Scale effect on the hypersonic inlet under fluid-thermal-structure interaction

Abstract

Hypersonic inlet is exposed to severe aerodynamic force/heat loads, the impacts caused by the Fluid-Thermal-Structure Interaction (FTSI) are crucial. This paper proposes a three-dimensional FTSI framework and studies the FTSI effects of inlet. Subsequently, the mechanism of FTSI is elaborated, and the scale effect on hypersonic inlet is analyzed. Research shows that the traditional design of thermal-protection materials on the forebody and the lip cannot meet the long-endurance flight requirements. FTSI will cause a sharp increase in the temperature at the inlet shoulder and the position of the first reflected shock wave in the isolator, which is prone to lead structural failure. Lift of forebody, pressing down of lip and inlet shoulder lead to the increasing of mass flow coefficient by approximately 10 % and the decreasing of total pressure recovery coefficient by about 7 %. Scale effect on inlet under FTSI is revealed. Small-scale inlet is likely to be unstart state under FTSI. Absolute thickness of structure and the boundary layer of the small-scale inlet is thinner, resulting in a more uniform and faster temperature rise of the structure, which leads to smaller y direction deformation of the small-scale inlet. Although the effect of the increasing wall temperature and the decrease in y direction deformation are opposite on the forward movement of the shock wave, FTSI makes the forward movement rate of the shock wave slightly larger in the small-scale isolator.