Paper presented at the 8th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Mauritius, 11-13 July, 2011.
Compared to RANS based combustion modelling, the Large
Eddy Simulation (LES) technique has recently emerged as a
more accurate and very adaptable technique in terms of
handling complex turbulent interactions in combustion
modelling problems. In this paper application of LES based
combustion modelling technique and the validation of models
in non-premixed and premixed situations are considered. Two
well defined experimental configurations where high quality
data are available for validation is considered as case studies to
demonstrate the methods, accuracy and capability of the LES
combustion modelling technique as a predictive tool. 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 nonpremixed
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 also 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.
