多级高负荷轴流压气机喘振特征分析

Surge behavior of a multi-stage highly loaded axial compressor

关键词:  轴流压气机  喘振  旋转失速  流动失稳  试验

Key words:  Axial compressor  Surge  Rotating stall  Flow instability  Experiment

摘要:

针对某十级高负荷轴流压气机，在第一级和第九级机匣壁面上布置动态压力传感器，通过减小排气阀门开度的方式进行逼喘试验，获得了不同转速下多级高负荷轴流压气机喘振时的动态压力数据，采用时序、FFT结合滤波分析方法研究了多级高负荷轴流压气机在不同转速下的喘振特征。结果表明：在高转速下，该压气机喘振模式为深度喘振，喘振引起的高温气体倒流使得入口总温瞬时升高约80 K，喘振由出口级的模态波扰动导致流动堵塞引起，模态波频率约为16%~20%转频，喘振时入口级工作于压升特性增长阶段而出口级工作于压升特性顶点位置；在低转速下，该压气机喘振模式为经典喘振，未发生气体倒流，喘振主要由尖脉冲扰动引起，压气机前后级工作于特性线的增长阶段。高转速喘振恢复阶段，伴随着明显的旋转失速和喘振特征，而低转速下在喘振的第一个周期内以喘振特征为主，之后喘振频率的幅值波动迅速减小，旋转失速频率的幅值逐渐增加并占主导。高转速下喘振恢复时间约4.1 s，而低转速下喘振恢复的时间为0.56 s。

Abstract:

For a ten-stage highly-loaded axial compressor， the dynamic pressure sensor were arranged on the surface of the first and ninth stage cases. The dynamic pressure data of the multi-stage highly-loaded axial compressor at different speeds was obtained through the surge experiment caused by reducing the opening of exhaust valve. The surge characteristics of the multi-stage highly-loaded axial compressor at different speeds were studied by the time series， FFT and filtering methods. The results show that at high speed， the compressor surge was deep. The inlet total temperature instantaneously increased about 80 K， which is caused by the backflow of hot air. Surge was mainly prompted by the flow blockage evolved by the modal disturbance of the rear stage. The frequency of modal is about 16% to 20% rotating frequency. During surge， the front stage works on the increasing branch of the compressor characteristic map and the rear stage works at the peak point of the compressor characteristic. At low speed， the compressor surge was classical without backflow of hot air， which process from spike disturbance. The front and rear stages of the compressor work on the increasing branch of the compressor characteristic. The surge recovery process was accompanied by the characteristics of rotating stall and surge in high speed. While in low speed， in the first period of surge， the surge characteristics are dominant， and then the amplitude fluctuation signal decreases rapidly. The stall frequency signal amplitude increases gradually and comes into prominence. The surge recovery time at high speed is about 4.1 s， while which is 0.56 s at the low speed.