膨胀规律可控的轴对称基准流场设计方法

为了提高流线追踪喷管设计方法的灵活性，从推力和力矩两方面考虑，引入特殊中心体，探索了壁面膨胀规律可控的轴对称基准流场设计方法.设计过程中利用特征线理论（MOC）实现了由膨胀规律求解气动壁面的反设计.针对基准流场的主要设计参数，包括膨胀规律、中心体及斜倾角等进行了参数化研究，得到了设计参数对基准流场结构及性能的影响规律.利用该基准流场，设计了矩形截面的流线追踪喷管(导出喷管)，并进行了分析.结果表明:利用特征线理论可以实现膨胀规律到壁面的反设计；在进口参数和落压比一定的条件下，存在一定的膨胀规律使得基准流场的内推力最大；流场的中心体尺度和长度比对推力影响很小，可作为调整导出喷管力矩的设计参数；出口斜倾角增大会导致基准流场的长度减小，同时推力下降明显，设计时应综合考虑. 

Design method of axisymmetric basic flowfield with controlled expansion law

In order to make the design methodology of streamline traced nozzle more flexible, an innovative axis symmetrical basic flow field design methodology with controlled expansion law on wall was explored while a centre body was placed in the flowfield. In the design process, Method of characteristics (MOC) was used to inversely solve the wall with given expansion law. The main design parameters, such as expansion law, centre body and oblique angle, were parametrically investigated. Then the variation of structure and performance of basic flowfield with these parameters were obtained. Using this basic flowfield, a rectangular streamline traced nozzle was designed and analyzed. Results show that, inverse design can be achieved by MOC; when the inlet and exit flow parameters are stable, there is a suitable expansion law corresponding to the maximum thrust performance. The radius of centre body and length ratio of basic flowfield, with less effect on thrust, can be used as the parameters to optimize the moment characteristics of derivative nozzle. When the oblique angle increases, the length and thrust of basic flowfield decrease rapidly, so the choice of oblique angle should be considered carefully.