Direct numerical solution of turbulent nonpremixed combustion with multistep hydrogen-oxygen kinetics

Montgomery, Christopher J.; Kosály, G.; Riley, James J.

doi:10.1016/s0010-2180(96)00128-9

Cited by 33 publications

(19 citation statements)

References 18 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The LSR model provides considerably more information that will be important, for example, in applications where fluctuations in the scalar dissipation rate lead to local extinction of chemical reactions. [40][41][42][43][44] In Fig. 14 typical Lagrangian time series following a single notional particle 38 are shown for R ϭ230 and Scϭ͑1,1/8͒.…”

Section: E Lagrangian Time Seriesmentioning

confidence: 99%

The Lagrangian spectral relaxation model for differential diffusion in homogeneous turbulence

Fox

1999

Physics of Fluids

View full text Add to dashboard Cite

The Lagrangian spectral relaxation ~LSR! model is extended to treat turbulent mixing of two passive scalars (fa and fb) with different molecular diffusivity coefficients ~i.e., differential-diffusion effects!. Because of the multiscale description employed in the LSR model, the scale dependence of differential-diffusion effects is described explicitly, including the generation of scalar decorrelation at small scales and its backscatter to large scales. The model is validated against DNS data for differential diffusion of Gaussian scalars in forced, isotropic turbulence at four values of the turbulence Reynolds number (Rl538, 90, 160, and 230! with and without uniform mean scalar gradients. The explicit Reynolds and Schmidt number dependencies of the model parameters allows for the determination of the Re ~integral-scale Reynolds number! and Sc ~Schmidt number! scaling of the scalar difference z5fa2fb . For example, its variance is shown to scale like ^z2& ;Re20.3. The rate of backscatter (bD) from the diffusive scales towards the large scales is found to be the key parameter in the model. In particular, it is shown that bD must be an increasing function of the Schmidt number for Sc<1 in order to predict the correct scalar-to-mechanical time-scale>ratios, and the correct long-time scalar decorrelation rate in the absence of uniform mean scalar gradients. Disciplines Catalysis and Reaction Engineering | Chemical Engineering CommentsThis article is from Physics of Fluids11(1999) The Lagrangian spectral relaxation ͑LSR͒ model is extended to treat turbulent mixing of two passive scalars ( ␣ and ␤ ) with different molecular diffusivity coefficients ͑i.e., differential-diffusion effects͒. Because of the multiscale description employed in the LSR model, the scale dependence of differential-diffusion effects is described explicitly, including the generation of scalar decorrelation at small scales and its backscatter to large scales. The model is validated against DNS data for differential diffusion of Gaussian scalars in forced, isotropic turbulence at four values of the turbulence Reynolds number (R ϭ38, 90, 160, and 230͒ with and without uniform mean scalar gradients. The explicit Reynolds and Schmidt number dependencies of the model parameters allows for the determination of the Re ͑integral-scale Reynolds number͒ and Sc ͑Schmidt number͒ scaling of the scalar difference zϭ ␣ Ϫ ␤ . For example, its variance is shown to scale like ͗z 2 ͘ ϳRe Ϫ0.3 . The rate of backscatter (␤ D ) from the diffusive scales towards the large scales is found to be the key parameter in the model. In particular, it is shown that ␤ D must be an increasing function of the Schmidt number for Scр1 in order to predict the correct scalar-to-mechanical time-scale ratios, and the correct long-time scalar decorrelation rate in the absence of uniform mean scalar gradients.

show abstract

Section: E Lagrangian Time Seriesmentioning

confidence: 99%

The Lagrangian spectral relaxation model for differential diffusion in homogeneous turbulence

Fox

1999

Physics of Fluids

View full text Add to dashboard Cite

show abstract

“…Due to its computational cost, only low-Reynolds-number situations can be handled by DNS. Nevertheless, it has been particularly important for testing combustion models and for providing detailed information on turbulence-combustion coupling [2][3][4][5].…”

Section: Introductionmentioning

confidence: 99%

LES of the Sandia Flame D Using Laminar Flamelet Decomposition for Conditional Source-Term Estimation

Ferraris

Wen

2008

Flow Turbulence Combust

View full text Add to dashboard Cite

A variation of the Laminar Flamelet Decomposition (LFD) method for the Conditional Source Term (CSE) model developed by Bushe and Steiner (Phys Fluids 15:1564-1575 is implemented into an existing LES code. In this approach, the set of basis functions, on which the decomposition is based, is reduced using the mixture fraction dissipation rate as external parameter for the selection. It was found that reducing the basis improves and stabilises the inversion, resulting in reasonably accurate approximation for the average conditional quantities. Some modifications have been introduced to improve the inversion process by reducing the number of flamelets. This modification is found to help stabilize the inversion and keep the dimension of the linear system small. The model is used to simulate the turbulent non-premixed piloted SANDIA Flame D. Reasonably good predictions for conditional and unconditional average variables were found for different planes and at centreline of the flow field. However, an over prediction of the consumption rate in the near field of the flame is found, which may be partially attributed to the use of the Steady Laminar Flamelets (SLF) as functions for the decomposition and the use of a constant boundary condition for the species mass fractions in solving the flamelets. The present simulation of a turbulent reacting jet is the first test of the LFD approach in a realistic scenario using only the temperature field to calculate the inversion. The model is found to be computationally inexpensive.

show abstract

“…Both investigations considered incompressible flow conditions. The new work of Montgomery et al (1997) presents three-dimensional direct numerical simulations of a seven-species, ten-reaction hydrogen-oxygen mechanism in decaying, variable density, isotropic turbulence.…”

Section: Direct Numerical Simulation Investigationsmentioning

confidence: 99%

Evaluation of Closure Models of Turbulent Diffusion Flames

Kosály¹,

Riley²

2000

View full text Add to dashboard Cite

Direct numerical solution of turbulent nonpremixed combustion with multistep hydrogen-oxygen kinetics

Cited by 33 publications

References 18 publications

The Lagrangian spectral relaxation model for differential diffusion in homogeneous turbulence

The Lagrangian spectral relaxation model for differential diffusion in homogeneous turbulence

LES of the Sandia Flame D Using Laminar Flamelet Decomposition for Conditional Source-Term Estimation

Evaluation of Closure Models of Turbulent Diffusion Flames

Contact Info

Product

Resources

About