EFFECTS OF SURFACE CATALYTICITY ON COMPUTED HEAT TRANSFER OVER A REENTRY VEHICLE

This paper reports on the research activities performed by the authors for the assessment of the aeroheating environment around a reentry vehicle devoted to manned or unmanned low earth orbit missions. Since hypersonic flow conditions are such that gas dissociation occurs, the surface convective heating rate may be significantly affected by recombination at the vehicle surfaces promoted by the wall catalyticity. In this context, good capabilities of simulating the flowfield environment around the descent vehicle are fundamental to detect the high-temperature phenomena of thermo-chemically reacting hypersonic flows occurring at the vehicle surface. Herein, both axisymmetric and 3D Navier-Stokes equations are numerically solved for non equilibrium airflow around a capsule-type reentry vehicle at the peak heating conditions. Computed stagnation point heating rates are compared with results from the Fay Riddell and Goulard formulae, and the effect of surface catalyticity on the heat shield thermal loading is highlighted and discussed.