Large-eddy simulation of turbulent combustion using different combustion models

The second-order moment (SOM) combustion model proposed by the present authors is compared with eddy-break-up (EBU) and presumed probability density function (PDF) combustion models in large-eddy simulation of jet diffusion combustion, swirling diffusion combustion and premixed combustion behind a bluff body. The statistical results for time-averaged and RMS fluctuation temperatures are validated by experimental results. It is seen that the SOM model can always give good statistical results in LES of both non-premixed and premixed combustion, whereas the EBU and presumed PDF models cannot always do. The instantaneous results indicate that organized large vortex and thin flame surface structures are observed in jet diffusion combustion and bluff-body stabilized premixed combustion, whereas no organized vortex and thin flame surface structures are observed in swirling diffusion combustion.