Large-eddy simulation of a jet flame using a SOM-SGS combustion model

A second-order moment algebraic (SOM) subgrid scale (SGS) combustion model was adopted for the 3D large eddy simulation of a piloted methane/air jet flame, i. e. Flame C, measured in the Sandia National Laboratory. The predicted time-averaged temperature, methane concentration and root mean square (RMS) value of temperature fluctuation are in good agreement with the experimental data, showing the feasibility of the proposed SGS combustion model. For averaged temperature and species concentration, the RANS-SOM modeling is fairly good. The LES statistical results, in particular for turbulence properties, are better than the RANS modeling results using the same combustion model. The proposed SOM-SGS combustion model is suitable for LES of a jet flame. The instantaneous results show that the coherent structures are abundant in the jet flame and they are enhanced by the reaction. At the same time, the coherent structures intensify the jet combustion, forming a wrinkled flame.