不同来流马赫数下激光能量形成高超声速进气道虚拟唇口的特性

Characteristics of virtual cowl formed by laser energy injected in hypersonic inlet under different inflow mach numbers

用基于三维非定常可压缩雷诺平均Navier-Stokes方程的有限体积法计算了马赫数低于设计值6时一种高超声速进气道的性能参数,发现其性能存在明显下降。为提升进气道性能,将功率为15kW的激光能量注入进气道固体唇口前的流场中,形成虚拟唇口,马赫数为4.5,5.0和5.5时,计算得到来流捕获率分别提高了34%,20.6%和15.6%。绘制了不同马赫数下来流捕获率达到峰值时的流场压强云图,说明了虚拟唇口的特性及形成机制。结果表明:来流马赫数越低,来流捕获率越小,但相对于无能量注入时的来流捕获率的提升程度越明显;在不同来流马赫数条件下,通过改变激光能量引致的激波结构和位置,可达到最优状态,即激波与进气道前缘斜激波相交后的透射波打在进气道肩部位置的状态。

The performance parameters of a hypersonic inlet（the designed mach number is 6） are computed using finite vol ume method with three dimensional unsteady compressible N S equations, and the performance is found descending clearly. In or der to improve the inlet performance, laser energy whose power is 15 kW is injected into the flow field in front of the solid cowl of inlet, and then the virtual cowl is formed. The inflow mass capture ratio increases by 34%, 20.6% and 15.6% when the inflow mach number is 4.5, 5 and 5.5 respectively. Pressure contours of the inlet at peak value of inflow mass capture ratio under differ ent mach numbers are illustrated. Characteristics and forming mechanism of the virtual cowl are explained. The results indicate that the smaller the inflow mach number is, the lower the inflow mass capture ratio is, but relative to that without laser energy being injected, the inflow mass capture advancing level is more obvious. Under different inflow mach numbers, the optimum can be achieved through changing the configuration and position of laser induced shock wave. The optimum is the state that transmis sion wave formed by laser induced shock intersecting with the oblique shock in the leading edge of inflow injects on the inlet shoul der.