Computations of Premixed Turbulent Flames

Until now and at least for the next few decades, combustion is and will be the major source of mechanical and electrical energy. For economic and ecological reasons, it is of primordial interest to master phenomena involved in a very important number of processes using combustion. The SFB 606, a german research initiative on unsteady combustion, established at the University of Karlsruhe aims to improve the understanding and control of such processes. The research program is divided into several parts dedicated to the study of fundamental phenomena. One numerical part of SFB 606, Project B8 is devoted to the investigation of effects of differential diffusion on the propagation of flames in premixed gas. These characterized by the Lewis number which is the ratio between diffusion of heat and mass, respectively. The goal of the present reseacht is to understand these mechanisms by using Direct Numerical Simulations (DNS) in comparaison with related experiments also realized in Karlsruhe within SFB 606. This will eventually allow comparison and close cross–validation. Such studies are the basis of modeling reactions in simulations of turbulent premixed flames and could be used in less costly numerical approaches such as statistical models or Large Eddy Simulation. In DNS, no model for turbulence is used and all the different length scales of the flow are computed, from the smallest in the flame front until the very large vortex structures. For these reasons the resolution demands are very high and hence the required CPU time. The present calculations in 2-D have been performed on the HP XC1 Cluster at the Karlsruhe Super Computing Center.