高超声速弹性飞行器后体/外喷管建模与分析

考虑到全尺寸吸气式高超声速飞行器的机体弹性弯曲振动极易被激发,提出了一种包含机体弹性弯曲影响的外喷管建模和分析方法.该方法首先用虚拟激波膨胀波法确定剪切层的位置,然后用影响系数法求解外喷管中的准一维流,并用活塞理论修正后体下表面的压力.用该方法对一个全尺寸吸气式高超声速飞行器的后体/外喷管进行了仿真分析,结果表明,仅考虑低频、小振幅的后体弹性弯曲运动对外喷管性能的影响并不显著.

Modeling and analyzing the afterbody external nozzle of a flexible hypersonic flight vehicle

To investigate the influence of airframe bending vibration on external nozzle for full-scale airbreathing hypersonic flight vehicles(AHFV),a new method is developed for modeling and analyzing the external nozzle of AHFVs under the airframe vibration.The first step of this method is to determine the shear layer position using virtual shock-expansion wave method.After that,the flow in the external nozzle modeled as quasi-one dimensional flow is solved using the influence coefficients method,and the pressure on the lower surface of afterbody is modified by the piston theory.To analyze the influence of airframe bending vibration on external nozzle performance,a simulation is carried out using the new developed method.The results show that the change of an external nozzle performance is not so remarkable,as long as the airframe bending motion is in the range of low frequency and small amplitude.