A projection method for LES of incompressible turbulent combustion

Abstract

In this paper, the “incompressible” property of a turbulent combustion with Ma»1 is analyzed, and a projection method for simulation of low Ma number turbulent combustions is discussed. The density is calculated explicitly, and the projection is only applied to the momentum equations and thus greatly saves the calculation cost. Large eddy simulation of methane-air turbulent planar jet combustion is performed using this projection method. A reduced fourstep chemical kinetic mechanism is applied for the simulation of methane-air combustion. A dynamic eddy viscosity model is utilized for the sub-grid scales turbulence modulation. The SGS model for the filtered reaction rate is a dynamic similarity model. Simulation results depict the detailed coherent structures in the jet flame along with the vortex-flame interactions in the flow field. Besides, it is found that the chemical reaction has the effect of “energy rearrangement” in the flow field, which may greatly reduce the turbulence. Simulation results show the satisfactory performance of this projection method in simulating turbulent combustion under the condition of Ma»1.