COMPARISON OF CATALYTIC WALL CONDITIONS FOR HYPERSONIC FLOW

The effects of several catalytic boundary conditions implemented in a hypersonic flow solver are analyzed for a sphere/cone geometry represe ntative of a re-entry body. The three-dimensional Navier-Stokes equati ons solver uses a five-chemical-specie model. The simulated surface is silica, representative of coatings for thermal protection systems. Th e range of wall temperatures explored is 300-1500 K, and fully catalyt ic, local-equilibrium, noncatalytic, and finite-rate catalysis boundar y conditions are applied and discussed. For finite-rate catalysis a re cent model for simultaneous recombination of O and N atoms, including NO formation, is used. A comparison of all the boundary conditions imp lemented with results from fit-based finite-rate catalysis boundary co nditions is made at surface temperatures of 1200 and 1500 K. Numerical simulations results are compared and discussed, and conclusions about which boundary conditions are best in each case are drawn.