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1

Petascale Simulations of Turbulent Nuclear Combustion | Argonne Leadership  

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

Flame Bubble in an Open Computational Domain for Constant Flame Speed, Gravitational Acceleration, and Changing Density Flame Bubble in an Open Computational Domain for Constant Flame Speed, Gravitational Acceleration, and Changing Density This image is from the simulation "Flame Bubble in an Open Computational Domain for Constant Flame Speed, Gravitational Acceleration, and Changing Density." Science: Ray Bair, Katherine Riley, Argonne National Laboratory; Anshu Dubey, Don Lamb, Dongwook Lee, University of Chicago; Robert Fisher, University of Massachusetts at Dartmouth and Dean Townsley, University of Alabama; Visualization: Jonathan Gallagher, University of Chicago; Randy Hudson, John Norris, and Michael E. Papka, Argonne National Laboratory/University of Chicago Petascale Simulations of Turbulent Nuclear Combustion PI Name: Don Lamb PI Email: lamb@oddjob.uchicago.edu

2

Preparing for Mira: experience with FLASH multiphysics simulations - Petascale Simulations of Turbulent Nuclear Combustion  

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

Code Code changes Optimization Performance Conclusion Preparing for Mira: experience with FLASH multiphysics simulations Petascale Simulations of Turbulent Nuclear Combustion Christopher Daley 1 2 1 The Flash Center for Computational Science at the University of Chicago 2 Argonne National Laboratory March 7, 2013 1 / 30 Outline Introduction Code changes Optimization Performance Conclusion 1 Introduction 2 Code changes Updating FLASH for BG/Q 3 Optimization Initialization Evolution 4 Performance Best FLASH configuration Scaling and hardware counter data 5 Conclusion 2 / 30 Outline Introduction Code changes Optimization Performance Conclusion Science objectives To improve our understanding of the explosion mechanism of Type Ia Supernova Simulate two key physical processes with the FLASH code: 1 Buoyancy-driven turbulent nuclear combustion Determines the amount of nuclear

3

Simulation of lean premixed turbulent combustion  

E-Print Network (OSTI)

turbulent methane combustion. Proc. Combust. Inst. , 29:in premixed turbulent combustion. Proc. Combust. Inst. ,for zero Mach number combustion. Combust. Sci. Technol. ,

2008-01-01T23:59:59.000Z

4

Four Lectures on Turbulent Combustion  

E-Print Network (OSTI)

Four Lectures on Turbulent Combustion N. Peters Institut f¨ur Technische Mechanik RWTH Aachen Turbulent Combustion: Introduction and Overview 1 1.1 Moment Methods in Modeling Turbulence with Combustion and Velocity Scales . . . . . . . . . . . 11 1.4 Regimes in Premixed Turbulent Combustion

Peters, Norbert

5

TURBULENT FRBRNNING MVK130 Turbulent Combustion  

E-Print Network (OSTI)

TURBULENT F�RBR�NNING MVK130 Turbulent Combustion Poäng: 3.0 Betygskala: TH Valfri för: M4 to combustion, McGraw-Hill 1996. #12;

6

The first turbulent combustion  

E-Print Network (OSTI)

The first turbulent combustion arises in a hot big bang cosmological model Gibson (2004) where nonlinear exothermic turbulence permitted by quantum mechanics, general relativity, multidimensional superstring theory, and fluid mechanics cascades from Planck to strong force freeze out scales with gravity balancing turbulent inertial-vortex forces. Interactions between Planck scale spinning and non-spinning black holes produce high Reynolds number turbulence and temperature mixing with huge Reynolds stresses driving the rapid inflation of space. Kolmogorovian turbulent temperature patterns are fossilized as strong-force exponential inflation stretches them beyond the scale of causal connection ct where c is light speed and t is time. Fossil temperature turbulence patterns seed nucleosynthesis, and then hydro-gravitational structure formation in the plasma epoch, Gibson (1996, 2000). Evidence about formation mechanisms is preserved by cosmic microwave background temperature anisotropies. CMB spectra indicate hydro-gravitational fragmentation at supercluster to galaxy masses in the primordial plasma with space stretched by \\~10^50. Bershadskii and Sreenivasan (2002, 2003) CMB multi-scaling coefficients support a strong turbulence origin for the anisotropies prior to the plasma epoch.

Carl H. Gibson

2005-01-19T23:59:59.000Z

7

TURBULENT FRBRNNING MVK 130 Turbulent Combustion  

E-Print Network (OSTI)

TURBULENT F�RBR�NNING MVK 130 Turbulent Combustion Antal poäng: 3.0. Valfri för: M4. Kursansvarig program med hänsyn till de modeller som används. Litteratur S.R. Turns: An introduction to combustion, Mc

8

Turbulent Combustion Properties of Premixed Syngases  

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

Turbulent Combustion Properties of Premixed Syngases Title Turbulent Combustion Properties of Premixed Syngases Publication Type Journal Article Year of Publication 2009 Authors...

9

Advanced Computational Methods for Turbulence and Combustion...  

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

Advanced Computational Methods for Turbulence and Combustion Advanced Computational Methods for Turbulence and Combustion Bell.png Key Challenges: Development and application of...

10

Fifteen Lectures on Laminar and Turbulent Combustion  

E-Print Network (OSTI)

Fifteen Lectures on Laminar and Turbulent Combustion N. Peters RWTH Aachen Ercoftac Summer School in Combustion Systems 1 Lecture 2: Calculation of Adiabatic Flame Temperatures and Chemical Equilibria 20: Laminar Diffusion Flames: Different Flow Geometries 156 Lecture 11: Turbulent Combustion: Introduction

Peters, Norbert

11

Lagrangian formulation of turbulent premixed combustion  

E-Print Network (OSTI)

The Lagrangian point of view is adopted to study turbulent premixed combustion. The evolution of the volume fraction of combustion products is established by the Reynolds transport theorem. It emerges that the burned-mass fraction is led by the turbulent particle motion, by the flame front velocity, and by the mean curvature of the flame front. A physical requirement connecting particle turbulent dispersion and flame front velocity is obtained from equating the expansion rates of the flame front progression and of the unburned particles spread. The resulting description compares favorably with experimental data. In the case of a zero-curvature flame, with a non-Markovian parabolic model for turbulent dispersion, the formulation yields the Zimont equation extended to all elapsed times and fully determined by turbulence characteristics. The exact solution of the extended Zimont equation is calculated and analyzed to bring out different regimes.

Pagnini, Gianni

2011-01-01T23:59:59.000Z

12

Turbulent Combustion in SDF Explosions  

Science Conference Proceedings (OSTI)

A heterogeneous continuum model is proposed to describe the dispersion and combustion of an aluminum particle cloud in an explosion. It combines the gas-dynamic conservation laws for the gas phase with a continuum model for the dispersed phase, as formulated by Nigmatulin. Inter-phase mass, momentum and energy exchange are prescribed by phenomenological models. It incorporates a combustion model based on the mass conservation laws for fuel, air and products; source/sink terms are treated in the fast-chemistry limit appropriate for such gasdynamic fields, along with a model for mass transfer from the particle phase to the gas. The model takes into account both the afterburning of the detonation products of the C-4 booster with air, and the combustion of the Al particles with air. The model equations were integrated by high-order Godunov schemes for both the gas and particle phases. Numerical simulations of the explosion fields from 1.5-g Shock-Dispersed-Fuel (SDF) charge in a 6.6 liter calorimeter were used to validate the combustion model. Then the model was applied to 10-kg Al-SDF explosions in a an unconfined height-of-burst explosion. Computed pressure histories are compared with measured waveforms. Differences are caused by physical-chemical kinetic effects of particle combustion which induce ignition delays in the initial reactive blast wave and quenching of reactions at late times. Current simulations give initial insights into such modeling issues.

Kuhl, A L; Bell, J B; Beckner, V E

2009-11-12T23:59:59.000Z

13

Premixed turbulent combustion to opposed streams  

DOE Green Energy (OSTI)

Premixed turbulent combustion in opposed streams has been studied experimentally by the use of two component laser doppler aneomometry. This flow geometry is part of a class of stagnating flows used to study turbulent combustion in recent years. It does not involve any surface near the flames because of the flow symmetry thus circumventing many of the effects of flame surface interaction. The mean non-reacting flow is found to be self-similar for all the conditions studied in this and the stagnation plate configuration. A homogeneous region of plane straining is produced in the vicinity of the stagnation and there is a strong interaction between the turbulence in the flow and the mean straining which can increase the rms velocity as the flow stagnates. The reacting flow fields are found to be symmetric about the free stagnation point. The traverses of mean axial velocity in the stagnation streamlines for reaction flows are not dramatically different from the non-reaction flows. These results differ from turbulent combustion experiments where the flow is stagnated by a flat plate. The extinction limits was studied for propane:air mixtures. 11 refs.

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

1992-03-01T23:59:59.000Z

14

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

15

Simulation of lean premixed turbulent combustion  

DOE Green Energy (OSTI)

There is considerable technological interest in developingnew fuel-flexible combustion systems that can burn fuels such ashydrogenor syngas. Lean premixed systems have the potential to burn thesetypes of fuels with high efficiency and low NOx emissions due to reducedburnt gas temperatures. Although traditional scientific approaches basedon theory and laboratory experiment have played essential roles indeveloping our current understanding of premixed combustion, they areunable to meet the challenges of designing fuel-flexible lean premixedcombustion devices. Computation, with itsability to deal with complexityand its unlimited access to data, hasthe potential for addressing thesechallenges. Realizing this potential requires the ability to perform highfidelity simulations of turbulent lean premixed flames under realisticconditions. In this paper, we examine the specialized mathematicalstructure of these combustion problems and discuss simulation approachesthat exploit this structure. Using these ideas we can dramatically reducecomputational cost, making it possible to perform high-fidelitysimulations of realistic flames. We illustrate this methodology byconsidering ultra-lean hydrogen flames and discuss how this type ofsimulation is changing the way researchers study combustion.

Bell, John B.; Day, Marcus S.; Almgren, Ann S.; Lijewski, MichaelJ.; Rendleman, Charles A.; Cheng, Robert K.; Shepherd, Ian G.

2006-06-25T23:59:59.000Z

16

A Topological Framework for the Interactive Exploration of Large Scale Turbulent Combustion  

E-Print Network (OSTI)

comparison of terascale combustion simulation data. Mathe-premixed hydrogen ?ames. Combustion and Flame, [7] J. L.of Large Scale Turbulent Combustion Peer-Timo Bremer 1 ,

Bremer, Peer-Timo

2010-01-01T23:59:59.000Z

17

A parallel solution - adaptive method for three-dimensional turbulent non-premixed combusting flows  

Science Conference Proceedings (OSTI)

A parallel adaptive mesh refinement (AMR) algorithm is proposed and applied to the prediction of steady turbulent non-premixed compressible combusting flows in three space dimensions. The parallel solution-adaptive algorithm solves the system of partial-differential ... Keywords: Adaptive mesh refinement, Parallel solution-adaptive algorithm, Turbulent combustion, Turbulent diffusion flames, Turbulent non-premixed flames

Xinfeng Gao; Clinton P. T. Groth

2010-05-01T23:59:59.000Z

18

A spray-suppression model for turbulent combustion  

SciTech Connect

A spray-suppression model that captures the effects of liquid suppressant on a turbulent combusting flow is developed and applied to a turbulent diffusion flame with water spray suppression. The spray submodel is based on a stochastic separated flow approach that accounts for the transport and evaporation of liquid droplets. Flame extinguishment is accounted for by using a perfectly stirred reactor (PSR) submodel of turbulent combustion. PSR pre-calculations of flame extinction times are determined using CHEMKIN and are compared to local turbulent time scales of the flow to determine if local flame extinguishment has occurred. The PSR flame extinguishment and spray submodels are incorporated into Sandia's flow fire simulation code, VULCAN, and cases are run for the water spray suppression studies of McCaffrey for turbulent hydrogen-air jet diffusion flames. Predictions of flame temperature decrease and suppression efficiency are compared to experimental data as a function of water mass loading using three assumed values of drop sizes. The results show that the suppression efficiency is highly dependent on the initial droplet size for a given mass loading. A predicted optimal suppression efficiency was observed for the smallest class of droplets while the larger drops show increasing suppression efficiency with increasing mass loading for the range of mass loadings considered. Qualitative agreement to the experiment of suppression efficiency is encouraging, however quantitative agreement is limited due to the uncertainties in the boundary conditions of the experimental data for the water spray.

DESJARDIN,PAUL E.; TIESZEN,SHELDON R.; GRITZO,LOUIS A.

2000-02-14T23:59:59.000Z

19

A spray-suppression model for turbulent combustion  

DOE Green Energy (OSTI)

A spray-suppression model that captures the effects of liquid suppressant on a turbulent combusting flow is developed and applied to a turbulent diffusion flame with water spray suppression. The spray submodel is based on a stochastic separated flow approach that accounts for the transport and evaporation of liquid droplets. Flame extinguishment is accounted for by using a perfectly stirred reactor (PSR) submodel of turbulent combustion. PSR pre-calculations of flame extinction times are determined using CHEMKIN and are compared to local turbulent time scales of the flow to determine if local flame extinguishment has occurred. The PSR flame extinguishment and spray submodels are incorporated into Sandia's flow fire simulation code, VULCAN, and cases are run for the water spray suppression studies of McCaffrey for turbulent hydrogen-air jet diffusion flames. Predictions of flame temperature decrease and suppression efficiency are compared to experimental data as a function of water mass loading using three assumed values of drop sizes. The results show that the suppression efficiency is highly dependent on the initial droplet size for a given mass loading. A predicted optimal suppression efficiency was observed for the smallest class of droplets while the larger drops show increasing suppression efficiency with increasing mass loading for the range of mass loadings considered. Qualitative agreement to the experiment of suppression efficiency is encouraging, however quantitative agreement is limited due to the uncertainties in the boundary conditions of the experimental data for the water spray.

DESJARDIN,PAUL E.; TIESZEN,SHELDON R.; GRITZO,LOUIS A.

2000-02-14T23:59:59.000Z

20

PDF Modeling of Turbulent Lean Premixed Combustion  

Science Conference Proceedings (OSTI)

The joint velocity-scalar-frequency probability density function (PDF) methodology is employed for prediction of a bluff-body stabilized lean premixed methane-air flame. A reduced mechanism with CO and NO chemistry is used to describe fuel oxidation. The predicted mean and rms values of the velocity, temperature and concentrations of major and minor species are compared with laboratory measurements. This technical effort was performed in support of the National Energy Technology Laboratory’s on-going research in “Assessment of Turbo-Chemistry Models for Gas Turbine Combustion Emissions” under the RDS contract DE-AC26-04NT41817.

Yilmaz, S.L.; •Givi, P.; Strakey, P.A.

2007-10-01T23:59:59.000Z

Note: This page contains sample records for the topic "turbulent nuclear combustion" 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

A Topological Framework for the Interactive Exploration of Large Scale Turbulent Combustion  

E-Print Network (OSTI)

A Topological Framework for the Interactive Exploration of Large Scale Turbulent Combustion Peer a new topological framework for the analysis of large scale, time-varying, turbulent combustion consumption thresh- olds for an entire time-dependent combustion simulation. By computing augmented merge

Tierny, Julien

22

A high-order public domain code for direct numerical simulations of turbulent combustion  

Science Conference Proceedings (OSTI)

A high-order scheme for direct numerical simulations of turbulent combustion is discussed. Its implementation in the massively parallel and publicly available Pencil Code is validated with the focus on hydrogen combustion. This is the first open source ... Keywords: Public domain DNS code, Turbulent combustion

N. Babkovskaia; N. E. L. Haugen; A. Brandenburg

2011-01-01T23:59:59.000Z

23

SYMPOSIUM ON TURBULENCE AND COMBUSTION - SPECIAL SYMPOSIUM TO BRING TOGETHER TOP RESEARCHERS IN THE FIELDS OF FLUID TURBULENCE AND COMBUSTION TO PROMOTE ADVANCES IN TURBULENT, REACTING FLOWS  

SciTech Connect

A Symposium on Turbulence and Combustion was held at Cornell University on August 3-4, 2009. The overall goal of the Symposium was to promote future advances in the study of turbulence and combustion, through an unique forum intended to foster interactions between leading members of these two research communities. The Symposium program consisted of twelve invited lectures given by world-class experts in these fields, two poster sessions consisting of nearly 50 presentations, an open forum, and other informal activities designed to foster discussion. Topics covered in the lectures included turbulent dispersion, wall-bounded flows, mixing, finite-rate chemistry, and others, using experiment, modeling, and computations, and included perspectives from an international community of leading researchers from academia, national laboratories, and industry.

Caughey, David

2010-10-08T23:59:59.000Z

24

Lattice Boltzmann equation simulations of turbulence, mixing, and combustion  

E-Print Network (OSTI)

We explore the capability of lattice Boltzmann equation (LBE) method for complex fluid flows involving turbulence, mixing, and reaction. In the first study, LBE schemes for binary scalar mixing and multi-component reacting flow with reactions are developed. Simulations of initially non-premixed mixtures yield scalar probability distribution functions that are in good agreement with numerical data obtained from Navier-Stokes (NS) equation based computation. One-dimensional chemically-reacting flow simulation of a premixed mixture yields a flame speed that is consistent with experimentally determined value. The second study involves direct numerical simulation (DNS) and large-eddy simulation (LES) of decaying homogenous isotropic turbulence (HIT) with and without frame rotation. Three categories of simulations are performed: (i) LBE-DNS in both inertial and rotating frames; (ii) LBE-LES in inertial frame; (iii) Comparison of the LBE-LES vs. NS-LES. The LBE-DNS results of the decay exponents for kinetic energy k and dissipation rate ?, and the low wave-number scaling of the energy spectrum agree well with established classical results. The LBE-DNS also captures rotating turbulence physics. The LBE-LES accurately captures low-wave number scaling, energy decay and large scale structures. The comparisons indicate that the LBE-LES simulations preserve flow structures somewhat more accurately than the NS-LES counterpart. In the third study, we numerically investigate the near-field mixing features in low aspect-ratio (AR) rectangular turbulent jets (RTJ) using the LBE method. We use D3Q19 multiple-relaxation-time (MRT) LBE incorporating a subgrid Smagorinsky model for LES. Simulations of four jets which characterized by AR, exit velocity, and Reynolds number are performed. The investigated near-field behaviors include: (1) Decay of mean streamwise velocity (MSV) and inverse MSV; (2) Spanwise and lateral profiles of MSV; (3) Half-velocity width development and MSV contours; and (4) Streamwise turbulence intensity distribution and spanwise profiles of streamwise turbulence intensity. The computations are compared against experimental data and the agreement is good. We capture both unique features of RTJ: the saddle-back spanwise profile of MSV and axis-switching of long axis from spanwise to lateral direction. Overall, this work serves to establish the feasibility of the LBE method as a viable tool for computing mixing, combustion, and turbulence.

Yu, Huidan

2004-12-01T23:59:59.000Z

25

TURBULENT COMBUSTION MODELING OF COAL:BIOMASS BLENDS IN A SWIRL BURNER I -PRELIMINARY RESULTS  

E-Print Network (OSTI)

TURBULENT COMBUSTION MODELING OF COAL:BIOMASS BLENDS IN A SWIRL BURNER I - PRELIMINARY RESULTS of Mathematics Texas A&M University College Station, TX 77843 ABSTRACT A combustion model using three mixture fractions has been developed for accurate simulation of coal:manure combustion. This model treats coal

Daripa, Prabir

26

Turbulent partially premixed combustion: DNS analysis and RANS simulation  

E-Print Network (OSTI)

progress in alternative energy technologies, such as solar cell, wind power, fuel cell and nuclear energy, significant limitation remains, such as high capital costs, low energy conversion efficiency, and low public acceptance level due to 1 safety... and security concerns (US Energy Information Administration, 2010). It is likely that combustion technology will remain as the primary means of energy production in the foreseeable future. This is particularly the case in high power density applications...

Ruan, S.

2013-03-12T23:59:59.000Z

27

The application of new combustion and turbulence models to H[sub 2]-air nonpremixed supersonic combustion  

SciTech Connect

Finite reaction rate effects and dilatation effects are explored using an extended laminar flamelet model and turbulence models including dilatation processes. For the H[sub 2]-air nonpremixed turbulent combustion experiment conducted by Evans et al. in a high-speed shear flow, the flamesheet model can reasonably predict the combustion region but fails to predict the profiles of mass fractions, especially for H[sub 2] near the jet axis and O[sub 2] close to the jet edge. The inclusion of both dilatation dissipation and pressure dilatation leads to no significant improvement of the simulation results in this relatively low Mach number test case. The results predicted by the laminar flamelet model dramatically improve the profiles of species mass fractions. This indicates that the high turbulent strain rate usually observed in high-speed flow has a significant influence on the turbulent combustion. The widely used assumptions, such as fast chemical reaction rate, and unity Prandtl and Lewis numbers, are not suitable for this high-speed turbulent flow. It is necessary to include effects of kinetic energy changes in the calculations. Numerical results also show that this supersonic nonpremixed turbulent combustion flow satisfies the criteria of the laminar flamelet model.

Zheng, L.L.; Bray, K.N.C. (Cambridge Univ. (United Kingdom). Dept. of Engineering)

1994-11-01T23:59:59.000Z

28

Assessment of RANS-based turbulent combustion models for prediction of gas turbine emissions: turbulence model and reaction mechanism effects  

DOE Green Energy (OSTI)

The goal of this study is to assess current, commonly applied turbulence and combustion models with respect to their performance in gas-turbine combustion (GTC). Reynolds Averaged Navier-Stokes (RANS)-based turbulence and chemistry models are two primary factors influencing the uncertainty in predicting turbulent combustion characteristics, especially for GTC. RANS-based methods are the design tools of choice in the gas turbine industry due to the high computational costs of LES (Large Eddy Simulation). In this study, lean premixed combustion of methane was simulated using two different reduced mechanisms (ARM9 and ARM19) along with the Eddy Dissipation Concept (EDC) turbulent chemistry interaction model to calculate the CO and NOx emissions. The effect of turbulence models was assessed by considering two different models. Both of the models tested performed well in the prediction of temperature and major species profiles. Predicted values of NO emission profiles showed an average difference of ±5 ppm compared to experimental values. Computed intermediate species profiles showed large qualitative and quantitative errors when compared with the experimental data. These discrepancies, especially the intermediate species hydrogen, indicate the challenges these reduced mechanisms and turbulence models can present when modeling pollutant emissions from gas turbine combustors.

Nanduri, J.R.; Celik, I.B.; Strakey, P.A.; Parsons, D.R.

2007-10-01T23:59:59.000Z

29

Finite-Rate Chemistry Effects in Turbulent Premixed Combustion.  

E-Print Network (OSTI)

??In recent times significant public attention has been drawn to the topic of combustion. This has been due to the fact that combustion is the… (more)

Dunn, Matthew John

2008-01-01T23:59:59.000Z

30

Terascale High-Fidelity Simulations of Turbulent Combustion with Detailed Chemistry  

SciTech Connect

The TSTC project is a multi-university collaborative effort to develop a high-fidelity turbulent reacting flow simulation capability utilizing terascale, massively parallel computer technology. The main paradigm of our approach is direct numerical simulation (DNS) featuring highest temporal and spatial accuracy, allowing quantitative observations of the fine-scale physics found in turbulent reacting flows as well as providing a useful tool for development of sub-models needed in device-level simulations. The code named S3D, developed and shared with Chen and coworkers at Sandia National Laboratories, has been enhanced with new numerical algorithms and physical models to provide predictive capabilities for spray dynamics, combustion, and pollutant formation processes in turbulent combustion. Major accomplishments include improved characteristic boundary conditions, fundamental studies of auto-ignition in turbulent stratified reactant mixtures, flame-wall interaction, and turbulent flame extinction by water spray. The overarching scientific issue in our recent investigations is to characterize criticality phenomena (ignition/extinction) in turbulent combustion, thereby developing unified criteria to identify ignition and extinction conditions. The computational development under TSTC has enabled the recent large-scale 3D turbulent combustion simulations conducted at Sandia National Laboratories.

Hong G. Im; Arnaud Trouve; Christopher J. Rutland; Jacqueline H. Chen

2009-02-02T23:59:59.000Z

31

Terascale High-Fidelity Simulations of Turbulent Combustion with Detailed Chemistry  

DOE Green Energy (OSTI)

The TSTC project is a multi-university collaborative effort to develop a high-fidelity turbulent reacting flow simulation capability utilizing terascale, massively parallel computer technology. The main paradigm of our approach is direct numerical simulation (DNS) featuring highest temporal and spatial accuracy, allowing quantitative observations of the fine-scale physics found in turbulent reacting flows as well as providing a useful tool for development of sub-models needed in device-level simulations. The code named S3D, developed and shared with Chen and coworkers at Sandia National Laboratories, has been enhanced with new numerical algorithms and physical models to provide predictive capabilities for spray dynamics, combustion, and pollutant formation processes in turbulent combustion. Major accomplishments include improved characteristic boundary conditions, fundamental studies of auto-ignition in turbulent stratified reactant mixtures, flame-wall interaction, and turbulent flame extinction by water spray. The overarching scientific issue in our recent investigations is to characterize criticality phenomena (ignition/extinction) in turbulent combustion, thereby developing unified criteria to identify ignition and extinction conditions. The computational development under TSTC has enabled the recent large-scale 3D turbulent combustion simulations conducted at Sandia National Laboratories.

Im, Hong G [University of Michigan; Trouve, Arnaud [University of Maryland; Rutland, Christopher J [University of Wisconsin; Chen, Jacqueline H [Sandia National Laboratories

2012-08-13T23:59:59.000Z

32

Terascale High-Fidelity Simulations of Turbulent Combustion with Detailed Chemistry: Spray Simulations  

DOE Green Energy (OSTI)

The Terascale High-Fidelity Simulations of Turbulent Combustion (TSTC) project is a multi-university collaborative effort to develop a high-fidelity turbulent reacting flow simulation capability utilizing terascale, massively parallel computer technology. The main paradigm of the approach is direct numerical simulation (DNS) featuring the highest temporal and spatial accuracy, allowing quantitative observations of the fine-scale physics found in turbulent reacting flows as well as providing a useful tool for development of sub-models needed in device-level simulations. Under this component of the TSTC program the simulation code named S3D, developed and shared with coworkers at Sandia National Laboratories, has been enhanced with new numerical algorithms and physical models to provide predictive capabilities for turbulent liquid fuel spray dynamics. Major accomplishments include improved fundamental understanding of mixing and auto-ignition in multi-phase turbulent reactant mixtures and turbulent fuel injection spray jets.

Rutland, Christopher J.

2009-04-26T23:59:59.000Z

33

Terascale High-Fidelity Simulations of Turbulent Combustion with Detailed Chemistry  

DOE Green Energy (OSTI)

This SciDAC project enabled a multidisciplinary research consortium to develop a high fidelity direct numerical simulation (DNS) software package for the simulation of turbulent reactive flows. Within this collaboration, the authors, based at CMU's Pittsburgh Supercomputing Center (PSC), focused on extensive new developments in Sandia National Laboratories' "S3D" software to address more realistic combustion features and geometries while exploiting Terascale computational possibilities. This work significantly advances the state-of-the-art of DNS of turbulent reacting flows.

Raghurama Reddy; Roberto Gomez; Junwoo Lim; Yang Wang; Sergiu Sanielevici

2004-10-15T23:59:59.000Z

34

Terascale Direct Numerical Simulations of Turbulent Combustion: Capabilities and Limits (PReSS Talk)  

DOE Green Energy (OSTI)

The rapid growth in computational capabilities has provided great opportunities for direct numerical simulations (DNS) of turbulent combustion, a type of simulations without any turbulence model. With the help of terascale high performance supercomputing (HPC) resources, we are now able to provide fundamental insight into turbulence-chemistry interaction in simple laboratory-scale turbulent flames with detailed chemistry using three-dimensional (3D) DNS. However, the actual domain size of 3D-DNS is still limited within {approx} O(10 cm{sup 3}) due to its tremendously high grid resolution required to resolve the smallest turbulent length scale as well as flame structures. Moreover, 3D-DNS will require more computing powers to investigate next-generation engines, of which operating conditions will be characterized by higher pressures, lower temperatures, and higher levels of dilution. In this talk, I will discuss the capabilities and limits of DNS of turbulent combustion and present some results of ignition/extinction characteristics of a highly diluted hydrogen flame counter-flowing against heated air. The results of our recent 3D-DNS of a spatially-developing turbulent lifted hydrogen jet flame in heated coflow will also be presented. The 3D-DNS was performed at a jet Reynolds number of 11,000 with {approx} 1 billion grid points, which required 3.5 million CPU hours on Cray XT3/XT4 at Oak Ridge National Laboratories.

Yoo, Chun Sang (Combustion Research Facility, SNL)

2009-03-26T23:59:59.000Z

35

NUMERICAL MODELING OF TURBULENT FLOW IN A COMBUSTION TUNNEL  

E-Print Network (OSTI)

combustion in a 1 ean propane~a1 of high sp r m·i xture thatned for a and temperature propane~ai due to r mixture at anrecorded photographically propane~air this Fig. The mixture,

Ghoniem, A.F.

2013-01-01T23:59:59.000Z

36

Proceedings of the Combustion Institute, Volume 28, 2000/pp. 903910 TURBULENT FLAME DYNAMICS OF HOMOGENEOUS SOLID PROPELLANT  

E-Print Network (OSTI)

903 Proceedings of the Combustion Institute, Volume 28, 2000/pp. 903­910 TURBULENT FLAME DYNAMICS University Park, PA 16802, USA A comprehensive numerical analysis has been conducted to study the combustion development and its influence on propellant combustion. The formulation is based on the Favre

Apte, Sourabh V.

37

Terascale direct numerical simulations of turbulent combustion using S3D.  

DOE Green Energy (OSTI)

Computational science is paramount to the understanding of underlying processes in internal combustion engines of the future that will utilize non-petroleum-based alternative fuels, including carbon-neutral biofuels, and burn in new combustion regimes that will attain high efficiency while minimizing emissions of particulates and nitrogen oxides. Next-generation engines will likely operate at higher pressures, with greater amounts of dilution and utilize alternative fuels that exhibit a wide range of chemical and physical properties. Therefore, there is a significant role for high-fidelity simulations, direct numerical simulations (DNS), specifically designed to capture key turbulence-chemistry interactions in these relatively uncharted combustion regimes, and in particular, that can discriminate the effects of differences in fuel properties. In DNS, all of the relevant turbulence and flame scales are resolved numerically using high-order accurate numerical algorithms. As a consequence terascale DNS are computationally intensive, require massive amounts of computing power and generate tens of terabytes of data. Recent results from terascale DNS of turbulent flames are presented here, illustrating its role in elucidating flame stabilization mechanisms in a lifted turbulent hydrogen/air jet flame in a hot air co-flow, and the flame structure of a fuel-lean turbulent premixed jet flame. Computing at this scale requires close collaborations between computer and combustion scientists to provide optimized scaleable algorithms and software for terascale simulations, efficient collective parallel I/O, tools for volume visualization of multiscale, multivariate data and automating the combustion workflow. The enabling computer science, applied to combustion science, is also required in many other terascale physics and engineering simulations. In particular, performance monitoring is used to identify the performance of key kernels in the DNS code, S3D and especially memory intensive loops in the code. Through the careful application of loop transformations, data reuse in cache is exploited thereby reducing memory bandwidth needs, and hence, improving S3D's nodal performance. To enhance collective parallel I/O in S3D, an MPI-I/O caching design is used to construct a two-stage write-behind method for improving the performance of write-only operations. The simulations generate tens of terabytes of data requiring analysis. Interactive exploration of the simulation data is enabled by multivariate time-varying volume visualization. The visualization highlights spatial and temporal correlations between multiple reactive scalar fields using an intuitive user interface based on parallel coordinates and time histogram. Finally, an automated combustion workflow is designed using Kepler to manage large-scale data movement, data morphing, and archival and to provide a graphical display of run-time diagnostics.

Sankaran, Ramanan; Mellor-Crummy, J.; DeVries, M.; Yoo, Chun Sang; Ma, K. L.; Podhorski, N.; Liao, W. K.; Klasky, S.; de Supinski, B.; Choudhary, A.; Hawkes, Evatt R.; Chen, Jacqueline H.; Shende, Sameer

2008-08-01T23:59:59.000Z

38

A high-order public domain code for direct numerical simulations of turbulent combustion  

E-Print Network (OSTI)

A high-order scheme for direct numerical simulations of turbulent combustion is discussed. Its implementation in the massively parallel and publicly available Pencil Code is validated with the focus on hydrogen combustion. Ignition delay times (0D) and laminar flame velocities (1D) are calculated and compared with results from the commercially available Chemkin code. The scheme is verified to be fifth order in space. Upon doubling the resolution, a 32-fold increase in the accuracy of the flame front is demonstrated. Finally, also turbulent and spherical flame front velocities are calculated and the implementation of the non-reflecting so-called Navier-Stokes Characteristic Boundary Condition is validated in all three directions.

Babkovskaia, N; Brandenburg, A

2010-01-01T23:59:59.000Z

39

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

40

Study of Buoyancy-Driven Turbulent Nuclear Burning and Validation...  

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

Study of Buoyancy-Driven Turbulent Nuclear Burning and Validation of Type Ia Supernova Models PI Name: Don Lamb PI Email: lamb@oddjob.uchicago.edu Institution: ASCAlliance Flash...

Note: This page contains sample records for the topic "turbulent nuclear combustion" 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

Study of Buoyancy-Driven Turbulent Nuclear Burning and Validation...  

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

created from a simulation run on the Blue GeneP at the Argonne Leadership Computing Facility in 2009. Study of Buoyancy-Driven Turbulent Nuclear Burning and Validation of Type Ia...

42

A Topological Framework for the Interactive Exploration of Large Scale Turbulent Combustion  

SciTech Connect

The advent of highly accurate, large scale volumetric simulations has made data analysis and visualization techniques an integral part of the modern scientific process. To develop new insights from raw data, scientists need the ability to define features of interest in a flexible manner and to understand how changes in the feature definition impact the subsequent analysis of the data. Therefore, simply exploring the raw data is not sufficient. This paper presents a new topological framework for the analysis of large scale, time-varying, turbulent combustion simulations. It allows the scientists to explore interactively the complete parameter space of fuel consumption thresholds for an entire time-dependent combustion simulation. By computing augmented merge trees and their corresponding data segmentations, the system allows the user complete flexibility to segment, select, and track burning cells through time thanks to a linked view interface. We developed this technique in the context of low-swirl turbulent pre-mixed flame simulation analysis, where the topological abstractions enable an efficient tracking through time of the burning cells and provide new qualitative and quantitative insights into the dynamics of the combustion process.

Bremer, P; Weber, G; Tierny, J; Pascucci, V; Day, M; Bell, J

2009-09-29T23:59:59.000Z

43

DNS of turbulent combustion with detailed chemistry on the Cenju-3 platform  

E-Print Network (OSTI)

Direct Numerical Simulation (DNS) of reacting flows became, in the last decade, one of the most attractive tools to study turbulent combustion. A high order finite difference method is used here to perform DNS of methane-air flames. An efficient parallel implementation based on domain decomposition methods in order to perform DNS on MPP platforms is presented in this paper. A 64 processor Cenju-3 computer was used to execute simulations of premixed methane air flames. Two dimensional flame-turbulence interactions were considered that match thermochemical and hydrodynamical parameters of an experimental investigation reported by Buschmann et al. in 1994. Main findings of previous DNS studies and observations in the experimental study were confirmed. In accordance with the latter study it is found that maximum levels of OH radicals do not deviate much from the maximum level in laminar flames. However, the laminar flamelet speed and maximum reaction rates are affected significantly by the...

Markus Baum

1998-01-01T23:59:59.000Z

44

High temperature combustion: Approaching equilibrium using nuclear networks  

E-Print Network (OSTI)

A method for integrating the chemical equations associated with nuclear combustion at high temperature is presented and extensively checked. Following the idea of E. M\\"uller, the feedback between nuclear rates and temperature was taken into account by simultaneously computing molar fraction changes and temperature response in the same matrix. The resulting algorithm is very stable and efficient at calculating nuclear combustion in explosive scenarios, especially in those situations where the reacting material manages to climb to the nuclear statistical equilibrium regime. The numerical scheme may be useful not only for those who carry out hydrodynamical simulations of explosive events, but also as a tool to investigate the properties of a nuclear system approaching equilibrium through a variety of thermodynamical trajectories.

Ruben M. Cabezon Gomez; Domingo Garcia-Senz; Eduardo Bravo

2004-01-07T23:59:59.000Z

45

Combustion Simulations [Heat Transfer and Fluid Mechanics] - Nuclear  

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

Combustion Simulations Combustion Simulations Capabilities Engineering Computation and Design Engineering and Structural Mechanics Systems/Component Design, Engineering and Drafting Heat Transfer and Fluid Mechanics Overview Thermal Hydraulic Optimization of Nuclear Systems Underhood Thermal Management Combustion Simulations Advanced Model and Methodology Development Multi-physics Reactor Performance and Safety Simulations Other Capabilities Work with Argonne Contact us For Employees Site Map Help Join us on Facebook Follow us on Twitter NE on Flickr Heat Transfer and Fluid Mechanics Bookmark and Share Combustion Simulations Density Distribution of Spray in Near-Injector Region Density Distribution of Spray in Near-Injector Region. Click on image to view larger image. Development of computer models based on Front-Tracking and

46

Uncertainty quantification of cinematic imaging for development of predictive simulations of turbulent combustion.  

Science Conference Proceedings (OSTI)

Recent advances in high frame rate complementary metal-oxide-semiconductor (CMOS) cameras coupled with high repetition rate lasers have enabled laser-based imaging measurements of the temporal evolution of turbulent reacting flows. This measurement capability provides new opportunities for understanding the dynamics of turbulence-chemistry interactions, which is necessary for developing predictive simulations of turbulent combustion. However, quantitative imaging measurements using high frame rate CMOS cameras require careful characterization of the their noise, non-linear response, and variations in this response from pixel to pixel. We develop a noise model and calibration tools to mitigate these problems and to enable quantitative use of CMOS cameras. We have demonstrated proof of principle for image de-noising using both wavelet methods and Bayesian inference. The results offer new approaches for quantitative interpretation of imaging measurements from noisy data acquired with non-linear detectors. These approaches are potentially useful in many areas of scientific research that rely on quantitative imaging measurements.

Lawson, Matthew; Debusschere, Bert J.; Najm, Habib N.; Sargsyan, Khachik; Frank, Jonathan H.

2010-09-01T23:59:59.000Z

47

Evolution equations for the joint probability of several compositions in turbulent combustion  

SciTech Connect

One-point statistical simulations of turbulent combustion require models to represent the molecular mixing of species mass fractions, which then determine the reaction rates. For multi-species mixing the Dirichlet distribution has been used to characterize the assumed joint probability density function (PDF) of several scalars, parametrized by solving modeled evolution equations for their means and the sum of their variances. The PDF is then used to represent the mixing state and to obtain the chemical reactions source terms in moment closures or large eddy simulation. We extend the Dirichlet PDF approach to transported PDF methods by developing its governing stochastic differential equation (SDE). The transport equation, as opposed to parametrizing the assumed PDF, enables (1) the direct numerical computation of the joint PDF (and therefore the mixing model to directly account for the flow dynamics (e.g. reaction) on the shape of the evolving PDF), and (2) the individual specification of the mixing timescales of each species. From the SDE, systems of equations are derived that govern the first two moments, based on which constraints are established that provide consistency conditions for material mixing. A SDE whose solution is the generalized Dirichlet PDF is also developed and some of its properties from the viewpoint of material mixing are investigated. The generalized Dirichlet distribution has the following advantages over the standard Dirichlet distribution due to its more general covariance structure: (1) its ability to represent differential diffusion (i.e. skewness) without affecting the scalar means, and (2) it can represent both negatively and positively correlated scalars. The resulting development is a useful representation of the joint PDF of inert or reactive scalars in turbulent flows: (1) In moment closures, the mixing physics can be consistently represented by one underlying modeling principle, the Dirichlet or the generalized Dirichlet PDF, and (2) based on the SDEs transported PDF mixing models for multi-species diffusion can be constructed by specifying the SDE coefficients.

Bakosi, Jozsef [Los Alamos National Laboratory

2010-01-01T23:59:59.000Z

48

Combustion Technologies Group  

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

Combustion Technologies Group Combustion research generates the fundamental physical and chemical knowledge on the interaction between flame and turbulence. Experimental and...

49

COMBUSTION  

E-Print Network (OSTI)

This document presents an overview of combustion as a waste management strategy in relation to the development of material-specific emission factors for EPA’s Waste Reduction Model (WARM). Included are estimates of the net greenhouse gas (GHG) emissions from combustion of most of the materials considered in WARM and several categories of mixed waste. 1. A SUMMARY OF THE GHG IMPLICATIONS OF COMBUSTION Combustion of municipal solid waste (MSW) results in emissions of CO 2 and N2O. Note that CO2 from combustion of biomass (such as paper products and yard trimmings) is not counted because it is biogenic (as explained in the Introduction & Overview chapter). WARM estimates emissions from combustion of MSW in waste-to-energy (WTE) facilities. WARM does not consider any recovery of materials from the MSW stream that may occur before MSW is delivered to the combustor. WTE facilities can be divided into three categories: (1) mass burn, (2) modular and (3) refusederived fuel (RDF). A mass burn facility generates electricity and/or steam from the combustion of

unknown authors

2012-01-01T23:59:59.000Z

50

Simulation of Turbulent Combustion Fields of Shock-Dispersed Aluminum Using the AMR Code  

DOE Green Energy (OSTI)

We present a Model for simulating experiments of combustion in Shock-Dispersed-Fuel (SDF) explosions. The SDF charge consisted of a 0.5-g spherical PETN booster, surrounded by 1-g of fuel powder (flake Aluminum). Detonation of the booster charge creates a high-temperature, high-pressure source (PETN detonation products gases) that both disperses the fuel and heats it. Combustion ensues when the fuel mixes with air. The gas phase is governed by the gas-dynamic conservation laws, while the particle phase obeys the continuum mechanics laws for heterogeneous media. The two phases exchange mass, momentum and energy according to inter-phase interaction terms. The kinetics model used an empirical particle burn relation. The thermodynamic model considers the air, fuel and booster products to be of frozen composition, while the Al combustion products are assumed to be in equilibrium. The thermodynamic states were calculated by the Cheetah code; resulting state points were fit with analytic functions suitable for numerical simulations. Numerical simulations of combustion of an Aluminum SDF charge in a 6.4-liter chamber were performed. Computed pressure histories agree with measurements.

