On the application of dynamic zone flamelet model to large eddy simulation of supersonic hydrogen flame

A dynamic zone flamelet model (DZFM) is proposed to decouple the turbulence-chemistry interactions in supersonic combustion modeling based on local statistical homogeneity assumption. The whole turbulent combustion field is divided into a finite number of control zones, and the chemical status in each zone is represented by a local flamelet, which evolves according to the spatial exchange with its neighbors, chemical reactions controlled by representative temperature, and differential diffusion in the mixture fraction space. Both the zone division and its representative flamelet are dynamically updated for better representing the local chemical status. The zone-based flamelet model is then applied to large eddy simulation of a supersonic hydrogen flame based on 106.23 million cells and 30,0 x 91 flamelet zones. The predictions agree well with the DNS calculation, with the auto-ignition process and the flame lift-off phenomenon well reproduced. Sensitivity and cost analysis under different numbers of flamelet zones were also conducted. (C) 2020 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.