Three-dimensional nonequilibrium viscous shock-layer flows over complex reentry vehicles

Abstract

A computer program for predicting the three-dimensional nonequilibrium viscous shock-layer flows over blunt spherecones, straight. and bent mul ticonics at angle-of-attack has been developed. The method used is the viscous shock-layer approach- for nonequilibrium, multi-component ionizing air. A seven species chemical reaction model with single ionizing species and an eleven species chemical reaction model with five ionizing species are used to represent the chemistry. The seven species model considers 7 reactions whereas the eleven species model considers 26 reactions and the results obtained using these models are compared with perfect gas and equilibrium air results. This code is capable of analyzing shock-slip or no-shock-slip boundary conditions and equilibrium or non-catalytic wall boundary conditions. In this study the diffusion model is limited to binary diffusion.

A sphere-cone-cylinder-flare with moderate flare angle, a straight biconic, and a bent biconic with seven deg. bend angle and a sphere-cone at various flight conditions are analyzed using this method. The bent biconic has been analyzed up to an angle-of-attack of 20 deg. with respect to the aft-cone axis and sample results are compared with inviscid and viscous results. The surface pressure distribution computed by this code compares well with that from a parabolized Navier-Stokes method. The diffusion heat transfer is about 15% of the total heat transfer for most cases. The aerodynamic forces and moments at the base of the body and computing time required for all cases are presented. The shock layer profiles at a streamwi se location of 8. 8 nose radii for one case computed using seven and eleven species models compare very well with each other.