吸雨对轴流压气机压缩失稳机制的影响研究

Effects of Rain Ingestion on Compression Stall Mechanism of Axial Flow Compressor

关键词:  航空发动机  压气机  吸雨  失稳机制  流动分离

Key words:  Aero engine  Compressor  Rain ingestion  Stall mechanism  Flow separation

摘要:

针对航空发动机吸雨对压气机运行稳定性的负面影响，以单级轴流压气机为研究对象，基于欧拉-拉格朗日两相流方法研究了吸雨前后压气机失稳演化过程及差异性，揭示了吸雨对压气机失稳机制的影响。结果表明，对于本文所选压气机，其在干、湿工况下的失稳均是由转子附面层分离产生的径向窜流堆积在叶顶，并形成正反馈不断加速叶顶区域低速区的发展和融合，最终在动静叶通道形成大范围堵塞区而导致的。吸雨后动静叶吸力面侧流动分离现象加剧，压气机通道内会过早地出现大尺度分离涡和回流涡，促使压气机失稳过程以更快的速度发展，在1.5T，2T，3T和4T时刻（T为转子转动周期），动叶出口阻塞程度较干工况加深了86.25%，98.27%，11.22%和3.07%，而静叶出口阻塞程度较干工况加深了99.74%，80.79%，23.06%和0.27%。通过比较干湿工况失稳过程的差异性可知，吸雨不会从根本上改变压气机的压缩失稳机制，仅影响其失稳过程发展速度。

Abstract:

Aiming at the negative effect of rain ingestion in aero-engine on compressor operation stability， a single-stage axial flow compressor was taken as the research object， the Euler-Lagrangian two-phase flow method was used to investigate the compressor stall evolution process and their differences before and after rain ingestion， and the effects of rain ingestion on compressor stall mechanism were revealed. Results show that， for the compressor in this paper， the reasons for its stall under dry and wet conditions are as follows： the radial flow generated by the separation of rotor boundary layer accumulates on rotor tip， a positive feedback is formed to continuously accelerate the development and fusion of the low-speed region in blade tip， and finally a large-scale blockage region forms in the rotor blade and stator vane passage. After rain ingestion， the flow separation phenomena on the suction surface of rotor blade and stator vane are aggravated， and the large-scale separation and return vortices will appear prematurely in the compressor passage， which promotes the stall process of compressor to develop at a faster speed. At the time of 1.5T， 2T， 3T and 4T （T is the rotor rotation period）， the blockage degree of rotor blade and stator vane outlet increased by 86.25%， 98.27%， 11.22%， 3.07%， and 99.74%， 80.79%， 23.06%， 0.27% respectively compared with the dry condition. By comparing the difference of stall process between dry and wet conditions， it can be concluded that rain ingestion will not fundamentally change the compression stall mechanism of the compressor， but only affect the development speed of its stall process.