Finite-Rate Chemistry Favre-Averaged Navier–Stokes Based Simulation of a Non-Premixed SynGas/AirFlame

Abstract

This paper is devoted to the study of the influence of chemical mechanisms, turbulence models, and gas radiative properties models on the characteristics of a turbulent diffusion CO/H2/N2−air flame, i.e., the so-called syngas flame in a Favre-averaged Navier–Stokes (FANS) environment. For this purpose, a transient FANS solver for combustion is used. The simulations are carried out using three distinct turbulence models, i.e., the standard k−ε, the renormalization group (RNG) k−ε, and the shear stress transport models. The turbulence–chemistry interaction is modeled using the partially stirred reaction model. The chemical mechanisms used in the present study are: (i) a compact skeletal C2 mechanism, (ii) a mechanism developed by Frassoldati–Faravelli–Ranzi containing 14 species and 33 reactions, and (iii) the optimized syngas mechanism by Varga. Radiation heat transfer is handled by the P-1 method. In addition, the performances of two gas radiative properties models, i.e., the gray mean gas and the weighted-sum-of-gray-gases (WSGG) models, are assessed in radiative heat transfer modeling of the syngas flame. The predicted results reveal that the combination of the RNG turbulence model and the C2 skeletal mechanism shows the best agreement with measurements. The WSGG model used predicts results with the same level accuracy as the gray gas model in modeling of the syngas flame.