底部边界排气的减阻效应

The Effect of Base Bleed on Base Drag

本文利用底部外侧周向多孔排气的方法研究具有圆柱后体的超声速旋成体底部流动特性及减阻问题。研究工作在超声速风洞进行，来流马赫数从１．５３到３．０１，单位雷诺数为２．２×ｌ０￣７／ｍ到２．８×ｌ０￣７／ｍ。文中讨论了排气流量、气体介质对尾流结构与波系分布的影响，对底部增压减阻的效果，测量了底压分布，拍摄了尾流场纹影。实验结果分析表明，采用此种方法能够有效地干扰尾流边界，控制尾流特性，其中氦气在最佳排气流量情况下，收到减少底阻约２０％左右的良好效果。

An experimental study of base flow features and drag reduction on the body of revolution has been carried out at supersonic speed corresponding to the freestream Mach number of 1.53～3.01 and the unit Reynolds number of2.2× l0￣7/m～2.8×l0￣7/m. The mass bleed around the boundary of model base was made in the test.The base pressure distributions have been measured and the wake flowfields have been visualized by schlieren photographes.The effects of bleed mass rate andgas medium on the wake structure and the shock wave system have been discussed in present paper.The results show that the wake flow-field shear layer and base drag are influenced by mass bleed,especially for helium bleeded at optimum bleed mass rate,the base drag of model can be reduced as many as 20 percent.