尾流型进口速度分布对亚音扩压器性能的影响

EFFECT OF WAKE-TYPE INLET VELOCITY PROFILES ON PERFORMANCE OF SUBSONIC DIFFUSER

试验用的二元亚音速扩压器的dMa/dx=常数,进口展弦比为1.33,在进口截面前180mm的等直段中心线处,横放一根垂直于流动方向并平行于扩压壁的杆(有四种截面),造成尾流型的不均匀进口速度分布,增加了核心流的紊流度,以便研究某对扩压器内流动和性能的影响。所用的试验设备和模型与文献[1]相同。此外,还用美国TSI风速仪接单热丝探头测进口截面速度紊流度分布和用小型高频响动态压力传感器(XCQ-080-25)测量进口和出口截面总压紊流度分布。

The paper discusses the experimental investigation on subsonic dif fuser. When in the front of the subsonic two-dimensional diffuser an elliptic bar is placed perpendicular to the flow stream and parallel to the diverging wall of the diffuser,the wake-type inlet velocity profile is created and the core-stream turbulence level at the entrance of the diffuser is increased, which results in flatter velocity profile implying an increase in momentum transport across the boundary layer.The value of the boundary layer shape factor is therefore decreased. Consequently,the flow separation is delayed and the separation range is reduced. As a result,the static and the total pressure recovery coefficients of the diffuser rise by 30% and by 3% respectively when the maximum Mach number of the diffuser inlet reaches 0.7.