中文摘要：

以低速单转子轴流压气机为对象,采用全圆周计算模型,以叶顶泄漏流周期性非定常波动为切入点,通过相对坐标系和绝对坐标系下信号数据的坐标变换、快速傅里叶变换和滤波分析,分析叶顶端区非定常波动特征沿叶片弦长的调频特性,研究占主导地位的非定常波动频率成分沿圆周方向的传播特征,得到占主导地位频率成分的调频关系和周向传播特征在压气机节流过程中的演变规律,揭示出近失速工况附近机匣壁面压力自相关系数降低的流体力学原因。结果表明,由叶顶泄漏流周期性非定常波动主导的叶顶端区流场特征是失速先兆信号分析和预测的流场依据。参考系、探针监测位置和分析方法的选取对分析结果有着重要影响,对同一流动现象可获得不同侧面的多样性表现特征。所得结果一方面为计算和试验数据的对比分析提供参考,另一方面也为不同流动特征的统一流体力学机理解释提供指导。

英文摘要：

For a low speed isolated axial compressor rotor, full annulus simulation model is adopted to numerically study the flow features in the rotor tip region dominated by periodical oscillation of unsteady tip leakage flow. And methods of coordinate transformation of pressure signals between the rotor relative and absolute stationary reference frames, fast Fourier transform and frequency band-pass filter are used. The modulated frequency features along blade chord in two reference frames are analyzed. For the dominated frequency component, the circumferential propagation characteristics are studied, and the evolutions of modulated frequency relation between two reference frames and circumferential propagation features during throttling process are also summarized. Further the fluid dynamic reason for the decrease of autocorrelation coefficient of pressure signals from transducer mounted on compressor casing is elucidated. It＇s shown that flow features near the rotor tip end wall dominated by periodical tip leakage flow unsteadiness are the basis for the analysis and prediction of stall precursors. Selection of reference frames, position of transducers and analysis method will greatly affect the results, and multiform features can be obtained for the same flow phenomenon. The results in this paper may give some guidelines for the comparison of results between experiment and numerical simulation, and also for the uniform fluid mechanism clarification for different flow features.