Kuhl, A L; Bell, J B; Beckner, V E; Khasainov, B

2006-11-02T23:59:59.000Z

51

Finite rate chemistry and presumed PDF models for premixed turbulent combustion  

SciTech Connect

The sensitivity of the prediction of mean reaction rates in turbulent premixed flames to presumed PDF shape is studied. Three different presumed PDF shapes are considered: (i) a beta function PDF, (ii) a twin delta function PDF, and (iii) a PDF based on unstrained laminar flame properties. The unstrained laminar flame has the same thermochemistry as the turbulent flame. Emphasis is placed on capturing the finite rate chemistry effects and obtaining a simple expression for the mean reaction rate. It is shown that, as the PDFs approach their bimodal limit, the mean reaction rate expressions obtained using the above three PDFs reduce to a common form. These expressions differ only in the numerical value of a multiplying factor. Predictions are compared with DNS data. Under the conditions of this comparison, the beta function and twin delta function PDFs lead to significant errors, while the PDF based on properties of an unstrained laminar flame gives good agreement with the DNS. (author)

Bray, K.N.C.; Swaminathan, N. [Cambridge University, Cambridge (United Kingdom); Champion, M. [Laboratoire de Combustion et de Detonique, UPR9028 CNRS, ENSMA, 86961 Futuroscope (France); Libby, P.A. [University of California, San Diego, La Jolla, CA (United States)

2006-09-15T23:59:59.000Z

52

Turbulence  

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

Turbulence Turbulence in Alcator C-Mod and Wendelstein 7-AS plasmas during controlled confinement transitions N.P.Basse, E.M.Edlund, C.L.Fiore, M.J.Greenwald, A.E.Hubbard, J.W.Hughes, J.H.Irby, G.J.Kramer 1 , L.Lin, Y.Lin, A.G.Lynn 2 , E.S.Marmar, D.R.Mikkelsen 1 , D.Mossessian, P.E.Phillips 2 , M.Porkolab, J.E.Rice, W.L.Rowan 2 , J.A.Snipes, J.L.Terry, S.M.Wolfe, S.J.Wukitch, K.Zhurovich, S.Zoletnik 3 and the C-Mod and W7-AS 4 Teams MIT Plasma Science and Fusion Center, Cambridge, USA 1 Princeton Plasma Physics Laboratory, Princeton, USA 2 University of Texas at Austin, Austin, USA 3 KFKI-RMKI, EURATOM Association, Budapest, Hungary 4 Max-Planck-Institut f¨ ur Plasmaphysik, EURATOM Association, Greifswald, Germany At certain values of the edge rotational transform, ι a = 1/q a , the confinement time of plasmas in the Wendelstein 7-AS (W7-AS) stellarator was found to

53

Computational Combustion  

DOE Green Energy (OSTI)

Progress in the field of computational combustion over the past 50 years is reviewed. Particular attention is given to those classes of models that are common to most system modeling efforts, including fluid dynamics, chemical kinetics, liquid sprays, and turbulent flame models. The developments in combustion modeling are placed into the time-dependent context of the accompanying exponential growth in computer capabilities and Moore's Law. Superimposed on this steady growth, the occasional sudden advances in modeling capabilities are identified and their impacts are discussed. Integration of submodels into system models for spark ignition, diesel and homogeneous charge, compression ignition engines, surface and catalytic combustion, pulse combustion, and detonations are described. Finally, the current state of combustion modeling is illustrated by descriptions of a very large jet lifted 3D turbulent hydrogen flame with direct numerical simulation and 3D large eddy simulations of practical gas burner combustion devices.

Westbrook, C K; Mizobuchi, Y; Poinsot, T J; Smith, P J; Warnatz, J

2004-08-26T23:59:59.000Z

54

COMBUSTION RESEARCH PROGRAM. CHAPTER FROM ENERGY & ENVIRONMENT ANNUAL REPORT 1977  

E-Print Network (OSTI)

Applied to Turbulent Combustion Flows J. W. Daily and C.Metals from Pulverized Coal Combustion P. Sherman and F.Applied to Turbulent Combustion Flows J. W. Daily and C.

Authors, Various

2011-01-01T23:59:59.000Z

55

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

56

Large-eddy simulations of turbulent flow for grid-to-rod fretting in nuclear reactors  

E-Print Network (OSTI)

The grid-to-rod fretting (GTRF) problem in pressurized water reactors is a flow-induced vibration problem that results in wear and failure of the fuel rods in nuclear assemblies. In order to understand the fluid dynamics of GTRF and to build an archival database of turbulence statistics for various configurations, implicit large-eddy simulations of time-dependent single-phase turbulent flow have been performed in 3x3 and 5x5 rod bundles with a single grid spacer. To assess the computational mesh and resolution requirements, a method for quantitative assessment of unstructured meshes with no-slip walls is described. The calculations have been carried out using Hydra-TH, a thermal-hydraulics code developed at Los Alamos for the Consortium for Advanced Simulation of Light water reactors, a United States Department of Energy Innovation Hub. Hydra-TH uses a second-order implicit incremental projection method to solve the single-phase incompressible Navier-Stokes equations. The simulations explicitly resolve the la...

Bakosi, J; Lowrie, R B; Pritchett-Sheats, L A; Nourgaliev, R R

2013-01-01T23:59:59.000Z

57

Modeling Compressed Turbulence  

Science Conference Proceedings (OSTI)

From ICE to ICF, the effect of mean compression or expansion is important for predicting the state of the turbulence. When developing combustion models, we would like to know the mix state of the reacting species. This involves density and concentration fluctuations. To date, research has focused on the effect of compression on the turbulent kinetic energy. The current work provides constraints to help development and calibration for models of species mixing effects in compressed turbulence. The Cambon, et al., re-scaling has been extended to buoyancy driven turbulence, including the fluctuating density, concentration, and temperature equations. The new scalings give us helpful constraints for developing and validating RANS turbulence models.

Israel, Daniel M. [Los Alamos National Laboratory

2012-07-13T23:59:59.000Z

58

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

59

A filtered tabulated chemistry model for LES of premixed combustion  

E-Print Network (OSTI)

A filtered tabulated chemistry model for LES of premixed combustion B. Fiorinaa , R. Vicquelina to turbulent combustion regimes by including subgrid scale wrinkling effects in the flame front propagation Simulation, Turbulent premixed combustion, Tabulated chemistry 1. Introduction Flame ignition and extinction

Paris-Sud XI, Université de

60

Quality Issues in Combustion LES  

Science Conference Proceedings (OSTI)

Combustion LES requires modelling of physics beyond the flow-field only. These additional models lead to further quality issues and an even stronger need to quantify simulation and modelling errors. We illustrate stability problems, the need for consistent ... Keywords: Combustion, Error landscape, LES, Large-Eddy simulation, Quality, Turbulence

A. M. Kempf; B. J. Geurts; T. Ma; M. W. Pettit; O. T. Stein

2011-10-01T23:59:59.000Z

Note: This page contains sample records for the topic "turbulent nuclear combustion" 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

Hydrogen-or-Fossil-Combustion Nuclear Combined-Cycle Systems for Base- and Peak-Load Electricity Production  

DOE Green Energy (OSTI)

A combined-cycle power plant is described that uses (1) heat from a high-temperature nuclear reactor to meet base-load electrical demands and (2) heat from the same high-temperature reactor and burning natural gas, jet fuel, or hydrogen to meet peak-load electrical demands. For base-load electricity production, fresh air is compressed; then flows through a heat exchanger, where it is heated to between 700 and 900 C by heat provided by a high-temperature nuclear reactor via an intermediate heat-transport loop; and finally exits through a high-temperature gas turbine to produce electricity. The hot exhaust from the Brayton-cycle gas turbine is then fed to a heat recovery steam generator that provides steam to a steam turbine for added electrical power production. To meet peak electricity demand, the air is first compressed and then heated with the heat from a high-temperature reactor. Natural gas, jet fuel, or hydrogen is then injected into the hot air in a combustion chamber, combusts, and heats the air to 1300 C-the operating conditions for a standard natural-gas-fired combined-cycle plant. The hot gas then flows through a gas turbine and a heat recovery steam generator before being sent to the exhaust stack. The higher temperatures increase the plant efficiency and power output. If hydrogen is used, it can be produced at night using energy from the nuclear reactor and stored until needed. With hydrogen serving as the auxiliary fuel for peak power production, the electricity output to the electric grid can vary from zero (i.e., when hydrogen is being produced) to the maximum peak power while the nuclear reactor operates at constant load. Because nuclear heat raises air temperatures above the auto-ignition temperatures of the various fuels and powers the air compressor, the power output can be varied rapidly (compared with the capabilities of fossil-fired turbines) to meet spinning reserve requirements and stabilize the electric grid. This combined cycle uses the unique characteristics of high-temperature reactors (T>700 C) to produce electricity for premium electric markets whose demands can not be met by other types of nuclear reactors. It may also make the use of nuclear reactors economically feasible in smaller electrical grids, such as those found in many developing countries. The ability to rapidly vary power output can be used to stabilize electric grid performance-a particularly important need in small electrical grids.

Forsberg, Charles W [ORNL; Conklin, Jim [ORNL

2007-09-01T23:59:59.000Z

62

Combustibles Alternativos  

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

Combustibles Alternativos Dispensador de Combustible Alternativo Los combustibles alternativos estn derivados de otras fuentes adems del petrleo. Unos son producidos en el...

63

Jet plume injection and combustion system for internal combustion engines  

DOE Patents (OSTI)

An improved combustion system for an internal combustion engine is disclosed wherein a rich air/fuel mixture is furnished at high pressure to one or more jet plume generator cavities adjacent to a cylinder and then injected through one or more orifices from the cavities into the head space of the cylinder to form one or more turbulent jet plumes in the head space of the cylinder prior to ignition of the rich air/fuel mixture in the cavity of the jet plume generator. The portion of the rich air/fuel mixture remaining in the cavity of the generator is then ignited to provide a secondary jet, comprising incomplete combustion products which are injected into the cylinder to initiate combustion in the already formed turbulent jet plume. Formation of the turbulent jet plume in the head space of the cylinder prior to ignition has been found to yield a higher maximum combustion pressure in the cylinder, as well as shortening the time period to attain such a maximum pressure.

Oppenheim, Antoni K. (Kensington, CA); Maxson, James A. (Berkeley, CA); Hensinger, David M. (Albany, CA)

1993-01-01T23:59:59.000Z

64

Jet plume injection and combustion system for internal combustion engines  

DOE Patents (OSTI)

This invention is comprised of an improved combustion system for an internal combustion engine is disclosed wherein a rich air/fuel mixture is furnished at high pressure to one or more jet plume generator cavities adjacent to a cylinder and then injected through one or more orifices from the cavities into the head space of the cylinder to form one or more turbulent jet plumes in the head space of the cylinder prior to ignition of the rich air/fuel mixture in the cavity of the jet plume generator. The portion of the rich air/fuel mixture remaining in the cavity of the generator is then ignited to provide a secondary jet, comprising incomplete combustion products which are injected into the cylinder to initiate combustion in the already formed turbulent jet plume. Formation of the turbulent jet plume in the head space of the cylinder prior to ignition has been found to yield a higher maximum combustion pressure in the cylinder, as well as shortening the time period to attain such a maximum pressure.

Oppenheim, A.K.; Maxson, J.A.; Hensinger, D.M.

1992-12-31T23:59:59.000Z

65

Jet plume injection and combustion system for internal combustion engines  

DOE Patents (OSTI)

An improved combustion system for an internal combustion engine is disclosed wherein a rich air/fuel mixture is furnished at high pressure to one or more jet plume generator cavities adjacent to a cylinder and then injected through one or more orifices from the cavities into the head space of the cylinder to form one or more turbulent jet plumes in the head space of the cylinder prior to ignition of the rich air/fuel mixture in the cavity of the jet plume generator. The portion of the rich air/fuel mixture remaining in the cavity of the generator is then ignited to provide a secondary jet, comprising incomplete combustion products which are injected into the cylinder to initiate combustion in the already formed turbulent jet plume. Formation of the turbulent jet plume in the head space of the cylinder prior to ignition has been found to yield a higher maximum combustion pressure in the cylinder, as well as shortening the time period to attain such a maximum pressure. 24 figures.

Oppenheim, A.K.; Maxson, J.A.; Hensinger, D.M.

1993-12-21T23:59:59.000Z

66

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

67

Fundamental combustion and diagnostics research at Sandia. Progress report, April-June 1980  

DOE Green Energy (OSTI)

The combustion research emphasizes basic research into fundamental problems associated with combustion. The overall program addresses detailed chemistry of combustion, fundamental processes associated with laminar and turbulent flames, development of research techniques specifically applicable to combustion environments, and operation of the user-oriented Combustion Research Facility. The first section of this report contains activities in Combustion Research, the second section contains activities in Molecular Physics and Spectroscopy, and the third section contains activities in Diagnostics Research.

Gusinow, M.A. (ed.)

1980-09-01T23:59:59.000Z

68

Simulation of turbulence in fireballs  

SciTech Connect

The ALE technique is applied to the calculation of a small yield, low altitude nuclear explosion. When artificial diffusion effects caused by numerical errors are minimized, the fireball rises too rapidly, reaching an altitude in excess of that which is observed. This suggests that turbulent diffusion and entrainmert may be important. Hence, a turbulence model has been added to later calculations of the fireball dynamics. Some of the more important features of the calculational technique and the turbulence model are discussed. Preliminary results for a set of turbulence parameters and a particular low altitude fireball are presented. (auth)

Ruppel, H.M.; Gentry, R.A.; Daly, B.J.

1973-11-01T23:59:59.000Z

69

Combustion chamber and thermal vapor stream producing apparatus and method  

DOE Patents (OSTI)

A new and improved method and apparatus for burning a hydrocarbon fuel for producing a high pressure thermal vapor stream comprising steam and combustion gases for injecting into a subterranean formation for the recovery of liquefiable minerals therefrom, wherein a high pressure combustion chamber having multiple refractory lined combustion zones of varying diameters is provided for burning a hydrocarbon fuel and pressurized air in predetermined ratios injected into the chamber for producing hot combustion gases essentially free of oxidizing components and solid carbonaceous particles. The combustion zones are formed by zones of increasing diameters up a final zone of decreasing diameter to provide expansion zones which cause turbulence through controlled thorough mixing of the air and fuel to facilitate complete combustion. The high pressure air and fuel is injected into the first of the multiple zones where ignition occurs with a portion of the air injected at or near the point of ignition to further provide turbulence and more complete combustion.

Sperry, John S. (Houston, TX); Krajicek, Richard W. (Sugar Land, TX); Cradeur, Robert R. (Spring, TX)

1978-01-01T23:59:59.000Z

70

Advanced Combustion  

Science Conference Proceedings (OSTI)

Topics covered in this presentation include: the continued importance of coal; related materials challenges; combining oxy-combustion & A-USC steam; and casting large superalloy turbine components.

Holcomb, Gordon R. [NETL

2013-03-05T23:59:59.000Z

71

Turbulent Combustion in Type Ia Supernova Models  

E-Print Network (OSTI)

We review the astrophysical modeling of type Ia supernova explosions and describe numerical methods to implement numerical simulations of these events. Some results of such simulations are discussed.

F. K. Roepke; W. Hillebrandt

2006-09-15T23:59:59.000Z

72

Simulation of lean premixed turbulent combustion  

E-Print Network (OSTI)

fuels such as hydrogen or syngas. Lean premixed systems havefuels such as hydrogen or syngas, which is obtained from

2008-01-01T23:59:59.000Z

73

Numerical simulation of premixed turbulent methane combustion  

E-Print Network (OSTI)

multicomponent transport properties. Sandia Technical ReportSAND86-8246, Sandia National Laboratories, 1986. [29] J .

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

2001-01-01T23:59:59.000Z

74

Combustion Theory and Modelling Vol. 11, No. 5, October 2007, 697714  

E-Print Network (OSTI)

Combustion Theory and Modelling Vol. 11, No. 5, October 2007, 697­714 Flame propagation in a small, to the emerging micro-combustion technology, and to the understanding of the effect of small scales; Turbulent combustion 1. Introduction The propagation of premixed flames in the presence of a flow whose

Heil, Matthias

75

COMBUSTION RESEARCH - FY-1979  

E-Print Network (OSTI)

Optical Measurement of Combustion Products by Zeeman Atomicand T. Hadeishi • . . • . • . • • . • Combustion Sources offrom Pulverized Coal Combustion J. Pennucci, R. Greif, F.

,

2012-01-01T23:59:59.000Z

76

NETL: Combustion Technologies  

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

Summary for the Combustion Program The Combustion Technologies Product promotes the advancement of coal combustion power generation for use in industrial, commercial, and utility...

77

Transilient Turbulence Theory. Part II: Turbulent Adjustment  

Science Conference Proceedings (OSTI)

Turbulent adjustment is a scheme where dynamic instabilities in the flow are eliminated by turbulence. It is a form of first-order turbulence closure that is applicable to numerical forecast models of the atmosphere. The responsive form of ...

Roland B. Stull; Takehiko Hasegawa

1984-12-01T23:59:59.000Z

78

Advanced Combustion  

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

Systems Systems Advanced Combustion Background Conventional coal-fired power plants utilize steam turbines to generate electricity, which operate at efficiencies of 35-37 percent. Operation at higher temperatures and pressures can lead to higher efficiencies, resulting in reduced fuel consumption and lower greenhouse gas emissions. Higher efficiency also reduces CO2 production for the same amount of energy produced, thereby facilitating a reduction in greenhouse gas emissions. When combined, oxy-combustion comes with an efficiency hit, so it will actually increase the amount of CO2 to be captured. But without so much N2 in the flue gas, it will be easier and perhaps more efficient to capture, utilize and sequester. NETL's Advanced Combustion Project and members of the NETL-Regional University

79

Compressible Turbulence and Interactions with Shock Waves and Material  

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

Compressible Turbulence Compressible Turbulence and Interactions with Shock Waves and Material Interfaces Compressible Turbulence and Interactions with Shock Waves and Material Interfaces Lele.jpg Alternate Title: High-fidelity simulations of supersonic turbulent mixing and combustion Key Challenges: Direct numerical simulation (DNS) of isotropic turbulence interacting with a normal shock wave and turbulent multi-material mixing in the Richtmyer-Meshkov instability (RMI) Why it Matters: Shock/turbulence interaction is a fundamental phenomenon in fluid mechanics that occurs in a wide range of interesting problems in various disciplines, including supernova explosions, inertial confinement fusion, hypersonic flight and propulsion, and shock wave lithotripsy. Accomplishments: A novel solution-adaptive algorithm that applies different

80

Turbulent Shear Flows 9: Selected Papers from the Ninth International Symposium on Turbulent Shear Flows, Kyoto, Japan, August 16-18, 1993, 1st edition  

Science Conference Proceedings (OSTI)

This volume from the well-known series on turbulent shear flows contains four parts on closures and fundamentals, free flows, wall flows and combustion and recirculating flows. Each section begins with an invited introductory article followed by a selection ...

Franz Durst; Nobuhide Kasagi; Brian E. Launder; Frank W. Schmidt; Kenjiro Suzuki; James H. Whitelaw

2012-07-01T23:59:59.000Z

Note: This page contains sample records for the topic "turbulent nuclear combustion" 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

Manifold methods for methane combustion  

SciTech Connect

Objective is to develop a new method for studying realistic chemistry in turbulent methane combustion with NO{sub x} mechanism. The realistic chemistry is a simplification to a more detailed chemistry based on the manifold method; accuracy is determined by interaction between the transport process and the chemical reaction. In this new (tree) method, probability density function or partially stirred reactor calculations are performed. Compared with the reduced mechanism, manifold, and tabulation methods, the new method overcomes drawbacks of the reduced mechanism method and preserves the advantages of the manifold method. Accuracy is achieved by specifying the size of the cell.

Yang, B.; Pope, S.B. [Cornell Univ., Ithaca, NY (United States)

1995-12-31T23:59:59.000Z

82

Advanced Combustion  

Science Conference Proceedings (OSTI)

The activity reported in this presentation is to provide the mechanical and physical property information needed to allow rational design, development and/or choice of alloys, manufacturing approaches, and environmental exposure and component life models to enable oxy-fuel combustion boilers to operate at Ultra-Supercritical (up to 650{degrees}C & between 22-30 MPa) and/or Advanced Ultra-Supercritical conditions (760{degrees}C & 35 MPa).

Holcomb, Gordon R. [NETL

2013-03-11T23:59:59.000Z

83

http://rcc.its.psu.edu/hpc Simulation of In-Cylinder Processes in Internal Combustion Engines  

E-Print Network (OSTI)

http://rcc.its.psu.edu/hpc Simulation of In-Cylinder Processes in Internal Combustion Engines into clean and efficient turbulent combustion remains imperative. A single grand challenge was identified in a 2006 DOE workshop on clean and efficient combustion of 21st century transportation fuels [1]: "The

Bjørnstad, Ottar Nordal

84

COMBUSTION RESEARCH Chapter from the Energy and Environment Division Annual Report 1980  

E-Print Network (OSTI)

Vortex with a Premixed Flame I. Namer, R. Bill, Jr. , F.W. Pitz and R. Savryer Flame C. Tien and S. Lee Tests andCOMBUSTION FLUID MECHANICS Flame in Turbulence R. Bill,

Authors, Various

2013-01-01T23:59:59.000Z

85

NETL: Combustion Technologies  

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

with Combustion A number of companies are participating in DOE's evaluation of Combustion Systems products. The list below gives you access to each participant company's home page....

86

On Challenges for Hypersonic Turbulent Simulations  

SciTech Connect

This short note discusses some of the challenges for design of suitable spatial numerical schemes for hypersonic turbulent flows, including combustion, and thermal and chemical nonequilibrium flows. Often, hypersonic turbulent flows in re-entry space vehicles and space physics involve mixed steady strong shocks and turbulence with unsteady shocklets. Material mixing in combustion poses additional computational challenges. Proper control of numerical dissipation in numerical methods beyond the standard shock-capturing dissipation at discontinuities is an essential element for accurate and stable simulations of the subject physics. On one hand, the physics of strong steady shocks and unsteady turbulence/shocklet interactions under the nonequilibrium environment is not well understood. On the other hand, standard and newly developed high order accurate (fourth-order or higher) schemes were developed for homogeneous hyperbolic conservation laws and mixed hyperbolic and parabolic partial differential equations (PDEs) (without source terms). The majority of finite rate chemistry and thermal nonequilibrium simulations employ methods for homogeneous time-dependent PDEs with a pointwise evaluation of the source terms. The pointwise evaluation of the source term might not be the best choice for stability, accuracy and minimization of spurious numerics for the overall scheme.

Yee, H C; Sjogreen, B

2009-01-14T23:59:59.000Z

87

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

88

Numerical Simulation Of Utility Boilers With Advanced Combustion Technologies  

E-Print Network (OSTI)

This paper presents calculations of a pulverized coal flame and a coal-fired utility boiler with advanced combustion technologies. A combustion model based on an extended Eddy Dissipation Concept (EDC) combined with finite rate chemistry is described and some applications are shown. This model can be regarded as an extension of the previously used Eddy Breakup model (EBU) where infinite fast chemistry is assumed. It is part of a 3D-prediction code for quasi-stationary turbulent reacting flows which is based on a conservative finite-volume solution procedure. Equations are solved for the conservation of mass, momentum and scalar quantities. A domain decomposition method is used to introduce locally refined grids. Validation and comparison of both combustion models are made by comparison with measurement data of a swirled flame with air staging in a semi-industrial pulverized coal combustion facility. The application to three-dimensional combustion systems is demonstrated by the simulati...

H. C. Magel; R. Schneider; B. Risio; U. Schnell; K. R. G. Hein

1995-01-01T23:59:59.000Z

89

Visual Analysis of Particle Behaviors to Understand Combustion Simulations  

Science Conference Proceedings (OSTI)

Simulations of turbulent flames have used particles to capture the dynamic behavior of combustion in next-generation engines. Each particle includes a history of its movement positions and changing thermochemical states. Analyzing such a set of many ... Keywords: visualization, simulation, modeling, machine learning, artificial intelligence, computer graphics, graphics and multimedia

Jishang Wei; Hongfeng Yu; Ray Grout; Jacqueline Chen; Kwan-Liu Ma

2012-01-01T23:59:59.000Z

90

Combustion 2000  

SciTech Connect

This report is a presentation of work carried out on Phase II of the HIPPS program under DOE contract DE-AC22-95PC95144 from June 1995 to March 2001. The objective of this report is to emphasize the results and achievements of the program and not to archive every detail of the past six years of effort. These details are already available in the twenty-two quarterly reports previously submitted to DOE and in the final report from Phase I. The report is divided into three major foci, indicative of the three operational groupings of the program as it evolved, was restructured, or overtaken by events. In each of these areas, the results exceeded DOE goals and expectations. HIPPS Systems and Cycles (including thermodynamic cycles, power cycle alternatives, baseline plant costs and new opportunities) HITAF Components and Designs (including design of heat exchangers, materials, ash management and combustor design) Testing Program for Radiative and Convective Air Heaters (including the design and construction of the test furnace and the results of the tests) There are several topics that were part of the original program but whose importance was diminished when the contract was significantly modified. The elimination of the subsystem testing and the Phase III demonstration lessened the relevance of subtasks related to these efforts. For example, the cross flow mixing study, the CFD modeling of the convective air heater and the power island analysis are important to a commercial plant design but not to the R&D product contained in this report. These topics are of course, discussed in the quarterly reports under this contract. The DOE goal for the High Performance Power Plant System ( HIPPS ) is high thermodynamic efficiency and significantly reduced emissions. Specifically, the goal is a 300 MWe plant with > 47% (HHV) overall efficiency and {le} 0.1 NSPS emissions. This plant must fire at least 65% coal with the balance being made up by a premium fuel such as natural gas. To achieve these objectives requires a change from complete reliance of coal-fired systems on steam turbines (Rankine cycles) and moving forward to a combined cycle utilizing gas turbines (Brayton cycles) which offer the possibility of significantly greater efficiency. This is because gas turbine cycles operate at temperatures well beyond current steam cycles, allowing the working fluid (air) temperature to more closely approach that of the major energy source, the combustion of coal. In fact, a good figure of merit for a HIPPS design is just how much of the enthalpy from coal combustion is used by the gas turbine. The efficiency of a power cycle varies directly with the temperature of the working fluid and for contemporary gas turbines the optimal turbine inlet temperature is in the range of 2300-2500 F (1260-1371 C). These temperatures are beyond the working range of currently available alloys and are also in the range of the ash fusion temperature of most coals. These two sets of physical properties combine to produce the major engineering challenges for a HIPPS design. The UTRC team developed a design hierarchy to impose more rigor in our approach. Once the size of the plant had been determined by the choice of gas turbine and the matching steam turbine, the design process of the High Temperature Advanced Furnace (HITAF) moved ineluctably to a down-fired, slagging configuration. This design was based on two air heaters: one a high temperature slagging Radiative Air Heater (RAH) and a lower temperature, dry ash Convective Air Heater (CAH). The specific details of the air heaters are arrived at by an iterative sequence in the following order:-Starting from the overall Cycle requirements which set the limits for the combustion and heat transfer analysis-The available enthalpy determined the range of materials, ceramics or alloys, which could tolerate the temperatures-Structural Analysis of the designs proved to be the major limitation-Finally the commercialization issues of fabrication and reliability, availability and maintenance. The program that has s

A. Levasseur; S. Goodstine; J. Ruby; M. Nawaz; C. Senior; F. Robson; S. Lehman; W. Blecher; W. Fugard; A. Rao; A. Sarofim; P. Smith; D. Pershing; E. Eddings; M. Cremer; J. Hurley; G. Weber; M. Jones; M. Collings; D. Hajicek; A. Henderson; P. Klevan; D. Seery; B. Knight; R. Lessard; J. Sangiovanni; A. Dennis; C. Bird; W. Sutton; N. Bornstein; F. Cogswell; C. Randino; S. Gale; Mike Heap

2001-06-30T23:59:59.000Z

91

First Hybrid Turbulence Modeling for Turbine Blade Cooling Sagar Kapadia*  

E-Print Network (OSTI)

First Hybrid Turbulence Modeling for Turbine Blade Cooling Sagar Kapadia* and Subrata Roy turbines require proper cooling mechanism to protect the airfoils from thermal stresses generated by exposure to hot combustion gases. The problem becomes aggravated by the growing trend to use higher turbine

Roy, Subrata

92

Vehículos de Célula de Combustible  

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

de Clula de Combustible Vehculo de Clula de Combustible Honda Clarity FCX Los vehculos de clula de combustible (FCVs)tambin llamados de pila de combustibletienen el...

93

Transport Properties for Combustion Modeling  

E-Print Network (OSTI)

a critical role in combustion processes just as chemicalparameters are essential for combustion modeling; molecularwith Application to Combustion. Transport Theor Stat 2003;

Brown, N.J.

2010-01-01T23:59:59.000Z

94

Solution Combustion Synthesis Impregnated Layer Combustion Synthesis is a Novel  

E-Print Network (OSTI)

Solution Combustion Synthesis Impregnated Layer Combustion Synthesis is a Novel Methodology Engineering University of Notre Dame University of Notre Dame #12;Outline: Overview of combustion synthesis Reaction system Combustion front analaysis Theoretical model results Conclusions Acknowledgements #12

Mukasyan, Alexander

95

HYDROGEN ASSISTED DIESEL COMBUSTION.  

E-Print Network (OSTI)

??In this study, the effect of hydrogen assisted diesel combustion on conventional and advanced combustion modes was investigated on a DDC/VM Motori 2.5L, 4-cylinder, turbocharged,… (more)

Lilik, Gregory

2008-01-01T23:59:59.000Z

96

Turbulent flow in graphene  

E-Print Network (OSTI)

We demonstrate the possibility of a turbulent flow of electrons in graphene in the hydrodynamic region, by calculating the corresponding turbulent probability density function. This is used to calculate the contribution of the turbulent flow to the conductivity within a quantum Boltzmann approach. The dependence of the conductivity on the system parameters arising from the turbulent flow is very different from that due to scattering.

Kumar S. Gupta; Siddhartha Sen

2009-11-03T23:59:59.000Z

97

Combustion oscillation control  

SciTech Connect

Premixing of fuel and air can avoid high temperatures which produce thermal NOx, but oscillating combustion must be eliminated. Combustion oscillations can also occur in Integrated Gasification Combined Cycle turbines. As an alternative to design or operating modifications, METC is investigating active combustion control (ACC) to eliminate oscillations; ACC uses repeated adjustment of some combustion parameter to control the variation in heat release that drives oscillations.

Richards, G.A.; Janus, M.C.

1996-12-31T23:59:59.000Z

98

Quantum Gravity and Turbulence  

E-Print Network (OSTI)

We apply recent advances in quantum gravity to the problem of turbulence. Adopting the AdS/CFT approach we propose a string theory of turbulence that explains the Kolmogorov scaling in 3+1 dimensions and the Kraichnan and Kolmogorov scalings in 2+1 dimensions. In the gravitational context, turbulence is intimately related to the properties of spacetime, or quantum, foam.

Vishnu Jejjala; Djordje Minic; Y. Jack Ng; Chia-Hsiung Tze

2010-05-18T23:59:59.000Z

99

Proceedings: Coal Combustion Workshop  

Science Conference Proceedings (OSTI)

The primary objective of the 2007 Coal Combustion workshop was to present a holistic view of the various combustion processes required for minimal emissions, peak performance, and maximum reliability in a coal-fired power plant. The workshop also defined needs for future RD in coal combustion technology.

2008-01-09T23:59:59.000Z

100

One-dimensional turbulence model simulations of autoignition of hydrogen/carbon monoxide fuel mixtures in a turbulent jet  

Science Conference Proceedings (OSTI)

The autoignition of hydrogen/carbon monoxide in a turbulent jet with preheated co-flow air is studied using the one-dimensional turbulence (ODT) model. The simulations are performed at atmospheric pressure based on varying the jet Reynolds number and the oxidizer preheat temperature for two compositions corresponding to varying the ratios of H{sub 2} and CO in the fuel stream. Moreover, simulations for homogeneous autoignition are implemented for similar mixture conditions for comparison with the turbulent jet results. The results identify the key effects of differential diffusion and turbulence on the onset and eventual progress of autoignition in the turbulent jets. The differential diffusion of hydrogen fuels results in a reduction of the ignition delay relative to similar conditions of homogeneous autoignition. Turbulence may play an important role in delaying ignition at high-turbulence conditions, a process countered by the differential diffusion of hydrogen relative to carbon monoxide; however, when ignition is established, turbulence enhances the overall rates of combustion of the non-premixed flame downstream of the ignition point. (author)

Gupta, Kamlesh G.; Echekki, Tarek [Department of Mechanical and Aerospace Engineering, North Carolina State University, NC (United States)

2011-02-15T23:59:59.000Z

Note: This page contains sample records for the topic "turbulent nuclear combustion" 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

Identification of hazards in non-nuclear power plants. [Public health hazards of fossil-fuel, combined cycle, combustion turbine, and geothermal power plants  

DOE Green Energy (OSTI)

Public health and safety hazards have been identified for five types of power plants: coal-fired, oil-fired steam turbine, combined cycle, combustion (gas) turbine, and geothermal. The results of the analysis show that air pollutants are the major hazard that affects the health and safety of the general public. A total of ninety plant hazards were identified for the five plant types. Each of these hazards were rated in six categories as to their affect on the general public. The criteria used in the analysis were: area/population exposed; duration; mitigation; quantity to toxicity ratio; nature of health effects; and public attitude. Even though ninety hazards were identified for the five plants analyzed, the large majority of hazards were similar for each plant. Highest ratings were given to the products of the combustion cycle or to hydrogen sulfide emissions from geothermal plants. Water pollution, cooling tower effects and noise received relatively low ratings. The highest rated of the infrequent or hypothetical hazards were those associated with potential fires, explosions, and chlorine releases at the plant. Hazards associated with major cooling water releases, water pollution and missiles received the lowest ratings. Since the results of the study clearly show that air pollutants are currently considered the most severe hazard, additional effort must be made to further understand the complex interactions of pollutants with man and his environment. Of particular importance is the determination of dose-response relationships for long term, low level exposure to air pollutants. (EDB)

Roman, W.S.; Israel, W.J.; Sacramo, R.F.

1978-07-01T23:59:59.000Z

102

MHD Turbulence Revisited  

E-Print Network (OSTI)

Kraichnan (1965) proposed that MHD turbulence occurs as a result of collisions between oppositely directed Alfvén wave packets. Recent work has generated some controversy over the nature of non linear couplings between colliding Alfvén waves. We find that the resolution to much of the confusion lies in the existence of a new type of turbulence, intermediate turbulence, in which the cascade of energy in the inertial range exhibits properties intermediate between those of weak and strong turbulent cascades. Some properties of intermediate MHD turbulence are: (i) in common with weak turbulent cascades, wave packets belonging to the inertial range are long lived; (ii) however, components of the strain tensor are so large that, similar to the situation in strong turbulence, perturbation theory is not applicable; (iii) the breakdown of perturbation theory results from the divergence of neighboring field lines due to wave packets whose perturbations in velocity and magnetic fields are localized, but whose perturba...

Goldreich, P

1996-01-01T23:59:59.000Z

103

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

104

3-D turbulent particle dispersion submodel development. Quarterly progress report No. 3, October 15, 1991--January 15, 1992  

Science Conference Proceedings (OSTI)

Many practical combustion processes which use solid particles, liquid droplets, or slurries as fuels introduce these fuels into turbulent environments. Examples include spray combustion, pulverized coal and coal slurry combustion, fluidized beds, sorbent injection, and hazardous waste incineration. The interactions of the condensed phases with turbulent environments have not been well described. Such a description is complicated by the difficulty of describing turbulence in general, even in the absence of particles or droplets. But the complications in describing the dispersion and reaction of the condensed phases in turbulent environments do not stem entirely or even primarily from the uncertainties in the description of the turbulence. Theoretical descriptions of the turbulent dispersion of particles and droplets are not well established, even when the characteristics of the turbulence are known. Several new theoretical descriptions of the turbulent dispersion of particles an droplets have proposed over the past five years. It is the purpose of this project to explore the potential of two of these theories for coupling with the other aspects of three-dimensional, reacting, turbulent, particle-laden systems to proved computational simulations that could be useful for addressing industrial problems.

Smith, P.J.

1994-09-01T23:59:59.000Z

105

Boiler using combustible fluid  

DOE Patents (OSTI)

A fluid fuel boiler is described comprising a combustion chamber, a cover on the combustion chamber having an opening for introducing a combustion-supporting gaseous fluid through said openings, means to impart rotation to the gaseous fluid about an axis of the combustion chamber, a burner for introducing a fluid fuel into the chamber mixed with the gaseous fluid for combustion thereof, the cover having a generally frustro-conical configuration diverging from the opening toward the interior of the chamber at an angle of between 15/sup 0/ and 55/sup 0/; means defining said combustion chamber having means defining a plurality of axial hot gas flow paths from a downstream portion of the combustion chamber to flow hot gases into an upstream portion of the combustion chamber, and means for diverting some of the hot gas flow along paths in a direction circumferentially of the combustion chamber, with the latter paths being immersed in the water flow path thereby to improve heat transfer and terminating in a gas outlet, the combustion chamber comprising at least one modular element, joined axially to the frustro-conical cover and coaxial therewith. The modular element comprises an inner ring and means of defining the circumferential, radial, and spiral flow paths of the hot gases.

Baumgartner, H.; Meier, J.G.

1974-07-03T23:59:59.000Z

106

Heat release effects on decaying homogeneous compressible turbulence  

E-Print Network (OSTI)

High Mach-number compressible flows with heat release are inherently more complicated than incompressible flows due to, among other reasons, the activation of the thermal energy mode. Such flow fields can experience significant fluctuations in density, temperature, viscosity, conductivity and specific heat, which affect velocity and pressure fluctuations. Furthermore, the flow field cannot be assumed to be dilatation-free in high Mach numbers and even in low Mach-number flows involving combustion, or in boundary layers on heated walls. The main issue in these high-speed and highly-compressible flows is the effect of thermal gradients and fluctuations on turbulence. The thermal field has various routes through which it affects flow structures of compressible turbulence. First, it has direct influence through pressure, which affects turbulence via pressure-strain correlation. The indirect effects of thermal fields on compressible turbulence are through the changes in flow properties. The high temperature gradients alter the transport coefficient and compressibility of the flow. The objective of this work is to answer the following questions: How do temperature fluctuations change the compressible flow structure and energetics? How does compressibility in the flow affect the non-linear pressure redistribution process? What is the main effect of spatial transport-coefficient variation? We perform direct numerical simulations (DNS) to answer the above questions. The investigations are categorized into four parts: 1) Turbulent energy cascade and kinetic-internal energy interactions under the influence of temperature fluctuations; 2) Return-to-isotropy of anisotropic turbulence under the influence of large temperature fluctuations; 3) The effect of turbulent Mach number and dilatation level on small-scale (velocity-gradient) dynamics; 4) The effect of variable transport-coefficients (viscosity and diffusivity) on cascade and dissipation processes of turbulence. The findings lead to a better understanding of temperature fluctuation effects on non-linear processes in compressible turbulence. This improved understanding is expected to provide direction for improving second-order closure models of compressible turbulence.

Lee, Kurn Chul

2008-05-01T23:59:59.000Z

107

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

108

Is combustion of plastics desirable?  

Science Conference Proceedings (OSTI)

Managing waste will always entail some tradeoffs. All of the three options--recycling, landfilling and combustion--have some disadvantages. Even landfilling, which produces no emissions, fails to take advantage of the energy value inherent in plastic. Waste combustion, on the other hand, recovers the energy in plastic materials and reduces the volume of disposed solid waste by up to 90% of its initial preburn volumes. However, this management option generates emissions and produces an ash residue that must be managed. As demonstrated by recent test burns, improvements in combustion and air-pollution-control technology have dramatically reduced the health risks from emissions and ash. Recent studies have shown that plastics--in quantities even higher than those normally found in municipal solid waste--do not adversely affect levels of emissions or the quality of ash from waste-to-energy facilities. In addition, waste-to-energy facilities may be a relatively economical source of fuel, and may be a more economic solution to waste management than the other available options. A waste-to-energy plant generally produces electricity that is sold to the electric utilities for approximately six cents per kilowatt-hour, a rate that is competitive with those offered by nuclear power plants and power plants that generate energy by burning fossil fuels.

Piasecki, B.; Rainey, D. [Rensselaer Polytechnic Inst., Troy, NY (United States). Lally School of Management and Technology; Fletcher, K.

1998-07-01T23:59:59.000Z

109

Radiosonde measurements of turbulence  

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

at Cranwell, Lincolnshire, W. H. Pick and G. A. Bull, 1926. 3 Talk structure * Geomagnetic sensors to measure orientation * Orientation variability as a turbulence measure *...

110

Precision Combustion, Inc  

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

Developing Reliable, Cost Effective Fuel Processors. Abstract: Precision Combustion, Inc. (PCI) is developing ultra-compact Fuel Processing systems for a range of Fuel Cells and...

111

Low NOx combustion  

DOE Patents (OSTI)

Combustion of hydrocarbon liquids and solids is achieved with less formation of NOx by feeding a small amount of oxygen into the fuel stream.

Kobayashi, Hisashi (Putnam Valley, NY); Bool, III, Lawrence E. (Aurora, NY)

2008-10-21T23:59:59.000Z

112

Low NOx combustion  

DOE Patents (OSTI)

Combustion of hydrocarbon liquids and solids is achieved with less formation of NOx by feeding a small amount of oxygen into the fuel stream.

Kobayashi; Hisashi (Putnam Valley, NY), Bool, III; Lawrence E. (Aurora, NY)

2007-06-05T23:59:59.000Z

113

Spectral Wave–Turbulence Decomposition  

Science Conference Proceedings (OSTI)

A new method of wave–turbulence decomposition is introduced, for which the only instrument required is one high-frequency pointwise velocity sensor. This is a spectral method that assumes equilibrium turbulence and no wave–turbulence interaction. ...

Jeremy D. Bricker; Stephen G. Monismith

2007-08-01T23:59:59.000Z

114

Contrôle de combustion en transitoires des moteurs à combustion interne.  

E-Print Network (OSTI)

??Cette thèse traite le problème du contrôle de combustion des moteurs automobiles à combustion interne. On propose une méthode complétant les stratégies de contrôle existantes… (more)

Hillion, Mathieu

2009-01-01T23:59:59.000Z

115

Fossil turbulence and fossil turbulence waves can be dangerous  

E-Print Network (OSTI)

Turbulence is defined as an eddy-like state of fluid motion where the inertial-vortex forces of the eddies are larger than any other forces that tend to damp the eddies out. By this definition, turbulence always cascades from small scales where vorticity is created to larger scales where turbulence fossilizes. Fossil turbulence is any perturbation in a hydrophysical field produced by turbulence that persists after the fluid is no longer turbulent at the scale of the perturbation. Fossil turbulence patterns and fossil turbulence waves preserve and propagate energy and information about previous turbulence. Ignorance of fossil turbulence properties can be dangerous. Examples include the Osama bin Laden helicopter crash and the Air France 447 Airbus crash, both unfairly blamed on the pilots. Observations support the proposed definitions, and suggest even direct numerical simulations of turbulence require caution.

Carl H Gibson

2012-11-25T23:59:59.000Z

116

COMBUSTION SOURCES OF NITROGEN COMPOUNDS  

E-Print Network (OSTI)

Rasmussen, R.A. (1976). Combustion as a source of nitrousx control for stationary combustion sources. Prog. Energy,CA, March 3-4, 1977 COMBUSTION SOURCES OF NITROGEN COMPOUNDS

Brown, Nancy J.

2011-01-01T23:59:59.000Z

117

Fifteenth combustion research conference  

Science Conference Proceedings (OSTI)

The BES research efforts cover chemical reaction theory, experimental dynamics and spectroscopy, thermodynamics of combustion intermediates, chemical kinetics, reaction mechanisms, combustion diagnostics, and fluid dynamics and chemically reacting flows. 98 papers and abstracts are included. Separate abstracts were prepared for the papers.

