Transported PDF Calculations of a Turbulent, Non-Premixed, Non-Piloted, Hydrogen-Air Flame with Differential Diffusion

摘要

Diffusive mass and heat fluxes cause unclosed terms in transported probability density function (TPDF) methods which need to be modeled accurately, in order to account for the effects as local extinction or stabilization of turbulent flames. The modeling of flame stabilization is addressed in this work with the example a non-piloted, non-premixed hydrogen-air flame. Experimental data suggest that differential diffusion plays a major role at the root of this flame. To account for this effect, a diffusion model recently introduced for TPDF/LES (Large-Eddy-Simulation) methods is modified and applied in RANS (Reynolds-Averaged-Navier Stokes) calculations. Several computations employing this model with varying particle-numbers and grid-resolutions demonstrate the capability of the diffusion model to take differential diffusion into account and thus improve flame stabilization.