Large Eddy Simulations of a turbulent premixed swirl flame using an algebraic scalar dissipation rate closure

Large Eddy Simulations (LES) of a swirl-stabilised turbulent premixed flame in the well-known TECFLAM burner configuration have been carried out by solving transport equations of Favre-filtered reaction progress variable and mixture fraction. A recently proposed closure for the Scalar Dissipation Rate (SDR) is used for the modelling of the filtered reaction rate of reaction progress variable, whereas the Favre filtered mixture fraction is used to account for mixture stratification due to entrainment. The computational results are utilised to analyse the nature of stratification at representative locations in the swirl flame to gain physical insight into the flame structure. Additionally, two algebraic Flame Surface Density (FSD) closures, which were found to perform well in a previous analysis (Ma et al., 2013), are used for the modelling of the filtered reaction rate of reaction progress variable. The predictions of SDR closure are compared to the corresponding results obtained from algebraic FSD closures. The predictions of SDR based simulations show reasonably good agreement with experimental findings; the level of accuracy is at least comparable to that achieved with algebraic FSD models and to the results reported in the literature.