NONE

1993-06-01T23:59:59.000Z

118

Coal Combustion Science  

SciTech Connect

The objective of this activity is to support the Office of Fossil Energy in executing research on coal combustion science. This activity consists of basic research on coal combustion that supports both the Pittsburgh Energy Technology Center Direct Utilization Advanced Research and Technology Development Program, and the International Energy Agency Coal Combustion Science Project. Specific tasks for this activity include: (1) coal devolatilization - the objective of this risk is to characterize the physical and chemical processes that constitute the early devolatilization phase of coal combustion as a function of coal type, heating rate, particle size and temperature, and gas phase temperature and oxidizer concentration; (2) coal char combustion -the objective of this task is to characterize the physical and chemical processes involved during coal char combustion as a function of coal type, particle size and temperature, and gas phase temperature and oxygen concentration; (3) fate of mineral matter during coal combustion - the objective of this task is to establish a quantitative understanding of the mechanisms and rates of transformation, fragmentation, and deposition of mineral matter in coal combustion environments as a function of coal type, particle size and temperature, the initial forms and distribution of mineral species in the unreacted coal, and the local gas temperature and composition.

Hardesty, D.R. (ed.); Fletcher, T.H.; Hurt, R.H.; Baxter, L.L. (Sandia National Labs., Livermore, CA (United States))

1991-08-01T23:59:59.000Z

119

Chemical turbulence equivalent to Nikolavskii turbulence  

E-Print Network (OSTI)

We find evidence that a certain class of reaction-diffusion systems can exhibit chemical turbulence equivalent to Nikolaevskii turbulence. The distinctive characteristic of this type of turbulence is that it results from the interaction of weakly stable long-wavelength modes and unstable short-wavelength modes. We indirectly study this class of reaction-diffusion systems by considering an extended complex Ginzburg-Landau (CGL) equation that was previously derived from this class of reaction-diffusion systems. First, we show numerically that the power spectrum of this CGL equation in a particular regime is qualitatively quite similar to that of the Nikolaevskii equation. Then, we demonstrate that the Nikolaevskii equation can in fact be obtained from this CGL equation through a phase reduction procedure applied in the neighborhood of a codimension-two Turing--Benjamin-Feir point.

Dan Tanaka

2004-03-09T23:59:59.000Z

120

SIAM Conference on Numerical Combustion Sedona, AZ May 9-12, 2004  

Science Conference Proceedings (OSTI)

The Society for Industrial and Applied Mathematics hosted the Tenth International Conference on Numerical Combustion held May 9-12, 2004 in Sedona, Arizona. This distinguished conference series began in 1985 in Sophia Antipolis, France and was followed by conferences in San Francisco, California (1987), Juan les Pins, France (1989), St. Petersburg Beach, Florida (1991), Garmisch, Germany (1993), New Orleans, Louisiana (1996), York, England (1998), Amelia Island, Florida (2000), and Sorrento, Italy (2002). SIAM is widely recognized as the originator and the U.S. anchor of this important meeting whose topics concerns the applied mathematics and computation associated with combustion and reactive flow. In particular, the International Numerical Combustion Symposiums have become one of the international major venues for research on direct simulation and modeling turbulent reacting flow. It is also one of the major international venues for theoretical work in reacting flows. This meeting drew approximately 200 participants from 30 countries whose research included the topics in turbulence, kinetics, detonation, flames, pollution, microgravity, micro-combustion, ignition, applications of parallel processing, tera-scale computation of combustion applications, material synthesis, droplets and sprays, heterogeneous combustion, energetic materials (propellants and explosives), engine and furnace combustion, fires, numerical methods and, software engineering for combustion applications.

None

2004-09-23T23:59:59.000Z

Note: This page contains sample records for the topic "turbulent nuclear combustion" 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

NUMERICAL MODELING OF TURBULENT FLOW IN A COMBUSTION TUNNEL  

E-Print Network (OSTI)

Chorin, A. J. (1980b) l• Flame Advection and Propagationc) Algorithm •. (d) Results •••. FLAME PROPAGATION (a)avoids ca"lculating the flame length as required by Eq. (

Ghoniem, A.F.

2013-01-01T23:59:59.000Z

122

Turbulent partially premixed combustion: DNS analysis and RANS simulation  

E-Print Network (OSTI)

7.1 Modelling Methodology . . . . . . . . . . . . . . . . . . . . . . . . 132 7.2 Model Implementation . . . . . . . . . . . . . . . . . . . . . . . . 135 7.2.1 Boundary Conditions . . . . . . . . . . . . . . . . . . . . . 136 7.2.2 Fluent UDF... 7.1 Modelling Methodology . . . . . . . . . . . . . . . . . . . . . . . . 132 7.2 Model Implementation . . . . . . . . . . . . . . . . . . . . . . . . 135 7.2.1 Boundary Conditions . . . . . . . . . . . . . . . . . . . . . 136 7.2.2 Fluent UDF...

Ruan, S.

2013-03-12T23:59:59.000Z

123

Transport Properties for Combustion Modeling  

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

Transport Properties for Combustion Modeling Title Transport Properties for Combustion Modeling Publication Type Journal Article Year of Publication 2011 Authors Brown, Nancy J.,...

124

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

E-Print Network (OSTI)

and as a friend. The experiences we have shared over the past few years, from turbulence to tea-breaks, are among my fondest memories of Cambridge. a Work at Sandia was supported by the United States Department of Energy, Office of Basic Energy Sciences... to the rapid advancement of newly industrialized countries such as China, India and Brazil. Combustion of fossil fuels accounts for the vast majority of energy production (67%), with natural gas combustion contributing approximately 22% of total energy...

Sweeney, Mark

2011-11-08T23:59:59.000Z

125

Oxy-coal Combustion Studies  

SciTech Connect

The objective of this project is to move toward the development of a predictive capability with quantified uncertainty bounds for pilot-scale, single-burner, oxy-coal operation. This validation research brings together multi-scale experimental measurements and computer simulations. The combination of simulation development and validation experiments is designed to lead to predictive tools for the performance of existing air fired pulverized coal boilers that have been retrofitted to various oxy-firing configurations. In addition, this report also describes novel research results related to oxy-combustion in circulating fluidized beds. For pulverized coal combustion configurations, particular attention is focused on the effect of oxy-firing on ignition and coal-flame stability, and on the subsequent partitioning mechanisms of the ash aerosol. To these ends, the project has focused on the following: â?¢ The development of reliable Large Eddy Simulations (LES) of oxy-coal flames using the Direct Quadrature Method of Moments (DQMOM) (Subtask 3.1). The simulations were validated for both non-reacting particle-laden jets and oxy-coal flames. â?¢ The modifications of an existing oxy-coal combustor to allow operation with high levels of input oxygen to enable in-situ laser diagnostic measurements as well as the development of strategies for directed oxygen injection (Subtask 3.2). Flame stability was quantified for various burner configurations. One configuration that was explored was to inject all the oxygen as a pure gas within an annular oxygen lance, with burner aerodynamics controlling the subsequent mixing. â?¢ The development of Particle Image Velocimetry (PIV) for identification of velocity fields in turbulent oxy-coal flames in order to provide high-fidelity data for the validation of oxy-coal simulation models (Subtask 3.3). Initial efforts utilized a laboratory diffusion flame, first using gas-fuel and later a pulverized-coal flame to ensure the methodology was properly implemented and that all necessary data and image-processing techniques were fully developed. Success at this stage of development led to application of the diagnostics in a large-scale oxy-fuel combustor (OFC). â?¢ The impact of oxy-coal-fired vs. air-fired environments on SO{sub x} (SO{sub 2}, SO{sub 3}) emissions during coal combustion in a pilot-scale circulating fluidized-bed (CFB) (Subtask 3.4). Profiles of species concentration and temperature were obtained for both conditions, and profiles of temperature over a wide range of O{sub 2} concentration were studied for oxy-firing conditions. The effect of limestone addition on SO{sub 2} and SO{sub 3} emissions were also examined for both air- and oxy- firing conditions. â?¢ The investigation of O{sub 2}/CO{sub 2} and O{sub 2}/N{sub 2} environments on SO{sub 2 emissions during coal combustion in a bench-scale single-particle fluidized-bed reactor (Subtask 3.5). Moreover, the sulfation mechanisms of limestone in O{sub 2}/CO{sub 2} and O{sub 2}/N{sub 2} environments were studied, and a generalized gassolid and diffusion-reaction single-particle model was developed to study the effect of major operating variables. â?¢ The investigation of the effect of oxy-coal combustion on ash formation, particle size distributions (PSD), and size-segregated elemental composition in a drop-tube furnace and the 100 kW OFC (Subtask 3.6). In particular, the effect of coal type and flue gas recycle (FGR, OFC only) was investigated.

J. Wendt; E. Eddings; J. Lighty; T. Ring; P. Smith; J. Thornock; Y. Jia, W. Morris; J. Pedel; D. Rezeai; L. Wang; J. Zhang; K. Kelly

2012-01-01T23:59:59.000Z

126

Computation of azimuthal combustion instabilities in an helicopter combustion chamber  

E-Print Network (OSTI)

Computation of azimuthal combustion instabilities in an helicopter combustion chamber C. Sensiau to compute azimuthal combustion instabilities is presented. It requires a thermoacoustic model using a n - formulation for the coupling between acoutics and combustion. The parameters n and are computed from a LES

Nicoud, Franck

127

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

128

Coal combustion products (CCPs  

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

combustion products (CCPs) combustion products (CCPs) are solid materials produced when coal is burned to generate electricity. Since coal provides the largest segment of U.S. electricity generation (45 percent in 2010), finding a sustainable solution for CCPs is an important environmental challenge. When properly managed, CCPs offer society environmental and economic benefits without harm to public health and safety. Research supported by the U.S. Department of Energy's (DOE) Office of Fossil Energy (FE) has made an important contribution in this regard. Fossil Energy Research Benefits Coal Combustion Products Fossil Energy Research Benefits

129

Gas turbine combustion instability  

DOE Green Energy (OSTI)

Combustion oscillations are a common problem in development of LPM (lean premix) combustors. Unlike earlier, diffusion style combustors, LPM combustors are especially susceptible to oscillations because acoustic losses are smaller and operation near lean blowoff produces a greater combustion response to disturbances in reactant supply, mixing, etc. In ongoing tests at METC, five instability mechanisms have been identified in subscale and commercial scale nozzle tests. Changes to fuel nozzle geometry showed that it is possible to stabilize combustion by altering the timing of the feedback between acoustic waves and the variation in heat release.

Richards, G.A.; Lee, G.T.

1996-09-01T23:59:59.000Z

130

Internal combustion engine  

SciTech Connect

An improvement to an internal combustion engine is disclosed that has a fuel system for feeding a fuel-air mixture to the combustion chambers and an electrical generation system, such as an alternator. An electrolytic cell is attached adjacent to the engine to generate hydrogen and oxygen upon the application of a voltage between the cathode and anode of the electrolytic cell. The gas feed connects the electrolytic cell to the engine fuel system for feeding the hydrogen and oxygen to the engine combustion chambers. Improvements include placing the electrolytic cell under a predetermined pressure to prevent the electrolyte from boiling off, a cooling system for the electrolytic cell and safety features.

Valdespino, J.M.

1981-06-09T23:59:59.000Z

131

Theoretical studies on hydrogen ignition and droplet combustion  

E-Print Network (OSTI)

1.2 Droplet Combustion . . . . . . . . . . . . .Combustion . . . . . . . . . . . . . . . . . . . . . . . . . .Lewis, B. and von Elbe, G. Combustion, Flames and Explosions

Del Álamo, Gonzalo

2006-01-01T23:59:59.000Z

132

Sandia Combustion Research: Technical review  

SciTech Connect

This report contains reports from research programs conducted at the Sandia Combustion Research Facility. Research is presented under the following topics: laser based diagnostics; combustion chemistry; reacting flow; combustion in engines and commercial burners; coal combustion; and industrial processing. Individual projects were processed separately for entry onto the DOE databases.

NONE

1995-07-01T23:59:59.000Z

133

Photo of Spray Combustion Chamber  

Science Conference Proceedings (OSTI)

NIST Spray Combustion Chamber. NIST, National Institute of Standards and Technology, Material Measurement Laboratory, ...

2013-07-15T23:59:59.000Z

134

Engine Combustion & Efficiency - FEERC  

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

Engine Combustion & Efficiency Engine Combustion & Efficiency ORNL currently and historically supports the U.S. DOE on multi-cylinder and vehicle applications of diesel combustion, lean burn gasoline combustion, and low temperature combustion processes, and performs principal research on efficiency enabling technologies including emission controls, thermal energy recovery, and bio-renewable fuels. Research areas span from fundamental concepts to engine/vehicle integration and demonstration with a particular emphasis on the following areas: Thermodynamics for identifying and characterizing efficiency opportunities for engine-systems as well as the development of non-conventional combustion concepts for reducing fundamental combustion losses. Nonlinear sciences for improving the physical understanding and

135

Definition: Combustion | Open Energy Information  

Open Energy Info (EERE)

Combustion Combustion Jump to: navigation, search Dictionary.png Combustion The process of burning; chemical oxidation accompanied by the generation of light and heat.[1][2] View on Wikipedia Wikipedia Definition "Burning" redirects here. For combustion without external ignition, see spontaneous combustion. For the vehicle engine, see internal combustion engine. For other uses, see Burning (disambiguation) and Combustion (disambiguation). Error creating thumbnail: Unable to create destination directory This article's introduction section may not adequately summarize its contents. To comply with Wikipedia's lead section guidelines, please consider modifying the lead to provide an accessible overview of the article's key points in such a way that it can stand on its own as a

136

Spontaneous Human Combustion  

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

Spontaneous Human Combustion Spontaneous Human Combustion Name: S. Phillips. Age: N/A Location: N/A Country: N/A Date: N/A Question: One of our 8th grade students has tried to find information in our library about spontaneous human combustion, but to no avail. Could you tell us where we might locate a simple reference, or provide some in information about this subject for him. Replies: Sorry, but this is definitely "fringe science"...try asking in bookstores. I seem to recall one of those "believe it or not" type of TV shows did an episode on spontaneous human combustion a few years ago in which they reported on some British scientists who investigated this purported phenomenon. Remember that people (back in the Dark Ages, and before) used to believe in "spontaneous generation" of certain plants and animals because they were not aware of the reproduction methods used by those plants and animals.

137

IN SITU COMBUSTION  

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

a combustion zone that moves through the formation toward production wells, providing a steam drive and an intense gas drive for the recovery of oil. This process is sometimes...

138

NETL: Combustion Technologies  

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

Combustion Technology (June 15-16, 1999) Animal Waste Remediation Roundtable PDF-78KB Advanced Coal-Based Power and Environmental Systems '98 Conference (July 21-23, 1998)...

139

Just the Basics: Combustion  

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

diesel fuel, transportation- based combustion accounts for the majority of our fossil fuel use in the United States, which has led the U.S. to demand a lot of imported oil....

140

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

Note: This page contains sample records for the topic "turbulent nuclear combustion" 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

Observations of Edge Turbulence  

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

Edge Turbulence Edge Turbulence near the X-point of Alcator C-Mod APS-2007 (1) J.L. Terry, S.J. Zweben*, B. LaBombard, I. Cziegler, O. Grulke + , D.P. Stotler* MIT - Plasma Science and Fusion Center *Princeton Plasma Physics Laboratory + MPI for Plasma Physics, EURATOM Assoc., Greifswald, Germany American Physical Society - Div. of Plasma Physics Orlando, FL Nov. 12 - Nov. 16, 2007 APS-2007 (2) Background and Motivation for "Xpt-region" View Strong edge turbulence has been observed in nearly all magnetic confinement devices. Desire predictive capability Most previous measurements made near outboard midplane where the turbulence has the following main features: - generation is ballooning-like (absent at inboard midplane, etc.) - filaments/blobs moves radially outward with some poloidal motion

142

ARM - Measurement - Atmospheric turbulence  

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

turbulence turbulence ARM Data Discovery Browse Data Comments? We would love to hear from you! Send us a note below or call us at 1-888-ARM-DATA. Send Measurement : Atmospheric turbulence High frequency velocity fluctuations that lead to turbulent transport of momentum, heat, mositure, and passive scalars, and often expressed in terms of variances and covariances. Categories Atmospheric State, Surface Properties Instruments The above measurement is considered scientifically relevant for the following instruments. Refer to the datastream (netcdf) file headers of each instrument for a list of all available measurements, including those recorded for diagnostic or quality assurance purposes. ARM Instruments CO2FLX : Carbon Dioxide Flux Measurement Systems ECOR : Eddy Correlation Flux Measurement System

143

MHD Turbulence Revisited  

E-Print Network (OSTI)

Kraichnan (1965) proposed that MHD turbulence occurs as a result of collisions between oppositely directed Alfv\\'en wave packets. Recent work has generated some controversy over the nature of non linear couplings between colliding Alfv\\'en waves. We find that the resolution to much of the confusion lies in the existence of a new type of turbulence, intermediate turbulence, in which the cascade of energy in the inertial range exhibits properties intermediate between those of weak and strong turbulent cascades. Some properties of intermediate MHD turbulence are: (i) in common with weak turbulent cascades, wave packets belonging to the inertial range are long lived; (ii) however, components of the strain tensor are so large that, similar to the situation in strong turbulence, perturbation theory is not applicable; (iii) the breakdown of perturbation theory results from the divergence of neighboring field lines due to wave packets whose perturbations in velocity and magnetic fields are localized, but whose perturbations in displacement are not; (iv) 3--wave interactions dominate individual collisions between wave packets, but interactions of all orders $n\\geq 3$ make comparable contributions to the intermediate turbulent energy cascade; (v) successive collisions are correlated since wave packets are distorted as they follow diverging field lines; (vi) in common with the weak MHD cascade, there is no parallel cascade of energy, and the cascade to small perpendicular scales strengthens as it reaches higher wave numbers; (vii) For an appropriate weak excitation, there is a natural progression from a weak, through an intermediate, to a strong cascade.

P. Goldreich; S. Sridhar

1996-12-31T23:59:59.000Z

144

METC Combustion Research Facility  

SciTech Connect

The objective of the Morgantown Energy Technology Center (METC) high pressure combustion facility is to provide a mid-scale facility for combustion and cleanup research to support DOE`s advanced gas turbine, pressurized, fluidized-bed combustion, and hot gas cleanup programs. The facility is intended to fill a gap between lab scale facilities typical of universities and large scale combustion/turbine test facilities typical of turbine manufacturers. The facility is now available to industry and university partners through cooperative programs with METC. High pressure combustion research is also important to other DOE programs. Integrated gasification combined cycle (IGCC) systems and second-generation, pressurized, fluidized-bed combustion (PFBC) systems use gas turbines/electric generators as primary power generators. The turbine combustors play an important role in achieving high efficiency and low emissions in these novel systems. These systems use a coal-derived fuel gas as fuel for the turbine combustor. The METC facility is designed to support coal fuel gas-fired combustors as well as the natural gas fired combustor used in the advanced turbine program.

Halow, J.S.; Maloney, D.J.; Richards, G.A.

1993-11-01T23:59:59.000Z

145

Coal combustion system  

SciTech Connect

In a coal combustion system suitable for a gas turbine engine, pulverized coal is transported to a rich zone combustor and burned at an equivalence ratio exceeding 1 at a temperature above the slagging temperature of the coal so that combustible hot gas and molten slag issue from the rich zone combustor. A coolant screen of water stretches across a throat of a quench stage and cools the combustible gas and molten slag to below the slagging temperature of the coal so that the slag freezes and shatters into small pellets. The pelletized slag is separated from the combustible gas in a first inertia separator. Residual ash is separated from the combustible gas in a second inertia separator. The combustible gas is mixed with secondary air in a lean zone combustor and burned at an equivalence ratio of less than 1 to produce hot gas motive at temperature above the coal slagging temperature. The motive fluid is cooled in a dilution stage to an acceptable turbine inlet temperature before being transported to the turbine.

Wilkes, Colin (Lebanon, IN); Mongia, Hukam C. (Carmel, IN); Tramm, Peter C. (Indianapolis, IN)

1988-01-01T23:59:59.000Z

146

Sandia Combustion Research Program  

DOE Green Energy (OSTI)

During the late 1970s, in response to a national energy crisis, Sandia proposed to the US Department of Energy (DOE) a new, ambitious program in combustion research. Shortly thereafter, the Combustion Research Facility (CRF) was established at Sandia's Livermore location. Designated a ''user facility,'' the charter of the CRF was to develop and maintain special-purpose resources to support a nationwide initiative-involving US inventories, industry, and national laboratories--to improve our understanding and control of combustion. This report includes descriptions several research projects which have been simulated by working groups and involve the on-site participation of industry scientists. DOE's Industry Technology Fellowship program, supported through the Office of Energy Research, has been instrumental in the success of some of these joint efforts. The remainder of this report presents results of calendar year 1988, separated thematically into eleven categories. Referred journal articles appearing in print during 1988 and selected other publications are included at the end of Section 11. Our traditional'' research activities--combustion chemistry, reacting flows, diagnostics, engine and coal combustion--have been supplemented by a new effort aimed at understanding combustion-related issues in the management of toxic and hazardous materials.

Johnston, S.C.; Palmer, R.E.; Montana, C.A. (eds.) [eds.

1988-01-01T23:59:59.000Z

147

NATURAL GAS REBURNING TECHNOLOGY FOR NOx REDUCTION FROM MSW COMBUSTION SYSTEMS  

E-Print Network (OSTI)

NATURAL GAS REBURNING TECHNOLOGY FOR NOx REDUCTION FROM MSW COMBUSTION SYSTEMS Discussion by CRAIG's increased turbulent mixing is on the CO profile and what the incremental NOx reduction experienced was from that this alone would contribute to a significant reduction in the NO", generated. The authors are careful

Columbia University

148

The Influence of Stratification and Nonlocal Turbulent Production on Estuarine Turbulence: An Assessment of Turbulence Closure with Field Observations  

Science Conference Proceedings (OSTI)

Field observations of turbulent kinetic energy (TKE), dissipation rate ?, and turbulent length scale demonstrate the impact of both density stratification and nonlocal turbulent production on turbulent momentum flux. The data were collected in a ...

Malcolm E. Scully; W. Rocky Geyer; John H. Trowbridge

2011-01-01T23:59:59.000Z

149

2009 Laser Diagnostics in Combustion GRC  

Science Conference Proceedings (OSTI)

Non-intrusive laser diagnostics for the spatially and temporally resolved measurement of temperature, chemical composition, and flow parameters have emerged over the last few decades as major tools for the study of both fundamental and applied combustion science. Many of the important advances in the field can be attributed to the discussions and ideas emanating from this meeting. This conference, originating in 1981 and held biennially, focuses on laser-based methods for measurement of both macroscopic parameters and the underlying microscale physical and chemical processes. Applications are discussed primarily to elucidate new chemical and physical issues and/or interferences that need to be addressed to improve the accuracy and precision of the various diagnostic approaches or to challenge the community of diagnosticians to invent new measurement techniques. Combustion environments present special challenges to the optical diagnostics community as they address measurements relevant to turbulence, spray and mixture formation, or turbulence/chemistry interactions important in practical combustion systems as well as fundamental chemical reactions in stationary laminar flames. The diagnostics considered may be generally classed as being incoherent, where the signals are radiated isotropically, or coherent, where the signals are generated in a directed, beam-like fashion. Both of the foregoing may employ either electronic or Raman resonance enhancement or a combination of both. Prominent incoherent approaches include laser induced fluorescence (LIF), spontaneous Raman scattering, Rayleigh scattering, laser induced incandescence, molecular flow tagging, and Mie scattering and their two- and three-dimensional imaging variants. Coherent approaches include coherent anti-Stokes Raman scattering (CARS), degenerate four wave mixing (DFWM), polarization spectroscopy (PS), laser induced grating spectroscopy (LIGS) and laser-based absorption spectroscopy. Spectroscopic modelling and validation are key elements to extract accurate parameter measurements and discussions focusing on key energy transfer processes, collisional models, and lineshapes. The properties and behaviour of lasers, optical arrangements and techniques, spectrally-selective and dispersive instruments and detectors are also important determinants of successful measurements and are discussed in detail. Recent developments in the conference have highlighted the application of techniques developed for combustion research that find application in other areas such as biological, atmospheric, chemical engineering or plasma processes.

Volker Sick

2009-08-16T23:59:59.000Z

150

LES/PDF based modeling of sootturbulence interactions in turbulent flames  

E-Print Network (OSTI)

number density function. This LES/PDF approach is then used to simulate a turbulent natural gas jet strong correlation between the gas phase composition and soot moments. Ã? 2012 The Combustion Institute and the gas-phase composition are often neglected. In this case, the PDF is written as the product of the mar

Raman, Venkat

151

Numerical simulation of turbulent flow in complex geometries used in power plants  

Science Conference Proceedings (OSTI)

Performance degradations or improvements of coal-fired power stations depend on effective functioning of pulveriser equipment and combustion efficiency of furnaces in boilers. The function of a pulveriser is to grind the lumped coal and transfer the ... Keywords: CFD, coal fired power station, flow simulation, geometrical modelling, grid generation, particle trajectories, pulveriser, roller mill, turbulent flow, two-phase flow

C. Bhasker

2002-02-01T23:59:59.000Z

152

COMBUSTION-GENERATED INDOOR AIR POLLUTION  

E-Print Network (OSTI)

Pollutants from Indoor Combustion Sources: I. Field Measure-Characteristics in Two Stage Combustion, paper presented atInternational) on Combustion, August, 1974, Tokyo, Japan. 8

Hollowell, C.D.

2011-01-01T23:59:59.000Z

153

Building America Expert Meeting: Combustion Safety | Department...  

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

Meeting: Combustion Safety Building America Expert Meeting: Combustion Safety This is a meeting overview of "The Best Approach to Combustion Safety in a Direct Vent World, held...

154

Coal Combustion Products | Department of Energy  

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

Coal Combustion Products Coal Combustion Products Coal combustion products (CCPs) are solid materials produced when coal is burned to generate electricity. Since coal provides the...

155

Ignition of Combustion Modified Polyurethane Foam  

E-Print Network (OSTI)

Modeling of smoldering combustion propagation," Prog. Energysmoldering to flaming combustion of horizontally orientedThermal decomposition, combustion and fire-retardancy of

Putzeys, Olivier; Fernandez-Pello, Carlos; Urban, Dave L.

2005-01-01T23:59:59.000Z

156

A Generalized Pyrolysis Model for Combustible Solids  

E-Print Network (OSTI)

decomposition fronts in wood,” Combustion and Flame 139: 16–dynamics modeling of wood combustion,” Fire Safety Journalduring the pyrolysis of wood,” Combustion and Flame 17: 79–

Lautenberger, Chris

2007-01-01T23:59:59.000Z

157

Coal Combustion Products | Department of Energy  

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

Combustion Products Coal Combustion Products Coal combustion products (CCPs) are solid materials produced when coal is burned to generate electricity. Since coal provides the...

158

Enlaces de Vehículos de Combustible Fexible  

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

combustible flexible provista por el Alternative Fuels & Advanced Vehicles Data Center (AFDC) del DOE Vehculos de Combustible Flexible: Una alternativa de combustible renovable...

159

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

160

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

Note: This page contains sample records for the topic "turbulent nuclear combustion" 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

Combustible structural composites and methods of forming combustible structural composites  

DOE Patents (OSTI)

Combustible structural composites and methods of forming same are disclosed. In an embodiment, a combustible structural composite includes combustible material comprising a fuel metal and a metal oxide. The fuel metal is present in the combustible material at a weight ratio from 1:9 to 1:1 of the fuel metal to the metal oxide. The fuel metal and the metal oxide are capable of exothermically reacting upon application of energy at or above a threshold value to support self-sustaining combustion of the combustible material within the combustible structural composite. Structural-reinforcing fibers are present in the composite at a weight ratio from 1:20 to 10:1 of the structural-reinforcing fibers to the combustible material. Other embodiments and aspects are disclosed.

Daniels, Michael A. (Idaho Falls, ID); Heaps, Ronald J. (Idaho Falls, ID); Steffler, Eric D (Idaho Falls, ID); Swank, William D. (Idaho Falls, ID)

2011-08-30T23:59:59.000Z

162

Combustion Safety Overview  

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

March 1-2, 2012 March 1-2, 2012 Building America Stakeholders Meeting Austin, Texas Combustion Safety in the Codes Larry Brand Gas Technology Institute Acknowledgement to Paul Cabot - American Gas Association 2 | Building America Program www.buildingamerica.gov Combustion Safety in the Codes Widely adopted fuel gas codes: * National Fuel Gas Code - ANSI Z223.1/NFPA 54, published by AGA and NFPA (NFGC) * International Fuel Gas Code - published by the International Code Council (IFGC) * Uniform Plumbing Code published by IAPMO (UPC) Safety codes become requirements when adopted by the Authority Having Jurisdiction (governments or fire safety authorities) 3 | Building America Program www.buildingamerica.gov Combustion Safety in the Codes Formal Relationships Between these codes: - The IFGC extracts many safety

163

Internal combustion engine  

DOE Patents (OSTI)

An improved engine is provided that more efficiently consumes difficult fuels such as coal slurries or powdered coal. The engine includes a precombustion chamber having a portion thereof formed by an ignition plug. The precombustion chamber is arranged so that when the piston is proximate the head, the precombustion chamber is sealed from the main cylinder or the main combustion chamber and when the piston is remote from the head, the precombustion chamber and main combustion chamber are in communication. The time for burning of fuel in the precombustion chamber can be regulated by the distance required to move the piston from the top dead center position to the position wherein the precombustion chamber and main combustion chamber are in communication.

Baker, Quentin A. (P.O. Box 6477, San Antonio, TX 78209); Mecredy, Henry E. (1630-C W. 6th, Austin, TX 78703); O' Neal, Glenn B. (6503 Wagner Way, San Antonio, TX 78256)

1991-01-01T23:59:59.000Z

164

A Theory of Baroclinic Turbulence  

Science Conference Proceedings (OSTI)

Understanding the physical mechanism maintaining fluid turbulence remains a fundamental theoretical problem. The two-layer model is an analytically and computationally simple system in which the dynamics of turbulence can be conveniently studied; ...

Brian F. Farrell; Petros J. Ioannou

2009-08-01T23:59:59.000Z

165

Statistical Predictability of Decaying Turbulence  

Science Conference Proceedings (OSTI)

We use statistical models of turbulence with “eddy damping” (EDQNM) in order to study the problem of predictability of freely evolving two- and three-dimensional isotropic turbulent flows.

Olivier Métais; Marcel Lesieur

1986-05-01T23:59:59.000Z

166

Supersaturation Intermittency in Turbulent Clouds  

Science Conference Proceedings (OSTI)

It is hypothesized that bursts of high supersaturation are produced in turbulent, convective clouds through interactions between cloud droplets and the small-scale structure of atmospheric turbulence. This hypothesis is based on the observation ...

Raymond A. Shaw

2000-10-01T23:59:59.000Z

167

The Decay of Convective Turbulence  

Science Conference Proceedings (OSTI)

Using simulations with a large-eddy model we have studied the decay of convective turbulence in the atmospheric boundary layer when the upward surface sensible heat flux is suddenly stopped. The decay of turbulent kinetic energy and temperature ...

F. T. M. Nieuwstadt; R. A. Brost

1986-03-01T23:59:59.000Z

168

turbulence | OpenEI  

Open Energy Info (EERE)

turbulence turbulence Dataset Summary Description This raw data reflects readings from instruments mounted on or near a 82 meter meteorological tower located at the National Wind Technology Center (NWTC), approximately 5 miles south of Boulder, CO (specifically: 39.9107 N, 105.2348 W, datum WGS84). Source NREL Date Released Unknown Date Updated Unknown Keywords DOE irradiance NREL NWTC temperature turbulence wind wind direction wind speed Data text/plain icon Raw data (txt, 82 KiB) application/vnd.openxmlformats-officedocument.spreadsheetml.sheet icon Raw data field descriptions (xlsx, 52.5 KiB) Quality Metrics Level of Review Some Review Comment Data have not been reviewed for accuracy or completeness; disclaimer available (http://www.nrel.gov/disclaimer.html). Temporal and Spatial Coverage

169

Thermal ignition combustion system  

DOE Patents (OSTI)

The thermal ignition combustion system comprises means for providing walls defining an ignition chamber, the walls being made of a material having a thermal conductivity greater than 20 W/m C and a specific heat greater than 480 J/kg C with the ignition chamber being in constant communication with the main combustion chamber, means for maintaining the temperature of the walls above a threshold temperature capable of causing ignition of a fuel, and means for conducting fuel to the ignition chamber. 8 figs.

Kamo, R.; Kakwani, R.M.; Valdmanis, E.; Woods, M.E.

1988-04-19T23:59:59.000Z

170

Three-dimensional turbulent particle dispersion submodel development. Final report, 15 April 1991--15 April 1993  

Science Conference Proceedings (OSTI)

Many practical combustion processes which use solid particles, liquid droplets, or slurries as fuels introduce these fuels into turbulent environments. Examples include spray combustion, pulverized coal and coal slurry combustion, fluidized beds, sorbent injection, and hazardous waste incineration. The interactions of the condensed phases with turbulent environments in such applications have not been well described. Such a description is complicated by the difficulty of describing turbulence in general, even in the absence of particles or droplets. But the complications in describing the dispersion and reaction of the condensed phases in turbulent environments do not stem entirely, or even primarily, from the uncertainties in the description of the turbulence. Even when the turbulence characteristics are known, computational methods for coupling the dynamics of the particulate phase with the continuous phase have not been well established. Several new theoretical descriptions of the turbulent dispersion of particles and droplets have been proposed over the past few years. It has been the purpose of this project to explore the potential of these theories for coupling with the other aspects of three-dimensional, reacting, turbulent, particle-laden systems, to provide computational simulations that could be useful for addressing industrial problems. Two different approaches were explored in this project. The major thrust of this project was on identifying a suitable dispersion submodel for dilute dispersed flows, implementing it in a comprehensive three-dimensional CFD code framework for combustion simulation and evaluating its performance rigorously. In another effort the potential of a dispersion submodel for densely loaded systems was analyzed. This report discusses the main issues that were resolved as part of this project.

Smith, P.J.

1993-12-31T23:59:59.000Z

171

Progress in sub-grid scale modeling of shock-turbulence interaction  

DOE Green Energy (OSTI)

The authors report on progress in the development of sub grid scale (SGS) closure relationships for the unresolved motion scales in compressible large eddy simulations (LES). At present they are refining the SGS model and overall LES procedure to include: a linearized viscoelastic model for finite thickness shock distortions and shocked turbulence field response; multiple scale asymptotic considerations to improve predictions of average near-wall surface behavior; and a spectral statistical model simulating the effects of high wave number stochastic feed-back from the unresolved SGS nonlinear motion influences on the explicitly resolved grid scale motions. Predicted amplification levels, modal energy partition, shock translational to turbulence kinetic energy transfer, and viscoelastic spatio-temporal response of turbulence to shock interaction are examined in comparison with available experimental evidence. Supplemental hypersonic compressible turbulence experimental information is developed from sub nanosecond interval pulsed shadowgraph evidence of laser impulse generated hypervelocity shocks interacting with intense, previously developed and carefully characterized initial turbulence. Accurate description of the influence of shock-turbulence interactions is vital for predicting their influence on: Supersonic/hypersonic flow field analysis, aerodynamic design, and aerostructural materials selection. Practical applications also include interior supersonic combustion analysis and combustion chamber design. It is also the essential foundation for accurately predicting the development and evolution of flow-field generated thermal and electromagnetic radiation important to hypersonic flight vehicle survivability, detection and communication.

Buckingham, A.C. [Lawrence Livermore National Lab., CA (United States). Center for Advanced Fluid Dynamics Applications; Grun, J. [Naval Research Lab., Washington, DC (United States). Plasma Physics Div.

1994-12-01T23:59:59.000Z

172

Vehicle Technologies Office: Combustion Engine Research  

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

Combustion Engine Combustion Engine Research to someone by E-mail Share Vehicle Technologies Office: Combustion Engine Research on Facebook Tweet about Vehicle Technologies Office: Combustion Engine Research on Twitter Bookmark Vehicle Technologies Office: Combustion Engine Research on Google Bookmark Vehicle Technologies Office: Combustion Engine Research on Delicious Rank Vehicle Technologies Office: Combustion Engine Research on Digg Find More places to share Vehicle Technologies Office: Combustion Engine Research on AddThis.com... Just the Basics Hybrid & Vehicle Systems Energy Storage Advanced Power Electronics & Electrical Machines Advanced Combustion Engines Combustion Engines Emission Control Waste Heat Recovery Fuels & Lubricants Materials Technologies Combustion Engine Research

173

Vehicle Technologies Office: Advanced Combustion Engines  

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

Advanced Combustion Advanced Combustion Engines to someone by E-mail Share Vehicle Technologies Office: Advanced Combustion Engines on Facebook Tweet about Vehicle Technologies Office: Advanced Combustion Engines on Twitter Bookmark Vehicle Technologies Office: Advanced Combustion Engines on Google Bookmark Vehicle Technologies Office: Advanced Combustion Engines on Delicious Rank Vehicle Technologies Office: Advanced Combustion Engines on Digg Find More places to share Vehicle Technologies Office: Advanced Combustion Engines on AddThis.com... Just the Basics Hybrid & Vehicle Systems Energy Storage Advanced Power Electronics & Electrical Machines Advanced Combustion Engines Combustion Engines Emission Control Waste Heat Recovery Fuels & Lubricants Materials Technologies Advanced Combustion Engines

174

Application and Practice of Regenerative Combustion Technology ...  

Science Conference Proceedings (OSTI)

Regenerative Combustion burning alternative to traditional flow control system is ... that regenerative combustion have many advantage in energy conservation ...

175

A Generalized Pyrolysis Model for Combustible Solids  

E-Print Network (OSTI)

different stages of combustion,” Biomass and Bioenergy 23:biomass pyrolysis,” to appear in Progress in Energy and Combustion

Lautenberger, Chris

2007-01-01T23:59:59.000Z

176

Packed Bed Combustion: An Overview  

E-Print Network (OSTI)

Packed Bed Combustion: An Overview William Hallett Dept. of Mechanical Engineering Université d'Ottawa - University of Ottawa #12;Packed Bed Combustion - University of Ottawa - CICS 2005 Introduction air fuel feedproducts xbed grate Packed Bed Combustion: fairly large particles of solid fuel on a grate, air supplied

Hallett, William L.H.

177

Fragments, Combustion and Earthquakes  

E-Print Network (OSTI)

This paper is devoted to show the advantages of introducing a geometric viewpoint and a non extensive formulation in the description of apparently unrelated phenomena: combustion and earthquakes. Here, it is shown how the introduction of a fragmentation analysis based on that formulation leads to find a common point for description of these phenomena

Oscar Sotolongo-Costa; Antonio Posadas

2005-03-16T23:59:59.000Z

178

Reversed flow fluidized-bed combustion apparatus  

DOE Patents (OSTI)

The present invention is directed to a fluidized-bed combustion apparatus provided with a U-shaped combustion zone. A cyclone is disposed in the combustion zone for recycling solid particulate material. The combustion zone configuration and the recycling feature provide relatively long residence times and low freeboard heights to maximize combustion of combustible material, reduce nitrogen oxides, and enhance sulfur oxide reduction.

Shang, Jer-Yu (Fairfax, VA); Mei, Joseph S. (Morgantown, WV); Wilson, John S. (Morgantown, WV)

1984-01-01T23:59:59.000Z

179

LES SOFTWARE FOR THE DESIGN OF LOW EMISSION COMBUSTION SYSTEMS FOR VISION 21 PLANTS  

DOE Green Energy (OSTI)

In this project, an advanced computational software tool was developed for the design of low emission combustion systems required for Vision 21 clean energy plants. Vision 21 combustion systems, such as combustors for gas turbines, combustors for indirect fired cycles, furnaces and sequestrian-ready combustion systems, will require innovative low emission designs and low development costs if Vision 21 goals are to be realized. The simulation tool will greatly reduce the number of experimental tests; this is especially desirable for gas turbine combustor design since the cost of the high pressure testing is extremely costly. In addition, the software will stimulate new ideas, will provide the capability of assessing and adapting low-emission combustors to alternate fuels, and will greatly reduce the development time cycle of combustion systems. The revolutionary combustion simulation software is able to accurately simulate the highly transient nature of gaseous-fueled (e.g. natural gas, low BTU syngas, hydrogen, biogas etc.) turbulent combustion and assess innovative concepts needed for Vision 21 plants. In addition, the software is capable of analyzing liquid-fueled combustion systems since that capability was developed under a concurrent Air Force Small Business Innovative Research (SBIR) program. The complex physics of the reacting flow field are captured using 3D Large Eddy Simulation (LES) methods, in which large scale transient motion is resolved by time-accurate numerics, while the small scale motion is modeled using advanced subgrid turbulence and chemistry closures. In this way, LES combustion simulations can model many physical aspects that, until now, were impossible to predict with 3D steady-state Reynolds Averaged Navier-Stokes (RANS) analysis, i.e. very low NOx emissions, combustion instability (coupling of unsteady heat and acoustics), lean blowout, flashback, autoignition, etc. LES methods are becoming more and more practical by linking together tens to hundreds of PCs and performing parallel computations with fine grids (millions of cells). Such simulations, performed in a few weeks or less, provide a very cost-effective complement to experimental testing. In 5 years, these same calculations can be performed in 24 hours or less due to the expected increase of computing power and improved numerical techniques. This project was a four-year program. During the first year, the project included the development and implementation of improved chemistry (reduced GRI mechanism), subgrid turbulence (localized dynamic), and subgrid combustion-turbulence interaction (Linear Eddy) models into the CFD-ACE+ code. University expertise (Georgia Tech and University of California, Berkeley) was utilized to help develop and implement these advanced submodels into the unstructured, parallel CFD flow solver, CFD-ACE+. Efficient numerical algorithms that rely on in situ look-up tables or artificial neural networks were implemented for chemistry calculations. In the second year, the combustion LES software was evaluated and validated using experimental data from lab-scale and industrial test configurations. This code testing (i.e., alpha testing) was performed by CFD Research Corporation's engineers. During the third year, six industrial and academic partners used the combustion LES code and exercised it on problems of their choice (i.e., beta testing). Final feedback and optimizations were then implemented into the final release (licensed) version of the combustion LES software to the general public. An additional one-year task was added for the fourth year of this program entitled, ''LES Simulations of SIMVAL Results''. For this task, CFDRC performed LES calculations of selected DoE SIMVAL cases, and compared predictions with measurements from NETL. In addition to comparisons with NOx and CO exit measurements, comparisons were made to measured pressure oscillations. Potential areas of improvement for combustion and turbulence models were identified. In conclusion, this program advanced the state-of-the-art in combustion LES an

Clifford E. Smith; Steven M. Cannon; Virgil Adumitroaie; David L. Black; Karl V. Meredith

2005-01-01T23:59:59.000Z

180

Low emission internal combustion engine  

DOE Patents (OSTI)

A low emission, internal combustion compression ignition engine having a cylinder, a piston movable in the cylinder and a pre-combustion chamber communicating with the cylinder near the top thereof and in which low emissions of NO.sub.x are achieved by constructing the pre-combustion chamber to have a volume of between 70% and 85% of the combined pre-chamber and main combustion chamber volume when the piston is at top dead center and by variably controlling the initiation of fuel injection into the pre-combustion chamber.

