Large eddy simulation of piloted turbulent jet flames using the multi-environment PDF model based on the flamelet generated manifold

Abstract

Using the multi-environment probability density function (MEPDF) approach, large Eddy simulation (LES) has been carried out for the piloted turbulent jet flames Sandia flames D and F, which are well documented for the validation of turbulent combustion model. In the present approach, the detailed chemistry is represented by the flamelet generated manifold (FGM) and the turbulence-chemistry interaction is modeled by the MEPDF approach. In this LES-based MEPDF model, the joint scalar PDF is modeled as a sum of weighted Dirac delta functions. As a result, filtered reaction term is closed without additional modellings. Moreover, a finite number of high order moments can be accurately reconstructed with direct quadrature method of moments. In terms of the unconditional and conditional means for mixture fraction, temperature, major and key radical species, numerical results are compared with experimental data. For flame D, the present LES-based MEPDF approach yields a good agreement with experimental data. However, for flame F, the conformity with measurements is not quite satisfactory compared to flame D. It is also found that the much finer grid refinement yields the noticeably improved agreements with experimental data in terms of the unconditional and conditional means. These numerical results have demonstrated that the present LES-MEPDF approach using the FGM tabulated chemistry has the prediction capability of the physically complex turbulent flames as well as computational efficiency and robustness.