The detector operated successfully, with no worse than 97% active channel count in any subsystem, from the start of collisions. There appears to be an excellent understanding of the detector performance via simulations. The BNL computing center has

460

Physics and detector simulation requirements  

Science Conference Proceedings (OSTI)

‘‘This document describes the computing environment needed to meet the requirements for high energy physics Monte Carlo Calculations for the simulation of Superconducting Super Collider Laboratory physics and detectors.’’ (AIP)

Computer Acquisition Working Group

1990-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "flame ionization detector" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


461

Fermilab Detectors CDF & D0  

NLE Websites -- All DOE Office Websites (Extended Search)

detectors and the need for upgrading to keep up with the advancements of the accelerators. As Fermilab prepares for the future in high-energy physics, the Laboratory must...

462

Ionization in Atmospheres of Brown Dwarfs and Extrasolar Planets V: Alfv\\'{e}n Ionization  

E-Print Network (OSTI)

Observations of continuous radio and sporadic X-ray emission from low-mass objects suggest they harbour localized plasmas in their atmospheric environments. For low-mass objects, the degree of thermal ionization is insufficient to qualify the ionized component as a plasma, posing the question: what ionization processes can efficiently produce the required plasma that is the source of the radiation? We propose Alfv\\'{e}n ionization as a mechanism for producing localized pockets of ionized gas in the atmosphere, having sufficient degrees of ionization ($\\geq10^{-7}$) that they constitute plasmas. We outline the criteria required for Alfv\\'{e}n ionization and demonstrate it's applicability in the atmospheres of low-mass objects such as giant gas planets, brown dwarfs and M-dwarfs for both solar and sub-solar metallicities. We find that Alfv\\'{e}n ionization is most efficient at mid to low atmospheric pressures where a seed plasma is easier to magnetize and the pressure gradients needed to drive the required neut...

Stark, Craig R; Diver, Declan A; Rimmer, Paul B

2013-01-01T23:59:59.000Z

463

Molecular Dynamics Model of Ultraviolet Matrix-Assisted Laser Desorption/Ionization Including Ionization Processes  

E-Print Network (OSTI)

Molecular Dynamics Model of Ultraviolet Matrix-Assisted Laser Desorption/Ionization Including A molecular dynamics model of UV-MALDI including ionization processes is presented. In addition/desorption of molecular systems, it includes radiative and nonradiative decay, exciton hopping, two pooling processes

Zhigilei, Leonid V.

464

Neutron detectors comprising boron powder  

DOE Patents (OSTI)

High-efficiency neutron detector substrate assemblies comprising a first conductive substrate, wherein a first side of the substrate is in direct contact with a first layer of a powder material comprising .sup.10boron, .sup.10boron carbide or combinations thereof, and wherein a conductive material is in proximity to the first layer of powder material; and processes of making said neutron detector substrate assemblies.

Wang, Zhehui; Morris, Christopher; Bacon, Jeffrey Darnell; Makela, Mark F; Spaulding, Randy Jay

2013-05-21T23:59:59.000Z

465

Development of a GEM based detector for the CBM Muon Chamber (MUCH)  

E-Print Network (OSTI)

The characteristics of triple GEM detectors have been studied systematically by using cosmic ray muons. The minimum ionizing particle (MIP) spectra has been taken for different GEM voltage setting. Efficiency of GEM detector has been measured for cosmic ray. At high rate operation of GEMs the value of the protection resistor influences the gain and the stability. This feature has been investigated varying both the rate and the value of the protection resistor. This measurement has been performed using both X-ray generator and Fe55 source. The ageing and long-term stability of GEM based detectors has been studied employing both X-ray generator and Fe55 source. The ageing study of one GEM module is performed by using a 8 keV Cu X-ray generator to verify the stability and integrity of the GEM detectors over a longer period of time. The accumulated charge on the detector is calculated from the rate of the X-ray and the average gain of the detector. The details of the measurement and results has been described in this article.

S. Biswas; D. J. Schmidt; A. Abuhoza; U. Frankenfeld; C. Garabatos; J. Hehner; V. Kleipa; T. Morhardt; C. J. Schmidt; H. R. Schmidt; J. Wiechula

2013-10-02T23:59:59.000Z

466

Effect of NO on extinction and re-ignition of vortex-perturbed hydrogen flames.  

