Optimization Design for Contour of Pintle Nozzle in Solid Rocket Motor Based on Response Surface Method

Abstract

In aim to gain the capability of providing variable thrust, the technology of an axial pintle inserted into the nozzle of the solid rocket motor had been used. As the pintle inserted into the nozzle, the loss of specific impulse will increase. In order to reduce the loss of fluid dynamics of the pintle nozzle, considering the interaction of the nozzle contour and the pintle contour, CFD method combined with the response surface method is used to optimize the contour of the pintle nozzle. The central composite design is used to introduce a design point; the Kriging algorithm is used to generate the response surface; and the Nonlinear Programming by Quadratic Lagrangian is used for optimization. After the optimization, the loss of fluid dynamics can be reduced significantly. To study the influence of the key parameters to the loss of specific impulse, the key parameters are optimized independently in this paper. It indicates that the main factor of the loss of specific impulse is the parameters of the nozzle. To reduce the computational consumption, the process of optimization has been improved. And the result shows that when optimizing a pintle nozzle, the nozzle part and the pintle part can be optimized separately. The method that bases on the response surface not only takes into account of the interactive effects of the shape parameters, but also works with less calculation. Additionally it maintains the high accuracy and reliability. It can be used to select the optimal shape parameters of the pintle nozzle quickly, which has certain engineering application value.