Assessment of kinetic BGK application to the internal and external flows in modeling RCC crack growth

Statistical BGK and Continuum CFD computational techniques are employed to study flows over the arcjet modeled specimen. The subject of the present study is flow over a SiC coated reinforced carbon-carbon specimen with a hole imitating the micro-meteoroid impact on the non-ablating spacecraft protection shield. The specimen was previously studied experimentally at the NASA Johnson Arcjet Facility and extensively modeled numerically making use of the CFD techniques. With the established data available, a statistical BGK approach was tested for the flow regimes which are dense enough to exceed the applicability range of the baseline DSMC technique. Both outer flow, preceding the micro hole entrance, and the flow inside the hole with chemically active boundary conditions were solved in a single setup thus covering the entire range of flow regimes starting from supersonic free-stream Mach=5.83 flow then capturing the shock layer, solving the dense stagnation region, the micro-flow inside the channel-hole and finally solving the flow acceleration and expansion at the exit of the hole. Additionally a supersonic flow over a cylinder was solved by the statistical BGK technique and compared with the mesh and particle resolved DSMC results to check the BGK accuracy of the shock layer region modeling.