轴向倾斜缝机匣处理影响压气机性能的机理

Investigation of the flow mechanisms of affecting compressor performance with axial skewed slots casing treatment

为了揭示缝式机匣处理影响轴流压气机性能的流动机理,对带轴向倾斜缝机匣处理的轴流压气机转子进行全三维非定常数值模拟,试验与数值结果均表明机匣处理在有效地扩大压气机稳定工作范围的同时,也使压气机等熵效率减少。通过详细地分析压气机内部流场,揭示了该机匣处理对该压气机转子性能及流场影响的机理,即倾斜缝内的回流具有抽吸或吹除端部低能流体的能力,在倾斜缝中形成的喷射流的作用下,叶顶通道内的低速气团得到了有利的激励,从而推迟转子的失速。但也使转子叶顶加功量下降,同时缝内的回流及其与叶顶主流的相互作用带来大的流动损失,最终降低压气机转子等熵效率。

Numerical investigation was performed on an axial-flow compressor rotor with 3D unsteady numerical method to explore the mechanism of slots casing treatment affecting the performance and flow field of axial compressor.The experimental and numerical results showed that the steady operating range of compressor rotor was extended and the compressor efficiency was reduced with casing treatment.The flow mechanisms of affecting compressor performance of the numerical simulation obtained by analyzing the flow-field in compressor with casing treatment,indicating that back flow formed in the slots has the ability to pump and blow the low energy liquids near end wall.Ejected flow formed in the slots inspirited the low velocity air mass of blade tip passage,which can suspend the rotor stall.The work of blade forcing on air in the blade tip was reduced with casing treatment.Back flow and the interaction between back flow and tip mainstream made serious flow loss.Thus,compressor rotor isentropic efficiency was reduced.