Effect of Thermal Protection System on Aerodynamics and Pressure of Reusable Launch Vehicle

Insulation felt is an essential thermal protection component of reusable launch vehicles. The non-smooth microstructure and local structure, such as gaps or grooves, formed during the laying process of insulation felt have a considerable influence on the aerodynamic performance of space shuttles in broad space and velocity areas. In particular, they cause a substantial deviation in the pressure at the flush air data sensing system measurement points in the transonic velocity area, relative to the theoretical shape. This study builds a geometric model of the thermal protection structure according to the optical scanning data of an actual thermal protection structure. A geometric error was added to the thermal protection structure at the aircraft head and wing. The influence of the geometric error on the surface pressure and aerodynamic performance of the aircraft was studied using numerical simulation and experiments with Ma = 0.4 to 2.0, angles of attack varying from 3° to 14°, and slide angles of 0° and 5°. The results indicate that the surface pressure deviation of the thermal protection structure on the aircraft head was less than 5%. The surface pressure deviation substantially increased because of the slide angle; it was approximately 7% for Ma = 0.95 and a 5° slide angle. Under subsonic and transonic speed conditions, the geometric error caused by the placement of thermal protection may lead to an axial force varying by 12.3% and a pitch moment varying by 5%.