跨声速压气机不同转速下失稳形式的实验研究

Study on Instability Evolution at Different Rotation Speed in a Transonic Compressor

关键词:  局部喘振  不同转速  跨声速压气机  失稳过程

Key words:  Partial surge  Different rotation speed  Transonic axial compressor  Instability evolution

摘要:

为了研究压气机在不同工作转速下失稳形式的不同，进而研究不同失稳先兆的发生机理，针对一台跨声速压气机在不同转速下的失稳过程进行了实验研究。分别在转子叶尖机匣、静子出口布置了高频响动态压力探针对压气机失稳过程进行实时监测和实验数据采集，采用FFT(Fast Fourier Transform)、WFT(Window Fourier Transform)、滤波等数据处理方法对实验数据进行频域和时域分析，得到了压气机在不同转速下流动失稳的变化规律。实验结果表明:随着工作转速的升高，该压气机的失稳过程也会发生改变，在低转速(亚声速)下表现为经典Spike引起的旋转失速，如65%设计转速；而在高转速(跨声速)下则表现为一种新型的失稳过程，由一种发生在近轮毂区域的低频、轴对称、大幅值的扰动诱导了失稳，如88%设计转速。这种失稳先兆被称为局部喘振。两种失稳模态之间的相互转换存在一个临界转速(约为78%设计转速)，在临界转速下，局部喘振几乎与旋转失速同时发生。

Abstract:

In order to study the physical mechanisms of the occurrences of different instability precursors，it is necessary to figure out instability behaviors of compressor at different rotation speed. Experimental investigations are carried out to study the instability evolutions at different rotation speed in a transonic compressor. High response transducers are mounted at both rotor tip region and stator outlet hub region to measure the whole instability evolutions data. After that，FFT (fast Fourier transform)，WFT (window Fourier transform)，filter are used to analyze data in both frequency domain and time domain. So that，the rule of instability evolution in this compressor is obtained. The instability evolution changes with the increasing of rotation speed. At low rotation speed (subsonic) such as 65% of design rotation speed，the compressor turns into instability because of rotating stall driven by spike. At high rotation speed (transonic) such as 88% of design rotation speed，a disturbance of low-frequency，axisymmetric，large amplitude，localized at hub region leads into instability. It is called as partial surge. As a critical rotation speed (78% of design rotation speed)，partial surge and rotating stall nearly occur at the same time.