发动机喷管对火箭气动静稳定及控制特性影响研究

发动机喷管外露于火箭尾部是常见情形,但在火箭气动设计过程中却经常不予考虑。利用数值计算方法,研究喷管外露部分对火箭气动静稳定及控制特性的影响。计算结果表明:在超声速Ma=2~12、攻角30°范围内,外露喷管对火箭气动静稳定性有1%~2%的增加,且气动控制效率明显,喷管±3°摆角产生的气动控制力矩约为头部空气舵±20°摆角的1~2倍。因此,对于确实存在喷管外露的火箭,在气动特性设计过程中需充分考虑喷管对静稳定性的影响,甚至可以考虑将喷管作为气动控制面,用于火箭无动力滑行段的姿态控制。

Study on the Influence of the Nozzle on Aero-static Stability and Control Characteristics of the Rocket

Jet nozzle is usually exposed at the tail of the rocket. However, its influence on rocket aerodynamics has not yet been considered during the aerodynamic design of rocket. In this paper, the influence of the exposed nozzle and the dynamic on the aerodynamic stability and control characteristics of the rocket is studied using numerical computation, based on the solution of Euler equations for compressible flow. It is shown that for Mach numbers ranging from 2 to 12 and angle of attack ranging from 0° to 30°, the aero static stability of the rocket is improved about 1%~2% due to the existence of the exposed nozzle, and the dynamic control efficiency of the jet is equal or even double of the canard, which means non negligible aerodynamic control efficiency and which should be considered during the aerodynamic design process. The result also suggests that the exposed surface of the nozzle can be used as an aerodynamic control surface for rocket attitude control.