RANS simulations of statistically stationary premixed turbulent combustion using Flame Speed Closure model

Artikel i vetenskaplig tidskrift, 2015

Turbulent Flame Closure (TFC) and Flame Speed Closure (FSC) models of the influence of turbulence on premixed combustion are applied to RANS simulations of five sets of experiments with (i) highly turbulent, oblique, confined ONERA flames under elevated temperatures, (ii) highly turbulent, conical, confined PSI flames under elevated temperatures and pressures, (iii) open V-shaped flames, and weakly turbulent Bunsen (iv) Erlangen and (v) Orl,ans flames under the room conditions. Besides flame geometry, pressure, and initial temperature, bulk flow velocities, turbulence characteristics, and mixture compositions are different in these five sets of flames, with the equivalence ratio being varied in each set. Turbulence is modeled invoking either the standard or RNG k - epsilon model. The same standard value A = 0.5 of a single constant of the TFC or FSC model is used in all these simulations, but certain input parameters of the turbulence model are tuned by investigating a single reference case for each set of flames. The TFC and FSC combustion models yield similar results when simulating the PSI flames, but the FSC model shows better performance in predicting burning rate for four other sets of flames. All in all, results computed using the FSC model agree reasonably well with the majority of the experimental data utilized to test the model, with a few exceptions discussed in the paper.