摘要：In this paper, the "incompressible" property of a turbulent comhustion with Ma<<l is analyzed, and a pro- jection 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 equa- tions 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 four-step 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 simi- larity model. Simulation results depict the detailed coherent structures in the jet flame along with the vortex-flame inter- actions in the flow field. Besides, it is fonnd that the chemical reaction has the effect of "energy rearrangement" in the flow field, which may greatly reduce the turbulence. Sinlulation results show the satisfactory performance of this projection method in simulating turbulent combustion under the condi- tion of Ma<<1.