Implementation of chemical non-equilibrium in a hypersonic unified CFD solver

Modeling the interaction between hypersonic flow and ablative material has been conducted by coupling a computational fluid dynamics (CFD) solver to a material response solver. The unified approach is one of the coupling methods that solves both gas region and solid region at the same time without partitioning two regions. Here, the Kentucky Aerothermodynamics and Thermal System-Universal Solver (KATS-US) which employs the unified approach, is used. Park’s two-temperature approach is adopted to model the chemistry, and only air chemistry without ionization is considered. The verification test cases are conducted to verify the functionalities in KATS-US, and the results show good agreement with the results computed using a validated hypersonic aerothermodynamics CFD code. The chemistry model in KATS-US is used to simulate the iso-Q test case, which has both solid and gas regions treated as a single domain, and the results regarding the non-equilibrium thermo-chemistry effect are presented. The test case with accounting chemical reactions is compared with the non-reacting case, and the test case considering both dissociation and exchange reaction is compared with the test case which only considers dissociation.