Large-eddy simulation of a bluff-body stabilised nonpremixed flame with radiation heat transfer

Abstract

Turbulence-radiation interactions are studied in this work for large-eddy simulations (LES) of an artificially scaled configuration based on the Sydney bluff-body burner. This investigation is performed by applying the combustion model flamelet generated manifolds, and the transported PDF Eulerian stochastic field method is employed to account for turbulence-chemistry interaction. The radiative transfer equation is solved with the finite volume method, while the gas radiative properties are calculated using the non-gray weighted-sum-of-gray-gases (WSGG) model. For the solution of the energy conservation equation in LES, the filtered radiative source term, which is the difference between the filtered absorption term and the filtered emission term, is required. The absorption term is modelled with the optically thin fluctuation approximation and the emission term is computed by either omitting or considering the subgrid-scale contribution. The results indicate that the difference between the emission term calculated with these two procedures is significant only in the regions where the emission term is relatively small. Moreover, no relevant differences in the profiles of mean temperature computed for those two cases were found. These results suggest that the subgrid-scale contribution may be neglected for LES investigation of the considered configuration.