Solid rocket engine nozzle expansion section inner profile optimization method

The invention provides a solid rocket engine nozzle expansion section inner molded surface optimization method, which can explore the influence rule of expansion section inner molded surface parameters on nozzle performance, and further iteratively solve the optimal inner molded surface. According to the method, the influence of the gas specific heat capacity change and condensed phase lag in the two-phase flow field of the solid rocket engine nozzle on the performance of the solid rocket engine nozzle is accurately considered, meanwhile, the simulation calculation amount is reduced, the design parameter interaction effect is visually analyzed, and profile optimization is carried out. According to the method, two-phase flow numerical simulation and a response surface method are combined, the nozzle performance of different expansion section inner molded surface parameters is solved through batch simulation based on a DPM model, a regression model is constructed as a basis for molded surface optimization, and