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

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.