基于 RBF 代理优化的固体火箭发动机喷管型面设计

The divergent section profile of two⁃dimensional axisymmetric solid rocket motor nozzles with a fixed divergent ratio and divergent section length,was optimized to maximize nozzle thrust.The optimization parameters included the radial position of the control points on the Bezier curve,and the RBF proxy optimization algorithm was employed as the optimization method.The two mod⁃ els of pure gas phase and two⁃phase flow were used to optimize the design respectively.The pure gas phase results show that the opti⁃ mized thrust is increased by 1.64% for the Bezier curve expressed by 10 control points. With this optimized surface as the initial surface,the number of control points is increased to 16,and the thrust after secondary optimization is increased by 0.095%.Expan⁃ ding the range of optimization parameters and introducing constraints to judging inflection points,the single⁃round optimization of Bezier curve expressed by 10 control points was carried out. The results were similar to the above results after two rounds of optimi⁃ zation.The optimized nozzle thrust was increased by 1.78 %,which demonstrates the algorithm's strong stability.By comparing the optimization process of Bezier curve with different number of control parameters,the method and suggestion for reasonably selecting the number of control points were given.The optimization results of two⁃phase flow show that the thrust of two⁃phase flow nozzle is smaller than that of pure gas phase nozzle due to two⁃phase flow loss resulting from the particle lag effect. However,the thrust of two⁃ phase flow nozzle after optimization is 1.87 % higher than that of the initial surface before optimization, and the increase proportion of thrust is slightly higher than that of pure gas phase nozzle.The RBF surrogate optimization algorithm is suitable for the optimiza⁃ tion of nozzle divergent section surface for Bezier curve expressed by any number of control points,which has high efficiency and strong stability.