Effects of Coriolis force on Complex Turbulent Flow Field in Compressor Rotor

通过对斜流和轴流转子叶尖泄漏流的实验和计算结果的比较，研究了科里奥利力即流面倾角对压气机转子内湍流流场的影响。结果表明，在斜流转子中，叶尖泄漏涡的“破裂”发生在通道后部。“涡破裂”使叶尖泄漏涡的性质发生了显著变化：涡核消失，涡大幅度膨胀，涡内出现相对速度较低的区域。这些变化导致了叶尖泄漏流的以下特性与轴流转子中的特性有很大的不同：1由于涡核的消失和涡量的集中，在斜流转子下游没有观察到叶尖泄漏涡的卷起; 2涡核的消失导致了压力梯度的损失; 3在斜流转子中，叶尖泄漏涡的涡核的消失和涡量的集中导致了叶尖泄漏涡的卷起。 关于我们 t由集中的涡量引起，从而使压力槽从转子后部的机匣壁消失。3涡核的消失似乎导致斜流转子的噪声级比轴流转子低得多。4由于低相对速度区与反向流动引起的泄漏涡的大的扩展，由于泄漏流导致的低能量流体从壳体扩散到大约半个跨度。因此，与轴流式转子相比，出现了更大的机匣壁边界层r的增长。5在斜流式转子的下游，机匣壁边界层r中的绝对切向速度显著增加，因为低相对速度区域中的流体具有较大的绝对速度切向分量，与尾流相似。6机匣壁边界层的大量增长导致叶尖间隙效率的大幅降低：效率降低率约为轴流式转子效率降低率的三倍。少

Effects of Coriolis force, namely, stream surface inclination on turbulent flow fields in compressor rotors have been investigated by comparing experimental and computational results of the tip leakage flow in a diagonal flow rotor with those in an axial flow rotor. It was found out that "breakdown" of the tip leakage vortex occurs at the aft part of the passage in the diagonal flow rotor. The "vortex breakdown" causes significant changes in the nature of the tip leakage vortex : disappearance of the vortex core, large expansion of the vortex, and appearance of low relative velocity region in the vortex. These changes result in the following behavior of the tip leakage flow substantially different from that in the axial flow rotor :1 Because of the disappearance of the vortex core with the concentrated vorticity, the rolling-up of the tip leakage vortex is not observed downstream of the diagonal flow rotor.2 The disappearance of the vortex core leads to the loss of the pressure gradien … More t induced by the concentrated vorticity, so that the pressure trough vanishes from the casing wall at the aft part of the rotor passage.3 The disappearance of the vortex core seems to results in the fact that the noise level of the diagonal flow rotor is considerably low, compared with the axial one.4 Because of the large expansion of the leakage vortex caused by the low relative velocity region with reverse flow, the low-energy fluid due to the leakage flow is spread out from the casing to about a half of span. As a result, much larger growth of the casing wall boundary layr occurs, compared with the axial flow rotor.5 Downstream of the diagonal flow rotor, the absolute tangential velocity increases considerably in the casing wall boundary layr, because the fluid in the low relative velocity region has a large tangential component of the absolute velocity, like the wake.6 The large growth of the casing wall boundary layr causes large reduction of efficiency with the tip clearance : the reducing rate of efficiency is about three times as large as that of the axial flow rotor. Less