不同波系配置的鼓包压缩面流动特性实验研究

Experimental Research on Flow Characteristics of Bumps with Different Compression Configurations

为探究波系配置对鼓包压缩面流动特性的影响,通过纹影和基于纳米粒子示踪的平面激光散射系统(NPLS)观测以及压力测量等实验手段,研究了三种不同波系配置的鼓包压缩面诱导的复杂流动,获得了鼓包压缩面上的压力分布、边界层分布特性以及鼓包压缩面上的精细流场结构。结果表明:三种不同波系配置的鼓包压缩面均具有边界层排移能力,在鼓包对称面上,沿流向边界层不断降低,边界层不断向两侧排移,在鼓包侧面形成堆积。尽管如此,压缩过程的不同,边界层的排移过程存在一定差异,对于单锥鼓包,其最先将低能边界层排移掉,而双锥和等熵锥鼓包略为迟缓,但三种鼓包末端的边界层厚度大体一致。此外,三种鼓包压缩面对称面上前中部压力梯度存在较大差异,但鼓包末端具有相同的压力分布。因此,在保证总偏转角一致的情况下,具体选用哪种鼓包配波方式对于边界层排移、增压能力而言没有显著的差异。

To investigate the effects of shock wave system configuration on the flow characteristics of the bump compression surface,the flow characteristics of three bumps with different compression configurations are experimentally investigated.Schlieren photography,nano particle-tracer based planar laser scattering(NPLS)methods as well as pressure measurement are employed during the test.The pressure distribution,boundary layer features and the fine flow structures on the bump are obtained.The results show that all the three bumps have the ability to remove the boundary layer,the boundary layer thickness on the center plane of the bump gets thinner along streamwise direction,the boundary layer is diverted to the two sides of the bump and accumulates there.However,the diverting process with different compression configurations is different.For the single bump,it first diverts the low energy boundary layer,whereas the process is delayed on the bipyramid bump and isentropic bump.However,the boundary layer thickness at the end of the bump is almost the same.In addition,though the pressure gradient on the fore and middle part of the symmetry plane of the three bumps is quite different,the pressure at the end of the bump is on the same level.Therefore,if the total deflection angle of the bump holds constant,the compression configuration has less impact on the diverting ability of boundary layer and compression capability.