可控转速机匣转动方向对高负荷压气机级稳定性的影响

Effects of Controllable Speed Casing Rotation Direction on Stability of High Load Compressor Stage

关键词:  压气机  可控转速机匣  叶顶泄漏  稳定工作裕度  数值研究

Key words:  Compressor  Controllable speed casing  Tip leakage  Stable operating margin  Numerical research

摘要:

可控转速机匣是一种新型的机匣处理方法，将机匣设计为可转动环段与固定环段两个部分，可转动环段会对转子叶顶区域的气流施加周向附加作用力并改变叶顶区域的周向压力梯度，进而对压气机级的稳定工作裕度产生影响。针对可转动环段在不同转动方向下的数值研究结果表明：当可控转速机匣与转子转动方向相反时，叶顶区域周向压力梯度的增大，加剧了转子的叶顶泄漏程度，泄漏涡及其破碎后气流的流动轨迹向相邻叶片压力面偏移，导致静子进口冲角逐渐减小至负冲角，压气机级失速提前。而当可控转速机匣与转子转动方向相同时，叶顶区域的周向压力梯度减少，降低了叶顶泄漏流动的原始驱动力，同时转子叶顶区域的泄漏涡及破碎后气流的流动轨迹远离相邻叶片压力面，通流能力增强。但静子进口冲角的增加使得静子吸力面分离加剧，限制了其扩稳能力的进一步提高，压气机级的稳定工作裕度最大可提升45.44%。

Abstract:

Controllable speed casing is a new type of casing treatment method， which transforms the casing into two parts： rotatable ring and stationary ring. The rotatable ring will exert circumferential additional force on the airflow in the tip area of rotor blade and change the circumferential pressure gradient of blade tip area， which will have an impact on the stable operating margin of the compressor stage. The numerical results of the rotatable ring in different rotation directions show that when the rotation direction of controllable speed casing is opposite to that of the rotor， the circumferential pressure gradient in the tip area of blade increases， which intensifies the tip leakage degree of rotor. Meanwhile， the flow path of the leakage vortex and its broken fluid deviates to the pressure surface of the adjacent blades， resulting the stator inlet attack angle gradually decreasing to negative， and the compressor stage stall in advance. When the rotation direction of controllable speed casing is the same as that of the rotor， the circumferential pressure gradient in the tip area of blade decreases， which reduces the original driving force of the tip leakage flow. At the same time， the flow path of the leakage vortex and the broken fluid in the rotor tip area is far away from the pressure surface of the adjacent blades， and the flow capacity is enhanced. However， the increase of stator inlet attack angle intensifies the separation of stator suction surface， which limits the further improvement of its stability expansion capacity. The maximum stable operating margin of compressor stage can be increased by 45.44%.