一种进气道内激波/边界层干扰控制的新方法及其流动机理

针对高超声速进气道内经常存在的激波/边界层干扰现象,提出了一种基于可变形壁面鼓包的激波/边界层干扰控制概念,并对相关流动机理及参数影响规律进行了细致研究,结果表明:可变形鼓包通过其迎风侧的预增压作用,外凸段膨胀波束对反射激波的削弱作用,以及膨胀波束对边界层气流的加速作用来对激波/边界层干扰现象进行抑制;当激波入射点位于鼓包背风侧膨胀波区时,鼓包对边界层分离的抑制效果明显,并且适当增加鼓包高度可增加其抑制效果;对于鼓包迎风侧型线,在设计时应尽量采用较小的内凹段曲率,同时在外凸段上其最大曲率点应尽量与激波入射点靠拢,而对于背风侧型线的设计则应选择相近的外凸段和内凹段曲率较为合适。

A New Method and Its Flow Mechanism for Control of Shock/Boundary Layer Interaction in Hypersonic Inlet

Shock/boundary layer interaction often exists in hypersonic inlets.Thus,a new method based on deformable bump to control boundary layer separation is brought forward in this paper.Computational results indicate that the method is effective to control shock/boundary-layer interaction by means of the precompression effect at windward side of the bump,the weakening effect on reflected shock and the accelerating effect on the boundary layer flow of expansion wave.When the shock impingement position is near the expansion wave-generated area at leeward side of the bump,the size of the separation bubble is greatly reduced.Furthermore,the control effect can be enhanced by increasing the bump height within the proper range.However,excessive height of the bump can strengthen the induced compression and expansion waves thus bringing negative effect on the inlet.In addition,the curvature of concave region at the bump windward side should be small and the largest curvature point in the expansion wave-generated area should be close to the shock impingement position while the curvatures of concave and prominent regions at the bump leeward side should be approximately equal.