Abstract: In order to reveal the frequency spectrum structure of unsteady pressure in multi-stage transonic compressor case，three-dimensional unsteady solver has been developed based on three-dimensional Denton steady solver. Steday and Unsteady numerical simulation have been conducted on multi-stage transonic compressor near stall point，then frequency-domain analysis of unsteady pressure have been conducted on three typical radial sections. Frequency-domain research make researchers analyze the unsteady flow field from a new perspective，researchers can see some of the phenomena that are difficult to see in the time domain，such as numerical reflection at outlet. The trailing edge of stator vane will be affected by large unsteady aerodynamic force，if downstream rotor works under transonic conditions. The spectrum structure of the rear stage of the multi-stage compressor is more abundant，the amplitude component at fourfold BPF is still large，and it needs to be considered in the selection of the dynamic pressure sensor.

Key words: Aero-engine；Transonic；Compressor；Unsteady calculation；Frequency analysis

摘要： 为揭示跨声速多级压气机中非定常压力的脉动频谱结构，基于三维定常Denton程序发展了三维非定常计算程序，对三维跨声速多级压气机近失速点进行了定常与非定常数值模拟，并在此基础上对三个典型径向截面的非定常压力进行了频域分析。结果表明:通过对非定常频域图谱的研究，从一个全新的视角来分析非定常流场，可以看到在时域流场中很难直观看到的出口数值反射等现象；在压气机静子的结构设计中，如果某级静子后续的转子工作在跨声速工况下，则该级静子尾缘处会受到较大的非定常气动力作用；多级压气机中后面级叶排频谱结构较为丰富，通过频率的4倍频振幅分量依然较大，在进行动态压力传感器的选型时需要考虑这点。

关键词: 航空发动机；跨声速；压气机；非定常计算；频域分析