Research on Multi-Stage Identification Method for the Time-Varying Heat Flux Load of Aerospace Vehicle

Aiming at accurately identifying the aerodynamic heating loads faced by reusable aerospace vehicles under service, a novel multi-stage identification method of time-varying heat flux loads based on a modified conjugate gradient method is proposed in this paper. Numerical research is carried out with an integrated thermal protection structure. The influence of the sensitivity analysis method, number of identification stages, and temperature measurement error on the accuracy and efficiency of the proposed identification method is analyzed. Research results indicate that, by introducing the complex-variable -differentiation method into the conjugate gradient method, the number of iterations can be reduced by more than 30% under the premise of ensuring identification accuracy. By using the proposed multi-stage identification method, the identification deviation of heat flux load can be reduced by more than 20%, but the increased calculation time is less than 10%. The proposed multi-stage identification method has good anti-noise performance under the appropriate convergence criterion. © 2023 Science Press. All rights reserved.