Karaba, Albert M. (Muskegon, MI)

1979-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "turbulent nuclear combustion" 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

LES SOFTWARE FOR THE DESIGN OF LOW EMISSION COMBUSTION SYSTEMS FOR VISION 21 PLANTS  

Science Conference Proceedings (OSTI)

Vision 21 combustion systems will require innovative low emission designs and low development costs if Vision 21 goals are to be realized. In this three-year project, an advanced computational software tool will be developed for the design of low emission combustion systems required for Vision 21 clean energy plants. The combustion Large Eddy Simulation (LES) software will be able to accurately simulate the highly transient nature of gaseous-fueled turbulent combustion so that innovative concepts can be assessed and developed with fewer high-cost experimental tests. During the first year, the project included the development and implementation of improved chemistry (reduced GRI mechanism), subgrid turbulence (localized dynamic), and subgrid combustion-turbulence interaction (Linear Eddy) models into the CFDACE+ code. University expertise (Georgia Tech and UC Berkeley) was utilized to help develop and implement these advanced submodels into the unstructured, parallel CFD flow solver, CFD-ACE+. Efficient numerical algorithms that rely on in situ look-up tables or artificial neural networks were implemented for chemistry calculations. In the second year, the combustion LES software was evaluated and validated using experimental data from lab-scale and industrial test configurations. This code testing (i.e., alpha testing) was performed by CFD Research Corporation's engineers. During the third year, six industrial and academic partners used the combustion LES code and exercised it on problems of their choice (i.e., beta testing). Final feedback and optimizations were then be implemented in the final release version of the combustion LES software that will be licensed to the general public. An additional one-year task was added for the fourth year of this program entitled, ''LES Simulations of SIMVAL Results''. For this task, CFDRC performed LES calculations of selected SIMVAL cases, and compared predictions with measurements. In addition to comparisons with NO{sub x} and CO exit measurements, comparisons were made to measured pressure oscillations. Possible gaps in the data sets were identified, as well as potential areas of improvement for combustion and turbulence models. Work in this seventeenth quarter (October-December 2004) consisted of writing the draft final report for review by DOE. The report was delivered to DOE in January, 2005.

Clifford E. Smith

2005-04-01T23:59:59.000Z

182

Advanced combustion technologies for gas turbine power plants  

DOE Green Energy (OSTI)

Objectives are to develop actuators for enhancing the mixing between gas streams, increase combustion stability, and develop hgih-temperature materials for actuators and sensors in combustors. Turbulent kinetic energy maps of an excited jet with co-flow in a cavity with a partially closed exhaust end are given with and without a longitudinal or a transverse acoustic field. Dielectric constants and piezoelectric coefficients were determined for Sr{sub 2}(Nb{sub x}Ta{sub 1-x}){sub 2}O{sub 7} ceramics.

Vandsburger, U. [Virginia Polytechnic Inst. and State Univ., Blacksburg, VA (United States). Dept. of Mechanical Engineering; Roe, L.A. [Arkansas Univ., Fayetteville, AR (United States). Dept. of Mechanical Engineering; Desu, S.B. [Virginia Polytechnic Inst. and State Univ., Blacksburg, VA (United States). Dept. of Materials Science and Engineering

1995-12-31T23:59:59.000Z

183

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

184

Numerical modeling of hydrogen-fueled internal combustion engines  

DOE Green Energy (OSTI)

The planned use of hydrogen as the energy carrier of the future introduces new challenges and opportunities, especially to the engine design community. Hydrogen is a bio-friendly fuel that can be produced from renewable resources and has no carbon dioxide combustion products; and in a properly designed ICE, almost zero NO{sub x} and hydrocarbon emissions can be achieved. Because of the unique properties of hydrogen combustion - in particular the highly wrinkled nature of the laminar flame front due to the preferential diffusion instability - modeling approaches for hydrocarbon gaseous fuels are not generally applicable to hydrogen combustion. This paper reports on the current progress to develop a engine design capability based on KIVA family of codes for hydrogen-fueled, spark-ignited engines in support of the National Hydrogen Program. A turbulent combustion model, based on a modified eddy-turnover model in conjunction with an intake flow valve model, is found to describe well the efficiency and NO{sub x} emissions of this engine satisfy the Equivalent Zero Emission Vehicle (EZEV) standard established by the California Resource Board. 26 refs., 10 figs., 1 tab.

Johnson, N.L.; Amsden, A.A.

1996-12-31T23:59:59.000Z

185

Hydrogen program combustion research: Three dimensional computational modeling  

DOE Green Energy (OSTI)

We have significantly increased our computational modeling capability by the addition of a vertical valve model in KIVA-3, code used internationally for engine design. In this report the implementation and application of the valve model is described. The model is shown to reproduce the experimentally verified intake flow problem examined by Hessel. Furthermore, the sensitivity and performance of the model is examined for the geometry and conditions of the hydrogen-fueled Onan engine in development at Sandia National Laboratory. Overall the valve model is shown to have comparable accuracy as the general flow simulation capability in KIVA-3, which has been well validated by past comparisons to experiments. In the exploratory simulations of the Onan engine, the standard use of the single kinetic reaction for hydrogen oxidation was found to be inadequate for modeling the hydrogen combustion because of its inability to describe both the observed laminar flame speed and the absence of autoignition in the Onan engine. We propose a temporary solution that inhibits the autoignition without sacrificing the ability to model spark ignition. In the absence of experimental data on the Onan engine, a computational investigation was undertaken to evaluate the importance of modeling the intake flow on the combustion and NO{sub x} emissions. A simulation that began with the compression of a quiescent hydrogen-air mixture was compared to a simulation of the full induction process with resolved opening and closing of the intake valve. Although minor differences were observed in the cylinder-averaged pressure, temperature, bulk-flow kinetic energy and turbulent kinetic energy, large differences where observed in the hydrogen combustion rate and NO{sub x} emissions. The flow state at combustion is highly heterogeneous and sensitive to the details of the bulk and turbulent flow and that an accurate simulation of the Onan engine must include the modeling of the air-fuel induction.

Johnson, N.L.; Amsden, A.A.; Butler, T.D.

1995-05-01T23:59:59.000Z

186

NETL: Combustion Technologies  

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

Abbreviations & Acronyms Abbreviations & Acronyms Reference Shelf Solicitations & Awards Abbreviations & Acronyms The Combustion Technologies Product uses a number of abbreviations and acronyms. This web page gives you a definition of frequently used terms, as follows: 1½-Generation PFBC -- A PFBC plant where the hot (about 1400ºF) PFBC exhaust gases are used as a vitiated air supply for a natural gas combustor supplying high-temperature gas (above 2000ºF) to a combustion turbine expander (synonym for "PFB-NGT"). 1st-Generation PFBC -- Commercial PFBC technology where an unfired low-temperature (below 1650ºF) ruggedized turbine expander expands PFBC exhaust gases (synonym for "PFB-EGT"). 2nd-Generation PFBC (see synonyms: "APFBC," "PFB-CGT") -- Advanced PFBC where a carbonizer (mild gasifier) provides hot (about 1400ºF) coal-derived synthetic fuel gas to a special topping combustor. The carbonizer char is burned in the PFBC, and the PFBC exhaust is used as a hot (about 1400ºF) vitiated air supply for the topping combustor. The syngas and vitiated air are burned in a topping combustor to provide high-temperature gas (above 1700ºF) to a combustion turbine expander.

187

NETL: Combustion Technologies  

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

Nebraska Public Power District's Sheldon Station with APFBC Technology Nebraska Public Power District's Sheldon Station with APFBC Technology FBC Repower APFBC AES Greenidge APFBC Dan River FBC, APFBC Four Corners CHIPPS H.F. Lee Products Summary Sheldon Summary APFBC Sheldon GFBCC Sheldon APFBC L.V. Sutton Contents: APFBC Repowering Project Summary Key Features Site Layout Performance Environmental Characteristics Cost Other Combustion Systems Repowering Study Links: A related study is underway that would repower Sheldon Unit 1 and Unit 2 with gasification fluidized-bed combined cycle technology (GFBCC). CLICK HERE to find out more about repowering the Sheldon station with GFBCC instead. APFBC Repowering Project Summary Click on picture to enlarge Advanced circulating pressurized fluidized-bed combustion combined cycle systems (APFBC) are systems with jetting-bed pressurized fluidized-bed (PFB) carbonizer/gasifier and circulating PFBC combustor. The PFB carbonizer and PFBC both operate at elevated pressures (10 to 30 times atmospheric pressure) to provide syngas for operating a gas turbine topping combustor giving high cycle energy efficiency. The remaining char from the PFB carbonizer is burned in the pressurized PFBC. The combustion gas from the PFB also feeds thermal energy to the gas turbine topping combustor. This provides combined cycle plant efficiency on coal by providing the opportunity to generate electricity using both high efficiency gas turbines and steam.

188

Modeling Turbulent Flow  

National Nuclear Security Administration (NNSA)

Turbulent Turbulent Flow with Implicit LES L.G. Margolin 1 Proceedings of the Joint Russian-American Five Laboratory Conference on Computational Mathematics/Physics 19-23 June, 2005 Vienna, Austria 1 Applied Physics Division, Los Alamos National Laboratory, Los Alamos, NM 87545, len@lanl.gov 1 Abstract Implicit large eddy simulation (ILES) is a methodology for modeling high Reynolds' num- ber flows that combines computational efficiency and ease of implementation with predictive calculations and flexible application. Although ILES has been used for more than fifteen years, it is only recently that significant effort has gone into providing a physical rationale that speaks to its capabilities and its limitations. In this talk, we will present new theoret- ical results aimed toward building a justification and discuss some remaining gaps in our understanding and our practical

189

Internal combustion engine using premixed combustion of stratified charges  

DOE Patents (OSTI)

During a combustion cycle, a first stoichiometrically lean fuel charge is injected well prior to top dead center, preferably during the intake stroke. This first fuel charge is substantially mixed with the combustion chamber air during subsequent motion of the piston towards top dead center. A subsequent fuel charge is then injected prior to top dead center to create a stratified, locally richer mixture (but still leaner than stoichiometric) within the combustion chamber. The locally rich region within the combustion chamber has sufficient fuel density to autoignite, and its self-ignition serves to activate ignition for the lean mixture existing within the remainder of the combustion chamber. Because the mixture within the combustion chamber is overall premixed and relatively lean, NO.sub.x and soot production are significantly diminished.

Marriott, Craig D. (Rochester Hills, MI); Reitz, Rolf D. (Madison, WI

2003-12-30T23:59:59.000Z

190

Fast Turbulent Reconnection  

E-Print Network (OSTI)

Reconnection is the process by which magnetic fields in a conducting fluid change their topology. This process is essential for understanding a wide variety of astrophysical processes, including stellar and galactic dynamos and astrophysical turbulence. To account for solar flares, solar cycles and the structure of the galactic magnetic field reconnection must be fast, propagating with a speed close to the Alfven speed. We show that the presence of a random magnetic field component substantially enhances the reconnection rate and enables fast reconnection, i.e. reconnection that does not depend on fluid resistivity. The enhancement of the reconnection rate is achieved via a combination of two effects. First of all, only small segments of magnetic field lines are subject to direct Ohmic annihilation. Thus the fraction of magnetic energy that goes directly into fluid heating goes to zero as fluid resistivity vanishes. However, the most important enhancement comes from the fact that unlike the laminar fluid case where reconnection is constrained to proceed line by line, the presence of turbulence enables many magnetic field lines to enter the reconnection zone simultaneously. A significant fraction of magnetic energy goes into MHD turbulence and this enhances reconnection rates through an increase in the field stochasticity. In this way magnetic reconnection becomes fast when field stochasticity is accounted for. As a consequence solar and galactic dynamos are also fast, i.e. do not depend on fluid resistivity.

A. Lazarian; E. Vishniac

2000-02-03T23:59:59.000Z

191

Combustion Research Facility | A Department of Energy Office...  

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

Heavy-Duty Heavy-Duty Low-Temperature and Diesel Combustion HCCISCCI Engine Fundamentals Spray Combustion Automotive Low-Temperature Diesel Combustion DISI Combustion...

192

Renormalized weak plasma turbulence theory  

SciTech Connect

A renormalized Vlasov turbulence theory, derived by neglecting a mode coupling term in the Direct Interaction Approximation, is discussed. The theory reduces correctly to weak turbulence theory; it predicts both diffusion and polarization effects of the turbulent medium on test particles, as well as the inverse effects of the test particles on the medium. A heuristic, physical algorithm is presented for constructing the equations. The theory of the renormalized dielectric function is reviewed.

Krommes, J.A.; Kleva, R.G.

1979-02-01T23:59:59.000Z

193

Computational tools for pulverized-coal combustion. Third quarterly report, October 1981-December 1981  

Science Conference Proceedings (OSTI)

This report summarizes the work conducted to develop and verify a computer code capable of modeling the major aspects of pulverized-coal combustion. Achieving this objective will lead to design methods applicable to industrial and utility furnaces. The combustion model (COMO) consists of a number of relatively independent modules that represent the major processes involved in pulverized-coal combustion. These modules will be continually upgraded over the course of the contract. Three distinct versions of the COMO will be developed over the duration of the contract. Version 1 of COMO will model all of the major features of pulverized-coal combustion but with a number of simplifying assumptions. It will be used primarily to determine a satisfactory means of integrating the numerical models of the combustion processes into an overall combustion model, since this is perhaps the major challenge. Later versions will relax these assumptions and incorporate state-of-the-art combustion information. Guidelines were prepared and reviewed to allow process modules to be developed relatively independently, while providing for the subsequent integration of these modules into COMO. The formulation and coding of the Version 1 gas-phase turbulence, chemistry and radiation models were completed. Test cases were run for each model, and good agreement was obtained with other analyses and with data when available. A formal method for documenting COMO was investigated, and preliminary specifications were developed.

Oberjohn, W.J.; Cornelius, D.K.; Fiveland, W.A.; Schnipke, R.J.; Wang, J.H.

1982-01-01T23:59:59.000Z

194

Measurement of spray combustion processes  

SciTech Connect

A free jet configuration was chosen for measuring noncombusting spray fields and hydrocarbon-air spray flames in an effort to develop computational models of the dynamic interaction between droplets and the gas phase and to verify and refine numerical models of the entire spray combustion process. The development of a spray combustion facility is described including techniques for laser measurements in spray combustion environments and methods for data acquisition, processing, displaying, and interpretation.

Peters, C.E.; Arman, E.F.; Hornkohl, J.O.; Farmer, W.M.

1984-04-01T23:59:59.000Z

195

Municipal Waste Combustion (New Mexico)  

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

This rule establishes requirements for emissions from, and design and operation of, municipal waste combustion units. "Municipal waste" means all materials and substances discarded from residential...

196

Filtering Turbulent Sparsely Observed Geophysical Flows  

Science Conference Proceedings (OSTI)

Filtering sparsely turbulent signals from nature is a central problem of contemporary data assimilation. Here, sparsely observed turbulent signals from nature are generated by solutions of two-layer quasigeostrophic models with turbulent cascades ...

John Harlim; Andrew J. Majda

2010-04-01T23:59:59.000Z

197

Measurements of Enhanced Turbulent Mixing near Highways  

Science Conference Proceedings (OSTI)

In August and September of 2010, measurements of turbulent fluxes and turbulent kinetic energy were made on highways in the Toronto area (Ontario, Canada). In situ turbulence measurements were made with a mobile laboratory while driving on the ...

Mark Gordon; Ralf M. Staebler; John Liggio; Paul Makar; Shao-Meng Li; Jeremy Wentzell; Gang Lu; Patrick Lee; Jeffrey R. Brook

2012-09-01T23:59:59.000Z

198

Effects of molecular transport on turbulence-chemistry interactions in a hydrogen-argon-air jet diffusion flame  

DOE Green Energy (OSTI)

A numerical simulation of entrainment, turbulent advection, molecular import and chemical kinetics in a turbulent diffusion flame is used to investigate effects of molecular transport on turbulence-chemistry interactions. A fun finite-rate chemical mechanism is used to represent the combustion of a hydrogen-argon mixture issuing into air. Results based on incorporation of differential diffusion and variable Lewis number are compared to cases with the former effect, or both-effects, suppressed. Significant impact on radical species production and on NO emission index (based on a reduced mechanism for thermal NO) is found. A reduced mechanism for hydrogen-air combustion, omitting both effects and incorporating other simplifications, performs comparably except that its NO predictions agree well with the case of full chemistry and molecular transport, possibly due to cancellation of errors.

Menon, S.; Calhoon, W.H. Jr.; Goldin, G. [Georgia Inst. of Tech., Atlanta, GA (United States). School of Aerospace Engineering; Kerstein, A.R. [Sandia National Labs., Livermore, CA (United States)

1994-01-01T23:59:59.000Z

199

Supercomputers Capture Turbulence in the Solar Wind  

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

Supercomputers Capture Turbulence in the Solar Wind Supercomputers Capture Turbulence in the Solar Wind Berkeley Lab visualizations could help scientists forecast destructive space...

200

Turbulent molecular clouds  

E-Print Network (OSTI)

Stars form within molecular clouds but our understanding of this fundamental process remains hampered by the complexity of the physics that drives their evolution. We review our observational and theoretical knowledge of molecular clouds trying to confront the two approaches wherever possible. After a broad presentation of the cold interstellar medium and molecular clouds, we emphasize the dynamical processes with special focus to turbulence and its impact on cloud evolution. We then review our knowledge of the velocity, density and magnetic fields. We end by openings towards new chemistry models and the links between molecular cloud structure and star--formation rates.

Hennebelle, Patrick

2012-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "turbulent nuclear combustion" 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

COMBUSTION-GENERATED INDOOR AIR POLLUTION  

E-Print Network (OSTI)

x A Emission Characteristics in Two Stage Combustion. PaperInternational) on Combustion, Tokyo (August, 1974). Chang,fll , J I ___F J "J LBL-S9lS COMBUSTION-GENERATED INDOOR AIR

Hollowell, C.D.

2010-01-01T23:59:59.000Z

202

Magnetized Turbulent Dynamo in Protogalaxies  

Science Conference Proceedings (OSTI)

The prevailing theory for the origin of cosmic magnetic fields is that they have been amplified to their present values by the turbulent dynamo inductive action in the protogalactic and galactic medium. Up to now, in calculation of the turbulent dynamo, it has been customary to assume that there is no back reaction of the magnetic field on the turbulence, as long as the magnetic energy is less than the turbulent kinetic energy. This assumption leads to the kinematic dynamo theory. However, the applicability of this theory to protogalaxies is rather limited. The reason is that in protogalaxies the temperature is very high, and the viscosity is dominated by magnetized ions. As the magnetic field strength grows in time, the ion cyclotron time becomes shorter than the ion collision time, and the plasma becomes strongly magnetized. As a result, the ion viscosity becomes the Braginskii viscosity. Thus, in protogalaxies the back reaction sets in much earlier, at field strengths much lower than those which correspond to field-turbulence energy equipartition, and the turbulent dynamo becomes what we call the magnetized turbulent dynamo. In this paper we lay the theoretical groundwork for the magnetized turbulent dynamo. In particular, we predict that the magnetic energy growth rate in the magnetized dynamo theory is up to ten times larger than that in the kinematic dynamo theory. We also briefly discuss how the Braginskii viscosity can aid the development of the inverse cascade of magnetic energy after the energy equipartition is reached.

Leonid Malyshkin; Russell M. Kulsrud

2002-01-28T23:59:59.000Z

203

Advances in compressible turbulent mixing  

Science Conference Proceedings (OSTI)

This volume includes some recent additions to original material prepared for the Princeton International Workshop on the Physics of Compressible Turbulent Mixing, held in 1988. Workshop participants were asked to emphasize the physics of the compressible mixing process rather than measurement techniques or computational methods. Actual experimental results and their meaning were given precedence over discussions of new diagnostic developments. Theoretical interpretations and understanding were stressed rather than the exposition of new analytical model developments or advances in numerical procedures. By design, compressibility influences on turbulent mixing were discussed--almost exclusively--from the perspective of supersonic flow field studies. The papers are arranged in three topical categories: Foundations, Vortical Domination, and Strongly Coupled Compressibility. The Foundations category is a collection of seminal studies that connect current study in compressible turbulent mixing with compressible, high-speed turbulent flow research that almost vanished about two decades ago. A number of contributions are included on flow instability initiation, evolution, and transition between the states of unstable flow onset through those descriptive of fully developed turbulence. The Vortical Domination category includes theoretical and experimental studies of coherent structures, vortex pairing, vortex-dynamics-influenced pressure focusing. In the Strongly Coupled Compressibility category the organizers included the high-speed turbulent flow investigations in which the interaction of shock waves could be considered an important source for production of new turbulence or for the enhancement of pre-existing turbulence. Individual papers are processed separately.

Dannevik, W.P.; Buckingham, A.C.; Leith, C.E. [eds.

1992-01-01T23:59:59.000Z

204

Method for in situ combustion  

DOE Patents (OSTI)

This invention relates to an improved in situ combustion method for the recovery of hydrocarbons from subterranean earth formations containing carbonaceous material. The method is practiced by penetrating the subterranean earth formation with a borehole projecting into the coal bed along a horizontal plane and extending along a plane disposed perpendicular to the plane of maximum permeability. The subterranean earth formation is also penetrated with a plurality of spaced-apart vertical boreholes disposed along a plane spaced from and generally parallel to that of the horizontal borehole. Fractures are then induced at each of the vertical boreholes which project from the vertical boreholes along the plane of maximum permeability and intersect the horizontal borehole. The combustion is initiated at the horizontal borehole and the products of combustion and fluids displaced from the earth formation by the combustion are removed from the subterranean earth formation via the vertical boreholes. Each of the vertical boreholes are, in turn, provided with suitable flow controls for regulating the flow of fluid from the combustion zone and the earth formation so as to control the configuration and rate of propagation of the combustion zone. The fractures provide a positive communication with the combustion zone so as to facilitate the removal of the products resulting from the combustion of the carbonaceous material.

Pasini, III, Joseph (Morgantown, WV); Shuck, Lowell Z. (Morgantown, WV); Overbey, Jr., William K. (Morgantown, WV)

1977-01-01T23:59:59.000Z

205

Utilization ROLE OF COAL COMBUSTION  

E-Print Network (OSTI)

Center for Products Utilization ROLE OF COAL COMBUSTION PRODUCTS IN SUSTAINABLE CONSTRUCTION and Applied Science THE UNIVERSITY OF WISCONSIN - MILWAUKEE #12;ROLE OF COAL COMBUSTION PRODUCTS, Federal Highway Administration, Washington, DC., U.S.A. SYNOPSIS Over one hundred million tonnes of coal

Wisconsin-Milwaukee, University of

206

Hydrogen engine and combustion control process  

DOE Patents (OSTI)

Hydrogen engine with controlled combustion comprises suction means connected to the crankcase reducing or precluding flow of lubricating oil or associated gases into the combustion chamber.

Swain, Michael R. (Coral Gables, FL); Swain, Matthew N. (Miami, FL)

1997-01-01T23:59:59.000Z

207

Improved Engine Design Through More Efficient Combustion ...  

Improved Engine Design Through More Efficient Combustion Simulations The Multi-Zone Combustion Model (MCM) is a software tool that enables ...

208

Advanced Vehicle Testing Activity: Other Internal Combustion...  

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

Other Internal Combustion Engine Vehicles to someone by E-mail Share Advanced Vehicle Testing Activity: Other Internal Combustion Engine Vehicles on Facebook Tweet about Advanced...

209

Measurement Technology for Benchmark Spray Combustion ...  

Science Conference Proceedings (OSTI)

Benchmark Spray Combustion Database. ... A1, uncertainty budget for the fuel flow rate. A2, uncertainty budget for the combustion air flow rate. ...

2013-07-15T23:59:59.000Z

210

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

211

Feature-Based Statistical Analysis of Combustion Simulation Data  

SciTech Connect

We present a new framework for feature-based statistical analysis of large-scale scientific data and demonstrate its effectiveness by analyzing features from Direct Numerical Simulations (DNS) of turbulent combustion. Turbulent flows are ubiquitous and account for transport and mixing processes in combustion, astrophysics, fusion, and climate modeling among other disciplines. They are also characterized by coherent structure or organized motion, i.e. nonlocal entities whose geometrical features can directly impact molecular mixing and reactive processes. While traditional multi-point statistics provide correlative information, they lack nonlocal structural information, and hence, fail to provide mechanistic causality information between organized fluid motion and mixing and reactive processes. Hence, it is of great interest to capture and track flow features and their statistics together with their correlation with relevant scalar quantities, e.g. temperature or species concentrations. In our approach we encode the set of all possible flow features by pre-computing merge trees augmented with attributes, such as statistical moments of various scalar fields, e.g. temperature, as well as length-scales computed via spectral analysis. The computation is performed in an efficient streaming manner in a pre-processing step and results in a collection of meta-data that is orders of magnitude smaller than the original simulation data. This meta-data is sufficient to support a fully flexible and interactive analysis of the features, allowing for arbitrary thresholds, providing per-feature statistics, and creating various global diagnostics such as Cumulative Density Functions (CDFs), histograms, or time-series. We combine the analysis with a rendering of the features in a linked-view browser that enables scientists to interactively explore, visualize, and analyze the equivalent of one terabyte of simulation data. We highlight the utility of this new framework for combustion science; however, it is applicable to many other science domains.

Bennett, J; Krishnamoorthy, V; Liu, S; Grout, R; Hawkes, E; Chen, J; Pascucci, V; Bremer, P T

2011-11-18T23:59:59.000Z

212

Combustion in porous media  

DOE Green Energy (OSTI)

A 2.8-liter tube-shaped combustion vessel was constructed to study flame propagation and quenching in porous media. For this experiment, hydrogen-air flames propagating horizontally into abed of 6 mm diameter glass beads were studied. Measurements of pressure and temperature along the length of the tube were used to observe flame propagation of quenching. The critical hydrogen concentration for Hz-air mixtures was found to be 11.5%, corresponding to a critical Peclet number of Pe* = 37. This value is substantially less than the value of Pe* = 65 quoted in the literature, for example Babkin et al. (1991). It is hypothesized that buoyancy and a dependence of Pe on the Lewis number account for the discrepancy between these two results.

Dillon, J. [California Inst. of Technology, CA (US)

1999-09-01T23:59:59.000Z

213

NETL: Combustion Technologies  

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

Gas Turbines for APFBC Gas Turbines for APFBC FBC Repower Simple Description Detailed Description APFBC Specs GTs for APFBC Suited for Repowering Existing Power Plants with Advanced Pressurized Fluidized-Bed Combined Cycles APFBC combined cycles have high energy efficiency levels because they use modern, high-temperature, high-efficiency gas turbines as the core of a combined power cycle. This web page discusses a current U.S. Department of Energy project that is evaluating combustion turbines suited for repowering existing steam plants. The natural-gas-fueled version of the Siemens Westinghouse Power Corporation W501F. Modified versions of this gas turbine core are suited for operating in APFBC power plants. Contents: Introduction APFBC Repowering Considerations

214

First-Principles Simulations of High-Speed Combustion and Detonation |  

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

Picture shows a numerically generated pseudo-schlieren image of the onset of a detonation in a turbulent boundary layer. Picture shows a numerically generated pseudo-schlieren image of the onset of a detonation in a turbulent boundary layer. Weak ignition behind a reflected Mach=1.5 shock in a stoichiometric hydrogen-oxygen mixture at 0.1 atm initial pressure. Picture shows a numerically generated pseudo-schlieren image of the onset of a detonation in a turbulent boundary layer. Alexei Khokhlov, University of Chicago, Charles Bacon, Argonne National Laboratory, Joanna Austin and Andrew Knisely, University of Illinois at Urbanna-Champaign. First-Principles Simulations of High-Speed Combustion and Detonation PI Name: Alexei Khokhlov PI Email: ajk@oddjob.uchicago.edu Institution: University of Chicago Allocation Program: INCITE Allocation Hours at ALCF: 150 Million Year: 2014

215

On Collective Properties of Turbulent QED Plasma  

E-Print Network (OSTI)

Polarization properties of turbulent stochastically inhomogeneous ultrarelativistic QED plasma are studied. It is shown that the sign of nonlinear turbulent Landau damping corresponds to an instability of the spacelike modes and, for sufficiently large turbulent fields, to an actual instability of a system. Modification of plasmon dispersion relations due to turbulent effects are studied.

Martin Kirakosyan; Andrei Leonidov; Berndt Muller

2013-05-19T23:59:59.000Z

216

Twenty-Seventh Symposium (International) on Combustion/The Combustion Institute, 1998/pp. 28152820 FINGERING INSTABILITY IN SOLID FUEL COMBUSTION  

E-Print Network (OSTI)

2815 Twenty-Seventh Symposium (International) on Combustion/The Combustion Institute, 1998/pp. 2815­2820 FINGERING INSTABILITY IN SOLID FUEL COMBUSTION: THE CHARACTERISTIC SCALES OF THE DEVELOPED STATE ORY ZIK, Israel We present new results on the fingering instability in solid fuel combustion. The instability

Moses, Elisha

217

Images from the Simulations Gallery of the Center for Integrated Turbulence Simulations (CITS)  

DOE Data Explorer (OSTI)

The Center for Integrated Turbulence Simulations (CITS) is a multidisciplinary organization established in July 1997 at Stanford University to develop advanced numerical simulation methodologies that will enable a new paradigm for the design of complex, large-scale systems in which turbulence plays a controlling role. The initial focus of the CITS is provided by a comprehensive program on gas turbine engines, supported by the Department of Energy under its Advanced Simulation and Computing. The key components of the CITS program are: Integrated Multicode Simulation Framework • Software Engineering • Physics Modeling • Verification and Validation. CITS research areas include numerical algorithms, physical models for turbulence, combustion, multiphase processes, multiple-code integration, compilers and programming languages, and computer architectures, driven by and supporting massively parallel simulations. (Acknowledgement: CITS website at http://www.stanford.edu/group/cits/index.html)

218

"Optimization of efficiency of internal combustion engines via using  

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

Optimization of efficiency of internal combustion engines via using Optimization of efficiency of internal combustion engines via using spinning gas and non-spectroscopic method of determining gas constituents through rotation ..--.. Inventors Nathaniel Fisch, Vasily Geyko An important use of the disclosed approach is the improvement efficiency of thermal cycles and as result efficiency of engines. Different cycles and different ways of compression of spinning gas may be used to maximize possible efficiency gain. In conventional internal combustion engines, gas spinning is either not used at all or used only with the purpose of increasing turbulence and better mixing. In the disclosed method, gas rotation is used for energy storage, hence it allows an improvement in thermal cycle efficiency. To achieve significant effect related to

219

Particulate waste product combustion system  

SciTech Connect

An apparatus is described for incinerating combustion material within a fluidized bed, including the steps of: feeding the material into a fluidizing zone within which the bed is formed; introducing combustion supporting gas to the fluidizing zone in a plurality of inflow streams of different velocities insufficient to fluidize the material; continuously agitating the material to mechanically fluidize the same within the fluidizing zone during combustion and cause displacement of residual ash from the zone; and withdrawing the residual ash from a discharge location in the apparatus outside of the fluidizing zone.

Chastain, C.E.; King, D.R.

1986-05-20T23:59:59.000Z

220

Dilute Oxygen Combustion Phase I Final Report  

SciTech Connect

A novel burner, in which fuel (natural gas) and oxidant (oxygen or air) are separately injected into a furnace, shows promise for achieving very low nitrogen oxide(s) (NOx) emissions for commercial furnace applications. The dilute oxygen combustion (DOC) burner achieves very low NOx through in-furnace dilution of the oxidant stream prior to combustion, resulting in low flame temperatures, thus inhibiting thermal NOx production. The results of a fundamental and applied research effort on the development of the DOC burner are presented. In addition, the results of a market survey detailing the potential commercial impact of the DOC system are disclosed. The fundamental aspects of the burner development project involved examining the flame characteristics of a natural gas turbulent jet in a high-temperature (~1366 K) oxidant (7-27% O2 vol. wet). Specifically, the mass entrainment rate, the flame lift-off height, the velocity field and major species field of the jet were evaluated as a function of surrounding-gas temperature and composition. The measured entrainment rate of the fuel jet decreased with increasing oxygen content in the surrounding high-temperature oxidant, and was well represented by the d+ scaling correlation found in the literature. The measured flame lift-off height decreased with increasing oxygen content and increasing temperature of the surrounding gas. An increase in surrounding-gas oxygen content and/or temperature inhibited the velocity decay within the jet periphery as a function of axial distance as compared to isothermal turbulent jets. However, the velocity measurements were only broadly represented by the d+ scaling correlation. Several DOC burner configurations were tested in a laboratory-scale furnace at a nominal firing rate of 185 kW (~0.63 MMBtu/h). The flue gas composition was recorded as a function of furnace nitrogen content, furnace temperature, burner geometric arrangement, firing rate, and fuel injection velocity. NOx emissions increased with increasing furnace nitrogen content and furnace temperature, but remained relatively insensitive to variations in fuel injection velocity and firing rate. NOx emissions below 5-10-3 g/MJ (10 ppm-air equivalent at 3% O2 dry) were obtained for furnace temperatures below 1533 K (2300°F) and furnace nitrogen levels between 1 and 40%. CO emissions were typically low (<35 ppm). Detailed in-furnace species measurements revealed the importance of the interior furnace circulation patterns, as influenced by fuel and oxidant injection schemes, on pollutant emissions. The combustion stability traits of several DOC burner arrangements were ascertained through furnace pressure measurements, wit6h increased stability occurring as furnace temperature increased and as the separation distance between fuel and oxidant inputs decreased. Based on current market conditions, oxy-fuel conversion of batch steel reheat furnaces with a DOC burner is justified on the basis of lower utility costs alone. However, conversion of continuous steel reheat furnaces, which are responsible for most steel production, required additional economic incentives, such as further fuel savings, increased furnace productivity, or emission credits.

Ryan, H.M.; Riley, M.F.; Kobayashi, H.

1997-10-31T23:59:59.000Z

Note: This page contains sample records for the topic "turbulent nuclear combustion" 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

Dilute Oxygen Combustion Phase 2 Final Report  

SciTech Connect

A novel burner, in which fuel (natural gas) and oxidant (oxygen or air) are separately injected into a furnace, shows promise for achieving very low nitrogen oxide(s) (NOx) emissions for commercial furnace applications. The dilute oxygen combustion (DOC) burner achieves very low NOx through in-furnace dilution of the oxidant stream prior to combustion, resulting in low flame temperatures, thus inhibiting thermal NOx production. The results of a fundamental and applied research effort on the development of the DOC burner are presented. In addition, the results of a market survey detailing the potential commercial impact of the DOC system are disclosed. The fundamental aspects of the burner development project involved examining the flame characteristics of a natural gas turbulent jet in a high-temperature (~1366 K) oxidant (7-27% O2 vol. wet). Specifically, the mass entrainment rate, the flame lift-off height, the velocity field and major species field of the jet were evaluated as a function of surrounding-gas temperature and composition. The measured entrainment rate of the fuel jet decreased with increasing oxygen content in the surrounding high-temperature oxidant, and was well represented by the d+ scaling correlation found in the literature. The measured flame lift-off height decreased with increasing oxygen content and increasing temperature of the surrounding gas. An increase in surrounding-gas oxygen content and/or temperature inhibited the velocity decay within the jet periphery as a function of axial distance as compared to isothermal turbulent jets. However, the velocity measurements were only broadly represented by the d+ scaling correlation. Several DOC burner configurations were tested in a laboratory-scale furnace at a nominal firing rate of 185 kW (~0.63 MMBtu/h). The flue gas composition was recorded as a function of furnace nitrogen content, furnace temperature, burner geometric arrangement, firing rate, and fuel injection velocity. NOx emissions increased with increasing furnace nitrogen content and furnace temperature, but remained relatively insensitive to variations in fuel injection velocity and firing rate. NOx emissions below 5-10-3 g/MJ (10 ppm-air equivalent at 3% O2 dry) were obtained for furnace temperatures below 1533 K (2300?F) and furnace nitrogen levels between 1 and 40%. CO emissions were typically low (<35 ppm). Detailed in-furnace species measurements revealed the importance of the interior furnace circulation patterns, as influenced by fuel and oxidant injection schemes, on pollutant emissions. The combustion stability traits of several DOC burner arrangements were ascertained through furnace pressure measurements, wit6h increased stability occurring as furnace temperature increased and as the separation distance between fuel and oxidant inputs decreased. Based on current market conditions, oxy-fuel conversion of batch steel reheat furnaces with a DOC burner is justified on the basis of lower utility costs alone. However, conversion of continuous steel reheat furnaces, which are responsible for most steel production, required additional economic incentives, such as further fuel savings, increased furnace productivity, or emission credits.

Ryan, H.M.; Riley, M.F.; Kobayashi, H.

2005-09-30T23:59:59.000Z

222

Droplet Combustion and Non-Reactive Shear-Coaxial Jets with Transverse Acoustic Excitation  

E-Print Network (OSTI)

Related Works in Droplet Combustion . . . . . . . .of Acoustics on Droplet Combustion . . . . . . . . . . . .Fuel Droplet Combustion . . . . . . . . . . . . . . .

Teshome, Sophonias

2012-01-01T23:59:59.000Z

223

COMBUSTION SYNTHESIS OF ADVANCED MATERIALS: PRINCIPLESAND APPLICATIONS  

E-Print Network (OSTI)

COMBUSTION SYNTHESIS OF ADVANCED MATERIALS: PRINCIPLESAND APPLICATIONS Arvind Varma, Alexander S. Gasless Combustion SynthesisFrom Elements B. Combustion Synthesis in Gas-Solid Systems C. Products of Thermite-vpe SHS D. Commercial Aspects IV. Theoretical Considerations A. Combustion Wave Propagation Theory

Mukasyan, Alexander

224

COMBUSTION ISSUES AND APPROACHES FOR CHEMICAL MICROTHRUSTERS  

E-Print Network (OSTI)

1 COMBUSTION ISSUES AND APPROACHES FOR CHEMICAL MICROTHRUSTERS Richard A. Yetter, Vigor Yang, Ming and the effects of downsizing on combustion performance. In particular, combustion of liquid nitromethane in a thruster combustion chamber with a volume of 108 mm3 and diameter of 5 mm was experimentally investigated

Yang, Vigor

225

The Combustion Institute 5001 Baum Boulevard  

E-Print Network (OSTI)

The Combustion Institute 5001 Baum Boulevard Pittsburgh, Pennsylvania, USA 15213-1851 CENTRAL STATES SECTION OF THE COMBUSTION INSTITUTE CALL FOR PAPERS TECHNICAL MEETING - SPRING 2002 COMBUSTION 7-9, 2002 #12;CENTRAL STATES SECTION OF THE COMBUSTION INSTITUTE www.cssci.org CALL FOR PAPERS

Tennessee, University of

226

Residential Wood Residential wood combustion (RWC) is  

E-Print Network (OSTI)

Residential Wood Combustion Residential wood combustion (RWC) is increasing in Europe because PM2.5. Furthermore, other combustion- related sources of OA in Europe may need to be reassessed. Will it affect global OA emission estimates? Combustion of biofuels is globally one of the major OA sources

227

Fundamental and semi-global kinetic mechanisms of hydrocarbon combustion. Progress report, March 1--September 30, 1977  

DOE Green Energy (OSTI)

Major emphasis in combustion research is being given to the study of oxidation of hydrocarbon fuels to lend insight into the modelling of combustion processes. The introduction of combustion chemistry into the already complex turbulent flow situations which exist in practical devices make modelling exceptionally difficult. Semi-global reaction mechanisms offer the potential of reducing the overall chemical kinetic complexity, thus substantially reducing the computational barriers to appropriate modelling of combustion processes. Reported here are the results of efforts presently underway at Princeton under ERDA support, to provide a general understanding of hydrocarbon oxidation. Specifically the results of studies of the lean oxidation of ethane along with the developed semi-global rates are reported. Initial results for the lean oxidation of propane are discussed and the present status of studies on methanol oxidation is also reported.

Glassman, I.; Dryer, F.L.

1977-09-01T23:59:59.000Z

228

High Efficiency, Clean Combustion  

DOE Green Energy (OSTI)

Energy use in trucks has been increasing at a faster rate than that of automobiles within the U.S. transportation sector. According to the Energy Information Administration (EIA) Annual Energy Outlook (AEO), a 23% increase in fuel consumption for the U.S. heavy duty truck segment is expected between 2009 to 2020. The heavy duty vehicle oil consumption is projected to grow between 2009 and 2050 while light duty vehicle (LDV) fuel consumption will eventually experience a decrease. By 2050, the oil consumption rate by LDVs is anticipated to decrease below 2009 levels due to CAFE standards and biofuel use. In contrast, the heavy duty oil consumption rate is anticipated to double. The increasing trend in oil consumption for heavy trucks is linked to the vitality, security, and growth of the U.S. economy. An essential part of a stable and vibrant U.S. economy is a productive U.S. trucking industry. Studies have shown that the U.S. gross domestic product (GDP) is strongly correlated to freight transport. Over 90% of all U.S. freight tonnage is transported by diesel power and over 75% is transported by trucks. Given the vital role that the trucking industry plays in the economy, improving the efficiency of the transportation of goods was a central focus of the Cummins High Efficient Clean Combustion (HECC) program. In a commercial vehicle, the diesel engine remains the largest source of fuel efficiency loss, but remains the greatest opportunity for fuel efficiency improvements. In addition to reducing oil consumption and the dependency on foreign oil, this project will mitigate the impact on the environment by meeting US EPA 2010 emissions regulations. Innovation is a key element in sustaining a U.S. trucking industry that is competitive in global markets. Unlike passenger vehicles, the trucking industry cannot simply downsize the vehicle and still transport the freight with improved efficiency. The truck manufacturing and supporting industries are faced with numerous challenges to reduce oil consumption and greenhouse gases, meet stringent emissions regulations, provide customer value, and improve safety. The HECC program successfully reduced engine fuel consumption and greenhouse gases while providing greater customer valve. The US EPA 2010 emissions standard poses a significant challenge for developing clean diesel powertrains that meet the DoE Vehicle Technologies Multi-Year Program Plan (MYPP) for fuel efficiency improvement while remaining affordable. Along with exhaust emissions, an emphasis on heavy duty vehicle fuel efficiency is being driven by increased energy costs as well as the potential regulation of greenhouse gases. An important element of the success of meeting emissions while significantly improving efficiency is leveraging Cummins component technologies such as fuel injection equipment, aftertreatment, turbomahcinery, electronic controls, and combustion systems. Innovation in component technology coupled with system integration is enabling Cummins to move forward with the development of high efficiency clean diesel products with a long term goal of reaching a 55% peak brake thermal efficiency for the engine plus aftertreatment system. The first step in developing high efficiency clean products has been supported by the DoE co-sponsored HECC program. The objectives of the HECC program are: (1) To design and develop advanced diesel engine architectures capable of achieving US EPA 2010 emission regulations while improving the brake thermal efficiency by 10% compared to the baseline (a state of the art 2007 production diesel engine). (2) To design and develop components and subsystems (fuel systems, air handling, controls, etc) to enable construction and development of multi-cylinder engines. (3) To perform an assessment of the commercial viability of the newly developed engine technology. (4) To specify fuel properties conducive to improvements in emissions, reliability, and fuel efficiency for engines using high-efficiency clean combustion (HECC) technologies. To demonstrate the technology is compatible with B2

Donald Stanton

2010-03-31T23:59:59.000Z

229

Effect of nozzle orifice geometry on spray, combustion, and emission characteristics under diesel engine conditions.  

