Optimization design for shape-transition curved isolator with controllable cross-sectional area

In order to obtain a type of variable cross-section curved isolator, a generic method was developed to design a supersonic curved isolator with controllable cross-sectional area by streamline tracing technique based on parameterizing and optimizing basic flow field. Firstly, traditional streamline tracing technique was conducted to design curved isolator. Analysis shows that the traced flow passage presents serious areal throats, which would be detrimental to the unstart performance of inlet and ability of stabilizing shock trains. It is unacceptable in practical applications. Then, the reason, which caused cross-sectional area changing non-monotonously, was analyzed and an improved method was proposed by introducing cross-sectional area constraints in the optimization process. What's more, two parameters, including total pressure recovery coefficient of basic flow field at the exit and maximum area deviation of traced area and designed area, are chosen as the optimization target. Finally, the basic flow field was optimized through modified method and the traced three-dimensional flow path was analyzed. The results show that the cross-sectional area can be controlled within a certain deviation range through the improving optimization method. And combining the blending function, the rectangular-to-circular isolator is designed and analyzed in the paper. It shows that the three-dimensional shape-transition curved isolator, which has well total pressure recovery performance, can be obtained through the method in this paper.