An insight into chemical mechanisms and combustion modeling in flameless mode

Computational Fluid Dynamics (CFD) study of flameless combustion condition is carried out solving the Reynolds-Averaged Navier-Stokes (RANS) equations in the open-source CFD package of OpenFOAM 2.1.0. Particular attention is devoted to the comparison of three global and detailed chemical mechanisms using the Partially Stirred Reactor (PaSR) combustion model for the turbulence-chemistry interaction treatment. The OpenFOAM simulations are assessed against previously published CFD results using the Eddy Dissipation Concept (EDC) combustion model as well as the experimental data available in the literature. Results show that global chemical mechanisms provide acceptable predictions of temperature field in flameless mode with much lower computational cost comparing with detailed mechanisms. However, detailed chemical mechanisms with proper combustion models are crucial for simulation of flameless mode especially when treating with production and destruction of minor species.