DOE Green Energy (OSTI)

Diesel engine performance and emissions are strongly coupled with fuel atomization and spray processes, which in turn are strongly influenced by injector flow dynamics. Modern engines employ micro-orifices with different orifice designs. It is critical to characterize the effects of various designs on engine performance and emissions. In this study, a recently developed primary breakup model (KH-ACT), which accounts for the effects of cavitation and turbulence generated inside the injector nozzle is incorporated into a CFD software CONVERGE for comprehensive engine simulations. The effects of orifice geometry on inner nozzle flow, spray, and combustion processes are examined by coupling the injector flow and spray simulations. Results indicate that conicity and hydrogrinding reduce cavitation and turbulence inside the nozzle orifice, which slows down primary breakup, increasing spray penetration, and reducing dispersion. Consequently, with conical and hydroground nozzles, the vaporization rate and fuel air mixing are reduced, and ignition occurs further downstream. The flame lift-off lengths are the highest and lowest for the hydroground and conical nozzles, respectively. This can be related to the rate of fuel injection, which is higher for the hydroground nozzle, leading to richer mixtures and lower flame base speeds. A modified flame index is employed to resolve the flame structure, which indicates a dual combustion mode. For the conical nozzle, the relative role of rich premixed combustion is enhanced and that of diffusion combustion reduced compared to the other two nozzles. In contrast, for the hydroground nozzle, the role of rich premixed combustion is reduced and that of non-premixed combustion is enhanced. Consequently, the amount of soot produced is the highest for the conical nozzle, while the amount of NOx produced is the highest for the hydroground nozzle, indicating the classical tradeoff between them.

Som, S.; Longman, D. E; Ramirez, A. I.; Aggarwal, S. K. (Energy Systems); (Univ. of Illinois at Chicago)

2011-03-01T23:59:59.000Z

230

Finescale Parameterizations of Turbulent Dissipation  

Science Conference Proceedings (OSTI)

Fine- and microstructure data from a free fall profiler are analysed to test models that relate the turbulent dissipation rate (?) to characteristics of the internal wave field. The data were obtained from several distinct internal wave ...

Kurt L. Polzin; John M. Toole; Raymond W. Schmitt

1995-03-01T23:59:59.000Z

231

Predictability of Rotating Stratified Turbulence  

Science Conference Proceedings (OSTI)

Although predictability represents one of the fundamental problems in atmospheric science, gaps in our knowledge remain. Theoretical understanding of the inverse error cascade is limited mostly to homogeneous, isotropic turbulence, whereas ...

K. Ngan; P. Bartello; D. N. Straub

2009-05-01T23:59:59.000Z

232

Plum Combustion | Open Energy Information  

Open Energy Info (EERE)

Plum Combustion Plum Combustion Jump to: navigation, search Name Plum Combustion Place Atlanta, Georgia Product Combustion technology, which reduces NOx-emissions. Coordinates 33.748315°, -84.391109° Loading map... {"minzoom":false,"mappingservice":"googlemaps3","type":"ROADMAP","zoom":14,"types":["ROADMAP","SATELLITE","HYBRID","TERRAIN"],"geoservice":"google","maxzoom":false,"width":"600px","height":"350px","centre":false,"title":"","label":"","icon":"","visitedicon":"","lines":[],"polygons":[],"circles":[],"rectangles":[],"copycoords":false,"static":false,"wmsoverlay":"","layers":[],"controls":["pan","zoom","type","scale","streetview"],"zoomstyle":"DEFAULT","typestyle":"DEFAULT","autoinfowindows":false,"kml":[],"gkml":[],"fusiontables":[],"resizable":false,"tilt":0,"kmlrezoom":false,"poi":true,"imageoverlays":[],"markercluster":false,"searchmarkers":"","locations":[{"text":"","title":"","link":null,"lat":33.748315,"lon":-84.391109,"alt":0,"address":"","icon":"","group":"","inlineLabel":"","visitedicon":""}]}

233

Predictive modeling of combustion processes  

E-Print Network (OSTI)

Recently, there has been an increasing interest in improving the efficiency and lowering the emissions from operating combustors, e.g. internal combustion (IC) engines and gas turbines. Different fuels, additives etc. are ...

Sharma, Sandeep, Ph. D. Massachusetts Institute of Technology

2009-01-01T23:59:59.000Z

234

Combustion modeling in waste tanks  

DOE Green Energy (OSTI)

This paper has two objectives. The first one is to repeat previous simulations of release and combustion of flammable gases in tank SY-101 at the Hanford reservation with the recently developed code GASFLOW-II. The GASFLOW-II results are compared with the results obtained with the HMS/TRAC code and show good agreement, especially for non-combustion cases. For combustion GASFLOW-II predicts a steeper pressure rise than HMS/TRAC. The second objective is to describe a so-called induction parameter model which was developed and implemented into GASFLOW-II and reassess previous calculations of Bureau of Mines experiments for hydrogen-air combustion. The pressure time history improves compared with the one-step model, and the time rate of pressure change is much closer to the experimental data.

Mueller, C.; Unal, C. [Los Alamos National Lab., NM (United States); Travis, J.R. [Los Alamos National Lab., NM (United States)]|[Forschungszentrum Karlsruhe (Germany). Inst. fuer Reaktorsicherheit

1997-08-01T23:59:59.000Z

235

Turbulence Regimes and Turbulence Intermittency in the Stable Boundary Layer during CASES-99  

Science Conference Proceedings (OSTI)

An investigation of nocturnal intermittent turbulence during the Cooperative Atmosphere–Surface Exchange Study in 1999 (CASES-99) revealed three turbulence regimes at each observation height: 1) regime 1, a weak turbulence regime when the wind ...

Jielun Sun; Larry Mahrt; Robert M. Banta; Yelena L. Pichugina

2012-01-01T23:59:59.000Z

236

Nuclear Thermal Rockets: The Physics of the Fission Reactor  

E-Print Network (OSTI)

Nuclear Thermal Rockets: The Physics of the Fission Reactor Shane D. Ross Control and Dynamical combustion are those powered by nuclear fission. Comparison of Chemical and Nuclear Rockets. Most existent.g., hydrogen and oxygen). In a nuclear rocket, or more precisely, a nuclear thermal rocket, the propellant

Ross, Shane

237

Thallium in Coal Combustion Products  

Science Conference Proceedings (OSTI)

Thallium is a naturally occurring trace element that is present in coal and coal combustion products (CCPs). Thallium is of interest because it has a relatively low maximum contaminant level (MCL) in drinking water. This Technical Brief provides EPRI data on thallium in CCPs, along with general information on its occurrence, health effects, and treatment. Most of the information presented is summarized from the 2008 EPRI Technical Report 1016801, Chemical Constituents in Coal Combustion Product Leachate: ..

2013-11-27T23:59:59.000Z

238

Oxy-Combustion Activities Worldwide  

Science Conference Proceedings (OSTI)

This report reviews oxy-combustion development activities throughout the world. The report opens by reviewing carbon dioxide (CO2) capture technologies and their relative advantages and disadvantages before focusing on oxy-combustion concepts and giving details on potential designs. It then delves into each sub-system (air separation, oxy boiler, gas quality control, and CO2 purification) giving the latest updates on technologies and associated development issues, pulling from work reported at the Second...

2012-06-26T23:59:59.000Z

239

Assessment of emissions prediction capability of RANS based PDF models for lean premixed combustion of methane  

DOE Green Energy (OSTI)

The high computational cost of Large Eddy Simulation (LES) makes Reynolds Averaged Navier-Stokes (RANS) methods the current standard for turbulent combustion modeling. Empirical models for turbulence, turbulence-combustion interaction and chemical kinetics are, however, a major source of uncertainty in RANS based combustion simulation. While Probability Density Function (PDF) based models overcome some of these issues, most commercial codes do not take full advantage of these models. In this study, lean premixed combustion of methane in a bluff-body combustor is simulated using two different reduced chemical mechanisms (ARM9 and ARM19) combined with the composition PDF transport combustion model in the commercial code FLUENT. Two different turbulence models, namely the RNG k-? model and the Reynolds Stress Model (RSM) are used and the results of the simulations are compared to experimental data. For all the models tested, the prediction of temperature and major species (CH4, O2, CO2, CO, H2, and H2O) was good when compared to experiments. While all of the model predictions for the intermediate species OH showed an order magnitude difference (compared to the experiments) close to the bluff body surface; downstream axial locations showed good quantitative and qualitative agreement with the experiments. In a trend similar to the previous study (Nanduri et al., 2007) using the Eddy Dissipation Concept (EDC) model, predicted values for NO emission radial profiles showed an average difference of ±5 ppm when compared to experimental values. The results were also compared to the results of a velocity-composition joint PDF model developed by researchers at the University of Pittsburgh. In terms of emissions (NO and CO) predictions the relatively expensive composition PDF model in FLUENT did not give significant improvement when compared to the computationally cheaper EDC models. However, the velocity-composition joint PFD model used by researchers at the University of Pittsburgh did show significant improvement over EDC models in the prediction of NO. Both of the PDF models resulted in better qualitative and quantitative agreement in H2 prediction, thus showing the promise of PDF based models in simulating lean premixed combustion of fuel blends like hydrogen enriched natural gas.

Parsons, D.R.; Nanduri, J.R.; Celik, Ismail; Strakey, P.A.

2008-01-01T23:59:59.000Z

240

Reducing mode circulating fluid bed combustion  

DOE Patents (OSTI)

A method for combustion of sulfur-containing fuel in a circulating fluid bed combustion system wherein the fuel is burned in a primary combustion zone under reducing conditions and sulfur captured as alkaline sulfide. The reducing gas formed is oxidized to combustion gas which is then separated from solids containing alkaline sulfide. The separated solids are then oxidized and recycled to the primary combustion zone.

Lin, Yung-Yi (Katy, TX); Sadhukhan, Pasupati (Katy, TX); Fraley, Lowell D. (Sugarland, TX); Hsiao, Keh-Hsien (Houston, TX)

1986-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "turbulent nuclear combustion" 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

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

242

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

243

Particulate emissions from combustion of biomass in conventional combustion (air) and oxy-combustion conditions.  

E-Print Network (OSTI)

??Oxy-fuel combustion is a viable technology for new and existing coal-fired power plants, as it facilitates carbon capture and thereby, can reduce carbon dioxide emissions.… (more)

Ruscio, Amanda

2013-01-01T23:59:59.000Z

244

Combustion of hydrogen:air mixtures in the VGES cylindrical tank. [PWR; BWR  

DOE Green Energy (OSTI)

Sandia National Laboratories is currently involved in a number of experimental projects to provide data that will help quantify the threat of hydrogen combustion during nuclear plant accidents. Several experimental facilities are part of the Variable Geometry Experimental System (VGES). The purpose of this report is to document the experimental results from the first round of combustion tests performed at one of these facilities: a 5-m/sup 3/ cylindrical tank. The data provided by tests at this facility can be used to guide further testing and for the development and assessment of analytical models to predict hydrogen combustion behavior.

Benedick, W.B.; Cummings, J.C.; Prassinos, P.G.

1984-05-01T23:59:59.000Z

245

Using Biofuel Tracers to Study Alternative Combustion Regimes  

E-Print Network (OSTI)

1979. J.B. Heywood, Internal Combustion Engine Fundamentals.Ignition Engine with Optimal Combustion Control. ” US PatentIntroduction to Internal Combustion Engines (3rd Edition).

Mack, John Hunter; Flowers, Daniel L.; Buchholz, Bruce A.; Dibble, Robert W.

2006-01-01T23:59:59.000Z

246

COMBUSTION OF COAL IN AN OPPOSED FLOW DIFFUSION BURNER  

E-Print Network (OSTI)

J.M. , liThe F1uidised Combustion of Coal," Sixteenth Sm osium {International} on Combustion, August 1976 (to beof Various Polymers Under Combustion Conditions," Fourteenth

Chin, W.K.

2010-01-01T23:59:59.000Z

247

Pre-Combustion Carbon Capture Research | Department of Energy  

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

Pre-Combustion Carbon Capture Research Pre-combustion capture refers to removing CO2 from fossil fuels before combustion is completed. For example, in gasification processes a...

248

HCCI Combustion: Analysis and Experiments  

DOE Green Energy (OSTI)

Homogeneous charge compression ignition (HCCI) is a new combustion technology that may develop as an alternative to diesel engines with high efficiency and low NOx and particulate matter emissions. This paper describes the HCCI research activities being currently pursued at Lawrence Livermore National Laboratory and at the University of California Berkeley. Current activities include analysis as well as experimental work. On analysis, we have developed two powerful tools: a single zone model and a multi-zone model. The single zone model has proven very successful in predicting start of combustion and providing reasonable estimates for peak cylinder pressure, indicated efficiency and NOX emissions. This model is being applied to develop detailed engine performance maps and control strategies, and to analyze the problem of engine startability. The multi-zone model is capable of very accurate predictions of the combustion process, including HC and CO emissions. The multi-zone model h as applicability to the optimization of combustion chamber geometry and operating conditions to achieve controlled combustion at high efficiency and low emissions. On experimental work, we have done a thorough evaluation of operating conditions in a 4-cylinder Volkswagen TDI engine. The engine has been operated over a wide range of conditions by adjusting the intake temperature and the fuel flow rate. Satisfactory operation has been obtained over a wide range of operating conditions. Cylinder-to-cylinder variations play an important role in limiting maximum power, and should be controlled to achieve satisfactory performance.

Salvador M. Aceves; Daniel L. Flowers; Joel Martinez-Frias; J. Ray Smith; Robert Dibble; Michael Au; James Girard

2001-05-14T23:59:59.000Z

249

Dilute Oxygen Combustion Phase I Final Report  

Science Conference Proceedings (OSTI)

A novel burner, in which fuel (natural gas) and oxidant (oxygen or air) are separately injected into a furnace, shows promise for achieving very low nitrogen oxide(s) (NOx) emissions for commercial furnace applications. The dilute oxygen combustion (DOC) burner achieves very low NOx through in-furnace dilution of the oxidant stream prior to combustion, resulting in low flame temperatures, thus inhibiting thermal NOx production. The results of a fundamental and applied research effort on the development of the DOC burner are presented. In addition, the results of a market survey detailing the potential commercial impact of the DOC system are disclosed. The fundamental aspects of the burner development project involved examining the flame characteristics of a natural gas turbulent jet in a high-temperature (~1366 K) oxidant (7-27% O2 vol. wet). Specifically, the mass entrainment rate, the flame lift-off height, the velocity field and major species field of the jet were evaluated as a function of surrounding-gas temperature and composition. The measured entrainment rate of the fuel jet decreased with increasing oxygen content in the surrounding high-temperature oxidant, and was well represented by the d+ scaling correlation found in the literature. The measured flame lift-off height decreased with increasing oxygen content and increasing temperature of the surrounding gas. An increase in surrounding-gas oxygen content and/or temperature inhibited the velocity decay within the jet periphery as a function of axial distance as compared to isothermal turbulent jets. However, the velocity measurements were only broadly represented by the d+ scaling correlation. Several DOC burner configurations were tested in a laboratory-scale furnace at a nominal firing rate of 185 kW (~0.63 MMBtu/h). The flue gas composition was recorded as a function of furnace nitrogen content, furnace temperature, burner geometric arrangement, firing rate, and fuel injection velocity. NOx emissions increased with increasing furnace nitrogen content and furnace temperature, but remained relatively insensitive to variations in fuel injection velocity and firing rate. NOx emissions below 5-10-3 g/MJ (10 ppm-air equivalent at 3% O2 dry) were obtained for furnace temperatures below 1533 K (2300°F) and furnace nitrogen levels between 1 and 40%. CO emissions were typically low (DOC burner arrangements were ascertained through furnace pressure measurements, wit6h increased stability occurring as furnace temperature increased and as the separation distance between fuel and oxidant inputs decreased. Based on current market conditions, oxy-fuel conversion of batch steel reheat furnaces with a DOC burner is justified on the basis of lower utility costs alone. However, conversion of continuous steel reheat furnaces, which are responsible for most steel production, required additional economic incentives, such as further fuel savings, increased furnace productivity, or emission credits.

Ryan, H.M.; Riley, M.F.; Kobayashi, H.

1997-10-31T23:59:59.000Z

250

Dilute Oxygen Combustion Phase 2 Final Report  

Science Conference Proceedings (OSTI)

A novel burner, in which fuel (natural gas) and oxidant (oxygen or air) are separately injected into a furnace, shows promise for achieving very low nitrogen oxide(s) (NOx) emissions for commercial furnace applications. The dilute oxygen combustion (DOC) burner achieves very low NOx through in-furnace dilution of the oxidant stream prior to combustion, resulting in low flame temperatures, thus inhibiting thermal NOx production. The results of a fundamental and applied research effort on the development of the DOC burner are presented. In addition, the results of a market survey detailing the potential commercial impact of the DOC system are disclosed. The fundamental aspects of the burner development project involved examining the flame characteristics of a natural gas turbulent jet in a high-temperature (~1366 K) oxidant (7-27% O2 vol. wet). Specifically, the mass entrainment rate, the flame lift-off height, the velocity field and major species field of the jet were evaluated as a function of surrounding-gas temperature and composition. The measured entrainment rate of the fuel jet decreased with increasing oxygen content in the surrounding high-temperature oxidant, and was well represented by the d+ scaling correlation found in the literature. The measured flame lift-off height decreased with increasing oxygen content and increasing temperature of the surrounding gas. An increase in surrounding-gas oxygen content and/or temperature inhibited the velocity decay within the jet periphery as a function of axial distance as compared to isothermal turbulent jets. However, the velocity measurements were only broadly represented by the d+ scaling correlation. Several DOC burner configurations were tested in a laboratory-scale furnace at a nominal firing rate of 185 kW (~0.63 MMBtu/h). The flue gas composition was recorded as a function of furnace nitrogen content, furnace temperature, burner geometric arrangement, firing rate, and fuel injection velocity. NOx emissions increased with increasing furnace nitrogen content and furnace temperature, but remained relatively insensitive to variations in fuel injection velocity and firing rate. NOx emissions below 5-10-3 g/MJ (10 ppm-air equivalent at 3% O2 dry) were obtained for furnace temperatures below 1533 K (2300?F) and furnace nitrogen levels between 1 and 40%. CO emissions were typically low (DOC burner arrangements were ascertained through furnace pressure measurements, wit6h increased stability occurring as furnace temperature increased and as the separation distance between fuel and oxidant inputs decreased. Based on current market conditions, oxy-fuel conversion of batch steel reheat furnaces with a DOC burner is justified on the basis of lower utility costs alone. However, conversion of continuous steel reheat furnaces, which are responsible for most steel production, required additional economic incentives, such as further fuel savings, increased furnace productivity, or emission credits.

Ryan, H.M.; Riley, M.F.; Kobayashi, H.

2005-09-30T23:59:59.000Z

251

Strong Turbulence in the Wave Crest Region  

Science Conference Proceedings (OSTI)

High-resolution vertical velocity profiles in the surface layer of a lake reveal the turbulence structure beneath strongly forced waves. Dissipation rates of turbulence kinetic energy are estimated based on centered second-order structure ...

Johannes Gemmrich

2010-03-01T23:59:59.000Z

252

Dust Motions Driven by MHD Turbulence  

E-Print Network (OSTI)

We discuss the relative grain motions due to MHD turbulence in interstellar medium. It has been known for decades that turbulent drag is an efficient way to induce grain relative motions. However, earlier treatments disregarded magnetic field and used Kolmogorov turbulence. Unlike hydro turbulence, MHD turbulence is anisotropic on small scales. Moreover, compressible modes are important for MHD and magnetic perturbations can directly interact with grains. We provide calculations of grain relative motion for realistic interstellar turbulence driving that is consistent with the velocity dispersions observed in diffuse gas and for realistic grain charging. We account for the turbulence cutoff arising from abmipolar drag. Our results on grain shattering are consistent with the customary accepted cutoff size. We obtain grain velocities for turbulence with parameters consistent with those in HI and dark clouds. These velocities are smaller than those in earlier papers, where MHD effects were disregarded. Finally, w...

Lazarian, A; Yan, Huirong

2002-01-01T23:59:59.000Z

253

Turbulent Kinetic Energy Budgets over Mountainous Terrain  

Science Conference Proceedings (OSTI)

The objective of this study is to describe the characteristics of the airflow and turbulence structure over mountainous terrain. Turbulent characteristics of the airflow were measured using well-instrumented aircraft. The shear, buoyancy, ...

Theodore S. Karacostas; John D. Marwitz

1980-02-01T23:59:59.000Z

254

Turbulent Mixing in Stably Stratified Shear Flows  

Science Conference Proceedings (OSTI)

Vertical mixing of momentum and heat is investigated in turbulent stratified shear flows. It is assumed that the flow has uniform shear and stratification with homogeneous turbulence and that an equilibrium is reached between kinetic and ...

U. Schumann; T. Gerz

1995-01-01T23:59:59.000Z

255

The Canopy Horizontal Array Turbulence Study  

Science Conference Proceedings (OSTI)

The Canopy Horizontal Array Turbulence Study (CHATS) took place in spring 2007 and is the third in the series of Horizontal Array Turbulence Study (HATS) experiments. The HATS experiments have been instrumental in testing and developing subfilterscale (...

Edward G. Patton; Thomas W. Horst; Peter P. Sullivan; Donald H. Lenschow; Steven P. Oncley; William O. J. Brown; Sean P. Burns; Alex B. Guenther; Andreas Held; Thomas Karl; Shane D. Mayor; Luciana V. Rizzo; Scott M. Spuler; Jielun Sun; Andrew A. Turnipseed; Eugene J. Allwine; Steven L. Edburg; Brian K. Lamb; Roni Avissar; Ronald J. Calhoun; Jan Kleissl; William J. Massman; Kyaw Tha Paw U; Jeffrey C. Weil

2011-05-01T23:59:59.000Z

256

Effects of Atmospheric Turbulence on Ballistic Testing  

Science Conference Proceedings (OSTI)

The effects of atmospheric turbulence on munition target scatter are determined from numerical simulations of ballistic trajectories through many realizations of realistic simulated turbulent wind fields. A technique is evaluated for correcting ...

Rod Frehlich; Robert Sharman; Charles Clough; Michael Padovani; Kelly Fling; Ward Boughers; W. Scott Walton

2008-05-01T23:59:59.000Z

257

Combustion instability modeling and analysis  

DOE Green Energy (OSTI)

It is well known that the two key elements for achieving low emissions and high performance in a gas turbine combustor are to simultaneously establish (1) a lean combustion zone for maintaining low NO{sub x} emissions and (2) rapid mixing for good ignition and flame stability. However, these requirements, when coupled with the short combustor lengths used to limit the residence time for NO formation typical of advanced gas turbine combustors, can lead to problems regarding unburned hydrocarbons (UHC) and carbon monoxide (CO) emissions, as well as the occurrence of combustion instabilities. The concurrent development of suitable analytical and numerical models that are validated with experimental studies is important for achieving this objective. A major benefit of the present research will be to provide for the first time an experimentally verified model of emissions and performance of gas turbine combustors. The present study represents a coordinated effort between industry, government and academia to investigate gas turbine combustion dynamics. Specific study areas include development of advanced diagnostics, definition of controlling phenomena, advancement of analytical and numerical modeling capabilities, and assessment of the current status of our ability to apply these tools to practical gas turbine combustors. The present work involves four tasks which address, respectively, (1) the development of a fiber-optic probe for fuel-air ratio measurements, (2) the study of combustion instability using laser-based diagnostics in a high pressure, high temperature flow reactor, (3) the development of analytical and numerical modeling capabilities for describing combustion instability which will be validated against experimental data, and (4) the preparation of a literature survey and establishment of a data base on practical experience with combustion instability.

Santoro, R.J.; Yang, V.; Santavicca, D.A. [Pennsylvania State Univ., University Park, PA (United States); Sheppard, E.J. [Tuskeggee Univ., Tuskegee, AL (United States). Dept. of Aerospace Engineering

1995-12-31T23:59:59.000Z

258

Combustion heater for oil shale  

DOE Patents (OSTI)

A combustion heater for oil shale heats particles of spent oil shale containing unburned char by burning the char. A delayed fall is produced by flowing the shale particles down through a stack of downwardly sloped overlapping baffles alternately extending from opposite sides of a vertical column. The delayed fall and flow reversal occurring in passing from each baffle to the next increase the residence time and increase the contact of the oil shale particles with combustion supporting gas flowed across the column to heat the shale to about 650 to 700/sup 0/C for use as a process heat source.

Mallon, R.; Walton, O.; Lewis, A.E.; Braun, R.

1983-09-21T23:59:59.000Z

259

Combustion heater for oil shale  

DOE Patents (OSTI)

A combustion heater for oil shale heats particles of spent oil shale containing unburned char by burning the char. A delayed fall is produced by flowing the shale particles down through a stack of downwardly sloped overlapping baffles alternately extending from opposite sides of a vertical column. The delayed fall and flow reversal occurring in passing from each baffle to the next increase the residence time and increase the contact of the oil shale particles with combustion supporting gas flowed across the column to heat the shale to about 650.degree.-700.degree. C. for use as a process heat source.

Mallon, Richard G. (Livermore, CA); Walton, Otis R. (Livermore, CA); Lewis, Arthur E. (Los Altos, CA); Braun, Robert L. (Livermore, CA)

1985-01-01T23:59:59.000Z

260

Engine Combustion Network Experimental Data  

DOE Data Explorer (OSTI)

Maintained by the Engine Combustion Department of Sandia National Laboratories, data currently available on the website includes reacting and non-reacting sprays in a constant-volume chamber at conditions typical of diesel combustion. The data are useful for model development and validation because of the well-defined boundary conditions and the wide range of conditions employed. A search utility displays data based on experimental conditions such as ambient temperature, ambient density, injection pressure, nozzle size, fuel, etc. Experiment-related visualizations are also available. The search utility for experimental data is located at http://public.ca.sandia.gov/ecn/cvdata/frameset.html (Specialized Interface)

Note: This page contains sample records for the topic "turbulent nuclear combustion" 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

LES SOFTWARE FOR THE DESIGN OF LOW EMISSION COMBUSTION SYSTEMS FOR VISION 21 PLANTS  

DOE Green Energy (OSTI)

In this project, an advanced computational software tool will be developed for the design of low emission combustion systems required for Vision 21 clean energy plants. This computational tool will utilize Large Eddy Simulation (LES) methods to predict the highly transient nature of turbulent combustion. The time-accurate software will capture large scale transient motion, while the small scale motion will be modeled using advanced subgrid turbulence and chemistry closures. This three-year project is composed of: Year 1--model development/implementation, Year 2--software alpha validation, and Year 3--technology transfer of software to industry including beta testing. In this first year of the project, subgrid models for turbulence and combustion are being developed through university research (Suresh Menon-Georgia Tech and J.-Y. Chen- UC Berkeley) and implemented into a leading combustion CFD code, CFD-ACE+. The commercially available CFDACE+ software utilizes unstructured , parallel architecture and 2nd-order spatial and temporal numerics. To date, the localized dynamic turbulence model and reduced chemistry models (up to 19 species) for natural gas, propane, hydrogen, syngas, and methanol have been incorporated. The Linear Eddy Model (LEM) for subgrid combustion-turbulence interaction has been developed and implementation into CFD-ACE+ has started. Ways of reducing run-time for complex stiff reactions is being studied, including the use of in situ tabulation and neural nets. Initial validation cases have been performed. CFDRC has also completed the integration of a 64 PC cluster to get highly scalable computing power needed to perform the LES calculations ({approx} 2 million cells) in several days. During the second year, further testing and validation of the LES software will be performed. Researchers at DOE-NETL are working with CFDRC to provide well-characterized high-pressure test data for model validation purposes. To insure practical, usable software is developed, a consortium of gas turbine and industrial burner manufacturers has been established to guide and direct the software development/validation effort. The consortium members include Siemens- Westinghouse, GE Power Systems, Pratt & Whitney, Rolls-Royce, Honeywell, Solar, Coen, McDermott, Vapor Power, Woodward FST, Parker Hannifin, John Zink, RamGen Power, Virginia Tech, DOE-NETL, Air Force Research Laboratory, DOE-ANL, and NASA GRC. Annual consortium meetings are being held in Huntsville, with the 2nd meeting scheduled for January 31-February 1, 2002. 2 Benefits of the program will include the ability to assess complex combustion challenges such as combustion instability, lean blowout, flashback, emissions and the effect of fuel type on performance. The software will greatly reduce development costs and the time cycle of combustor development. And perhaps the greatest benefit will be that the software will stimulate new, creative ideas to solve the combustion challenges of the Vision 21 plant.

Cannon, Steven M.; Adumitroaie, Virgil; McDaniel, Keith S.; Smith, Clifford E.

2001-11-06T23:59:59.000Z

262

Three-dimensional hydrodynamic simulations of the combustion of a neutron star into a quark star  

Science Conference Proceedings (OSTI)

We present three-dimensional numerical simulations of turbulent combustion converting a neutron star into a quark star. Hadronic matter, described by a microphysical finite-temperature equation of state, is converted into strange quark matter. We assume this phase, represented by a bag-model equation of state, to be absolutely stable. Following the example of thermonuclear burning in white dwarfs leading to type Ia supernovae, we treat the conversion process as a potentially turbulent deflagration. Solving the nonrelativistic Euler equations using established numerical methods we conduct large eddy simulations including an elaborate subgrid scale model, while the propagation of the conversion front is modeled with a level-set method. Our results show that for large parts of the parameter space the conversion becomes turbulent and therefore significantly faster than in the laminar case. Despite assuming absolutely stable strange quark matter, in our hydrodynamic approximation an outer layer remains in the hadronic phase, because the conversion front stops when it reaches conditions under which the combustion is no longer exothermic.

Herzog, Matthias; Roepke, Friedrich K. [Max-Planck-Institut fuer Astrophysik, Karl-Schwarzschild-Str. 1, D-85741 Garching (Germany); Institut fuer Theoretische Physik und Astrophysik, Universitaet Wuerzburg, Emil-Fischer-Str. 31, D-97074 Wuerzburg (Germany)

2011-10-15T23:59:59.000Z

263

Combustion in Homogeneous Charge Compression Ignition Engines: Experiments and Detailed Chemical Kinetic Simulations  

DOE Green Energy (OSTI)

Homogeneous charge compression ignition (HCCI) engines are being considered as an alternative to diesel engines. The HCCI concept involves premixing fuel and air prior to induction into the cylinder (as is done in current spark-ignition engine) then igniting the fuel-air mixture through the compression process (as is done in current diesel engines). The combustion occurring in an HCCI engine is fundamentally different from a spark-ignition or Diesel engine in that the heat release occurs as a global autoignition process, as opposed to the turbulent flame propagation or mixing controlled combustion used in current engines. The advantage of this global autoignition is that the temperatures within the cylinder are uniformly low, yielding very low emissions of oxides of nitrogen (NO{sub x}, the chief precursors to photochemical smog). The inherent features of HCCI combustion allows for design of engines with efficiency comparable to, or potentially higher than, diesel engines. While HCCI engines have great potential, several technical barriers exist which currently prevent widespread commercialization of this technology. The most significant challenge is that the combustion timing cannot be controlled by typical in-cylinder means. Means of controlling combustion have been demonstrated, but a robust control methodology that is applicable to the entire range of operation has yet to be developed. This research focuses on understanding basic characteristics of controlling and operating HCCI engines. Experiments and detailed chemical kinetic simulations have been applied to the characterize some of the fundamental operational and design characteristics of HCCI engines. Experiments have been conducted on single and multi-cylinder engines to investigate general features of how combustion timing affects the performance and emissions of HCCI engines. Single-zone modeling has been used to characterize and compare the implementation of different control strategies. Multi-zone modeling has been applied to investigate combustion chamber design with respect to increasing efficiency and reducing emissions in HCCI engines.

Flowers, D L

2002-06-07T23:59:59.000Z

264

Stimulated Neutrino Transformation Through Turbulence  

E-Print Network (OSTI)

We derive an analytical solution for the flavor evolution of a neutrino through a turbulent density profile which is found to accurately predict the amplitude and transition wavelength of numerical solutions on a case-by-case basis. The evolution is seen to strongly depend upon those Fourier modes in the turbulence which are approximately the same as the splitting between neutrino eigenvalues and, unexpectedly, we also find a dependence upon the long wavelength modes when the ratio of their amplitude and the wavenumber is of order, or greater than, the first root of the Bessel function $J_0$.

Kelly M. Patton; James P. Kneller; Gail C. McLaughlin

2013-10-21T23:59:59.000Z

265

Transonic Combustion Inc | Open Energy Information  

Open Energy Info (EERE)

Transonic Combustion Inc Transonic Combustion Inc Jump to: navigation, search Name Transonic Combustion, Inc. Place Camarillo, California Zip CA 93012 Sector Efficiency, Renewable Energy Product Transonic Combustion, Inc. is a US based research & development company focused on developing ultra-high efficiency automotive engines that run on gasoline and bio-renewable flex fuels. References Transonic Combustion, Inc.[1] LinkedIn Connections CrunchBase Profile No CrunchBase profile. Create one now! This article is a stub. You can help OpenEI by expanding it. Transonic Combustion, Inc. is a company located in Camarillo, California . References ↑ "Transonic Combustion, Inc." Retrieved from "http://en.openei.org/w/index.php?title=Transonic_Combustion_Inc&oldid=352376

266

Free Energy and Internal Combustion Engine Cycles  

E-Print Network (OSTI)

The performance of one type (Carnot) of Internal Combustion Engine (ICE) cycle is analyzed within the framework of thermodynamic free energies. ICE performance is different from that of an External Combustion Engine (ECE) which is dictated by Carnot's rule.

Harris, William D

2012-01-01T23:59:59.000Z

267

Engine control system for multiple combustion modes  

Science Conference Proceedings (OSTI)

To reduce the emission by Diesel-engine in railway traction, continuous development and innovation in combustion, sensing net, control method and strategies are required to met the legal requirements. Multiple combustion modes by Diesel engines can reduce ...

D. Bonta; V. Tulbure; Cl. Festila

2008-05-01T23:59:59.000Z

268

Large-Scale Hydrogen Combustion Experiments  

Science Conference Proceedings (OSTI)

Large-scale combustion experiments show that deliberate ignition can limit hydrogen accumulation in reactor containments. The collected data allow accurate evaluation of containment pressures and temperatures associated with hydrogen combustion.

1988-10-18T23:59:59.000Z

269

Method for storing radioactive combustible waste  

DOE Patents (OSTI)

A method is described for preventing pressure buildup in sealed containers which contain radioactively contaminated combustible waste material by adding an oxide getter material to the container so as to chemically bind sorbed water and combustion product gases. (Official Gazette)

Godbee, H.W.; Lovelace, R.C.

1973-10-01T23:59:59.000Z

270

Combustion Synthesis of Silicon Carbide 389 Combustion Synthesis of Silicon Carbide  

E-Print Network (OSTI)

Combustion Synthesis of Silicon Carbide 389 X Combustion Synthesis of Silicon Carbide Alexander S. Mukasyan University of Notre Dame USA 1. Introduction Combustion synthesis (CS) is an effective technique by which combustion synthesis can occur: self - propagating high-temperature synthesis (SHS) and volume

Mukasyan, Alexander

271

ME 6990 -Combustion Catalog Data: ME 6990: Combustion. Sem. 2. Class 3, Credit 3 (el.).  

E-Print Network (OSTI)

ME 6990 - Combustion Catalog Data: ME 6990: Combustion. Sem. 2. Class 3, Credit 3 (el.). Physical and chemical aspects of basic combustion phenomena. Classification of flames. Measurement of laminar flame. Fuels. Atomization and evaporation of liquid fuels. Theories of ignition, stability and combustion

Panchagnula, Mahesh

272

Supersonic combustion studies using a multivariate quadrature based method for combustion modeling  

E-Print Network (OSTI)

Supersonic combustion studies using a multivariate quadrature based method for combustion modeling function (PDF) of thermochemical variables can be used for accurately computing the combustion source term of predictive models for supersonic combustion is a critical step in design and development of scramjet engines

Raman, Venkat

273

Combustion Synthesis of Doped Calcium Cobaltate Thermoelectric ...  

Science Conference Proceedings (OSTI)

Symposium, Innovative Processing and Synthesis of Ceramics, Glasses and Composites. Presentation Title, Combustion Synthesis of Doped Calcium Cobaltate ...

274

Review of Combustion Modification Emerging Technologies  

Science Conference Proceedings (OSTI)

Combustion modification emerging technologies for coal-fired boilers represent new developments in NOx control through changes in the fuel/air mixing of the combustion process. Technologies examined in this report fall into the categories of low-NOX burners (LNB), overfire air (OFA), enriched combustion, and combustion diagnostics. The technology reviews are comprised of the following sections where sufficient information was available: background, NOX reduction principle, performance and experience base...

2008-02-26T23:59:59.000Z

275

Oxy-combustion Boiler Material Development  

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

Oxy-combustion Boiler Material Oxy-combustion Boiler Material Development Background In an oxy-combustion system, combustion air (79 percent nitrogen, 21 percent oxygen) is replaced by oxygen and recycled flue gas (carbon dioxide [CO 2 ] and water), eliminating nitrogen in the flue gas stream. When applied to an existing boiler, the flue gas recirculation rate is adjusted to enable the boiler to maintain its original air-fired heat absorption performance, eliminating the need to derate the boiler

276

Theoretical studies on hydrogen ignition and droplet combustion  

E-Print Network (OSTI)

Combustion Theory Second Edition, Addison-Wesley, Red- woodCombustion Theory. Second Edition, Addison-Wesley, Red- wood

Del Álamo, Gonzalo

2006-01-01T23:59:59.000Z

277

Combustion joining of refractory materials: Carboncarbon composites  

E-Print Network (OSTI)

Combustion joining of refractory materials: Carbon­carbon composites Jeremiah D.E. White Department­carbon composite is achieved by employing self-sustained, oxygen-free, high-temperature combustion reactions to a used "core" to produce a brake that meets the performance specifications. The combustion-joining (CJ

Mukasyan, Alexander

278

Reduced No.sub.x combustion method  

DOE Patents (OSTI)

A combustion method enabling reduced NO.sub.x formation wherein fuel and oxidant are separately injected into a combustion zone in a defined velocity relation, combustion gases are aspirated into the oxidant stream prior to intermixture with the fuel, and the fuel is maintained free from contact with oxygen until the intermixture.

Delano, Mark A. (Briarcliff Manor, NY)

1991-01-01T23:59:59.000Z

279

INTEGRAL CATALYTIC COMBUSTION/FUEL REFORMING  

E-Print Network (OSTI)

INTEGRAL CATALYTIC COMBUSTION/FUEL REFORMING FOR GAS TURBINE Prepared For: California Energy REPORT (FAR) INTEGRAL CATALYTIC COMBUSTION/FUEL REFORMING FOR GAS TURBINE CYCLES EISG AWARDEE University://www.energy.ca.gov/research/index.html. #12;Page 1 Integral Catalytic Combustion/Fuel Reforming for Gas Turbine Cycles EISG Grant # 99

280

Method and device for diagnosing and controlling combustion instabilities in internal combustion engines operating in or transitioning to homogeneous charge combustion ignition mode  

DOE Patents (OSTI)

This invention is a method of achieving stable, optimal mixtures of HCCI and SI in practical gasoline internal combustion engines comprising the steps of: characterizing the combustion process based on combustion process measurements, determining the ratio of conventional and HCCI combustion, determining the trajectory (sequence) of states for consecutive combustion processes, and determining subsequent combustion process modifications using said information to steer the engine combustion toward desired behavior.

Wagner, Robert M [Knoxville, TN; Daw, Charles S [Knoxville, TN; Green, Johney B [Knoxville, TN; Edwards, Kevin D [Knoxville, TN

2008-10-07T23:59:59.000Z

Note: This page contains sample records for the topic "turbulent nuclear combustion" 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

Comparison of iso-octane burning rates between single-phase and two-phase combustion for small droplets  

Science Conference Proceedings (OSTI)

Two-phase combustion is a widespread mechanism of energy conversion that is of practical importance in gas turbines, diesel and spark ignition engines, furnaces, and hazardous environments. However, the exploration of important parameters in combustion systems of practical application is difficult, due to the multiplicity of dependent variables. In the present work, combustion rates of well-defined droplet suspensions of iso-octane have been measured using techniques employed for gaseous combustion. This required a full characterization of the aerosols produced in the combustion apparatus, which determined that the maximum droplet size produced was around 30 {mu}m. Comparisons of two-phase with single-phase laminar mixtures suggest that there were negligible differences in the burning velocity of an aerosol and a gaseous mixture at the same overall equivalence ratio and similar conditions for iso-octane. At high stretch rates, flames remained smooth and droplet enhancement was negligible. However, at lower rates of stretch, both gaseous and aerosol flames became unstable and cellular, and this cellularity, in some cases, increased the burning rate. The values of Markstein length measured for aerosol flames had trends similar to those for gaseous-phase mixtures (Markstein length decreased with equivalence ratio), but were lower than in gaseous combustion. The values of Markstein length in aerosol flames also decreased with liquid equivalence ratio and/or Sauter mean diameter. All this indicates a higher tendency to instabilities in aerosol flames compared to gaseous combustion. A qualitative explanation for the lower values of Markstein length in aerosol combustion is given. It is suggested in the present work that aerosol flames became unstable, and hence had faster burning rates, under conditions that would not result in unstable gaseous flames. Comparisons, qualitative and in terms of dimensionless groups, of two-phase with single-phase turbulent combustion also suggest no enhancement. (author)

Lawes, M.; Lee, Y. [School of Mechanical Engineering, The University of Leeds (United Kingdom); Marquez, N. [Escuela de Ingenieria Mecanica, Universidad del Zulia, Maracaibo 4011 Apto. 526 (Venezuela)

2006-02-01T23:59:59.000Z

282

Boron in Coal Combustion Products  

Science Conference Proceedings (OSTI)

This Technical Brief summarizes EPRI data on boron in CCPs, along with general information on its occurrence, health effects, and treatment. Much of the information presented is summarized from the 2005 EPRI technical report 1005258, Chemical Constituents in Coal Combustion Product Leachate: Boron, and is updated where appropriate.

2012-12-30T23:59:59.000Z

283

Pressurized fluidized-bed combustion  

SciTech Connect

If pressurised fluidised-bed combustion is to be used in combined cycle electricity generation, gas turbines must be made reliable and flue gas emission standards must be met. This report examines the issues of particulate cleaning before the turbine and stack, as well as recent work on the development of advanced gas filters.

Yeager, K.

1983-06-01T23:59:59.000Z

284

Combustor nozzle for a fuel-flexible combustion system  

DOE Patents (OSTI)

A combustor nozzle is provided. The combustor nozzle includes a first fuel system configured to introduce a syngas fuel into a combustion chamber to enable lean premixed combustion within the combustion chamber and a second fuel system configured to introduce the syngas fuel, or a hydrocarbon fuel, or diluents, or combinations thereof into the combustion chamber to enable diffusion combustion within the combustion chamber.

