针对高负荷扩压叶栅,实验测试了叶顶间隙尺寸变化对叶栅气动特性的影响规律。结果表明,在马赫数和冲角固定时,随着间隙尺寸的增加,由于间隙泄漏流动与横向压力梯度的相互作用,近端壁附面层低能流体的聚集和发展受到影响,叶栅损失呈现先减小后增大的趋势,存在最佳间隙尺寸使得损失最小。本文研究的高负荷扩压叶栅中实验测的最佳间隙为1%相对叶高。
In this paper,an experimental investigation was conducted to validate the effect of magnitude of tip clearance on the aerodynamic performance for a highly-loaded compressor cascade.The experimental results show that,under the specific Mach number and incidence angle,the loss of cascade exhibits the tendency of increasing after an initial decreasing with the increase of tip clearance magnitude.The reason for this phenomenon is considered to have relationship with the accumulation and expansion of low-energy fluid in boundary layer,affecting by the interaction of tip leakage flow and cross pressure gradient.The best magnitude of tip clearance which represents the minimal loss was validated as 1%of relative span for a highly-loaded compressor cascade experimentally.