Configuration optimization and optical transmission simulation of a conformal fairing under a hypersonic thermal environment.

When an aerospace vehicle flies within the atmosphere, aerodynamic heating can affect the surface shape and the refractive index of the optical fairing, leading to imaging distortion and deviation in the subsequent optical system. To address this issue, this paper proposes a novel, to the best of our knowledge, concept for a conformal optical fairing design. This compares the imaging performance, stagnation point temperature, and drag coefficient of four traditional fairings. Considering the effects of aerodynamic heating and imaging performance comprehensively, a conformal fairing model based on the combination of a hyperbolic curve and a von Kármán curve is established. The optimal combination location and the length-to-diameter ratio of the new conformal fairing are determined using a multi-objective genetic algorithm according to the performance requirements. The new conformal fairing model has been validated to show a 9.83% reduction in the drag coefficient compared to a purely hyperbolic fairing, a 39.21% reduction compared to the widely used ellipsoidal fairing, and a 4.56% reduction compared to a parabolic fairing. Regarding the impact of aerodynamic thermal effects, the changes in the surface shape and the refractive index are reduced by 32.25% and 16.77%, respectively, compared to the ellipsoidal fairing. Additionally, the imaging quality is improved by 90.48% compared to a standalone von Kármán fairing. This novel design offers superior performance, providing what we believe is a new approach for future optical fairing design.