Haynes, Joel Meier (Niskayuna, NY); Mosbacher, David Matthew (Cohoes, NY); Janssen, Jonathan Sebastian (Troy, NY); Iyer, Venkatraman Ananthakrishnan (Mason, OH)

2011-03-22T23:59:59.000Z

285

Combustion engineering issues for solid fuel systems  

SciTech Connect

The book combines modeling, policy/regulation and fuel properties with cutting edge breakthroughs in solid fuel combustion for electricity generation and industrial applications. This book provides real-life experiences and tips for addressing the various technical, operational and regulatory issues that are associated with the use of fuels. Contents are: Introduction; Coal Characteristics; Characteristics of Alternative Fuels; Characteristics and Behavior of Inorganic Constituents; Fuel Blending for Combustion Management; Fuel Preparation; Conventional Firing Systems; Fluidized-Bed Firing Systems; Post-Combustion Emissions Control; Some Computer Applications for Combustion Engineering with Solid Fuels; Gasification; Policy Considerations for Combustion Engineering.

Bruce Miller; David Tillman [Pennsylvania State University, University Park, PA (United States). Energy Institute

2008-05-15T23:59:59.000Z

286

Method of combustion for dual fuel engine  

DOE Patents (OSTI)

Apparatus and a method of introducing a primary fuel, which may be a coal water slutty, and a high combustion auxiliary fuel, which may be a conventional diesel oil, into an internal combustion diesel engine comprises detecting the load conditions of the engine, determining the amount of time prior to the top dead center position of the piston to inject the main fuel into the combustion chamber, and determining the relationship of the timing of the injection of the auxiliary fuel into the combustion chamber to achieve a predetermined specific fuel consumption, a predetermined combustion efficiency, and a predetermined peak cylinder firing pressure.

Hsu, Bertrand D. (Erie, PA); Confer, Gregory L. (Erie, PA); Shen, Zujing (Erie, PA); Hapeman, Martin J. (Edinboro, PA); Flynn, Paul L. (Fairview, PA)

1993-12-21T23:59:59.000Z

287

Method of combustion for dual fuel engine  

DOE Patents (OSTI)

Apparatus and a method of introducing a primary fuel, which may be a coal water slurry, and a high combustion auxiliary fuel, which may be a conventional diesel oil, into an internal combustion diesel engine comprises detecting the load conditions of the engine, determining the amount of time prior to the top dead center position of the piston to inject the main fuel into the combustion chamber, and determining the relationship of the timing of the injection of the auxiliary fuel into the combustion chamber to achieve a predetermined specific fuel consumption, a predetermined combustion efficiency, and a predetermined peak cylinder firing pressure. 19 figures.

Hsu, B.D.; Confer, G.L.; Zujing Shen; Hapeman, M.J.; Flynn, P.L.

1993-12-21T23:59:59.000Z

288

Light Duty Efficient, Clean Combustion  

SciTech Connect

Cummins has successfully completed the Light Duty Efficient Clean Combustion (LDECC) cooperative program with DoE. This program was established in 2007 in support of the Department of Energy's Vehicles Technologies Advanced Combustion and Emissions Control initiative to remove critical barriers to the commercialization of advanced, high efficiency, emissions compliant internal combustion (IC) engines for light duty vehicles. Work in this area expanded the fundamental knowledge of engine combustion to new regimes and advanced the knowledge of fuel requirements for these diesel engines to realize their full potential. All of the following objectives were met with fuel efficiency improvement targets exceeded: (1) Improve light duty vehicle (5000 lb. test weight) fuel efficiency by 10.5% over today's state-of-the-art diesel engine on the FTP city drive cycle; (2) Develop and design an advanced combustion system plus aftertreatment system that synergistically meets Tier 2 Bin 5 NOx and PM emissions standards while demonstrating the efficiency improvements; (3) Maintain power density comparable to that of current conventional engines for the applicable vehicle class; and (4) Evaluate different fuel components and ensure combustion system compatibility with commercially available biofuels. Key accomplishments include: (1) A 25% improvement in fuel efficiency was achieved with the advanced LDECC engine equipped with a novel SCR aftertreatment system compared to the 10.5% target; (2) An 11% improvement in fuel efficiency was achieved with the advanced LDECC engine and no NOx aftertreamtent system; (3) Tier 2 Bin 5 and SFTP II emissions regulations were met with the advanced LDECC engine equipped with a novel SCR aftertreatment system; (4) Tier 2 Bin 5 emissions regulations were met with the advanced LDECC engine and no NOx aftertreatment, but SFTP II emissions regulations were not met for the US06 test cycle - Additional technical barriers exist for the no NOx aftertreatment engine; (5) Emissions and efficiency targets were reached with the use of biodiesel. A variety of biofuel feedstocks (soy, rapeseed, etc.) was investigated; (6) The advanced LDECC engine with low temperature combustion was compatible with commercially available biofuels as evaluated by engine performance testing and not durability testing; (7) The advanced LDECC engine equipped with a novel SCR aftertreatment system is the engine system architecture that is being further developed by the Cummins product development organization. Cost reduction and system robustness activities have been identified for future deployment; (8) The new engine and aftertreatment component technologies are being developed by the Cummins Component Business units (e.g. fuel system, turbomachinery, aftertreatment, electronics, etc.) to ensure commercial viability and deployment; (9) Cummins has demonstrated that the technologies developed for this program are scalable across the complete light duty engine product offerings (2.8L to 6.7L engines); and (10) Key subsystems developed include - sequential two stage turbo, combustions system for low temperature combustion, novel SCR aftertreatment system with feedback control, and high pressure common rail fuel system. An important element of the success of this project was leveraging Cummins engine component technologies. Innovation in component technology coupled with system integration is enabling Cummins to move forward with the development of high efficiency clean diesel products with a long term goal of reaching a 40% improvement in thermal efficiency for the engine plus aftertreatment system. The 40% improvement is in-line with the current light duty vehicle efficiency targets set by the 2010 DoE Vehicle Technologies MYPP and supported through co-operative projects such as the Cummins Advanced Technology Powertrains for Light-Duty Vehicles (ATP-LD) started in 2010.

Donald Stanton

2010-12-31T23:59:59.000Z

289

Light Duty Efficient, Clean Combustion  

DOE Green Energy (OSTI)

Cummins has successfully completed the Light Duty Efficient Clean Combustion (LDECC) cooperative program with DoE. This program was established in 2007 in support of the Department of Energy's Vehicles Technologies Advanced Combustion and Emissions Control initiative to remove critical barriers to the commercialization of advanced, high efficiency, emissions compliant internal combustion (IC) engines for light duty vehicles. Work in this area expanded the fundamental knowledge of engine combustion to new regimes and advanced the knowledge of fuel requirements for these diesel engines to realize their full potential. All of the following objectives were met with fuel efficiency improvement targets exceeded: (1) Improve light duty vehicle (5000 lb. test weight) fuel efficiency by 10.5% over today's state-of-the-art diesel engine on the FTP city drive cycle; (2) Develop and design an advanced combustion system plus aftertreatment system that synergistically meets Tier 2 Bin 5 NOx and PM emissions standards while demonstrating the efficiency improvements; (3) Maintain power density comparable to that of current conventional engines for the applicable vehicle class; and (4) Evaluate different fuel components and ensure combustion system compatibility with commercially available biofuels. Key accomplishments include: (1) A 25% improvement in fuel efficiency was achieved with the advanced LDECC engine equipped with a novel SCR aftertreatment system compared to the 10.5% target; (2) An 11% improvement in fuel efficiency was achieved with the advanced LDECC engine and no NOx aftertreamtent system; (3) Tier 2 Bin 5 and SFTP II emissions regulations were met with the advanced LDECC engine equipped with a novel SCR aftertreatment system; (4) Tier 2 Bin 5 emissions regulations were met with the advanced LDECC engine and no NOx aftertreatment, but SFTP II emissions regulations were not met for the US06 test cycle - Additional technical barriers exist for the no NOx aftertreatment engine; (5) Emissions and efficiency targets were reached with the use of biodiesel. A variety of biofuel feedstocks (soy, rapeseed, etc.) was investigated; (6) The advanced LDECC engine with low temperature combustion was compatible with commercially available biofuels as evaluated by engine performance testing and not durability testing; (7) The advanced LDECC engine equipped with a novel SCR aftertreatment system is the engine system architecture that is being further developed by the Cummins product development organization. Cost reduction and system robustness activities have been identified for future deployment; (8) The new engine and aftertreatment component technologies are being developed by the Cummins Component Business units (e.g. fuel system, turbomachinery, aftertreatment, electronics, etc.) to ensure commercial viability and deployment; (9) Cummins has demonstrated that the technologies developed for this program are scalable across the complete light duty engine product offerings (2.8L to 6.7L engines); and (10) Key subsystems developed include - sequential two stage turbo, combustions system for low temperature combustion, novel SCR aftertreatment system with feedback control, and high pressure common rail fuel system. An important element of the success of this project was leveraging Cummins engine component technologies. Innovation in component technology coupled with system integration is enabling Cummins to move forward with the development of high efficiency clean diesel products with a long term goal of reaching a 40% improvement in thermal efficiency for the engine plus aftertreatment system. The 40% improvement is in-line with the current light duty vehicle efficiency targets set by the 2010 DoE Vehicle Technologies MYPP and supported through co-operative projects such as the Cummins Advanced Technology Powertrains for Light-Duty Vehicles (ATP-LD) started in 2010.

Donald Stanton

2010-12-31T23:59:59.000Z

290

Light Duty Efficient, Clean Combustion  

SciTech Connect

Cummins has successfully completed the Light Duty Efficient Clean Combustion (LDECC) cooperative program with DoE. This program was established in 2007 in support of the Department of Energy’s Vehicles Technologies Advanced Combustion and Emissions Control initiative to remove critical barriers to the commercialization of advanced, high efficiency, emissions compliant internal combustion (IC) engines for light duty vehicles. Work in this area expanded the fundamental knowledge of engine combustion to new regimes and advanced the knowledge of fuel requirements for these diesel engines to realize their full potential. All of the following objectives were met with fuel efficiency improvement targets exceeded: 1. Improve light duty vehicle (5000 lb. test weight) fuel efficiency by 10.5% over today’s state-ofthe- art diesel engine on the FTP city drive cycle 2. Develop & design an advanced combustion system plus aftertreatment system that synergistically meets Tier 2 Bin 5 NOx and PM emissions standards while demonstrating the efficiency improvements. 3. Maintain power density comparable to that of current conventional engines for the applicable vehicle class. 4. Evaluate different fuel components and ensure combustion system compatibility with commercially available biofuels. Key accomplishments include: ? A 25% improvement in fuel efficiency was achieved with the advanced LDECC engine equipped with a novel SCR aftertreatment system compared to the 10.5% target ? An 11% improvement in fuel efficiency was achieved with the advanced LDECC engine and no NOx aftertreamtent system ? Tier 2 Bin 5 and SFTP II emissions regulations were met with the advanced LDECC engine equipped with a novel SCR aftertreatment system ? Tier 2 Bin 5 emissions regulations were met with the advanced LDECC engine and no NOx aftertreatment, but SFTP II emissions regulations were not met for the US06 test cycle – Additional technical barriers exist for the no NOx aftertreatment engine ? Emissions and efficiency targets were reached with the use of biodiesel. A variety of biofuel feedstocks (soy, rapeseed, etc.) was investigated. ? The advanced LDECC engine with low temperature combustion was compatible with commercially available biofuels as evaluated by engine performance testing and not durability testing. ? The advanced LDECC engine equipped with a novel SCR aftertreatment system is the engine system architecture that is being further developed by the Cummins product development organization. Cost reduction and system robustness activities have been identified for future deployment. ? The new engine and aftertreatment component technologies are being developed by the Cummins Component Business units (e.g. fuel system, turbomachinery, aftertreatment, electronics, etc.) to ensure commercial viability and deployment ? Cummins has demonstrated that the technologies developed for this program are scalable across the complete light duty engine product offerings (2.8L to 6.7L engines) ? Key subsystems developed include – sequential two stage turbo, combustions system for low temperature combustion, novel SCR aftertreatment system with feedback control, and high pressure common rail fuel system An important element of the success of this project was leveraging Cummins engine component technologies. Innovation in component technology coupled with system integration is enabling Cummins to move forward with the development of high efficiency clean diesel products with a long term goal of reaching a 40% improvement in thermal efficiency for the engine plus aftertreatment system. The 40% improvement is in-line with the current light duty vehicle efficiency targets set by the 2010 DoE Vehicle Technologies MYPP and supported through co-operative projects such as the Cummins Advanced Technology Powertrains for Light- Duty Vehicles (ATP-LD) started in 2010.

Stanton, Donald W

2011-06-03T23:59:59.000Z

291

Combustion diagnostic for active engine feedback control  

DOE Patents (OSTI)

This invention detects the crank angle location where combustion switches from premixed to diffusion, referred to as the transition index, and uses that location to define integration limits that measure the portions of heat released during the combustion process that occur during the premixed and diffusion phases. Those integrated premixed and diffusion values are used to develop a metric referred to as the combustion index. The combustion index is defined as the integrated diffusion contribution divided by the integrated premixed contribution. As the EGR rate is increased enough to enter the low temperature combustion regime, PM emissions decrease because more of the combustion process is occurring over the premixed portion of the heat release rate profile and the diffusion portion has been significantly reduced. This information is used to detect when the engine is or is not operating in a low temperature combustion mode and provides that feedback to an engine control algorithm.

Green, Jr., Johney Boyd (Knoxville, TN); Daw, Charles Stuart (Knoxville, TN); Wagner, Robert Milton (Knoxville, TN)

2007-10-02T23:59:59.000Z

292

A summary report on combustion and gasification processes  

DOE Green Energy (OSTI)

Six poster papers regarding combustion and gasification were reviewed. These six papers address various different technology subjects: (1) underground coal gasification modeling, (2) wood gasification kinetics, (3) heat transfer surface pretreatment by iron implantation, (4) coal water slurry stabilization technology, (5) coal log pipeline technology, and (6) nuclear reactor decontamination. Summaries and comments of the following papers are presented: Characterization of Flow and Chemical Processes in an Underground Gasifier at Great Depth; Model for Reaction Kinetics in Pyrolysis of Wood; Development of a Stainless Steel Heat Transfer Surface with Low Scaling Tendency; Storage and Transportation of Coal Water Mixtures; Coal Log Pipeline: Development Status of the First Commercial System; and Decontamination of Nuclear Systems at the Grand Gulf Nuclear Station.

Rath, L.K.; Lee, G.T.

1996-08-01T23:59:59.000Z

293

Low Temperature Combustion Demonstrator for High Efficiency Clean Combustion  

SciTech Connect

The project which extended from November 2005 to May of 2010 demonstrated the application of Low Temperature Combustion (LTC) with engine out NOx levels of 0.2 g/bhp-hr throughout the program target load of 12.6bar BMEP. The project showed that the range of loads could be extended to 16.5bar BMEP, therefore matching the reference lug line of the base 2007 MY Navistar 6.4L V8 engine. Results showed that the application of LTC provided a dramatic improvement over engine out emissions when compared to the base engine. Furthermore LTC improved thermal efficiency by over 5% from the base production engine when using the steady state 13 mode composite test as a benchmark. The key enablers included improvements in the air, fuel injection, and cooling systems made in Phases I and II. The outcome was the product of a careful integration of each component under an intelligent control system. The engine hardware provided the conditions to support LTC and the controller provided the necessary robustness for a stable combustion. Phase III provided a detailed account on the injection strategy used to meet the high load requirements. During this phase, the control strategy was implemented in a production automotive grade ECU to perform cycle-by-cycle combustion feedback on each of the engine cylinders. The control interacted on a cycle base with the injection system and with the Turbo-EGR systems according to their respective time constants. The result was a unique system that could, first, help optimize the combustion system and maintain high efficiency, and secondly, extend the steady state results to the transient mode of operation. The engine was upgraded in Phase IV with a Variable Valve Actuation system and a hybrid EGR loop. The impact of the more versatile EGR loop did not provide significant advantages, however the application of VVA proved to be an enabler to further extend the operation of LTC and gain considerable benefits in fuel economy and soot reduction. Finally, the transient demonstration was performed in Phase IV. The project demonstrated the achievement of meeting US10 emissions without NOx aftertreatment. The successful execution of the project has served to highlight the effectiveness of closely matched combustion predictive tools to engine testing. It has further served to highlight the importance of key technologies and future areas of research and development. In this regard, recommendations are made towards further improvements in the areas of engine hardware, fuel injection systems, controls and fuels.

Ojeda, William de

2010-07-31T23:59:59.000Z

294

An Energy Analysis of the Catalytic Combustion Burner  

E-Print Network (OSTI)

The gas boilers of conventional flame always produce varying degrees of combustion products NOx and CO, which pollute the environment and waste energy. As a new way of combustion, catalytic combustion breaks the flammable limits of conventional flame combustion, and realizes the combustion of ultra-natural gas/air mixture under the flammable limits. Its combustion efficiency is higher, which improves the ratio of energy utilization. Applying the catalytic combustion to gas boilers could solve the gas boilers' lower combustion efficiency, and achieve energy savings. On the basis of the catalytic combustion burner, the catalytic combustion burner was designed according to the catalytic combustion and water heaters. In this paper, we analyzed the heat loss and thermal efficiency of the catalytic combustion burner, and compared it to that of flame combustion boilers. The results showed that catalytic combustion burner ?'s heat loss is not so high as originally considered, and its pollutant emissions are lower.

Dong, Q.; Zhang, S.; Duan, Z.; Zhou, Q.

2006-01-01T23:59:59.000Z

295

Combustion Control and Diagnostics Sensor Testing in a Thermal Barrier Coated Combustor  

Science Conference Proceedings (OSTI)

The combustion control and diagnostics sensor (CCADS) continues to be developed as an in-situ combustion sensor, with immediate application to natural gas fired turbines. In-situ combustion monitoring is also expected to benefit advanced power plants of the future, fueled by coal-derived syngas, liquified natural gas (LNG), hydrogen, or hydrogen blend fuels. The in-situ monitoring that CCADS provides can enable the optimal operation of advanced, fuel-flexible turbines for minimal pollutant emissions and maximum efficiency over the full operating range of an advanced turbine. Previous work has demonstrated CCADS as a useful sensor for in-situ monitoring of natural gas combustion, including detection of important combustion events such as flashback and lean blowoff, in experimental combustors without thermal barrier coatings (TBC). Since typical TBC materials are electrical insulators at room temperature, and CCADS operation requires conduction of electrical current to the walls of the combustor, a TBC on the combustion liner was identified as a potential barrier to CCADS operation in commercial application. This paper reports on CCADS experiments in a turbulent lean premixed combustor with a yttria-stabilized zirconia (YSZ) thermal barrier coating on the combustor wall. The tests were conducted at 0.1 MPa (1 atm), with a 15V excitation voltage on the CCADS electrodes. The results confirm that for a typical thermal barrier coating, CCADS operates properly, and the total measured average resistance is close to that of an uncoated combustor. This result is consistent with previous materials studies that found the electrical resistance of typical TBC materials considerably decreases at combustor operating temperatures.

Chorpening, B.T.; Dukes, M.G.; Robey, E.H.; Thornton, J.D.

2007-05-01T23:59:59.000Z

296

Dust Motions Driven by MHD Turbulence  

E-Print Network (OSTI)

We discuss the relative grain motions due to MHD turbulence in interstellar medium. It has been known for decades that turbulent drag is an efficient way to induce grain relative motions. However, earlier treatments disregarded magnetic field and used Kolmogorov turbulence. Unlike hydro turbulence, MHD turbulence is anisotropic on small scales. Moreover, compressible modes are important for MHD and magnetic perturbations can directly interact with grains. We provide calculations of grain relative motion for realistic interstellar turbulence driving that is consistent with the velocity dispersions observed in diffuse gas and for realistic grain charging. We account for the turbulence cutoff arising from abmipolar drag. Our results on grain shattering are consistent with the customary accepted cutoff size. We obtain grain velocities for turbulence with parameters consistent with those in HI and dark clouds. These velocities are smaller than those in earlier papers, where MHD effects were disregarded. Finally, we consider grain velocities arising from photoelectric emission, radiation pressure and the thrust due to molecular hydrogen formation. These are lower than relative velocities induced by turbulence. We conclude that turbulence should prevent these mechanisms from segregating grains by size.

A. Lazarian; Huirong Yan

2002-05-17T23:59:59.000Z

297

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

298

Transportable Combustion Turbine Demonstration Project  

Science Conference Proceedings (OSTI)

New York State Electric and Gas Corporation (NYSEG) installed a 7.15-MW Solar® Taurus™ 70 (nominal 7 MW) gas combustion turbine (CT) at its State Street substation in Auburn, New York. As a demonstration project supported through EPRI's Tailored Collaboration (TC) program, it is intended to aid in better understanding the "complete picture" for siting this particular technology as a distributed resource (DR).

2001-12-14T23:59:59.000Z

299

Control circuit for combustion systems  

SciTech Connect

A control circuit is described for gas fired burners and the like such as are employed in commercial laundry fabric ironers requiring the energization of a blower motor and the resulting opening of a gas valve and ignition of a gas burner only after an air pressure sensitive switch is actuated through the operation of the blower motor for purging the system of combustible gases.

Kamberg, E.

1981-11-10T23:59:59.000Z

300

Oil shale combustion/retorting  

SciTech Connect

The Morgantown Energy Technology Center (METC) conducted a number of feasibility studies on the combustion and retorting of five oil shales: Celina (Tennessee), Colorado, Israeli, Moroccan, and Sunbury (Kentucky). These studies generated technical data primarily on (1) the effects of retorting conditions, (2) the combustion characteristics applicable to developing an optimum process design technology, and (3) establishing a data base applicable to oil shales worldwide. During the research program, METC applied the versatile fluidized-bed process to combustion and retorting of various low-grade oil shales. Based on METC's research findings and other published information, fluidized-bed processes were found to offer highly attractive methods to maximize the heat recovery and yield of quality oil from oil shale. The principal reasons are the fluidized-bed's capacity for (1) high in-bed heat transfer rates, (2) large solid throughput, and (3) selectivity in aromatic-hydrocarbon formation. The METC research program showed that shale-oil yields were affected by the process parameters of retorting temperature, residence time, shale particle size, fluidization gas velocity, and gas composition. (Preferred values of yields, of course, may differ among major oil shales.) 12 references, 15 figures, 8 tables.

Not Available

1983-05-01T23:59:59.000Z

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301

Reflective ghost imaging through turbulence  

SciTech Connect

Recent work has indicated that ghost imaging may have applications in standoff sensing. However, most theoretical work has addressed transmission-based ghost imaging. To be a viable remote-sensing system, the ghost imager needs to image rough-surfaced targets in reflection through long, turbulent optical paths. We develop, within a Gaussian-state framework, expressions for the spatial resolution, image contrast, and signal-to-noise ratio of such a system. We consider rough-surfaced targets that create fully developed speckle in their returns and Kolmogorov-spectrum turbulence that is uniformly distributed along all propagation paths. We address both classical and nonclassical optical sources, as well as a computational ghost imager.

Hardy, Nicholas D.; Shapiro, Jeffrey H. [Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)

2011-12-15T23:59:59.000Z

302

Fluid dynamics of bacterial turbulence  

E-Print Network (OSTI)

Self-sustained turbulent structures have been observed in a wide range of living fluids, yet no quantitative theory exists to explain their properties. We report experiments on active turbulence in highly concentrated 3D suspensions of Bacillus subtilis and compare them with a minimal fourth-order vector-field theory for incompressible bacterial dynamics. Velocimetry of bacteria and surrounding fluid, determined by imaging cells and tracking colloidal tracers, yields consistent results for velocity statistics and correlations over two orders of magnitude in kinetic energy, revealing a decrease of fluid memory with increasing swimming activity and linear scaling between energy and enstrophy. The best-fit model parameters allow for quantitative agreement with experimental data.

Jörn Dunkel; Sebastian Heidenreich; Knut Drescher; Henricus H. Wensink; Markus Bär; Raymond E. Goldstein

2013-02-21T23:59:59.000Z

303

Simulating flame lift-off characteristics of diesel and biodiesel fuels using detailed chemical-kinetic mechanisms and LES turbulence model.  

DOE Green Energy (OSTI)

Combustion in direct-injection diesel engines occurs in a lifted, turbulent diffusion flame mode. Numerous studies indicate that the combustion and emissions in such engines are strongly influenced by the lifted flame characteristics, which are in turn determined by fuel and air mixing in the upstream region of the lifted flame, and consequently by the liquid breakup and spray development processes. From a numerical standpoint, these spray combustion processes depend heavily on the choice of underlying spray, combustion, and turbulence models. The present numerical study investigates the influence of different chemical kinetic mechanisms for diesel and biodiesel fuels, as well as Reynolds-averaged Navier-Stokes (RANS) and large eddy simulation (LES) turbulence models on predicting flame lift-off lengths (LOLs) and ignition delays. Specifically, two chemical kinetic mechanisms for n-heptane (NHPT) and three for biodiesel surrogates are investigated. In addition, the RNG k-{epsilon} (RANS) model is compared to the Smagorinsky based LES turbulence model. Using adaptive grid resolution, minimum grid sizes of 250 {micro}m and 125 {micro}m were obtained for the RANS and LES cases respectively. Validations of these models were performed against experimental data from Sandia National Laboratories in a constant volume combustion chamber. Ignition delay and flame lift-off validations were performed at different ambient temperature conditions. The LES model predicts lower ignition delays and qualitatively better flame structures compared to the RNG k-{epsilon} model. The use of realistic chemistry and a ternary surrogate mixture, which consists of methyl decanoate, methyl 9-decenoate, and NHPT, results in better predicted LOLs and ignition delays. For diesel fuel though, only marginal improvements are observed by using larger size mechanisms. However, these improved predictions come at a significant increase in computational cost.

Som, S; Longman, D. E.; Luo, Z; Plomer, M; Lu, T; Senecal, P.K.; Pomraning, E (Energy Systems); (Univ. of Connecticut); (CONVERGENT Science)

2012-01-01T23:59:59.000Z

304

Physical Processes of Interstellar Turbulence  

E-Print Network (OSTI)

I discuss the role of self-gravity and radiative heating and cooling in shaping the nature of the turbulence in the interstellar medium (ISM) of our galaxy. The heating and cooling cause it to be highly compressible, and, in some regimes of density and temperature, to become thermally unstable, tending to spontaneously segregate into warm/diffuse and cold/dense phases. On the other hand, turbulence is an inherently mixing process, tending to replenish the density and temperature ranges that would be forbidden under thermal processes alone. The turbulence in the ionized ISM appears to be transonic (i.e, with Mach numbers $\\Ms \\sim 1$), and thus to behave essentially incompressibly. However, in the neutral medium, thermal instability causes the sound speed of the gas to fluctuate by up to factors of $\\sim 30$, and thus the flow can be highly supersonic with respect to the dense/cold gas, although numerical simulations suggest that this behavior corresponds more to the ensemble of cold clumps than to the clumps' internal velocity dispersion. Finally, coherent large-scale compressions in the warm neutral medium (induced by, say, the passage of spiral arms or by supernova shock waves) can produce large, dense molecular clouds that are subject to their own self-gravity, and begin to contract gravitationally. Because they are populated by nonlinear density fluctuations, whose local free-fall times are significantly smaller than that of the whole cloud, the fluctuations terminate their collapse earlier, giving rise to a regime of hierarchical gravitational fragmentation, with small-scale collapses occurring within larger-scale ones. Thus, the "turbulence" in molecular clouds may be dominated by a gravitationally contracting component at all scales.

Enrique Vazquez-Semadeni

2012-02-20T23:59:59.000Z

305

Generation Maintenance Applications Center: Combined-Cycle Combustion Turbine Steam Bypass Model Maintenance Guide  

Science Conference Proceedings (OSTI)

BackgroundCombustion turbine combined-cycle (CTCC) facilities use various systems and components that are unique to this type of power generation plants and are not typically found in a nuclear or fossil power plant. As such, current CTCC facility owners’ use of the Electric Power ...

2013-12-14T23:59:59.000Z

306

Probability Densities in Strong Turbulence  

E-Print Network (OSTI)

According to modern developments in turbulence theory, the "dissipation" scales (u.v. cut-offs) $\\eta$ form a random field related to velocity increments $\\delta_{\\eta}u$. In this work we, using Mellin's transform combined with the Gaussain large -scale boundary condition, calculate probability densities (PDFs) of velocity increments $P(\\delta_{r}u,r)$ and the PDF of the dissipation scales $Q(\\eta, Re)$, where $Re$ is the large-scale Reynolds number. The resulting expressions strongly deviate from the Log-normal PDF $P_{L}(\\delta_{r}u,r)$ often quoted in the literature. It is shown that the probability density of the small-scale velocity fluctuations includes information about the large (integral) scale dynamics which is responsible for deviation of $P(\\delta_{r}u,r)$ from $P_{L}(\\delta_{r}u,r)$. A framework for evaluation of the PDFs of various turbulence characteristics involving spatial derivatives is developed. The exact relation, free of spurious Logarithms recently discussed in Frisch et al (J. Fluid Mech. {\\bf 542}, 97 (2005)), for the multifractal probability density of velocity increments, not based on the steepest descent evaluation of the integrals is obtained and the calculated function $D(h)$ is close to experimental data. A novel derivation (Polyakov, 2005), of a well-known result of the multi-fractal theory [Frisch, "Turbulence. {\\it Legacy of A.N.Kolmogorov}", Cambridge University Press, 1995)), based on the concepts described in this paper, is also presented.

Victor Yakhot

2005-12-12T23:59:59.000Z

307

A SHELL MODEL TURBULENT DYNAMO  

Science Conference Proceedings (OSTI)

Turbulent dynamo phenomena, observed almost everywhere in astrophysical objects and also in the laboratory in the recent VKS2 experiment, are investigated using a shell model technique to describe magnetohydrodynamic turbulence. Detailed numerical simulations at very high Rossby numbers ({alpha}{sup 2} dynamo) show that as the magnetic Reynolds number increases, the dynamo action starts working and different regimes are observed. The model, which displays different large-scale coherent behaviors corresponding to different regimes, is able to reproduce the magnetic field reversals observed both in a geomagnetic dynamo and in the VKS2 experiment. While rough quantitative estimates of typical times associated with the reversal phenomenon are consistent with paleomagnetic data, the analysis of the transition from oscillating intermittent through reversal and finally to stationary behavior shows that the nature of the reversals we observe is typical of {alpha}{sup 2} dynamos and completely different from VKS2 reversals. Finally, the model shows that coherent behaviors can also be naturally generated inside the many-mode dynamical chaotic model, which reproduces the complexity of fluid turbulence, as described by the shell technique.

Perrone, D.; Nigro, G.; Veltri, P. [Universita della Calabria, Dipartimento di Fisica and Centro Nazionale Interuniversitario Struttura della Materia, Unita di Cosenza, I-87030 Arcavacata di Rende (Italy)

2011-07-10T23:59:59.000Z

308

Physical Processes of Interstellar Turbulence  

E-Print Network (OSTI)

I discuss the role of self-gravity and radiative heating and cooling in shaping the nature of the turbulence in the interstellar medium (ISM) of our galaxy. The heating and cooling cause it to be highly compressible, and, in some regimes of density and temperature, to become thermally unstable, tending to spontaneously segregate into warm/diffuse and cold/dense phases. On the other hand, turbulence is an inherently mixing process, tending to replenish the density and temperature ranges that would be forbidden under thermal processes alone. The turbulence in the ionized ISM appears to be transonic (i.e, with Mach numbers $\\Ms \\sim 1$), and thus to behave essentially incompressibly. However, in the neutral medium, thermal instability causes the sound speed of the gas to fluctuate by up to factors of $\\sim 30$, and thus the flow can be highly supersonic with respect to the dense/cold gas, although numerical simulations suggest that this behavior corresponds more to the ensemble of cold clumps than to the clumps'...

Vazquez-Semadeni, Enrique

2012-01-01T23:59:59.000Z

309

Planar Richtmyer-Meshkov instabilities and transition to turbulence  

Science Conference Proceedings (OSTI)

Extensive recent work has demonstrated that predictive under-resolved simulations of the velocity fields in turbulent flows are possible without resorting to explicit subgrid models. When using a class of physics-capturing high-resolution finite-volume numerical algorithms. This strategy is denoted implicit large eddy simulation (ILES, MILES). The performance of ILES in the substantially more difficult problem of under-resolved material mixing driven by under-resolved velocity fields and initial conditions (ICs) is a focus of the present work. Progress is presented in analyzing the effects of IC combined spectral content and thickness parametrizations. In the large eddy simulation (LES). the large energy containing structures are resolved, the smaller, presumably more isotropic, structures are filtered out, and effects of subgrid scales (SGS) are modeled. ILES effectively addresses the seemingly insurmountable issues posed to LES by under-resolution. by relying on the use of SGS modeling and filtering provided implicitly by a class of physics capturing numerics; extensive verification and validation in areas of engineering. geophysics. and astrophysics has been reported. In many areas of interest such as. inertial confinement fusion. understanding the collapse of the outer cores of supernovas. and supersonic combustion engines, vorticity is introduced at material interfaces by the impulsive loading of shock waves. and turbulence is generated via Richtmyer-Meshkov instabilities (RMI). Given that ILES is based on locally-adaptive, non-oscillatory. finite-volume methods it is naturally suited to emulate shock physics. The unique combination of shock and turbulence emulation capabilities supports direct use of ILES as an effective simulation anzatz for RMI. Here, we further test this approach using a particular strategy based on a nominally-inviscid, Schmidt number {approx} 1, simulation model that uses the LANL RAGE code to investigate planar RMI. Issues of initial material interface characterization and modeling difficulties, and effects of IC resolved spectral content on transitional and late-time turbulent mixing were examined in our previous work. The focus here is to carry out a systematic analysis of effects of combined IC spectral content and thickness.

Grinstein, Fernando F [Los Alamos National Laboratory; Gowardhan, Akshay [Los Alamos National Laboratory; Ristorcelli, Ray [Los Alamos National Laboratory

2011-01-21T23:59:59.000Z

310

Quantifying Turbulence for Tidal Power Applications  

SciTech Connect

Using newly collected data from a tidal power site in Puget Sound, WA, metrics for turbulence quantification are assessed and discussed. The quality of raw ping Acoustic Doppler Current Profiler (ADCP) data for turbulence studies is evaluated against Acoustic Doppler Velocimeter (ADV) data at a point. Removal of Doppler noise from the raw ping data is shown to be a crucial step in turbulence quantification. Excluding periods of slack tide, the turbulent intensity estimates at a height of 4.6 m above the seabed are 8% and 11% from the ADCP and ADV, respectively. Estimates of the turbulent dissipation rate are more variable, from 10e-3 to 10e-1 W/m^3. An example analysis of coherent Turbulent Kinetic Energy (TKE) is presented.

Thomson, Jim; Richmond, Marshall C.; Polagye, Brian; Durgesh, Vibhav

2010-08-01T23:59:59.000Z

311

Sandia Combustion Research Program: Annual report, 1986  

DOE Green Energy (OSTI)

This report presents research results of the past year, divided thematically into some ten categories. Publications and presentations arising from this work are included in the appendix. Our highlighted accomplishment of the year is the announcement of the discovery and demonstration of the RAPRENOx process. This new mechanism for the elimination of nitrogen oxides from essentially all kinds of combustion exhausts shows promise for commercialization, and may eventually make a significant contribution to our nation's ability to control smog and acid rain. The sections of this volume describe the facility's laser and computer system, laser diagnostics of flames, combustion chemistry, reacting flows, liquid and solid propellant combustion, mathematical models of combustion, high-temperature material interfaces, studies of engine/furnace combustion, coal combustion, and the means of encouraging technology transfer. 182 refs., 170 figs., 12 tabs.

Not Available

1986-01-01T23:59:59.000Z

312

Progress in BNL High-Temperature Hydrogen Combustion Research Program  

DOE Green Energy (OSTI)

The objectives of the BNL High-Temperature Hydrogen Combustion Research Program are discussed. The experimental facilities are described and two sets of preliminary experiments are presented. Chemical reaction time experiments have been performed to determine the length of time reactive mixtures of interest can be kept at temperature before reaction in the absence of ignition sources consumes the reactants. Preliminary observations are presented for temperatures in the range 588K--700K. Detonation experiments are described in which detonation cell width is measured as a measure of mixture sensitivity to detonation. Preliminary experiments are described which are being carried out to establish data reproducibility with previous measurements in the literature and to test out and refine experimental methods. Intensive studies of hydrogen combustion phenomena were carried out during the 1980s. Much of this effort was driven by issues related to nuclear reactor safety. The high-speed'' combustion phenomena of flame acceleration, deflagration-to-detonation transition, direct initiation of detonation, detonation propagation, limits of detonation in tubes and channels, transmission of detonations from confined to unconfined geometry and other related phenomena were studied using a variety of gaseous fuel-oxidant systems, including hydrogen-steam-air systems of interest in reactor safety studies. Several reviews are available which document this work [Lee, 1989; Berman, 1986].

Ciccarelli, G.; Ginsberg, T.; Boccio, J.; Curtiss, J.; Economos, C.; Jahelka, J.; Sato, K.

1992-01-01T23:59:59.000Z

313

Progress in BNL High-Temperature Hydrogen Combustion Research Program  

DOE Green Energy (OSTI)

The objectives of the BNL High-Temperature Hydrogen Combustion Research Program are discussed. The experimental facilities are described and two sets of preliminary experiments are presented. Chemical reaction time experiments have been performed to determine the length of time reactive mixtures of interest can be kept at temperature before reaction in the absence of ignition sources consumes the reactants. Preliminary observations are presented for temperatures in the range 588K--700K. Detonation experiments are described in which detonation cell width is measured as a measure of mixture sensitivity to detonation. Preliminary experiments are described which are being carried out to establish data reproducibility with previous measurements in the literature and to test out and refine experimental methods. Intensive studies of hydrogen combustion phenomena were carried out during the 1980s. Much of this effort was driven by issues related to nuclear reactor safety. The ``high-speed`` combustion phenomena of flame acceleration, deflagration-to-detonation transition, direct initiation of detonation, detonation propagation, limits of detonation in tubes and channels, transmission of detonations from confined to unconfined geometry and other related phenomena were studied using a variety of gaseous fuel-oxidant systems, including hydrogen-steam-air systems of interest in reactor safety studies. Several reviews are available which document this work [Lee, 1989; Berman, 1986].

Ciccarelli, G.; Ginsberg, T.; Boccio, J.; Curtiss, J.; Economos, C.; Jahelka, J.; Sato, K.

1992-12-31T23:59:59.000Z

314

Supercomputers Capture Turbulence in the Solar Wind  

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

Provide Web Site Feedback: info@es.net Supercomputers Capture Turbulence in the Solar Wind Berkeley Lab visualizations could help scientists forecast destructive space...

315

Visualizing the unseen forces of turbulence  

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

Grasping the vast power of turbulence could help researchers design better weather forecasts, more efficient cars, quieter helicopters and even faster ships that "float" through...

316

NETL: IEP – Post-Combustion CO2 Emissions Control - Oxy-Combustion Boiler  

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

Oxy-Combustion Boiler Material Development Oxy-Combustion Boiler Material Development Project No.: DE-NT0005262 CLICK ON IMAGE TO ENLARGE Foster Wheeler Oxy-combustion CFD Graphic The objectives of this Foster Wheeler Corporation-managed program are to assess the corrosion characteristics of oxy-combustion relative to air-fired combustion; identify the corrosion mechanisms involved; and determine the effects of oxy-combustion on conventional boiler tube materials, conventional protective coatings, and alternative materials and coatings when operating with high to low sulfur coals. The program involves the prediction of oxy-combustion gas compositions by computational fluid dynamic calculations, exposure of coupons of boiler materials and coverings coated with coal ash deposit to simulated oxy-combustion gases in electric

317

ME 374C Combustion Engine Processes ABET EC2000 syllabus  

E-Print Network (OSTI)

ME 374C ­ Combustion Engine Processes Page 1 ABET EC2000 syllabus ME 374C ­ Combustion Engine combustion engines, fuels, carburetion, combustion, exhaust emissions, knock, fuel injection, and factors to an appropriate major sequence in engineering. Textbook(s): Internal Combustion Engines and Automotive Engineering

Ben-Yakar, Adela

318

NISTIR 6458 Characterization of the Inlet Combustion Air in  

E-Print Network (OSTI)

NISTIR 6458 Characterization of the Inlet Combustion Air in NIST's Reference Spray Combustion January 2000 #12;ii Contents page Introduction 1 Reference Spray Combustion Facility 3 Numerical;1 Characterization of the Inlet Combustion Air in NIST's Reference Spray Combustion Facility: Effect of Vane Angle

Magee, Joseph W.

319

Characteristics of Langmuir Turbulence in the Ocean Mixed Layer  

Science Conference Proceedings (OSTI)

This study uses large-eddy simulation (LES) to investigate the characteristics of Langmuir turbulence through the turbulent kinetic energy (TKE) budget. Based on an analysis of the TKE budget a velocity scale for Langmuir turbulence is proposed. ...

Alan L. M. Grant; Stephen E. Belcher

2009-08-01T23:59:59.000Z

320

Kinetic Energy Transfer between Internal Gravity Waves and Turbulence  

Science Conference Proceedings (OSTI)

We describe a reliable method for distinguishing the mean, wave and turbulence fields when internal waves with changing amplitude perturb the turbulent boundary layer. By integrating the component wave and turbulence kinetic energy budgets ...

J. J. Finnigan

1988-02-01T23:59:59.000Z

Note: This page contains sample records for the topic "turbulent nuclear combustion" 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

Combustion turbine operation and optimization model.  

E-Print Network (OSTI)

??Combustion turbine performance deterioration, quantified by loss of system power, is an artifact of increased inlet air temperature and continuous degradation of the machine. Furthermore,… (more)

Sengupta, Jeet

2012-01-01T23:59:59.000Z

322

Premixed Combustion of Hydrogen Augmented Natural Gas  

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

premixed combustion * Effective for emission reduction with natural gas * High hydrogen flame speed requires care in premixer design for SGH fuels * UC Irvine study quantifies...

323

Combustion Process Contact NETL Technology Transfer Group  

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

the Reactivity and Capacity of Oxygen Carriers for the Chemical Looping Combustion Process Contact NETL Technology Transfer Group techtransfer@netl.doe.gov February 2013 This...

324

Engine Valve Actuation For Combustion Enhancement  

DOE Patents (OSTI)

A combustion chamber valve, such as an intake valve or an exhaust valve, is briefly opened during the compression and/or power strokes of a 4-stroke combustion cycle in an internal combustion engine (in particular, a diesel or CI engine). The brief opening may (1) enhance mixing withing the combustion chamber, allowing more complete oxidation of particulates to decrease engine emissions; and/or may (2) delay ignition until a more desirable time, potentially allowing a means of timing ignition in otherwise difficult-to-control conditions, e.g., in HCCI (Homogeneous Charge Compression Ignition) conditions.

