A Parametric Study on Large Eddy Simulations of Turbulent Premixed Flames

A parametric study has been carried out on the use of large eddy simulations (LES) technique for the prediction of turbulent premixed flames. A flame surface density (FSD) model is used together with an algebraic closure to calculate the filtered reaction rate. This reaction rate needs to be appropriately modelled. One main objective of the present study is to evaluate and validate the model used against measured data obtained from laboratory scale experiments. In particular, the model performance is examined by varying controlling parameters such as ignition radius, model constant, filter width and test to grid filter ratio. Flame structure, speed and generated overpressure are used for model evaluations at different times following ignition. The experimental combustion chamber is 0.625 litres in volume with three built-in solid obstacles. The mixture used is a stoichiometric propane/air mixture with equivalence ratio 1.0. The results show sensitivity of the model to the specification of the initial ignition radius and grid resolution. However, the model is found to be less sensitive to the selected filter width.