Thermal–optical coupling analysis of aero-optical imaging deviation in blunt-bi-conic vehicle at hypersonic speed

Under a hypersonic aero-thermal environment, vehicles are subjected to complex turbulent flow fields and intense aero-thermal effects, which significantly degrade the imaging performance of onboard optical systems. This study establishes a 3D model of a blunt-bi-conic vehicle and constructs a coupling fluid–structure–thermal–optical multifield model to analyze the influence of the aero-optical effect on imaging quality. Compared with the blunt-nose front-window design, when the line-of-sight angles exceed 25 deg, the blunt-bi-conic vehicle effectively mitigates the impact of aero-optics and aero-thermal effects on imaging deviation. The results are that the deflections of light inside the flow field partially cancel each other out, however, within the optical dome, it consistently refracts close to the normal. The variation characteristics of imaging deviation for fluid–structure interaction are obtained using reverse light tracing, which is smaller with increasing altitude and larger with increasing Mach number and angle of attack. The optical dome has a greater effect on the imaging deviation; its imaging deviation magnitude is similar to the total imaging deviation magnitude. This article provides a theoretical basis for the thermal–optical coupling design and optimizing the influence of aero-optics on imaging deviation in hypersonic vehicles.