Reitz, Rolf Deneys (Madison, WI); Rutland, Christopher J. (Madison, WI); Jhavar, Rahul (Madison, WI)

2004-05-18T23:59:59.000Z

325

Engine valve actuation for combustion enhancement  

DOE Patents (OSTI)

A combustion chamber valve, such as an intake valve or an exhaust valve, is briefly opened during the compression and/or power strokes of a 4-strokes combustion cycle in an internal combustion engine (in particular, a diesel or CI engine). The brief opening may (1) enhance mixing withing the combustion chamber, allowing more complete oxidation of particulates to decrease engine emissions; and/or may (2) delay ignition until a more desirable time, potentially allowing a means of timing ignition in otherwise difficult-to-control conditions, e.g., in HCCI (Homogeneous Charge Compression Ignition) conditions.

Reitz, Rolf Deneys (Madison, WI); Rutland, Christopher J. (Madison, WI); Jhavar, Rahul (Madison, WI)

2008-03-04T23:59:59.000Z

326

Advanced Vehicle Testing Activity- Other Internal Combustion...  

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

Other Internal Combustion Engine Vehicles What's New 2012 Honda Civic CNG Baseline Performance Testing (PDF 292KB) 2013 Volkswagen Jetta TDI Baseline Performance Testing (PDF...

327

ENGINE COMBUSTION CONTROL VIA FUEL REACTIVITY ...  

A compression ignition engine uses two or more fuel charges having two or more reactivities to control the timing and duration of combustion. In a ...

328

Investigation of Solution Combustion Synthesis and Precipitation ...  

Science Conference Proceedings (OSTI)

Presentation Title, Investigation of Solution Combustion Synthesis and Precipitation Synthesis Conditions on TiO2 and ZnO Nanopowder Characteristics

329

Advanced Vehicle Testing Activity: Hydrogen Internal Combustion...  

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

to someone by E-mail Share Advanced Vehicle Testing Activity: Hydrogen Internal Combustion Engine Vehicle Basics on Facebook Tweet about Advanced Vehicle Testing Activity:...

330

Advanced Vehicle Testing Activity: Other Internal Combustion...  

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

Other Internal Combustion Engine Vehicles The Advanced Vehicle Testing Activity (AVTA) is tasked by the U.S. Department of Energy's (DOE) Vehicle Technology Office (VTO) to conduct...

331

Insitu Oxygen Conduction Into Internal Combustion Chamber  

Insitu Oxygen Conduction Into Internal Combustion Chamber Note: The technology described above is an early stage opportunity. Licensing rights to this ...

332

High Performance Alloys for Advanced Combustion Systems  

Science Conference Proceedings (OSTI)

For steam turbines, it is necessary to raise temperatures in excess of 700?C. For gas turbines, raising the temperature also works but migrating the combustion ...

333

Session Overview: Heterogeneous Combustion Randall E. Winans...  

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

Heterogeneous Combustion Randall E. Winans, Session Chair X-ray Science Division, Advanced Photon Source, Argonne National Laboratory, Argonne, IL 60439, USA Heterogeneous...

334

Advanced Vehicle Testing Activity: Hydrogen Internal Combustion...  

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

to someone by E-mail Share Advanced Vehicle Testing Activity: Hydrogen Internal Combustion Engine Vehicle Specifications and Test Procedures on Facebook Tweet about Advanced...

335

Pyrolysis reactor and fluidized bed combustion chamber  

DOE Patents (OSTI)

A solid carbonaceous material is pyrolyzed in a descending flow pyrolysis reactor in the presence of a particulate source of heat to yield a particulate carbon containing solid residue. The particulate source of heat is obtained by educting with a gaseous source of oxygen the particulate carbon containing solid residue from a fluidized bed into a first combustion zone coupled to a second combustion zone. A source of oxygen is introduced into the second combustion zone to oxidize carbon monoxide formed in the first combustion zone to heat the solid residue to the temperature of the particulate source of heat.

Green, Norman W. (Upland, CA)

1981-01-06T23:59:59.000Z

336

Vehicle Technologies Office: Combustion and Emission Control  

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

and fuel formulation to arrive at the most cost-effective approach to optimizing advanced combustion engine efficiency and performance while reducing emissions to near-zero levels....

337

Nanotechnology Combustion Sensors: Prototype Development  

Science Conference Proceedings (OSTI)

The release of nitrogen oxides (NOx) and sulfur dioxide (SO2) from the combustion of fossil fuels and other sources is linked to various ecosystem impacts and human health effects, including acid rain, coastal eutrophication, damage to forest ecosystems, chronic bronchitis, respiratory problems, and heart attacks. The U.S. Environmental Protection Agency (EPA) estimates that in 2003, total NOx and SO2 emissions from various sources in the United States were 20.8 million tons and 15.9 million tons, respec...

2008-12-23T23:59:59.000Z

338

Electromagnetic weak turbulence theory revisited  

SciTech Connect

The statistical mechanical reformulation of weak turbulence theory for unmagnetized plasmas including fully electromagnetic effects was carried out by Yoon [Phys. Plasmas 13, 022302 (2006)]. However, the wave kinetic equation for the transverse wave ignores the nonlinear three-wave interaction that involves two transverse waves and a Langmuir wave, the incoherent analogue of the so-called Raman scattering process, which may account for the third and higher-harmonic plasma emissions. The present paper extends the previous formalism by including such a term.

Yoon, P. H. [IPST, University of Maryland, College Park, Maryland 20742 (United States); Ziebell, L. F. [Instituto de Fisica, UFRGS, Porto Alegre, RS (Brazil); Gaelzer, R.; Pavan, J. [Instituto de Fisica e Matematica, UFPel, Pelotas, RS (Brazil)

2012-10-15T23:59:59.000Z

339

A Total Turbulent Energy Closure Model for Neutrally and Stably Stratified Atmospheric Boundary Layers  

Science Conference Proceedings (OSTI)

This paper presents a turbulence closure for neutral and stratified atmospheric conditions. The closure is based on the concept of the total turbulent energy. The total turbulent energy is the sum of the turbulent kinetic energy and turbulent ...

Thorsten Mauritsen; Gunilla Svensson; Sergej S. Zilitinkevich; Igor Esau; Leif Enger; Branko Grisogono

2007-11-01T23:59:59.000Z

340

Locality and stability of the cascades of two-dimensional  

E-Print Network (OSTI)

chemical combustion Stabilize plasma in a nuclear fusion reactor Propagation of laser through turbulence;Outline Why study turbulence? Brief overview of K41 theory (3D turbulence) Frisch reformulation of K41 theory. KLB theory (2D turbulence). My reformulation of Frisch to address 2D turbulence Locality

Gkioulekas, Eleftherios - Department of Mathematics, University of Texas

Note: This page contains sample records for the topic "turbulent nuclear combustion" 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

Simulation and Beyond: Computing in the 21st John Guckenheimer  

E-Print Network (OSTI)

chemical combustion Stabilize plasma in a nuclear fusion reactor Propagation of laser through turbulence;Outline Why study turbulence? Brief overview of K41 theory (3D turbulence) Frisch reformulation of K41 theory. KLB theory (2D turbulence). My reformulation of Frisch to address 2D turbulence Locality

Guckenheimer, John

342

A Quadratic Closure for Compressible Turbulence  

Science Conference Proceedings (OSTI)

We have investigated a one-point closure model for compressible turbulence based on third- and higher order cumulant discard for systems undergoing rapid deformation, such as might occur downstream of a shock or other discontinuity. In so doing, we find the lowest order contributions of turbulence to the mean flow, which lead to criteria for Adaptive Mesh Refinement. Rapid distortion theory (RDT) as originally applied by Herring closes the turbulence hierarchy of moment equations by discarding third order and higher cumulants. This is similar to the fourth-order cumulant discard hypothesis of Millionshchikov, except that the Millionshchikov hypothesis was taken to apply to incompressible homogeneous isotropic turbulence generally, whereas RDT is applied only to fluids undergoing a distortion that is 'rapid' in the sense that the interaction of the mean flow with the turbulence overwhelms the interaction of the turbulence with itself. It is also similar to Gaussian closure, in which both second and fourth-order cumulants are retained. Motivated by RDT, we develop a quadratic one-point closure for rapidly distorting compressible turbulence, without regard to homogeneity or isotropy, and make contact with two equation turbulence models, especially the K-{var_epsilon} and K-L models, and with linear instability growth. In the end, we arrive at criteria for Adaptive Mesh Refinement in Finite Volume simulations.

Futterman, J A

2008-09-16T23:59:59.000Z

343

The Turbulence Structure of Nocturnal Slope Flow  

Science Conference Proceedings (OSTI)

Measurements of the turbulence structure of nocturnal slope flow are used to test the hypothesis that slope flow turbulence in the region above the low-level wind maximum is decoupled from the surface and has a local structure similar to that ...

T. W. Horst; J. C. Doran

1988-02-01T23:59:59.000Z

344

Towards a detailed soot model for internal combustion engines  

Science Conference Proceedings (OSTI)

In this work, we present a detailed model for the formation of soot in internal combustion engines describing not only bulk quantities such as soot mass, number density, volume fraction, and surface area but also the morphology and chemical composition of soot aggregates. The new model is based on the Stochastic Reactor Model (SRM) engine code, which uses detailed chemistry and takes into account convective heat transfer and turbulent mixing, and the soot formation is accounted for by SWEEP, a population balance solver based on a Monte Carlo method. In order to couple the gas-phase to the particulate phase, a detailed chemical kinetic mechanism describing the combustion of Primary Reference Fuels (PRFs) is extended to include small Polycyclic Aromatic Hydrocarbons (PAHs) such as pyrene, which function as soot precursor species for particle inception in the soot model. Apart from providing averaged quantities as functions of crank angle like soot mass, volume fraction, aggregate diameter, and the number of primary particles per aggregate for example, the integrated model also gives detailed information such as aggregate and primary particle size distribution functions. In addition, specifics about aggregate structure and composition, including C/H ratio and PAH ring count distributions, and images similar to those produced with Transmission Electron Microscopes (TEMs), can be obtained. The new model is applied to simulate an n-heptane fuelled Homogeneous Charge Compression Ignition (HCCI) engine which is operated at an equivalence ratio of 1.93. In-cylinder pressure and heat release predictions show satisfactory agreement with measurements. Furthermore, simulated aggregate size distributions as well as their time evolution are found to qualitatively agree with those obtained experimentally through snatch sampling. It is also observed both in the experiment as well as in the simulation that aggregates in the trapped residual gases play a vital role in the soot formation process. (author)

Mosbach, Sebastian; Celnik, Matthew S.; Raj, Abhijeet; Kraft, Markus [Department of Chemical Engineering and Biotechnology, University of Cambridge, Pembroke Street, Cambridge CB2 3RA (United Kingdom); Zhang, Hongzhi R. [Department of Chemical Engineering, University of Utah, 1495 East 100 South, Kennecott Research Building, Salt Lake City, UT 84112 (United States); Kubo, Shuichi [Frontier Research Center, Toyota Central R and D Labs., Inc., Nagakute, Aichi 480-1192 (Japan); Kim, Kyoung-Oh [Higashifuji Technical Center, Toyota Motor Corporation, Mishuku 1200, Susono, Shizuoka 480-1193 (Japan)

2009-06-15T23:59:59.000Z

345

CMR17  

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

0 Petascale Simulations of Turbulent Nuclear Combustion ALCF-2 Early Science Program Technical Report Argonne Leadership Computing Facility About Argonne National Laboratory...

346

Interactive exploration and analysis of large scale turbulent combustion using topology-based data segmentation  

E-Print Network (OSTI)

Abstract—Large-scale simulations are increasingly being used to study complex scientific and engineering phenomena. As a result, advanced visualization and data analysis are also becoming an integral part of the scientific process. Often, a key step in extracting insight from these large simulations involves the definition, extraction, and evaluation of features in the space and time coordinates of the solution. However, in many applications these features involve a range of parameters and decisions that will affect the quality and direction of the analysis. Examples include particular level sets of a specific scalar field, or local inequalities between derived quantities. A critical step in the analysis is to understand how these arbitrary parameters/decisions impact the statistical properties of the features, since such a characterization will help to evaluate the conclusions of the analysis as a whole. We present a new topological framework that in a single pass extracts and encodes entire families of possible features definitions as well as their statistical properties. For each time step we construct a hierarchical merge tree a highly compact, yet flexible feature representation. While this data structure is more than two orders of magnitude smaller than the raw simulation data it allows us to extract a set of feature for any given parameter selection in a post-processing step. Furthermore, we augment the trees with additional attributes making it possible to gather a large number of useful global, local, as well as conditional statistic that would otherwise be extremely difficult to compile. We also use this representation to create tracking graphs that describe the temporal evolution of the features over time. Our system provides a linked-view interface to explore the time-evolution of the graph interactively alongside the segmentation, thus making it possible to perform extensive data analysis in a very efficient manner. We demonstrate our framework

Peer-timo Bremer; Gunther H. Weber; Julien Tierny; Valerio Pascucci; Marcus S. Day; John B. Bell

2011-01-01T23:59:59.000Z

347

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

348

Spectrum of gravitational radiation from primordial turbulence  

Science Conference Proceedings (OSTI)

Energy injection into the early universe can induce turbulent motions of the primordial plasma, which in turn act as a source for gravitational radiation. Earlier work computed the amplitude and characteristic frequency of the relic gravitational wave background, as a function of the total energy injected and the stirring scale of the turbulence. This paper computes the frequency spectrum of relic gravitational radiation from a turbulent source of the stationary Kolmogoroff form which acts for a given duration, making no other approximations. We also show that the limit of long source wavelengths, commonly employed in aeroacoustic problems, is an excellent approximation. The gravitational waves from cosmological turbulence around the electroweak energy scale will be detectable by future space-based laser interferometers for a substantial range of turbulence parameters.

Gogoberidze, Grigol [Centre for Plasma Astrophysics, K.U. Leuven, Celestijnenlaan 200B, 3001 Leuven (Belgium); National Abastumani Astrophysical Observatory, 2A Kazbegi Ave, GE-0160 Tbilisi (Georgia); Kahniashvili, Tina [Center for Cosmology and Particle Physics, New York University, 4 Washington Plaza, New York, New York 10003 (United States); National Abastumani Astrophysical Observatory, 2A Kazbegi Ave, GE-0160 Tbilisi (Georgia); Kosowsky, Arthur [Department of Physics and Astronomy, University of Pittsburgh, 3941 O'Hara Street, Pittsburgh, Pennsylvania 15260 (United States)

2007-10-15T23:59:59.000Z

349

Sandia combustion research program: Annual report, 1987  

DOE Green Energy (OSTI)

More than a decade ago, in response to a national energy crisis, Sandia proposed to the US Department of Energy a new, ambitious program in combustion research. Our strategy was to apply the rapidly increasing capabilities in lasers and computers to combustion science and technology. Shortly thereafter, the Combustion Research Facility (CRF) was established at Sandia's Livermore location. Designated a ''User Facility,'' the charter of the CRF was to develop and maintain special-purpose resources to support a nationwide initiative--involving US universities, industry, and national laboratories--to improve our understanding and control of combustion. This report includes descriptions of several research projects which have been stimulated by Working Groups and involve the on-site participation of industry scientists. DOE's Industry Technology Fellowship Program has been instrumental in the success of some of the joint efforts. The remainder of this report presents research results of calendar year 1987, separated thematically into nine categories. Refereed journal articles appearing in print during 1987, along with selected other publications, are included at the end of Section 10. In addition to our ''traditional'' research--chemistry, reacting flow, diagnostics, engine combustion, and coal combustion--you will note continued progress in somewhat recent themes: pulse combustion, high temperature materials, and energetic materials, for example. Moreover, we have just started a small, new effort to understand combustion-related issues in the management of toxic and hazardous materials.

Palmer, R.E.; Sanders, B.R.; Ivanetich, C.A. (eds.)

1988-01-01T23:59:59.000Z

350

Method and system for controlled combustion engines  

DOE Patents (OSTI)

A system for controlling combustion in internal combustion engines of both the Diesel or Otto type, which relies on establishing fluid dynamic conditions and structures wherein fuel and air are entrained, mixed and caused to be ignited in the interior of a multiplicity of eddies, and where these structures are caused to sequentially fill the headspace of the cylinders.

Oppenheim, A. K. (Berkeley, CA)

1990-01-01T23:59:59.000Z

351

Application of Computed Tomography to Microgravity Combustion  

Science Conference Proceedings (OSTI)

This paper describes applications of computed tomography (CT) to combustion phenomena under microgravity conditions. Infrared Thermography (IT) has been considered as a promising method for two-dimensional measurement of flames. We have applied IT to ... Keywords: computed tomography, diffusion flame, infrared thermography, microgravity combustion, spectroscopy

H. Sato; K. Itoh; M. Shimizu; S. Hayashi; Y. Fujimori; K. Maeno

1999-12-01T23:59:59.000Z

352

Oscillating combustion from a premix fuel nozzle  

DOE Green Energy (OSTI)

Stringent emissions requirements for stationary gas turbines have produced new challenges in combustor design. In the past, very low NOx pollutant emissions have been achieved through various combustion modifications, such as steam or water injection, or post-combustion cleanup methods such as selective catalytic reduction (SCR). An emerging approach to NOx abatement is lean premix combustion. Lean premix combustion avoids the cost and operational problems associated with other NOx control methods. By premixing fuel and air at very low equivalence ratios, the high temperatures which produce NOx are avoided. The challenges of premix combustion include avoiding flashback, and ensuring adequate fuel/air premixing. In addition, the combustion must be stable. The combustor should not operate so close to extinction that a momentary upset will extinguish the flame (static stability), and the flame should not oscillate (dynamic stability). Oscillations are undesirable because the associated pressure fluctuations can shorten component lifetime. Unfortunately, experience has shown that premix fuel nozzles burning natural gas are susceptible to oscillations. Eliminating these oscillations can be a costly and time consuming part of new engine development. As part of the U.S. Department of Energy`s Advanced Turbine Systems Program, the Morgantown Energy Technology Center (METC) is investigating the issue of combustion oscillations produced by lean premix fuel nozzles. METC is evaluating various techniques to stabilize oscillating combustion in gas turbines. Tests results from a premix fuel nozzle using swirl stabilization and a pilot flame are reported here.

Richards, G.A.; Yip, M.J.

1995-08-01T23:59:59.000Z

353

Interaction of the burning spherical droplets in oxygen-enriched turbulent environment  

SciTech Connect

Three-dimensional numerical studies on the interaction of vaporizing and burning droplets were conducted to understand the burning characteristics of multiple droplets in a turbulent environment. The burning droplets characteristics, such as lifetime, surface temperature, vaporization, reaction, and burning rate were examined for various oxygen mole-fractions and geometrical arrangements of droplets. Results from a single droplet combustion test were first verified and validated against existing experimental data. Results indicate that turbulent intensity has a moderate effect on droplet burning rate, but not as prominent an effect as the oxygen mole-fraction. At high oxygen mole-fractions, droplet lifetime was short due to enhanced burning. It is shown that evaporation processes of multiple droplets are notably affected by the inter-space distance between droplets both in streamwise and spanwise directions. The burning rate as a function of oxygen mole-fraction and inter-space distance is determined and can be used as a guideline for future studies on spray combustion. (author)

Cho, Chong Pyo [Automobile Energy and Environment Research Center, Korea Institute of Energy Research, 71-2 Jangdong, Yuseonggu, Daejeon, 305-343 (Korea); Kim, Ho Young; Yoon, Sam S. [Department of Mechanical Engineering, Korea University, Anamdong, 5-Ga, Sungbukgu, Seoul, 136-701 (Korea)

2009-01-15T23:59:59.000Z

354

A hybrid 2-zone/WAVE engine combustion model for simulating combustion instabilities during dilute operation  

Science Conference Proceedings (OSTI)

Internal combustion engines are operated under conditions of high exhaust gas recirculation (EGR) to reduce NO x emissions and promote enhanced combustion modes such as HCCI. However, high EGR under certain conditions also promotes nonlinear feedback between cycles, leading to the development of combustion instabilities and cyclic variability. We employ a two-zone phenomenological combustion model to simulate the onset of combustion instabilities under highly dilute conditions and to illustrate the impact of these instabilities on emissions and fuel efficiency. The two-zone in-cylinder combustion model is coupled to a WAVE engine-simulation code through a Simulink interface, allowing rapid simulation of several hundred successive engine cycles with many external engine parametric effects included. We demonstrate how this hybrid model can be used to study strategies for adaptive feedback control to reduce cyclic combustion instabilities and, thus, preserve fuel efficiency and reduce emissions.

Edwards, Kevin Dean [ORNL; Wagner, Robert M [ORNL; Chakravarthy, Veerathu K [ORNL; Daw, C Stuart [ORNL; Green Jr, Johney Boyd [ORNL

2006-01-01T23:59:59.000Z

355

Argonne TTRDC - Engines - Combustion Visualization - emissions,  

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

Combustion Visualization Combustion Visualization Exploring Combustion Using Advanced Imaging Techniques In the photo, the GM diesel test cell is shown with vehicle exhaust aftertreatment hardware (diesel particulate filtration and diesel oxidation catalyst) along with other advanced technology-such as a variable geometry turbocharger, cooled exhaust gas recirculation and a common-rail fuel injection system. Fig. 1. The GM diesel test cell is shown with vehicle exhaust aftertreatment hardware (diesel particulate filtration and diesel oxidation catalyst) along with other advanced technology-such as a variable geometry turbocharger, cooled exhaust gas recirculation and a common-rail fuel injection system. Two-dimensional image of hydrogen combustion OH chemiluminescence. Fig. 2. Two-dimensional image of hydrogen combustion OH chemiluminescence.

356

Fine Particle Emissions from Combustion Systems  

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

Fine Particle Emissions from Combustion Systems Fine Particle Emissions from Combustion Systems Speaker(s): Allen Robinson Date: November 11, 2005 - 12:00pm Location: 90-3122 Combustion systems such as motor vehicles and power plants are major sources of fine particulate matter. This talk describes some of the changes in fine particle emissions that occur as exhaust from combustion systems mix with background air. This mixing cools and dilutes the exhaust which influences gas-particle partitioning of semi-volatile species, the aerosol size distribution, and the fine particle mass. Dilution sampling is used to characterize fine particle emissions from combustion systems because it simulates the rapid cooling and dilution that occur as exhaust mixes with the atmosphere. Results from dilution sampler

357

Advanced Combustion Technologies | Department of Energy  

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

Science & Innovation » Clean Coal » Advanced Combustion Science & Innovation » Clean Coal » Advanced Combustion Technologies Advanced Combustion Technologies Joe Yip, a researcher at FE's National Energy Technology Laboratory, uses laser-based Rayleigh light scattering to measure flame density and speed over a flat flame burner. Oxyfuel combustion, using oxygen in place of air with diluents such as steam or carbon dioxide, can reduce pollutant emissions in advanced power cycles using gas turbines. Photo courtesy of NETL Multimedia. Joe Yip, a researcher at FE's National Energy Technology Laboratory, uses laser-based Rayleigh light scattering to measure flame density and speed over a flat flame burner. Oxyfuel combustion, using oxygen in place of air with diluents such as steam or carbon dioxide, can reduce pollutant

358

High resolution fossil fuel combustion CO2 emission fluxes for...  

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

High resolution fossil fuel combustion CO2 emission fluxes for the United States Title High resolution fossil fuel combustion CO2 emission fluxes for the United States Publication...

359

Method of launching a missile using secondary combustion  

SciTech Connect

A method is described of selectively increasing the energy output of a gas generator utilized to launch a missile from a launch tube without igniting the missile until after it is launched from the tube comprising the steps of: providing combustible products in the products of combustion produced by primary combustion within the gas generator; providing varying quantities of oxidant in the launch tube to burn the combustible products in the products of combustion produced by the gas generator; and controlling the temperature of the products of combustion produced by the gas generator to permit secondary combustion of the combustible products.

Erikson, E.E.

1987-06-09T23:59:59.000Z

360

NREL: Vehicles and Fuels Research - Advanced Combustion and Fuels...  

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

Advanced Combustion and Fuels Projects NREL's advanced combustion and fuels projects bridge fundamental chemical kinetics and engine research to investigate how new vehicle fuels...

Note: This page contains sample records for the topic "turbulent nuclear combustion" 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

Study on the Combustion Characteristics and Kinetics of Blending ...  

Science Conference Proceedings (OSTI)

The changes of combustion characteristic parameters o f pulverized coals are analyzed. The results show that DTG curves of coal combustion move to low ...

362

2.61 Internal Combustion Engines, Spring 2004  

E-Print Network (OSTI)

Fundamentals of how the design and operation of internal combustion engines affect their performance, operation, fuel requirements, and environmental impact. Study of fluid flow, thermodynamics, combustion, heat transfer ...

Heywood, John B.

363

Post-Combustion Carbon Capture Research | Department of Energy  

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

Post-Combustion Carbon Capture Research Post-Combustion Carbon Capture Research Fossil fuel fired electric generating plants are the cornerstone of America's central power system....

364

FEMP Technology Brief: Boiler Combustion Control and Monitoring...  

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

Boiler Combustion Control and Monitoring System FEMP Technology Brief: Boiler Combustion Control and Monitoring System October 7, 2013 - 9:12am Addthis This composite photo shows...

365

Groundbreaking Combustion Research by LBNL Featured on Cover...  

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

matches a combustion experiment. Gaining a better understanding of combustion, which powers everything from automobiles to aircraft to power generating plants, can help improve...

366

Pages that link to "Coal Combustion By-Products (Maryland)" ...  

Open Energy Info (EERE)

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367

Changes related to "Coal Combustion By-Products (Maryland)" ...  

Open Energy Info (EERE)

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368

NETL: Staged, High-Pressure Oxy-Combustion Technology: Development...  

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

tool Conducting CFD-aided design of a novel staged combustion vessel and radiative heat exchanger Performing lab-scale experiments of staged combustion without flue gas...

369

Coal combustion science. Quarterly progress report, April 1994--June 1994  

Science Conference Proceedings (OSTI)

Research on coal combustion continued. This report presents results on: kinetics and mechanisms of coal char combustion, and deposit growth and property development in coal-fired furnaces.

Hardesty, D.R. [ed.; Baxter, L.L.; Davis, K.A.

1995-07-01T23:59:59.000Z

370

Vehicle Technologies Office: Materials for High Efficiency Combustion...  

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

High Efficiency Combustion Engines to someone by E-mail Share Vehicle Technologies Office: Materials for High Efficiency Combustion Engines on Facebook Tweet about Vehicle...

371

Measurement and Mapping of Pulse Combustion Impingement Heat Transfer Rates .  

E-Print Network (OSTI)

??Current research shows that pulse combustion impingement drying is an improvement over the steady impingement drying currently in commercial use. Pulse combustion impingement has higher… (more)

Hagadorn, Charles C., III

2005-01-01T23:59:59.000Z

372

Improving the Carbon Dioxide Emission Estimates from the Combustion...  

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

the Carbon Dioxide Emission Estimates from the Combustion of Fossil Fuels in California Title Improving the Carbon Dioxide Emission Estimates from the Combustion of Fossil Fuels in...

373

NETL: Pre-Combustion Carbon Capture by a Nanoporous, Superhydrophobic...  

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

Pre-Combustion Carbon Capture by a Nanoporous, Superhydrophobic Membrane Contactor Process Project No.: DE-FE0000646 The Gas Technology Institute is developing a pre-combustion...

374

Multi-stage combustion using nitrogen-enriched air - Energy ...  

Multi-stage combustion technology combined with nitrogen-enriched air technology for controlling the combustion temperature and products to extend the maintenance and ...

375

Study of abnormal combustion oscillations in gas fired appliances.  

E-Print Network (OSTI)

??The thesis work discusses abnormal combustion noise in gas-fired appliances. An experimental model was made to provide insight into the causes of abnormal combustion noises.… (more)

Kumar, Dasari

2006-01-01T23:59:59.000Z

376

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

377

Dry low NOx combustion system with pre-mixed direct-injection secondary fuel nozzle  

Science Conference Proceedings (OSTI)

A combustion system includes a first combustion chamber and a second combustion chamber. The second combustion chamber is positioned downstream of the first combustion chamber. The combustion system also includes a pre-mixed, direct-injection secondary fuel nozzle. The pre-mixed, direct-injection secondary fuel nozzle extends through the first combustion chamber into the second combustion chamber.

Zuo, Baifang; Johnson, Thomas; Ziminsky, Willy; Khan, Abdul

2013-12-17T23:59:59.000Z

378

High temperature nuclear gas turbine  

SciTech Connect

Significance of gas turbine cycle, process of the development of gas turbines, cycle and efficiency of high-temperature gas turbines, history of gas turbine plants and application of nuclear gas turbines are described. The gas turbines are directly operated by the heat from nuclear plants. The gas turbines are classified into two types, namely open cycle and closed cycle types from the point of thermal cycle, and into two types of internal combustion and external combustion from the point of heating method. The hightemperature gas turbines are tbe type of internal combustion closed cycle. Principle of the gas turbines of closed cycle and open cycle types is based on Brayton, Sirling, and Ericsson cycles. Etficiency of the turbines is decided only by pressure ratio, and is independent of gas temperature. An example of the turbine cycle for the nuclear plant Gestacht II is explained. The thermal efficiency of that plant attains 37%. Over the gas temperature of about 750 deg C, the thermal efficiency of the gas turbine cycle is better than that of steam turbine cycle. As the nuclear fuel, coated particle fuel is used, and this can attain higher temperature of core outlet gas. Direct coupling of the nuclear power plants and the high temperature gas turbines has possibility of the higher thermal efficiency. (JA)

Kurosawa, A.

1973-01-01T23:59:59.000Z

379

Advances in pulverized coal combustion  

Science Conference Proceedings (OSTI)

A combustion system has been developed to operate cost effectively in the difficult regulatory and economic climate of the 1980's. The system is designed to reduce auxiliary fuel oil comsumption by at least 30% while meeting all relevant emissions limits. This is achieved with the fewest components consistent with practical reliable design criteria. The Controlled Flow Split/Flame low NO/sub x/ burner, MBF pulverizer and Two-Stage ignition system are integrated into a mutually supporting system which is applicable to both new steam generators and, on a retrofit basis, to existing units. In the future, a pulverized coal ignition system will be available to eliminate fuel oil use within the boiler.

Vatsky, J.

1981-01-01T23:59:59.000Z

380

Combustion turbine repowering: Final report  

SciTech Connect

The study discusses the findings of a conceptual site-specific investigation into the feasibility of repowering an existing reheat fossil unit utilizing combustion turbines. It identifies a potentially attractive repowering project, through the evaluation and selective elimination of a large number of alternatives. A conceptual design is performed on the selected alternative. Capital costs are developed for this alternative including new equipment and modifications to existing equipment. The results of an economic evaluation and sensitivity analysis are presented, to serve as a basis for a decision on whether or not to proceed with final design, procurement, and construction of the system. The steps presented in the report are intended to provide for the utility industry a detailed methodology for investigating repowering at a specific utility site. 4 refs., 21 figs., 15 tabs.

Oliker, I.; Silaghy, F.J.

1987-11-01T23:59:59.000Z

Note: This page contains sample records for the topic "turbulent nuclear combustion" 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

Wind turbulence characterization for wind energy development  

DOE Green Energy (OSTI)

As part of its support of the US Department of Energy's (DOE's) Federal Wind Energy Program, the Pacific Northwest Laboratory (PNL) has initiated an effort to work jointly with the wind energy community to characterize wind turbulence in a variety of complex terrains at existing or potential sites of wind turbine installation. Five turbulence characterization systems were assembled and installed at four sites in the Tehachapi Pass in California, and one in the Green Mountains near Manchester, Vermont. Data processing and analyses techniques were developed to allow observational analyses of the turbulent structure; this analysis complements the more traditional statistical and spectral analyses. Preliminary results of the observational analyses, in the rotating framework or a wind turbine blade, show that the turbulence at a site can have two major components: (1) engulfing eddies larger than the rotor, and (2) fluctuating shear due to eddies smaller than the rotor disk. Comparison of the time series depicting these quantities at two sites showed that the turbulence intensity (the commonly used descriptor of turbulence) did not adequately characterize the turbulence at these sites. 9 refs., 10 figs.,

Wendell, L.L.; Gower, G.L.; Morris, V.R.; Tomich, S.D.

1991-09-01T23:59:59.000Z

382

Anisotropic MHD Turbulence in the Interstellar Medium and Solar Wind  

E-Print Network (OSTI)

Anisotropic MHD Turbulence in the Interstellar Medium and Solar Wind C. S. Ng Center for Magnetic (MHD) turbulence Observations in ISM and solar wind · Anisotropy due to magnetic field · Electron MHD turbulence #12;Interstellar turbulence From Cordes (1999) Observation: power law relation between electron

Ng, Chung-Sang

383

Great Plains Turbulence Environment: Its Origins, Impact, and Simulation  

SciTech Connect

This paper summarizes the known impacts of nocturnal turbulence on wind turbine performance and operations.

Kelley, N. D.; Jonkman, B. J.; Scott, G. N.

2006-12-01T23:59:59.000Z

384

Modeling the motion of a hot, turbulent gas  

Science Conference Proceedings (OSTI)

Keywords: animation, convection, gas simulations, gaseous phenomena, physics-based modeling, smoke, steam, turbulent flow

Nick Foster; Dimitris Metaxas

1997-08-01T23:59:59.000Z

385

Magnetic field effects on the thermonuclear combustion front of Chandrasekhar mass white dwarfs  

E-Print Network (OSTI)

The explosion of a type Ia supernova starts in a white dwarf as a laminar deflagration at the center of the star and soon several hydrodynamic instabilities, in particular, the Rayleigh-Taylor instability, begin to act. A cellular stationary combustion and a turbulent combustion regime are rapidly achieved by the flame and maintained up to the end of the so-called flamelet regime when the transition to detonation is believed to occur. The burning velocity at these regimes is well described by the fractal model of combustion. Using a semi-analytic approach, we describe the effect of magnetic fields on the fractalization of the front considering a white dwarf with a nearly dipolar magnetic field. We find an intrinsic asymmetry on the velocity field that may be maintained up to the free expansion phase of the remnant. Considering the strongest values inferred for a white dwarf's magnetic fields with strengths up to $10^{8}-10^{9}$ G at the surface and assuming that the field near the centre is roughly 10 times greater, asymmetries in the velocity field higher than $10-20 %$ are produced between the magnetic polar and the equatorial axis of the remnant which may be related to the asymmetries found from recent spectropolarimetric observations of very young SN Ia remnants. Dependence of the asymmetry with white dwarf composition is also analyzed.

Cristian R. Ghezzi; Elisabete M. de Gouveia Dal Pino; Jorge E. Horvath

2000-12-06T23:59:59.000Z

386

Improved Heat Transfer and Performance of High Intensity Combustion Systems for Reformer Furnace Applications  

E-Print Network (OSTI)

Developments over the past fifteen years have evolved new short flame, high intensity (1,000,000 BTU/HR/ft3 ) combustion systems for industrial uses. Such systems produce a more uniform and higher heat flux than conventional low intensity systems and should enable substantial capital cost savings in new furnace applications. Recent performance improvements established from tests of high intensity combustion systems are described along with advances made in the analytical prediction of design performance. High intensity combustion systems can operate at zero excess air conditions without generating undesirable constituents in the exhaust. A more uniform gas temperature and gas emissivity renders modeling and design of the furnace radiant heat transfer section more realistic. 'Over-design' to allow for the less determinate conditions typical of low intensity, turbulent diffusion oil flame systems should be avoidable. A model has been set up and results generated which indicate the potentialities of the above premise. The application of vortex stabilized high intensity burners for reformer furnaces in the petrochemical industry is then reviewed and emphasized.

Williams, F. D. M.; Kondratas, H. M.

1983-01-01T23:59:59.000Z

387

Vehicle Technologies Office: Advanced Combustion Engines  

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

Combustion Engines Combustion Engines Improving the efficiency of internal combustion engines is one of the most promising and cost-effective near- to mid-term approaches to increasing highway vehicles' fuel economy. The Vehicle Technologies Office's research and development activities address critical barriers to commercializing higher efficiency, very low emissions advanced internal combustion engines for passenger and commercial vehicles. This technology has great potential to reduce U.S. petroleum consumption, resulting in greater economic, environmental, and energy security. Already offering outstanding drivability and reliability to over 230 million passenger vehicles, internal combustion engines have the potential to become substantially more efficient. Initial results from laboratory engine tests indicate that passenger vehicle fuel economy can be improved by more than up to 50 percent, and some vehicle simulation models estimate potential improvements of up to 75 percent. Advanced combustion engines can utilize renewable fuels, and when combined with hybrid electric powertrains could have even further reductions in fuel consumption. As the EIA reference case forecasts that by 2035, more than 99 percent of light- and heavy-duty vehicles sold will still have internal combustion engines, the potential fuel savings is tremendous.

388

Research on late-robust combustion  

E-Print Network (OSTI)

To better understand the role that turbulence plays in causing cycle-by-cycle variations, an experimental study was carried out in which charge motion or laminar flame speed was varied. Two sets of tests were done. The ...

Wildman, Craig B. E. (Craig Bradley Edward), 1987-

2005-01-01T23:59:59.000Z

389

Annual Report: Advanced Combustion (30 September 2012)  

SciTech Connect

The Advanced Combustion Project addresses fundamental issues of fire-side and steam-side corrosion and materials performance in oxy-fuel combustion environments and provides an integrated approach into understanding the environmental and mechanical behavior such that environmental degradation can be ameliorated and long-term microstructural stability, and thus, mechanical performance can lead to longer lasting components and extended power plant life. The technical tasks of this effort are Oxy-combustion Environment Characterization, Alloy Modeling and Life Prediction, and Alloy Manufacturing and Process Development.

Hawk, Jeffrey [NETL] [NETL; Richards, George

2012-09-30T23:59:59.000Z

390

Post combustion trials at Dofasco's KOBM furnace  

DOE Green Energy (OSTI)

Post combustion trials were conducted at Dofasco's 300 tonne KOBM furnace as part of the AISI Direct Steelmaking Program. The purpose of the project work was to measure the post combustion ratio (PCR) and heat transfer efficiency (HTE) of the post combustion reaction in a full size steelmaking vessel. A method of calculating PCR and HTE using off gas analysis and gas temperature was developed. The PCR and HTE were determined under normal operating conditions. Trials assessed the effect of lance height, vessel volume, foaming slag and pellet additions on PCR and HTE.

Farrand, B.L.; Wood, J.E.; Goetz, F.J.

1992-01-01T23:59:59.000Z

391

Computationally efficient implementation of combustion chemistry in parallel PDF calculations  

Science Conference Proceedings (OSTI)

In parallel calculations of combustion processes with realistic chemistry, the serial in situ adaptive tabulation (ISAT) algorithm [S.B. Pope, Computationally efficient implementation of combustion chemistry using in situ adaptive tabulation, Combustion ... Keywords: 07.05.Mh, 46.15.-x, 47.11.-j, Combustion chemistry, Distribution strategy, ISAT, Load balance, Parallel calculation

Liuyan Lu; Steven R. Lantz; Zhuyin Ren; Stephen B. Pope

2009-08-01T23:59:59.000Z

392

Using Biofuel Tracers to Study Alternative Combustion Regimes  

E-Print Network (OSTI)

Wood, “Investigation of the Fate of Specific Hydrocarbon Fuel Components in Diesel Engine Combustion

Mack, John Hunter; Flowers, Daniel L.; Buchholz, Bruce A.; Dibble, Robert W.

2006-01-01T23:59:59.000Z

393

Using Biofuel Tracers to Study Alternative Combustion Regimes  

E-Print Network (OSTI)

Section B (NIMB) Using Biofuel Tracers to Study Alternativeinjection. We investigate biofuel HCCI combustion, and use

Mack, John Hunter; Flowers, Daniel L.; Buchholz, Bruce A.; Dibble, Robert W.

2006-01-01T23:59:59.000Z

394

Coal Combustion Science quarterly progress report, April--June 1990  

SciTech Connect

This document provides a quarterly status report of the Coal Combustion Science Program that is being conducted at the Combustion, Research Facility, Sandia National Laboratories, Livermore, California. Coal devolatilization, coal char combustion, and fate of mineral matter during coal combustion. 56 refs., 25 figs., 13 tabs.

Hardesty, D.R. (ed.); Baxter, L.L.; Fletcher, T.H.; Mitchell, R.E.

1990-11-01T23:59:59.000Z

395

Pulse combustion: an assessment of opportunities for increased efficiency  

SciTech Connect

The results of a literature review on pulse combustion are discussed. Current, near-future, and potential opportunities for pulse combustion applications are summarized, and the barriers to developing and using pulse combustion technology are discussed, along with research and development needs. Also provided are the proceedings of a pulse combustion workshop held in May, 1984 in Seattle, Washington. (LEW)

Brenchley, D.L.; Bomelburg, H.J.

1984-12-01T23:59:59.000Z

396

Supercomputers Capture Turbulence in the Solar Wind  

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

Supercomputers Supercomputers Capture Turbulence in the Solar Wind Supercomputers Capture Turbulence in the Solar Wind Berkeley Lab visualizations could help scientists forecast destructive space weather December 16, 2013 Linda Vu, +1 510 495 2402, lvu@lbl.gov eddies1.jpg This visualization zooms in on current sheets revealing the "cascade of turbulence" in the solar wind occurring down to electron scales. This is a phenomenon common in fluid dynamics-turbulent energy injected at large eddies is transported to successively smaller scales until it is dissipated as heat. (Image by Burlen Loring, Berkeley Lab) As inhabitants of Earth, our lives are dominated by weather. Not just in the form of rain and snow from atmospheric clouds, but also a sea of charged particles and magnetic fields generated by a star sitting 93

397

Radar Detection of Turbulence in Precipitation Environments  

Science Conference Proceedings (OSTI)

Imperfect particle tracer response is incorporated into the relations describing the turbulent air motion contribution to Doppler radar spectrum mean and variance. Tracer effects on radar estimates of the eddy dissipation rate (?) increase with ...

Alan R. Bohne

1982-08-01T23:59:59.000Z

398

An Analysis of Wave-Turbulence Interaction  

Science Conference Proceedings (OSTI)

We present the results of an analytical and numerical calculation of the interaction between an internal gravity wave and a wave-induced turbulence. The initial atmospheric state, assumed horizontally homogeneous, is statically and dynamically ...

D. Fua; G. Chimonas; F. Einaudi; O. Zeman

1982-11-01T23:59:59.000Z

399

A LES-Langevin model for turbulence  

E-Print Network (OSTI)

We propose a new model of turbulence for use in large-eddy simulations (LES). The turbulent force, represented here by the turbulent Lamb vector, is divided in two contributions. The contribution including only subfilter fields is deterministically modeled through a classical eddy-viscosity. The other contribution including both filtered and subfilter scales is dynamically computed as solution of a generalized (stochastic) Langevin equation. This equation is derived using Rapid Distortion Theory (RDT) applied to the subfilter scales. The general friction operator therefore includes both advection and stretching by the resolved scale. The stochastic noise is derived as the sum of a contribution from the energy cascade and a contribution from the pressure. The LES model is thus made of an equation for the resolved scale, including the turbulent force, and a generalized Langevin equation integrated on a twice-finer grid. The model is validated by comparison to DNS and is tested against classical LES models for i...

Laval, J P; Dubrulle, Berengere; Laval, Jean-Philippe

2006-01-01T23:59:59.000Z

400

k-? turbulence modeling for a wind turbine.  

