Large-eddy simulation of bluff-body stabilized premixed flames with low-dissipative, structure-preserving convection schemes

Abstract

Large eddy simulation (LES) has the potential to predict turbulent combustion phenomena in modern practical combustors. As errors from sub-grid models may be comparable to the numerical errors in the LES approach, mitigating the impact of the numerical errors is as important as constructing accurate sub-grid models. Therefore, a low-dissipative, structure-preserving ROUND (Reconstruction Operators on Unified Normalized-variable Diagram) scheme is tested for the LES of reacting flows in this study. The high efficiency of this scheme is demonstrated by evaluating its accuracy, central processing unit cost, and structure-preserving property by simulating the convection–diffusion process of a passive scalar. Simulations of two bluff body stabilized flames are studied using this scheme. For low turbulence intensity, the current scheme improves the numerical resolution of the instantaneous and averaged flow fields. The prediction of flow statistics is also improved by the ROUND schemes compared to the conventional schemes. Moreover, the ROUND schemes preserve the axisymmetry of the averaged flow better than the conventional schemes for the cases investigated here. For the high turbulence intensity case, the ROUND scheme avoids nonphysical numerical oscillations. The flow and flame statistics obtained using this scheme compare well with measurements. Therefore, this work demonstrates the advantages of using ROUND schemes for LES of reacting flows.