基于记忆合金的可变形涡流发生器控制唇罩激波/边界层干扰研究

Control of Cowl Shock/Boundary Layer Interaction by Variable Microramps Based on Shape Memory Alloy

关键词:  超声速进气道  形状记忆合金  涡流发生器  激波/边界层干扰

Key words:  Supersonic inlet  Shape memory alloy  Microramp  Shock/boundary layer interaction

摘要:

为了对超声速进气道口部唇罩激波/边界层干扰进行有效的控制，提出了一种基于记忆合金的可变形大长高比涡流发生器，并通过风洞实验验证了该方案的可行性和控制效果。结果表明:在记忆合金的驱动下，大长高比的涡流发生器可以实现自主变形，并且其变形量与设计值吻合较好，在没有外界气流干扰条件下涡流发生器尾缘变形高度与设计值的相对误差为3%，在风洞吹风条件下，变形完成的涡流发生器尾缘高度与设计值的误差为5.4%。在大长高比的可变形涡流发生器控制下，进气道入口因唇罩激波/边界层干扰导致的边界层分离包被有效控制，其被分割破碎为多个沿展向分布的小尺度分离包。同时，涡流发生器尾部诱导的旋涡增强了分离包内的低能流与主流的掺混，促使分离气流迅速再附。当进气道在马赫3.8工作时，进气道出口的总压恢复系数从无控制时的0.557提升至0.603。

Abstract:

In order to control the cowl shock/boundary layer interaction in a supersonic inlet， a set of variable microramps with large length height ratio based on the shape memory alloy is brought forward. The feasibility and control effect of the variable microramp are verified by the wind tunnel test. The results show that the microramps with large length height ratio can transform their profiles automatically driven by the shape memory alloy. The deformation value of the microramp fits the design one well. The error between the height of the microramp tail and the design one is 3% at the air flow static condition while the value is 5.4% at the wind tunnel test. Under the control of the variable microramps with large length height ratio， the large separation bubble induced by the cowl shock/boundary layer interaction is effectively controlled which is broken into series small ones in the spanwise direction. Meanwhile， the microramp-induced vortex pair strengthens the mixing effect between the low-momentum flow in the separation bubbles and the main flow. As a result， the reattachment of the separated flow is enhanced. When the inlet operates at Mach 3.8， the mass weighted average total pressure recovery on the inlet exit plane is 0.603 while the value in the uncontrolled condition is only 0.557.