E-Print Network (OSTI)

?? In this report we discuss the use of k-? RANS (Reynolds-averaged Navier-Stokes equations) turbulence model for wind turbine applications. This model has been implemented… (more)

EREK, ERMAN

2011-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "turbulent nuclear combustion" 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

Estimating Oceanic Turbulence Dissipation from Seismic Images  

Science Conference Proceedings (OSTI)

Seismic images of oceanic thermohaline finestructure record vertical displacements from internal waves and turbulence over large sections at unprecedented horizontal resolution. Where reflections follow isopycnals, their displacements can be used ...

W. Steven Holbrook; Ilker Fer; Raymond W. Schmitt; Daniel Lizarralde; Jody M. Klymak; L. Cody Helfrich; Robert Kubichek

402

Generation of Turbulence by Atmospheric Gravity Waves  

Science Conference Proceedings (OSTI)

The standard current criterion for the generation of turbulence by atmospheric gravity waves and for the associated limitation on wave growth is based upon the standard criterion for static instability of the unperturbed atmosphere, namely, that ...

Colin O. Hines

1988-04-01T23:59:59.000Z

403

Tracer dispersion in the turbulent convective layer  

Science Conference Proceedings (OSTI)

Experimental results for passive tracer dispersion in the turbulent surface layer under convective conditions are presented. In this case, the dispersion of tracer particles is determined by the interplay of two mechanisms: buoyancy and advection. ...

Alex Skvortsov; Milan Jamriska; Timothy C. DuBois

404

Turbulence and Diapycnal Mixing in Drake Passage  

Science Conference Proceedings (OSTI)

Direct measurements of turbulence levels in the Drake Passage region of the Southern Ocean show a marked enhancement over the Phoenix Ridge. At this site, the Antarctic Circumpolar Current (ACC) is constricted in its flow between the southern tip ...

L. St. Laurent; A. C. Naveira Garabato; J. R. Ledwell; A. M. Thurnherr; J. M. Toole; A. J. Watson

2012-12-01T23:59:59.000Z

405

Stratified Turbulence near a Critical Dissipation Rate  

Science Conference Proceedings (OSTI)

Turbulence in the thermocline was investigated using data observed by the submarine Dolphin. Various length scales, the Reynolds and the Froude numbers of the Dolphin data were compared to those values of a laboratory experiment presented in ...

Hidekatsu Yamazaki

1990-10-01T23:59:59.000Z

406

A Comparison of Turbulence Measurements from Aircraft  

Science Conference Proceedings (OSTI)

A performance analysis of the three turbulence-measuring aircraft which participated in the GATE is presented. These aircraft were a Lockheed C-130 operated by the Meteorological Research Flight Centre of the U.K. Meteorological Office, a Douglas ...

Margaret A. Lemone; William T. Pennell

1980-12-01T23:59:59.000Z

407

Observations of Turbulence in Stratified Flow  

Science Conference Proceedings (OSTI)

Various theoretical properties of the structure function are evaluated. Additional functions are constructed to describe the overall influence of stratification, the anisotropy and intermittency of the turbulence, and the asymmetry of the main ...

L. Mahrt; N. Gamage

1987-04-01T23:59:59.000Z

408

Marine Stratocumulus Layers. Part II: Turbulence Budgets  

Science Conference Proceedings (OSTI)

This paper discusses the turbulence profiles and budgets for two days of radiation, dynamical and thermodynamical observations by the NCAR Electra in shallow marine stratocumulus off the California coast in June 1976.

R. A. Brost; J. C. Wyngaard; D. H. Lenschow

1982-04-01T23:59:59.000Z

409

ENERGETIC PARTICLE DIFFUSION IN STRUCTURED TURBULENCE  

Science Conference Proceedings (OSTI)

In the full-orbit particle simulations of energetic particle transport in plasmas, the plasma turbulence is typically described as a homogeneous superposition of linear Fourier modes. The turbulence evolution is, however, typically a nonlinear process, and, particularly in the heliospheric context, the solar wind plasma is inhomogeneous due to the transient structures, as observed by remote and in situ measurements. In this work, we study the effects of the inhomogeneities on energetic particle transport by using spatially distributed, superposed turbulence envelopes. We find that the cross-field transport is significantly reduced, when compared to the results obtained with homogeneous turbulence. The reduction can reach an order of magnitude when the enveloping breaks the wave phase coherence along the mean magnetic field direction.

Laitinen, T.; Dalla, S.; Kelly, J. [Jeremiah Horrocks Institute, University of Central Lancashire, PR1 2HE Preston (United Kingdom)

2012-04-20T23:59:59.000Z

410

Example of Reduced Turbulence during Thunderstorm Outflow  

Science Conference Proceedings (OSTI)

The vertical structures of turbulence, winds, and temperatures are analyzed from a 92-m instrumented tower and a collocated acoustic sodar during an outflow episode from a weak thunderstorm over sloping terrain in northern New Mexico. Prior to ...

Brent M. Bowen

1996-06-01T23:59:59.000Z

411

Interstellar MHD Turbulence and Star Formation  

E-Print Network (OSTI)

This chapter reviews the nature of turbulence in the Galactic interstellar medium (ISM) and its connections to the star formation (SF) process. The ISM is turbulent, magnetized, self-gravitating, and is subject to heating and cooling processes that control its thermodynamic behavior. The turbulence in the warm and hot ionized components of the ISM appears to be trans- or subsonic, and thus to behave nearly incompressibly. However, the neutral warm and cold components are highly compressible, as a consequence of both thermal instability in the atomic gas and of moderately-to-strongly supersonic motions in the roughly isothermal cold atomic and molecular components. Within this context, we discuss: i) the production and statistical distribution of turbulent density fluctuations in both isothermal and polytropic media; ii) the nature of the clumps produced by thermal instability, noting that, contrary to classical ideas, they in general accrete mass from their environment; iii) the density-magnetic field correla...

Vazquez-Semadeni, Enrique

2012-01-01T23:59:59.000Z

412

An Improved Model for the Turbulent PBL  

Science Conference Proceedings (OSTI)

Second-order turbulence models of the Mellor and Yamada type have been widely used to simulate the planetary boundary layer (PBL). It is, however, known that these models have several deficiencies. For example, assuming the production of the ...

Y. Cheng; V. M. Canuto; A. M. Howard

2002-05-01T23:59:59.000Z

413

Can Quasigeostrophic Turbulence Be Modeled Stochastically?  

Science Conference Proceedings (OSTI)

Numerically generated data of quasigeostrophic turbulence in an equilibrated shear flow are analyzed to determine the extent to which they can be modeled by a Markov model. The time lagged covariances are collected into a matrix, C?, and are ...

Timothy DelSole

1996-06-01T23:59:59.000Z

414

Ertel's Potential Vorticity in Unstratified Turbulence  

Science Conference Proceedings (OSTI)

The evolution of Ertel's potential vorticity (PV) is examined in direct numerical simulations (DNS) of decaying turbulence advecting passive scalars and in a generalized Taylor-Green vortex (TGV). It is noted that although PV itself is advected ...

J. R. Herring; R. M. Kerr; R. Rotunno

1994-01-01T23:59:59.000Z

415

Dispersion of Heavy Particles by Turbulent Motion  

Science Conference Proceedings (OSTI)

Accurate prediction of heavy particle dispersion in turbulent flows requires a simultaneous consideration of particle's inertia and particle's drift velocity. A mathematically simple and physically comprehensive analysis was developed to solve ...

Lian-Ping Wang; Davd E. Stock

1993-07-01T23:59:59.000Z

416

Coal Combustion Products Extension Program  

SciTech Connect

This final project report presents the activities and accomplishments of the ''Coal Combustion Products Extension Program'' conducted at The Ohio State University from August 1, 2000 to June 30, 2005 to advance the beneficial uses of coal combustion products (CCPs) in highway and construction, mine reclamation, agricultural, and manufacturing sectors. The objective of this technology transfer/research program at The Ohio State University was to promote the increased use of Ohio CCPs (fly ash, FGD material, bottom ash, and boiler slag) in applications that are technically sound, environmentally benign, and commercially competitive. The project objective was accomplished by housing the CCP Extension Program within The Ohio State University College of Engineering with support from the university Extension Service and The Ohio State University Research Foundation. Dr. Tarunjit S. Butalia, an internationally reputed CCP expert and registered professional engineer, was the program coordinator. The program coordinator acted as liaison among CCP stakeholders in the state, produced information sheets, provided expertise in the field to those who desired it, sponsored and co-sponsored seminars, meetings, and speaking at these events, and generally worked to promote knowledge about the productive and proper application of CCPs as useful raw materials. The major accomplishments of the program were: (1) Increase in FGD material utilization rate from 8% in 1997 to more than 20% in 2005, and an increase in overall CCP utilization rate of 21% in 1997 to just under 30% in 2005 for the State of Ohio. (2) Recognition as a ''voice of trust'' among Ohio and national CCP stakeholders (particularly regulatory agencies). (3) Establishment of a national and international reputation, especially for the use of FGD materials and fly ash in construction applications. It is recommended that to increase Ohio's CCP utilization rate from 30% in 2005 to 40% by 2010, the CCP Extension Program be expanded at OSU, with support from state and federal agencies, utilities, trade groups, and the university, to focus on the following four specific areas of promise: (a) Expanding use in proven areas (such as use of fly ash in concrete); (b) Removing or reducing regulatory and perceptual barriers to use (by working in collaboration with regulatory agencies); (c) Developing new or under-used large-volume market applications (such as structural fills); and (d) Placing greater emphasis on FGD byproducts utilization.

Tarunjit S. Butalia; William E. Wolfe

2006-01-11T23:59:59.000Z

417

Biomass Combustion Systems Inc | Open Energy Information  

Open Energy Info (EERE)

Combustion Systems Inc Combustion Systems Inc Jump to: navigation, search Name Biomass Combustion Systems Inc Address 67 Millbrook St Place Worcester, Massachusetts Zip 01606 Sector Biomass Product Combustion systems for wood fuel Website http://www.biomasscombustion.c Coordinates 42.290195°, -71.799627° Loading map... {"minzoom":false,"mappingservice":"googlemaps3","type":"ROADMAP","zoom":14,"types":["ROADMAP","SATELLITE","HYBRID","TERRAIN"],"geoservice":"google","maxzoom":false,"width":"600px","height":"350px","centre":false,"title":"","label":"","icon":"","visitedicon":"","lines":[],"polygons":[],"circles":[],"rectangles":[],"copycoords":false,"static":false,"wmsoverlay":"","layers":[],"controls":["pan","zoom","type","scale","streetview"],"zoomstyle":"DEFAULT","typestyle":"DEFAULT","autoinfowindows":false,"kml":[],"gkml":[],"fusiontables":[],"resizable":false,"tilt":0,"kmlrezoom":false,"poi":true,"imageoverlays":[],"markercluster":false,"searchmarkers":"","locations":[{"text":"","title":"","link":null,"lat":42.290195,"lon":-71.799627,"alt":0,"address":"","icon":"","group":"","inlineLabel":"","visitedicon":""}]}

418

Chemical Looping for Combustion and Hydrogen Production  

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

ChemiCal looping for Combustion and ChemiCal looping for Combustion and hydrogen produCtion Objective The objective of this project is to determine the benefits of chemical looping technology used with coal to reduce CO 2 emissions. Background Chemical looping is a new method to convert coal or gasified coal to energy. In chemical looping, there is no direct contact between air and fuel. The chemical looping process utilizes oxygen from metal oxide oxygen carrier for fuel combustion, or for making hydrogen by "reducing" water. In combustion applications, the products of chemical looping are CO 2 and H 2 O. Thus, once the steam is condensed, a relatively pure stream of CO 2 is produced ready for sequestration. The production of a sequestration ready CO 2 stream does not require any additional separation units

419

Combustion properties of Kraft Black Liquors  

DOE Green Energy (OSTI)

In a previous study of the phenomena involved in the combustion of black liquor droplets a numerical model was developed. The model required certain black liquor specific combustion information which was then not currently available, and additional data were needed for evaluating the model. The overall objectives of the project reported here was to provide experimental data on key aspects of black liquor combustion, to interpret the data, and to put it into a form which would be useful for computational models for recovery boilers. The specific topics to be investigated were the volatiles and char carbon yields from pyrolysis of single black liquor droplets; a criterion for the onset of devolatilization and the accompanying rapid swelling; and the surface temperature of black liquor droplets during pyrolysis, combustion, and gasification. Additional information on the swelling characteristics of black liquor droplets was also obtained as part of the experiments conducted.

Frederick, W.J. Jr.; Hupa, M. (Aabo Akademi, Turku (Finland))

1993-04-01T23:59:59.000Z

420

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

Note: This page contains sample records for the topic "turbulent nuclear combustion" 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

Predicting combustion properties of hydrocarbon fuel mixtures  

E-Print Network (OSTI)

In this thesis, I applied computational quantum chemistry to improve the accuracy of kinetic mechanisms that are used to model combustion chemistry. I performed transition state theory calculations for several reactions ...

Goldsmith, Claude Franklin, III

2010-01-01T23:59:59.000Z

422

Combustion systems for power-MEMS applications  

E-Print Network (OSTI)

As part of an effort to develop a micro-scale gas turbine engine for power generation and micro-propulsion applications, this thesis presents the design, fabrication, experimental testing, and modeling of the combustion ...

Spadaccini, Christopher M. (Christopher Michael), 1974-

2004-01-01T23:59:59.000Z

423

Simplifying Chemistry for Computational Efficiency in Combustion...  

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

Simplifying Chemistry for Computational Efficiency in Combustion Calculations Speaker(s): Shaheen Tonse Date: February 28, 2002 - 12:00pm Location: Bldg. 90 Seminar HostPoint of...

424

Oil shale retorting and combustion system  

DOE Patents (OSTI)

The present invention is directed to the extraction of energy values from l shale containing considerable concentrations of calcium carbonate in an efficient manner. The volatiles are separated from the oil shale in a retorting zone of a fluidized bed where the temperature and the concentration of oxygen are maintained at sufficiently low levels so that the volatiles are extracted from the oil shale with minimal combustion of the volatiles and with minimal calcination of the calcium carbonate. These gaseous volatiles and the calcium carbonate flow from the retorting zone into a freeboard combustion zone where the volatiles are burned in the presence of excess air. In this zone the calcination of the calcium carbonate occurs but at the expense of less BTU's than would be required by the calcination reaction in the event both the retorting and combustion steps took place simultaneously. The heat values in the products of combustion are satisfactorily recovered in a suitable heat exchange system.

Pitrolo, Augustine A. (Fairmont, WV); Mei, Joseph S. (Morgantown, WV); Shang, Jerry Y. (Fairfax, VA)

1983-01-01T23:59:59.000Z

425

Control of NOx by combustion process modifications  

E-Print Network (OSTI)

A theoretical and experimental study was carried out to determine lower bounds of NOx emission from staged combustion of a 0.7%N #6 fuel oil. Thermodynamic and chemical kinetic calculations have shown minimum NOx emissions ...

Ber?, J. M.

1981-01-01T23:59:59.000Z

426

Coal Combustion By-Products (Maryland)  

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

The Department of the Environment is responsible for regulating fugitive air emissions from the transportation of coal combustion by-products and the permissible beneficial uses of these by...

427

Two phase exhaust for internal combustion engine  

Science Conference Proceedings (OSTI)

An internal combustion engine having a reciprocating multi cylinder internal combustion engine with multiple valves. At least a pair of exhaust valves are provided and each supply a separate power extraction device. The first exhaust valves connect to a power turbine used to provide additional power to the engine either mechanically or electrically. The flow path from these exhaust valves is smaller in area and volume than a second flow path which is used to deliver products of combustion to a turbocharger turbine. The timing of the exhaust valve events is controlled to produce a higher grade of energy to the power turbine and enhance the ability to extract power from the combustion process.

Vuk, Carl T. (Denver, IA)

2011-11-29T23:59:59.000Z

428

Chemical Characterization of Fossil Fuel Combustion Wastes  

Science Conference Proceedings (OSTI)

Fossil fuel combustion wastes differ considerably in total composition and in the key chemical characteristics of their extracts, making leachate composition difficult to predict. A new mechanistic approach, however, shows promise for more-accurate prediction.

1987-08-26T23:59:59.000Z

429

Vortex driven flame dynamics and combustion instability  

E-Print Network (OSTI)

Combustion instability in premixed combustors mostly arises due to the coupling between heat release rate dynamics and system acoustics. It is crucial to understand the instability mechanisms to design reliable, high ...

Altay, Hurrem Murat

2005-01-01T23:59:59.000Z

430

Active combustion control : modeling, design and implementation  

E-Print Network (OSTI)

Continuous combustion systems common in propulsion and power generation applications are susceptible to thermoacoustic instability, which occurs under lean burn conditions close to the flammability where most emissions and ...

Park, Sungbae, 1973-

2004-01-01T23:59:59.000Z

431

Engine combustion control via fuel reactivity stratification  

Science Conference Proceedings (OSTI)

A compression ignition engine uses two or more fuel charges having two or more reactivities to control the timing and duration of combustion. In a preferred implementation, a lower-reactivity fuel charge is injected or otherwise introduced into the combustion chamber, preferably sufficiently early that it becomes at least substantially homogeneously dispersed within the chamber before a subsequent injection is made. One or more subsequent injections of higher-reactivity fuel charges are then made, and these preferably distribute the higher-reactivity matter within the lower-reactivity chamber space such that combustion begins in the higher-reactivity regions, and with the lower-reactivity regions following thereafter. By appropriately choose the reactivities of the charges, their relative amounts, and their timing, combustion can be tailored to achieve optimal power output (and thus fuel efficiency), at controlled temperatures (and thus controlled NOx), and with controlled equivalence ratios (and thus controlled soot).

Reitz, Rolf Deneys; Hanson, Reed M; Splitter, Derek A; Kokjohn, Sage L

2013-12-31T23:59:59.000Z

432

Is there a statistical mechanics of turbulence  

SciTech Connect

The statistical-mechanical treatment of turbulence is made questionable by strong nonlinearity and strong disequilibrium that result in the creation of ordered structures imbedded in disorder. Model systems are described which may provide some hope that a compact, yet faithful, statistical description of turbulence nevertheless is possible. Some essential dynamic features of the models are captured by low-order statistical approximations despite strongly non-Gaussian behavior. 31 refs., 5 figs.

Kraichnan, R.H.; Chen, S.Y.

1988-09-01T23:59:59.000Z

433

Quantum light in the turbulent atmosphere  

E-Print Network (OSTI)

Nonclassical properties of light propagating through the turbulent atmosphere are studied. We demonstrate by numerical simulation that the probability distribution of the transmission coefficient, which characterizes the effects of the atmosphere on the quantum state of light, can be reconstructed by homodyne detection. Nonclassical photon-statistics and, more generally, nonclassical Glauber-Sudarshan functions appear to be more robust against turbulence for weak light fields rather than for bright ones.

A. A. Semenov; W. Vogel

2009-02-24T23:59:59.000Z

434

Oxy-combustion: Oxygen Transport Membrane Development  

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

combustion: Oxygen Transport combustion: Oxygen Transport Membrane Development Background The mission of the U.S. Department of Energy's (DOE) Existing Plants, Emissions & Capture (EPEC) Research & Development (R&D) Program is to develop innovative environmental control technologies to enable full use of the nation's vast coal reserves, while at the same time allowing the current fleet of coal-fired power plants to comply with existing and emerging environmental regulations. The EPEC R&D

435

Combustion Turbine Experience and Intelligence Reports: 2007  

Science Conference Proceedings (OSTI)

Combustion turbine (CT) efficiency improvements coupled with heat recovery bottoming steam cycles has risen dramatically over the past 20 years. Much of this improvement is attributed to gas turbine technology transferred from military and commercial aircraft design. This technology advantage coupled with lower emissions inherent to natural gas combustion has effectively set the standard for new large generation additions in many regions. However, there are many concerns and issues related to effectively...

2008-03-27T23:59:59.000Z

436

Internal combustion engine and method for control  

SciTech Connect

In one exemplary embodiment of the invention an internal combustion engine includes a piston disposed in a cylinder, a valve configured to control flow of air into the cylinder and an actuator coupled to the valve to control a position of the valve. The internal combustion engine also includes a controller coupled to the actuator, wherein the controller is configured to close the valve when an uncontrolled condition for the internal engine is determined.

Brennan, Daniel G

2013-05-21T23:59:59.000Z

437

Building America Expert Meeting: Combustion Safety  

SciTech Connect

This is a meeting overview of 'The Best Approach to Combustion Safety in a Direct Vent World', held June 28, 2012, in San Antonio, Texas. The objective of this Expert Meeting was to identify gaps and barriers that need to be addressed by future research, and to develop data-driven technical recommendations for code updates so that a common approach for combustion safety can be adopted by all members of the building energy efficiency and code communities.

Brand, L.

2013-03-01T23:59:59.000Z

438

Combustion Turbine Experience and Intelligence Reports: 2006  

Science Conference Proceedings (OSTI)

Generation markets worldwide present both business opportunities and challenges for combustion turbine plant owners, operators, and project developers. EPRI's comprehensive Combustion Turbine/Combined Cycle (CT/CC) program provides a range of tools, methodologies, and approaches to help owner/operators and project developers face these challenges and prosper in this evolving marketplace. The rising cost of fuel gas is the dominant issue in today's market. The EPRI CT Experience and intelligence Reports (...

2007-03-27T23:59:59.000Z

439

Combustion Turbine Experience and Intelligence Report: 2010  

Science Conference Proceedings (OSTI)

Generation markets worldwide present both business opportunities and challenges for combustion turbine plant owners, operators, and project developers. EPRI's comprehensive Combustion Turbine/Combined Cycle (CT/CC) program provides a range of tools, methodologies, and approaches to help owner/operators and project developers face these challenges and prosper in this evolving marketplace. The rising cost of fuel gas is the dominant issue in today's market. The EPRI CT Experience and Intelligence Reports (...

2010-12-14T23:59:59.000Z

440

Oxy-Combustion Activities Worldwide: 2013 Update  

Science Conference Proceedings (OSTI)

This report provides a review of oxy-combustion development activities throughout the world, most of which occurred in the calendar year of 2013. The report opens by introducing oxy-combustion and discussing its relative advantages and disadvantages and associated costs. It then delves into each sub-system (air separation, oxy boiler, gas quality control system [GQCS], and carbon dioxide [CO2] purification) giving the latest updates on technologies and associated development issues in ...

2013-12-18T23:59:59.000Z

Note: This page contains sample records for the topic "turbulent nuclear combustion" 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.


441

Combustion Turbine Experience and Intelligence Report: 2008  

Science Conference Proceedings (OSTI)

Combustion turbine (CT) efficiency improvements, coupled with heat recovery bottoming steam cycles, have risen dramatically over the past 20 years. Much improvement is attributed to gas turbine technology transferred from military and commercial aircraft design. This technology advantage in combination with the lower emissions inherent to natural gas combustion has effectively set the standard for new large generation additions in many regions. However, there are many concerns and issues related to effec...

2009-03-23T23:59:59.000Z

442

Combustion Turbine Experience and Intelligence Report: 2005  

Science Conference Proceedings (OSTI)

Generation markets worldwide present both business opportunities and challenges for combustion turbine plant owners, operators, and project developers. EPRI's comprehensive Combustion Turbine/Combined Cycle (CT/CC) program provides a range of tools, methodologies, and approaches to help owner/operators and project developers face these challenges and prosper in this evolving marketplace. The rising cost of fuel gas is the dominant issue in today's market. The EPRI CT Experience and Intelligence Reports (...

2006-03-06T23:59:59.000Z

443

Fundamental Studies in Syngas Premixed Combustion Dynamics  

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

Studies Studies in Syngas Premixed Combustion Dynamics Ahmed F. Ghoniem, Anuradha M. Annaswamy, Raymond L. Speth, H. Murat Altay Massachusetts Institute of Technology SCIES Project 05-01-SR121 Project Awarded (08/01/2005, 36 Month Duration) Needs & Objectives Gas Turbine Needs Flexibility to operate with variable syngas compositions Ensure stable operation over a wide range of conditions Reduce emissions of CO and NO x Project Objectives Study experimentally lean premixed syngas combustion

444

Proceedings of the Combustion Institute, Volume 28, 2000/pp. 16631669 COMBUSTION CHEMISTRY OF PROPANE: A CASE STUDY OF DETAILED  

E-Print Network (OSTI)

1663 Proceedings of the Combustion Institute, Volume 28, 2000/pp. 1663­1669 COMBUSTION CHEMISTRY Detailed chemical reaction mechanisms describing hydrocarbon combustion chemistry are conceptually to small-hydrocarbon combustion data are secure foundations upon which to optimize the rate parameters

Wang, Hai

445

Progress in Energy and Combustion Science 34 (2008) 377416 Discrete reaction waves: Gasless combustion of solid powder mixtures  

E-Print Network (OSTI)

Progress in Energy and Combustion Science 34 (2008) 377­416 Discrete reaction waves: Gasless combustion of solid powder mixtures A.S. Mukasyana,�, A.S. Rogachevb a Department of Chemical Abstract This review considers a specific domain in combustion science, so-called discrete combustion waves

Mukasyan, Alexander

446

Combustion, Explosion, and Shock Waves, Vol. 46, No. 3, pp. , 2010 Combustion of Heterogeneous Nanostructural Systems (Review)  

E-Print Network (OSTI)

Combustion, Explosion, and Shock Waves, Vol. 46, No. 3, pp. ­, 2010 Combustion of Heterogeneous submitted November 26, 2009. The current status of research in the field of combustion of heterogeneous mechanisms of combustion in such systems and prospects of their further applications are discussed. Key words

Mukasyan, Alexander

447

Hydrogen-combustion analyses of large-scale tests  

DOE Green Energy (OSTI)

This report uses results of the large-scale tests with turbulence performed by the Electric Power Research Institute at the Nevada Test Site to evaluate hydrogen burn-analysis procedures based on lumped-parameter codes like COMPARE-H2 and associated burn-parameter models. The test results: (1) confirmed, in a general way, the procedures for application to pulsed burning, (2) increased significantly our understanding of the burn phenomenon by demonstrating that continuous burning can occur, and (3) indicated that steam can terminate continuous burning. Future actions recommended include: (1) modification of the code to perform continuous-burn analyses, which is demonstrated, (2) analyses to determine the type of burning (pulsed or continuous) that will exist in nuclear containments and the stable location if the burning is continuous, and (3) changes to the models for estimating burn parameters.

Gido, R.G.; Koestel, A.

1986-01-01T23:59:59.000Z

448

Diffusion Processes in Turbulent Magnetic Fields  

E-Print Network (OSTI)

We study of the effect of turbulence on diffusion processes within magnetized medium. While we exemplify our treatment with heat transfer processes, our results are quite general and are applicable to different processes, e.g. diffusion of heavy elements. Our treatment is also applicable to describing the diffusion of cosmic rays arising from magnetic field wandering. In particular, we find that when the energy injection velocity is smaller than the Alfven speed the heat transfer is partially suppressed, while in the opposite regime the effects of turbulence depend on the intensity of driving. In fact, the scale $l_A$ at which the turbulent velocity is equal the Alfven velocity is a new important parameter. When the electron mean free path $\\lambda$ is larger than $l_A$, the stronger the the turbulence, the lower thermal conductivity by electrons is. The turbulent motions, however, induces their own advective transport, that can provide effective diffusivity. For clusters of galaxies, we find that the turbulence is the most important agent for heat transfer. We also show that the domain of applicability of the subdiffusion concept is rather limited.

Alex Lazarian

2007-07-04T23:59:59.000Z

449

Diffusion Processes in Turbulent Magnetic Fields  

E-Print Network (OSTI)

We study of the effect of turbulence on diffusion processes within magnetized medium. While we exemplify our treatment with heat transfer processes, our results are quite general and are applicable to different processes, e.g. diffusion of heavy elements. Our treatment is also applicable to describing the diffusion of cosmic rays arising from magnetic field wandering. In particular, we find that when the energy injection velocity is smaller than the Alfven speed the heat transfer is partially suppressed, while in the opposite regime the effects of turbulence depend on the intensity of driving. In fact, the scale $l_A$ at which the turbulent velocity is equal the Alfven velocity is a new important parameter. When the electron mean free path $\\lambda$ is larger than $l_A$, the stronger the the turbulence, the lower thermal conductivity by electrons is. The turbulent motions, however, induces their own advective transport, that can provide effective diffusivity. For clusters of galaxies, we find that the turbule...

Lazarian, Alex

2007-01-01T23:59:59.000Z

450

Operational Flexibility Guidelines for Gas Turbine Low NOx Combustion Systems  

Science Conference Proceedings (OSTI)

Gas turbine low-NOx combustion systems can differ in hardware from manufacturer to manufacturer, but the principle is the same. Low-NOx combustors reduce peak flame temperatures by mixing fuel and air before combustion and by keeping the fuel-to-air ratio as low (lean) as possible, while still maintaining combustion stability over the broadest possible operating range. Low-NOx combustion systems are inherently more complex than diffusion combustion systems, a fact that impacts operational flexibility, re...

2011-12-14T23:59:59.000Z

451

Impacts of Venturi Turbulent Mixing on the Size Distribution of Sodium Chloride and Dioctyl-Phthalate Aerosols  

DOE Green Energy (OSTI)

Internal combustion engines are a major source of airborne particulate matter (PM). The size of the engine PM is in the sub-micrometer range. The number of engine particles per unit volume is high, normally in the range of 10{sup 12} to 10{sup 14}. To measure the size distribution of the engine particles dilution of an aerosol sample is required. A diluter utilizing a venturi ejector mixing technique is commercially available and tested. The purpose of this investigation was to determine if turbulence created by the ejector in the mini-dilutor changes the size of particles passing through it.

Cheng, M.-D.; Wainman, T.; Storey, J.

2000-08-01T23:59:59.000Z

452

Pressurized fluidized-bed combustion  

Science Conference Proceedings (OSTI)

The US DOE pressurized fluidized bed combustion (PFBC) research and development program is designed to develop the technology and data base required for the successful commercialization of the PFBC concept. A cooperative program with the US, West Germany, and the UK has resulted in the construction of the 25 MWe IEA-Grimethorpe combined-cycle pilot plant in England which will be tested in 1981. A 13 MWe coal-fired gas turbine (air cycle) at Curtis-Wright has been designed and construction scheduled. Start-up is planned to begin in early 1983. A 75 MWe pilot plant is planned for completion in 1986. Each of these PFBC combined-cycle programs is discussed. The current status of PFB technology may be summarized as follows: turbine erosion tolerance/hot gas cleanup issues have emerged as the barrier technology issues; promising turbine corrosion-resistant materials have been identified, but long-term exposure data is lacking; first-generation PFB combustor technology development is maturing at the PDU level; however, scale-up to larger size has not been demonstrated; and in-bed heat exchanger materials have been identified, but long-term exposure data is lacking. The DOE-PFB development plan is directed at the resolution of these key technical issues. (LCL)

Not Available

1980-10-01T23:59:59.000Z

453

Carburetor for internal combustion engines  

DOE Patents (OSTI)

A carburetor for internal combustion engines having a housing including a generally discoidal wall and a hub extending axially from the central portion thereof, an air valve having a relatively flat radially extending surface directed toward and concentric with said discoidal wall and with a central conoidal portion having its apex directed toward the interior of said hub portion. The housing wall and the radially extending surface of the valve define an air passage converging radially inwardly to form an annular valving construction and thence diverge into the interior of said hub. The hub includes an annular fuel passage terminating at its upper end in a circumferential series of micro-passages for directing liquid fuel uniformly distributed into said air passage substantially at said valving constriction at right angles to the direction of air flow. The air valve is adjustable axially toward and away from the discoidal wall of the carburetor housing to regulate the volume of air drawn into the engine with which said carburetor is associated. Fuel is delivered under pressure to the fuel metering valve and from there through said micro-passages and controlled cams simultaneously regulate the axial adjustment of said air valve and the rate of delivery of fuel through said micro-passages according to a predetermined ratio pattern. A third jointly controlled cam simultaneously regulates the ignition timing in accordance with various air and fuel supply settings. The air valve, fuel supply and ignition timing settings are all independent of the existing degree of engine vacuum.

Csonka, John J. (625 Linwood Ave., Buffalo, NY 14209); Csonka, Albert B. (109 Larchmont Rd., Buffalo, NY 14214)

1978-01-01T23:59:59.000Z

454

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

455

Dust Combustion Safety Issues for Fusion Applications  

SciTech Connect

This report summarizes the results of a safety research task to identify the safety issues and phenomenology of metallic dust fires and explosions that are postulated for fusion experiments. There are a variety of metal dusts that are created by plasma erosion and disruptions within the plasma chamber, as well as normal industrial dusts generated in the more conventional equipment in the balance of plant. For fusion, in-vessel dusts are generally mixtures of several elements; that is, the constituent elements in alloys and the variety of elements used for in-vessel materials. For example, in-vessel dust could be composed of beryllium from a first wall coating, tungsten from a divertor plate, copper from a plasma heating antenna or diagnostic, and perhaps some iron and chromium from the steel vessel wall or titanium and vanadium from the vessel wall. Each of these elements has its own unique combustion characteristics, and mixtures of elements must be evaluated for the mixture’s combustion properties. Issues of particle size, dust temperature, and presence of other combustible materials (i.e., deuterium and tritium) also affect combustion in air. Combustion in other gases has also been investigated to determine if there are safety concerns with “inert” atmospheres, such as nitrogen. Several coolants have also been reviewed to determine if coolant breach into the plasma chamber would enhance the combustion threat; for example, in-vessel steam from a water coolant breach will react with metal dust. The results of this review are presented here.

L. C. Cadwallader

2003-05-01T23:59:59.000Z

456

Rapid Deployment of Rich Catalytic Combustion  

SciTech Connect

The overall objective of this research under the Turbines Program is the deployment of fuel flexible rich catalytic combustion technology into high-pressure ratio industrial gas turbines. The resulting combustion systems will provide fuel flexibility for gas turbines to burn coal derived synthesis gas or natural gas and achieve NO{sub x} emissions of 2 ppmvd or less (at 15 percent O{sub 2}), cost effectively. This advance will signify a major step towards environmentally friendly electric power generation and coal-based energy independence for the United States. Under Phase 1 of the Program, Pratt & Whitney (P&W) performed a system integration study of rich catalytic combustion in a small high-pressure ratio industrial gas turbine with a silo combustion system that is easily scalable to a larger multi-chamber gas turbine system. An implementation plan for this technology also was studied. The principal achievement of the Phase 1 effort was the sizing of the catalytic module in a manner which allowed a single reactor (rather than multiple reactors) to be used by the combustion system, a conclusion regarding the amount of air that should be allocated to the reaction zone to achieve low emissions, definition of a combustion staging strategy to achieve low emissions, and mechanical integration of a Ceramic Matrix Composite (CMC) combustor liner with the catalytic module.

Richard S. Tuthill

2004-06-10T23:59:59.000Z

457

Internal combustion electric power hybrid power plant  

SciTech Connect

An internal combustion-electric motor hybrid power plant for an automotive vehicle is disclosed. The power plant includes an internal combustion engine and a direct current electric motor generator which are connected to a drive shaft for the vehicle. A clutch mechanism is provided to connect the internal combustion engine, the direct current electric motor generator and the drive shaft for selectively engaging and disengaging the drive shaft with the internal combustion engine and the motor generator. A storage battery is electrically connected to the motor generator to supply current to and receive current therefrom. Thermoelectric semi-conductors are arranged to be heated by the waste heat of the internal combustion engine. These thermoelectric semi-conductors are electrically connected to the battery to supply current thereto. The thermoelectric semi-conductors are mounted in contact with the outer surfaces of the exhaust pipe of the internal combustion engine and also with the outer surfaces of the cylinder walls of the engine.

Cummings, T.A.

1979-04-10T23:59:59.000Z

458

A numerical study comparing the combustion and emission characteristics of biodiesel with petrodiesel.  

DOE Green Energy (OSTI)

Combustion and emission characteristics of compression ignition engines strongly depend upon inner-nozzle flow and spray behavior. These processes control the fuel-air mixing, which in turn is critical for the combustion process. Previous studies by us highlighted the differences in the physical and chemical properties of petrodiesel and biodiesel, which significantly altered the inner-nozzle flow and spray structure. The current study is another step in this direction to gain a fundamental understanding on the influence of fuel properties on the combustion and emission characteristics of the compression ignition engine. n-Heptane and methyl butanoate were selected as surrogates for diesel and biodiesel fuels, respectively, because the chemical kinetic pathways were well-understood. Liquid length and flame lift-off length for diesel and biodiesel fuels were validated against data available in the literature. Liquid lengths were always higher for biodiesel because of its higher heat of vaporization, which resulted in increased interplay between spray and combustion processes under all conditions investigated. Ambient air entrainment was also lower for biodiesel mainly because of slower atomization and breakup. The mechanism for flame stabilization is further analyzed by estimating the turbulent burning velocity for both of the fuels. This analysis revealed that neither flame propagation nor isolated ignition kernels upstream and detached from high-temperature regions can be the mechanism for flame stabilization. Flame propagation speeds were observed to be similar for both fuels. Biodiesel predicted lower soot concentrations, which were also reflected in reduced C{sub 2}H{sub 2} mole fractions. Although prompt NO{sub x} was higher for biodiesel, total NO{sub x} was lower because of reduced thermal NO{sub x}. The ignition delay and NO{sub x} emissions predicted by these simulations do not agree with trends reported in the literature; hence, this study highlights the need for better fuel surrogates for diesel and biodiesel fuels.

Som, S.; Longman, D. (Energy Systems)

2011-04-01T23:59:59.000Z

459

Simulations of Turbulent Flows with Strong Shocks and Density Variations: Final Report  

SciTech Connect

The target of this SciDAC Science Application was to develop a new capability based on high-order and high-resolution schemes to simulate shock-turbulence interactions and multi-material mixing in planar and spherical geometries, and to study Rayleigh-Taylor and Richtmyer-Meshkov turbulent mixing. These fundamental problems have direct application in high-speed engineering flows, such as inertial confinement fusion (ICF) capsule implosions and scramjet combustion, and also in the natural occurrence of supernovae explosions. Another component of this project was the development of subgrid-scale (SGS) models for large-eddy simulations of flows involving shock-turbulence interaction and multi-material mixing, that were to be validated with the DNS databases generated during the program. The numerical codes developed are designed for massively-parallel computer architectures, ensuring good scaling performance. Their algorithms were validated by means of a sequence of benchmark problems. The original multi-stage plan for this five-year project included the following milestones: 1) refinement of numerical algorithms for application to the shock-turbulence interaction problem and multi-material mixing (years 1-2); 2) direct numerical simulations (DNS) of canonical shock-turbulence interaction (years 2-3), targeted at improving our understanding of the physics behind the combined two phenomena and also at guiding the development of SGS models; 3) large-eddy simulations (LES) of shock-turbulence interaction (years 3-5), improving SGS models based on the DNS obtained in the previous phase; 4) DNS of planar/spherical RM multi-material mixing (years 3-5), also with the two-fold objective of gaining insight into the relevant physics of this instability and aiding in devising new modeling strategies for multi-material mixing; 5) LES of planar/spherical RM mixing (years 4-5), integrating the improved SGS and multi-material models developed in stages 3 and 5. This final report is outlined as follows. Section 2 shows an assessment of numerical algorithms that are best suited for the numerical simulation of compressible flows involving turbulence and shock phenomena. Sections 3 and 4 deal with the canonical shock-turbulence interaction problem, from the DNS and LES perspectives, respectively. Section 5 considers the shock-turbulence inter-action in spherical geometry, in particular, the interaction of a converging shock with isotropic turbulence as well as the problem of the blast wave. Section 6 describes the study of shock-accelerated mixing through planar and spherical Richtmyer-Meshkov mixing as well as the shock-curtain interaction problem In section 7 we acknowledge the different interactions between Stanford and other institutions participating in this SciDAC project, as well as several external collaborations made possible through it. Section 8 presents a list of publications and presentations that have been generated during the course of this SciDAC project. Finally, section 9 concludes this report with the list of personnel at Stanford University funded by this SciDAC project.

Sanjiva Lele

2012-10-01T23:59:59.000Z

460

Generation Maintenance Application Center: Combustion Turbine Combined-Cycle Steam Valves Maintenance Guide  

Science Conference Proceedings (OSTI)

 BackgroundCombustion turbine combined-cycle (CTCC) facilities use various components that are unique to these types of power generation plants. Therefore, use of the Electric Power Research Institute (EPRI) Preventive Maintenance Basis Database (1018758) by owners of CTCC facilities is somewhat limited to only those components that are common to both CTCC facilities and nuclear or fossil power plants. With the projected growth in the number of CTCC facilities, the ...

2013-05-14T23:59:59.000Z

Note: This page contains sample records for the topic "turbulent nuclear combustion" from the National Library of EnergyBeta (NLEBeta).
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461

Assessment of ISLOCA risk-methodology and application to a combustion engineering plant  

Science Conference Proceedings (OSTI)

Inter-system loss-of-coolant accidents (ISLOCAs) have been identified as important contributors to offsite risk for some nuclear power plants. A methodology has been developed for identifying and evaluating plant-specific hardware designs, human factors issues, and accident consequence factors relevant to the estimation of ISOLOCA core damage frequency and risk. This report presents a detailed of description of the application of this analysis methodology to a Combustion Engineering plant.

Kelly, D.L.; Auflick, J.L.; Haney, L.N. [EG and G Idaho, Inc., Idaho Falls, ID (United States)

1992-04-01T23:59:59.000Z

462

Generation Maintenance Application Center: Combined Cycle Combustion Turbine Continuous Emissions Monitoring Maintenance Guide  

Science Conference Proceedings (OSTI)

Combustion turbine combined cycle (CTCC) facilities utilize various components that are unique to these types of power-generation plants and that are not typically found in a nuclear or fossil-power plant.  As such, use of the EPRI PM Basis Database (PMDB) by current owners of CTCC facilities is limited to only those components that are common to both types of power plants and already in the database.  With the projected growth in the number of CTCC facilities, EPRI General Maintenance ...

2012-12-31T23:59:59.000Z

463

MCO combustible gas management leak test acceptance criteria  

DOE Green Energy (OSTI)

Existing leak test acceptance criteria for mechanically sealed and weld sealed multi-canister overpacks (MCO) were evaluated to ensure that MCOs can be handled and stored in stagnant air without compromising the Spent Nuclear Fuel Project's overall strategy to prevent accumulation of combustible gas mixtures within MCO's or within their surroundings. The document concludes that the integrated leak test acceptance criteria for mechanically sealed and weld sealed MCOs (1 x 10{sup -5} std cc/sec and 1 x 10{sup -7} std cc/sec, respectively) are adequate to meet all current and foreseeable needs of the project, including capability to demonstrate compliance with the NFPA 60 Paragraph 3-3 requirement to maintain hydrogen concentrations [within the air atmosphere CSB tubes] t or below 1 vol% (i.e., at or below 25% of the LFL).

SHERRELL, D.L.

1999-05-11T23:59:59.000Z

464

Evidence of critical balance in kinetic Alfven wave turbulence simulations  

Science Conference Proceedings (OSTI)

A numerical simulation of kinetic plasma turbulence is performed to assess the applicability of critical balance to kinetic, dissipation scale turbulence. The analysis is performed in the frequency domain to obviate complications inherent in performing a local analysis of turbulence. A theoretical model of dissipation scale critical balance is constructed and compared to simulation results, and excellent agreement is found. Thi