顶部缝隙影响跨声速压气机转子稳定性的机理研究

Mechanism of Top Slot Affecting Stability of Transonic Compressor Rotor

关键词:  压气机  转子  泄漏流  激波  失速  气动性能

Key words:  Compressor  Rotor  Leakage flow  Shock wave  Stall  Aerodynamic performance

摘要:

跨声速转子叶尖泄漏涡与通道激波的相互作用对压气机在小流量工况下的稳定性具有重要影响，泄漏涡破碎是导致压气机失速的直接原因。为了削弱通道激波与叶顶泄漏流的相互作用，设计了一种进气口与出气口均在通道激波之前的顶部缝隙结构，数值研究了其进、出气口所在轴向位置对压气机气动性能的影响规律。结果表明，压气机的稳定工作流量范围最大拓宽了74.9%，在综合表现最佳的缝隙进、出口位置下拓宽了69.1%；在原型压气机流量范围内缝隙转子与原型转子气动特性基本一致，最高效率相对下降小于0.4%，总压比相对下降小于0.5%。对顶部缝隙改善压气机工作稳定性的深入分析发现，顶部开缝后压气机叶顶间隙的泄漏强度得到重新分布，中部弦长范围内的泄漏得到有效控制，压气机顶部通道内的激波强度得到削弱，进而引起泄漏涡穿过激波后形成的低动量区尺度减小。而究其本质原因，是转子开缝后尖部区域叶型负荷得到了重新组织。

Abstract:

The interaction between tip leakage vortex and channel shock wave has a significant impact on the stability of transonic compressor rotor under small mass flow conditions， and the breakdown of leakage vortex is the directly cause of compressor stall. In order to weaken the interaction between channel shock wave and tip leakage flow， a top slot structure with both inlet and outlet in front of channel shock wave was designed. The influence of axial position of top slot inlet and outlet on the aerodynamic performance of compressor was numerically studied. Results show that， with the slot， the stable working mass flow range of the compressor is widened by 74.9% at the maximum， and it is widened by 69.1% at the inlet and outlet positions of the best overall performance. At the same time， within the flow range of the prototype compressor， the aerodynamic characteristics of the slotted rotor and the prototype rotor are basically the same. The relative decrease of the maximum efficiency is less than 0.4% and the relative decrease of the total pressure ratio is less than 0.5%. The in-depth analysis of the top slot to improve the working stability of the compressor found that， with the top slot， the leakage intensity through the compressor blade tip clearance is redistributed， the leakage within the middle chord range is effectively controlled， and the shock wave intensity in the compressor channel near to the shroud is weakened， which in turn decreases the scale of the low-momentum region formed after the leakage vortex passes through the shock wave. However， the essential reason is that the blade loading in the tip area is reorganized with the top slot.