可控转速机匣转速对跨声速压气机转子流动稳定性的影响

Effects of Speed of Controllable Speed Casing on Flow Stability for Transonic Compressor Rotor

可控转速机匣是一种通过控制机匣结构中的可转动环段旋转对叶顶间隙流场施加作用的机匣处理方式,可以一定程度上改善机匣处理中存在的效率下降以及难以完全适应变工况条件的难题。针对起始于动叶叶顶前缘、宽度为叶顶轴向弦长的可转动环段,对设计转速下的跨声速压气机转子流动稳定性的数值研究结果显示,随着可转动环段转速的增加,转子的稳定工作裕度逐渐提高,扩稳效果先弱后强,当可转动环段转速为转子设计转速时,在保证最高效率基本不变的情况下,稳定工作裕度提高了52.56%。可控转速机匣在较低转速时主要是通过减小叶顶的堵塞区实现扩稳,而高转速时则主要是通过抑制叶顶泄漏涡的破碎推迟失稳,不同转速下稳定工作裕度均有不同程度提升。

Controllable speed casing is a kind of casing treatment method by controlling the rotation of the rotatable ring in casing structure to exert an effect on the tip clearance flow field.It can improve the problem of efficiency reduction and poor adaptability under off-design conditions in casing treatment to a certain extent.A numerical study was carried out on the flow stability of a rotatable ring which started from tip leading edge and had a width of the whole axial chord length of the blade tip at the design speed of a transonic compressor rotor.The results show that the increase of rotatable ring speed can continuously raise the stable operating margin of the rotor.The effect of stability expansion is poor first and then significant.When rotatable ring rotates at the design rotor speed,the stable operating margin is improved by 52.56%under the condition that the maximum efficiency is almost constant.It is found that,at low speed,the stability expansion is mainly achieved by reducing the tip blockage area while,at high speed,the instability is delayed by controlling the breakdown of tip leakage vortex.The stable operating margin is improved to different degrees at various speeds.