Rate-Controlled Constrained Equilibrium (RCCE) simulations of turbulent partially premixed flames (Sandia D/E/F) and comparison with detailed chemistry

This paper investigates the potential of the RCCE mechanism reduction approach for modelling turbulent flames within the framework of transported PDF methods. For this purpose, PDF simulations are performed with an RCCE-reduced mechanism via direct integration of the RCCE ODEs, without any tabulation, and comparison is made with both the experimental results and those from a PDF simulation with direct integration of the detailed mechanism. The flames simulated are the Sandia flames D/E/F and the simulations are carried out with a RANS approach and a Lagrangian particle method for solving the transported joint-scalar PDF equation. The detailed mechanism is the well known GRI 3.0 CH4 combustion mechanism. The turbulence closure employed is the k-ε model, while the micromixing closure in the PDF transport equation is the Interaction with the Mean (IEM) model. The RCCE-reduced mechanism incorporates 18 constraints, selected from the original 53 species based on laminar flamelet simulations. Excellent agreement was observed between the RCCE simulations and direct integration, indicating that the reduced mechanism can reproduce very well the features of the full mechanism. Agreement with experimental results is also very good, given the turbulence and mixing models employed.