DOE Green Energy (OSTI)

The catalytic effect of nitric oxide (NO) on the dynamics of extinction and re-ignition of a vortex-perturbed non-premixed hydrogen-air flame is studied in a counterflow burner. A diffusion flame is established with counterflowing streams of nitrogen-diluted hydrogen at ambient temperature and air heated to a range of temperatures that brackets the auto-ignition temperature. Localized extinction is induced by impulsively driving a fuel-side toroidal vortex into the steady flame, and the recovery of the extinguished region is monitored by planar laser-induced fluorescence (PLIF) of the hydroxyl radical (OH). The dynamics of flame recovery depend on the air temperature and fuel concentration, and four different recovery modes are identified. These modes involve combinations of edge-flame propagation and the expansion of an auto-ignition kernel that forms within the extinguished region. The addition of a small amount of NO significantly alters the re-ignition process by shifting the balance between chain-termination and chain-propagation reactions to enhance auto-ignition. The ignition enhancement by this catalytic effect causes a shift in the conditions that govern the recovery modes. In addition, the effects of NO concentration and vortex strength on the flame recovery are examined. Direct numerical simulations of the flame-vortex interaction with and without NO doping show how the small amount of OH produced by NO-catalyzed reactions has a significant impact on the development of an auto-ignition kernel. This joint experimental and numerical study provides detailed insight into the interaction between transient flows and ignition processes.

Yoo, Chun Sang; Chen, Jacqueline H.; Frank, Jonathan H.; Lee, Uen Do (KITECH, Cheonan, Chungnam, South Korea)

2009-01-01T23:59:59.000Z

467

Experimental and theoretical study of flame inhibition by bromine-containing compounds  

DOE Green Energy (OSTI)

The present paper represents the first effort to date in which a combined experimental and theoretical approach has been used to study the effects of several inhibitors on hydrocarbon-air flames. This work is part of an attempt to build a consistent picture of chemical kinetic flame inhibition, beginning with a simple halogen molecule such as HBr and progressing sequentially towards more complex and more practical inhibitors such as CF/sub 3/Br. Inhibition efficiency can be defined as the rate of flame speed reduction, the amount of flame speed change per unit inhibitor added. Both the numerical model and the flame tube measurements found that the inhibition efficiency gradually decreases as the amount of inhibitor is increased. The present experimental and modeling results are shown, together with earlier data for CF/sub 3/Br-CH/sub 4/-air and CF/sub 3/Br-C/sub 3/H/sub 8/-air as well as HBr-CH/sub 4/-air, CH/sub 3/Br-CH/sub 4/-air and CF/sub 3/Br-CH/sub 4/-air. In the numerical study it was found that a stoichiometric methane-air mixture with up to 8% methyl bromide could support a flame, propagating at a speed of about 5 cm/sec, even though the addition of the first 1% of CH/sub 3/Br had reduced the flame speed from 38 cm/sec to about 26 cm/sec. Extensions of the model to include CF/sub 3/Br are currently under development. The available experimental data suggest that CF/sub 3/Br is somewhat more efficient as an inhibitor than HBr or CH/sub 3/Br.

Westbrook, C.K.; Beason, D.G.; Alvares, N.J.

1981-01-20T23:59:59.000Z

468

Precise reddening and metallicity of NGC6752 from FLAMES spectra  

E-Print Network (OSTI)

(abridged) Accurate reddenings for Globular Clusters could be obtained by comparing the colour-temperature obtained using temperatures from reddening-free indicator (Halpha), with that given by standard colour-temperature calibrations. From a single 1300 seconds exposure with FLAMES at VLT2 we obtained spectra centred on Halpha (R=6000, 5

Gratton, R G; Carretta, E; De Angeli, F; Lucatello, S; Momany, Y; Piotto, G; Recio-Blanco, A

2005-01-01T23:59:59.000Z

469

THE EFFECTS OF FLAME TEMPERATURE, PARTICLE SIZE AND EUROPIUM DOPING CONCENTRATION ON THE PROPERTIES OF Y2O3:EU PARTICLES FORMED IN A FLAME AEROSOL PROCESS  

E-Print Network (OSTI)

Y2O3:Eu particles are phosphors that have found wide applications. Flamesynthesized Y2O3:Eu particles may have either the cubic or the monoclinic structure. The effects of particle size and Eu doping concentration on crystal structure and the surface elemental composition of the flame-synthesized Y2O3:E