Large eddy simulation of premixed and non-premixed combustion

This paper summarises the authors experience in using the Large Eddy Simulation (LES) technique for the modelling of premixed and non-premixed combustion. The paper describes the application of LES based combustion modelling technique to two well defined experimental configurations where high quality data is available for validation. The large eddy simulation technique for the modelling flow and turbulence is based on the solution of governing equations for continuity and momentum in a structured Cartesian grid arrangement. Smagorinsky eddy viscosity model with a localised dynamic procedure is used as the sub-grid scale turbulence model. A swirl flame is considered as the non-premixed combustion application. For non-premixed combustion modelling a conserved scalar mixture fraction based steady laminar flamelet model is used. A radiation model incorporating the discrete transfer method is included in the non-premixed swirl flame calculations. For premixed combustion where the application considered here is flame propagation in a confined explosion chamber a model based on dynamic flame surface density (DSFD) is used. It is shown that in both cases LES based combustion models perform remarkably well and results agree well with the experimental data.