A numerical investigation of the Eulerian PDF transport approach for modeling of turbulent non-premixed pilot stabilized flames

Presumed shape multi-environment Eulerian PDF Transport method (MEPDF), which involves representing the joint composition PDF shape as a collection of finite number of Delta functions, has been used to model the turbulence-chemistry interactions. The governing transport equations are solved for the probability and the probability weighted mass fraction of species and enthalpy in an Eulerian frame. The radiation heat transfer is included using the non-gray modeling of the radiative properties of the medium by weighted sum of gray gases (WSGG) considering four fictitious gray gases. The absorption coefficients as well as the weight functions of the gray gases are calculated from published literature as a function of the species mass fraction and temperature. The effect of turbulence radiation interaction (TRI) is included using an empirical relations for emission enhancement. The combined tool is then used to model two pilot stabilized hydrocarbon flames (Sandia Flame D and Delft Flame III) with realistic finite rate chemistry. A parametric study of the micro-mixing constant is performed to understand its impact in flame stabilization. In case of Delft Flame III, two different pilot treatments are considered and also the impact of pilot flame power is studied with the MEPDF model. The current model results have been compared with the experimental data and also with the Lagrangian solution of the joint composition PDF transport equation. The discrepancies of the current predictions with the experimental data and other published results have been quantified and discussed.