逆向喷流对双锥导弹外形减阻特性的影响

逆向喷流是一种主动流动控制技术，具有减阻降热特性，可用于高超声速飞行器设计。以典型双锥导弹外形的球头、单锥、双锥（全弹）为研究对象，将喷流发生器和弹体固连，采用CFD方法对逆向喷流的减阻特性进行了数值研究，对比分析了喷流马赫数、喷流压比等参数对不同对象减阻效果的影响。结果表明：逆向喷流流场存在长、短射流穿透两种模态；球头在小压比长射流模态时的减阻效果最佳；单锥和双锥在大压比短射流模态时的减阻效果更好。存在一个最佳压比，使得逆向喷流的减阻效果最佳；喷流压力过大，减阻效果变差，甚至出现阻力系数不降反增情形。逆向喷流减阻效果对控制体选取敏感，若将逆向喷流对头部的减阻特性（超过40%）直接推广至飞行器整机（6%左右），评估结果过于乐观。综合最佳减阻效果、最佳喷流压比、流量与所需储气瓶体积等影响因素，工程应用时逆向喷流应优先选用声速喷流。

Effect of opposing jet on drag reduction characteristics of double-cone missile shape

The opposing jet, an active flow control technology capable of drag and heat reduction, can be used in the design of hypersonic vehicles. The drag reduction characteristics of the opposing jet for the ball head, single cone, and double cone in typical missile shapes are numerically studied using CFD method, with the opposing jet generator fixedly connected to the missile body. The effects of the Mach number, jet pressure ratio and other parameters on the drag reduction effect of different objects are comparatively analyzed. The results show the existence of two modes of long and short penetration in the opposing jet flow field. The ball head has the best drag reduction effect with a small pressure ratio in the long penetration mode, while the single cone and the double-cone have better effects in the short penetration mode with large pressure ratios. An optimal pressure ratio exists to induce the best drag reduction effect. If the pressure ratio is too large, the drag reduction effect becomes worse such that the drag coefficient even increases instead of decreasing. The drag reduction effect of opposing jet is sensitive to control body selection. If the drag reduction characteristics of the opposing jet on the head were directly extended to the whole aircraft, the evaluation result would be too optimistic. Comprehensively considering the best drag reduction effect, the best pressure ratio, the mass flow rate, the required gas cylinder volume, and other influencing factors, we propose that the opposing jet should preferentially use sonic jet flow in engineering applications.