Application of the Evolution-Variable Manifold Model to Turbulent Hydrogen Combustion

Modeling the effects of turbulent combustion is important for the design of propulsion systems, but full finite-rate chemistry (FRC) models pose significant numerical challenges in cost and stiffness. The present work examines Evolution Variable Manifold (EVM), a tabulated chemistry model which seeks to reduce this cost for highly turbulent, compressible combustion. A representative chemical source term is precomputed and stored as a function of the thermochemical state, replacing direct integration with interpolation at runtime. Two comparison studies were conducted for hydrogen-air combustion: a direct numerical simulation (DNS) of a temporal mixing layer and a Reynolds-Averaged Navier-Stokes (RANS) jet in supersonic crossflow (JISCF). The mixing layer compared an EVM-DNS against an FRC-DNS in the absence of strong shocks or turbulence models. The JISCF configuration compared an EVM Reynolds-Averaged Navier-Stokes (RANS) approach with a FRC-RANS in the face of shocks and near-wall recirculation regions. Results indicate that EVM slightly underpredicts temperature and water vapor production in recirculation regions, and suggests areas of investigation to augment the current approach.