Thickened Flame LES methodology for turbulent propagating flames in non-homogeneous mixtures: application to a constant volume chamber

Abstract

A Large Eddy Simulation methodology is presented in the framework of the Thickened Flame model, to predict the dynamics of turbulent propagating flames in non-homogeneous mixtures at variable pressure and temperature. At first, an analytical model is introduced to evaluate dilution by burnt gases and correct the chemical scheme. This method is then coupled with a new combustion model (the Stretched-Thickened Flame model or S-TF) allowing to capture stretch effects on thickened flame fronts. The S-TF model is also extended to accommodate multiple gas conditions. This numerical approach is applied to simulate multiple cycles of the pistonless constant volume combustion (CVC) chamber CV2, operating at the Pprime laboratory in Poitiers, France. The experimental ignition sequence and flame propagation is taken as reference. Results demonstrate the capability of this model to predict flame evolution in the CVC chamber. Comparisons with the classical Thickened Flame model underscore the effectiveness of the S-TF model, also for turbulent flames.