结合次流控制的壁面鼓包对激波/边界层干扰的控制方法研究

Control of Incident Shock/Boundary Layer Interactionby a Bump Com bined with Secondary Flow Control

关键词:  超声速/高超声速进气道  激波/边界层干扰  次流控制  壁面鼓包

Key words:  Hypersonic/Supersonic inlet  Shock wave/boundary layer interaction  Secondary flow control  Bump

摘要:

为了对超声速、高超声速进气道内激波/边界层干扰现象进行有效控制，提出了一种结合次流控制的壁面鼓包控制激波/边界层干扰的方法，并对相关流动机理及参数影响规律进行了研究。结果表明:将次流控制与壁面鼓包相结合，利用鼓包前后存在的压差，将激波入射导致的分离区内的低能流引入鼓包下方的引流腔，在减少分离包内低能流的同时，促进分离包的再附着，有效地缩小了激波入射导致的边界层分离，改善了通道内的流动状态，降低了流动损失。同时，将引流腔中的气流从鼓包下游的吹气缝中喷出，对当地边界层起到了一定的能量补充效果，并避免了捕获流量的损失。相较于现有的壁面鼓包控制方案，结合次流控制后可以在较大激波入射范围内实现对激波/边界层干扰的控制，通道出口的总压恢复系数的最大改善幅度可以达到5%以上。此外，将引气缝布置在鼓包迎风面，并且当单条引气缝的宽度和间距固定不变，而引气缝总宽度和单条引气缝宽度之比不大于3时，可以获得较好的控制效果。

Abstract:

To control the shock wave/boundary layer interaction in a supersonic/hypersonic inlet， a new control method by a bump combined with secondary flow control is put forward. The flow mechanism and effects of parameters are investigated by computational method. Results show that the separation bubble induced by the shock wave/boundary layer interaction can be reduced effectively by the pressure differential which drives the low-momentum flow of the separation bubble induced by the incident shock wave/boundary layer interaction to the cavity and then facilitate the attachment of the boundary layer. The flow condition in the inlet is improved and the loss of flow is decreased. Meanwhile， the flow in the cavity injects downstream of the bump to reenergize the boundary layer and avoid the loss of the mass flow. As compared with the only bump control case， the method combined with the secondary flow control can realize the control of the shock wave/boundary layer in a wider range. The total pressure recovery ratio can be improved more than 5%. In addition， when the bleed slots are located on the windward side of the bump and the ratio of the overall slots width and single slot width is not more than 3 with fixed width of single slot and gap between the slots， the better improvement can be achieved.