Large-Eddy Simulation of Autoignition-Dominated Supersonic Combustion

The simulation of low-speed combustion flows is well established. However, at high-speed conditions where radical formation and ignition delay are important, there is much less experience with turbulent combustion modeling. In the present work, a novel evolution variable manifold (EVM) approach of Cymbalist and Dimotakis is implemented in a production CFO code and preliminary RANS and large-eddy simulations are computed for a hydrogen combustion test case. The EVM approach solves a scalar conservation equation for the induction time to represent ignition delay. The state or the combustion products is tabulated as a function of density, energy, mixture fraction, and the evolution variable. A thermodynamically-consistent numerical flux function is developed and the approach for coupling the EVM table to CFD is discussed. Initial simulations show that the EVM approach produces good agreement with full chemical kinetics and model simulations. Work remains to be done to improve the numerical stability, extend the grid, and increase the order or accuracy of the simulations