Large Eddy Simulations of a piloted lean premix jet flame using finite-rate chemistry

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Large Eddy Simulations of a piloted lean premix jet flame using finite-rate chemistry. / Duwig, Christophe; Nogenmyr, Karl-Johan; Chan, Cheong-ki; Dunn, Matthew J.

In: Combustion Theory and Modelling, Vol. 15, No. 4, 2011, p. 537-568.

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Duwig, Christophe ; Nogenmyr, Karl-Johan ; Chan, Cheong-ki ; Dunn, Matthew J. / Large Eddy Simulations of a piloted lean premix jet flame using finite-rate chemistry. In: Combustion Theory and Modelling. 2011 ; Vol. 15, No. 4. pp. 537-568.

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TY - JOUR

T1 - Large Eddy Simulations of a piloted lean premix jet flame using finite-rate chemistry

AU - Duwig, Christophe

AU - Nogenmyr, Karl-Johan

AU - Chan, Cheong-ki

AU - Dunn, Matthew J.

PY - 2011

Y1 - 2011

N2 - A Large Eddy Simulation (LES) model capable of accurately representing finite-rate chemistry effects in turbulent premixed combustion is presented. The LES computations use finite-rate chemistry and implicit LES combustion modelling to simulate an experimentally well-documented lean-premixed jet flame stabilized by a stoichiometric pilot. The validity of the implicit LES assumption is discussed and criteria are expressed in terms of subgrid scale Damkohler and Karlovitz numbers. Simulation results are compared to experimental data for velocity, temperature and species mass fractions of CH4, CO and OH. The simulation results highlight the validity and capability of the present approach for the flame and in general the combustion regime examined. A sensitivity analysis to the choice of the finite-rate chemistry mechanism is reported, this analysis indicates that the one and two-step global reaction mechanisms evaluated fail to capture the reaction layer with sufficient accuracy, while a 20-species skeletal mechanism reproduces the experimental observations accurately including the key finite-rate chemistry indicators CO and OH. The LES results are shown to be grid insensitive and that the grid resolution within the bounds examined is far less important compared to the sensitivity of the finite-rate chemistry representation. The results are analyzed in terms of the flame dynamics and it is shown that intense small scale mixing (high Karlovitz number) between the pilot and the jet is an important mechanism for the stabilization of the flame.

AB - A Large Eddy Simulation (LES) model capable of accurately representing finite-rate chemistry effects in turbulent premixed combustion is presented. The LES computations use finite-rate chemistry and implicit LES combustion modelling to simulate an experimentally well-documented lean-premixed jet flame stabilized by a stoichiometric pilot. The validity of the implicit LES assumption is discussed and criteria are expressed in terms of subgrid scale Damkohler and Karlovitz numbers. Simulation results are compared to experimental data for velocity, temperature and species mass fractions of CH4, CO and OH. The simulation results highlight the validity and capability of the present approach for the flame and in general the combustion regime examined. A sensitivity analysis to the choice of the finite-rate chemistry mechanism is reported, this analysis indicates that the one and two-step global reaction mechanisms evaluated fail to capture the reaction layer with sufficient accuracy, while a 20-species skeletal mechanism reproduces the experimental observations accurately including the key finite-rate chemistry indicators CO and OH. The LES results are shown to be grid insensitive and that the grid resolution within the bounds examined is far less important compared to the sensitivity of the finite-rate chemistry representation. The results are analyzed in terms of the flame dynamics and it is shown that intense small scale mixing (high Karlovitz number) between the pilot and the jet is an important mechanism for the stabilization of the flame.

KW - implicit LES

KW - combustion modelling

KW - finite-rate chemistry

KW - turbulent

KW - premixed combustion

KW - LES validation

U2 - 10.1080/13647830.2010.548531

DO - 10.1080/13647830.2010.548531

M3 - Article

VL - 15

SP - 537

EP - 568

JO - Combustion Theory and Modelling

JF - Combustion Theory and Modelling

SN - 1364-7830

IS - 4

ER -