Direct numerical simulation of high pressure turbulent lean premixed CH4/H2 - Air slot flames

A general description of the three flames is provided, evidencing their macroscopic differences in terms of turbulent displacement speed, flame surface areas and mean flame brush thickness. Furthermore, topological features of the flames are explored by analyzing the probability density functions of several quantities: curvature, curvature shape factor, alignment between vorticity and principal strain rate vectors with flame surface normal, displacement speed and its components. Finally the differential diffusivity effect on the local equivalence ratio in the three flames is investigated showing a strong effect of the turbulent flame thickness of the high pressure flames on light species differential diffusivity.