Large Eddy Simulation of mixing effects on the course of parallel chemical reactions and comparison with k-ɛ modeling

The way in which reagents are mixed can have a large influence on the product distribution of chemical reactions. To model effects of mixing on various scales on the course of chemical reactions the method of Large Eddy Simulation (LES) of non-premixed, turbulent reactive flows of incompressible fluids is considered in this work. The subgrid modeling of chemical reaction is based on a beta distribution of the mixture fraction in combination with a conditional moment closure based on linear interpolation of local instantaneous reactant concentration values. The predictions obtained with LES are compared with experimental data for fast parallel chemical reactions, the fluid velocity measured using Particle Image Velocity (PIV) technique and the passive tracer concentration measured using the Planar Laser Induced Fluorescence (PLIF) technique. Predictions of the model based on LES are compared as well with results obtained using the non-equilibrium multiple-time-scale mixing model combined with a standard k-ɛ model and employing similar conditional moment closure as LES, applied, however, at larger scale. All comparisons show a very good performance of the model based on LES.