微射流作用下的超声速流场控制机理研究

以24°压缩拐角为流场模型,针对不同注入总压微射流作用下来流马赫数为2.9的超声速压缩拐角流场进行了数值研究,喷射方向与来流垂直。研究表明,微射流阻挡作用下,其下游速度被减小,而减弱了分离激波强度。此外,微射流与来流耦合会产生正反向旋转流向涡对,在其下洗作用下,高能量流体被带入到边界层底部近壁面处,使此处低能流体被激活,进而增强了边界层的抗逆压能力不易发生分离,且这种激活能力会随注入总压的增加而增强。权衡控制效果和注入能量认为,注入压比(注入总压/来流总压)为0.60的微射流为最优方案,在其作用下,拐角区分离面积被减小了近70%、激波交汇点与壁面的距离被降低了近37%、分离激波强度被削弱近12%。

Study of supersonic flow field control mechanism with micro jet

An numerical investigation was conducted to study the influence of micro jet with different total injection pressure on the supersonic flow field (Ma =2.9) for a 24° compression corner.The ejecting direction is vertical to incoming flow.The results show that the velocity of the fluid downstream the micro jet decreases due to the obstruction of micro jet,and then the decrease can weaken the separation shock intensity.In addition,high-energy fluid is brought into the bottom of the boundary layer near the wall to activate it to be fuller with the downwash effect of counter-rotating vortex pair generated by coupling of micro jet and mainstream,which leads to the stronger ability of resisting adverse pressure and the separation of the boundary layer.The activation ability enhances with the increase of total injection pressure.Weighing the control result and injection power,we think the scheme is the best when the total injection pressure ratio (total injection pressure/total freestream pressure) is 0.60.The boundary layer separation area is restrained by nearly 70％,the distance of the intersection point of λ shock wave and the wall is reduced by almost 37％,and the separation shock intensity is weakened by nearly 12％ under this scheme.