上游叶片尾迹对转子叶片非定常表面压力频谱特性影响的研究

Effects of the up-stream blade wakes on the spectrum of rotor blade unsteady surface pressure

为了研究上游叶片尾迹对轴流压气机转子叶片非定常表面压力的影响,采用在叶片表面埋设微型压力传感器的方法,测量了一个单级低速轴流压气机转子叶片的非定常压力分布。对转子叶片非定常压力分布的分析显示:转子叶片压力面非定常表面压力主要受上游叶片尾迹影响,其主导频率为上游叶片尾迹频率及其倍频,压力波动幅度随上游叶片尾迹的衰减而沿流向减弱。转子叶片吸力面非定常压力受叶片附面层和上游叶片尾迹共同影响,其主导频率为上游叶片尾迹频率及其倍频,但是在吸力面前部气流加速区压力波动幅度沿流向增大,而在吸力面后部气流减速区压力波动幅度沿流向减小。在存在尾缘分离的情况下,在分离区附近产生较大压力波动。尾缘气流分离产生的压力波动频谱中含有上游叶片尾迹频率及其倍频的分量,但其频谱可能比较复杂,并非单一地受上游叶片尾迹影响。

The unsteady surface pressures on the rotor blades of a single-stage low-speed axial compressor were measured by means of mounting micro-sensors on the surface the blades. The effects of up-stream blade wakes on the spectrum of rotor blades unsteady surface pressure were analyzed. On the rotor blade pressure surface, the dominant frequencies of unsteady surface pressure are the up-stream blade wake passing frequency and its harmonics, and the amplitudes of pressure fluctuations decrease from leading edge to trailing edge. However,on the blade suction side from leading edge to trailing edge, the amplitudes of pressure fluctuations increase at the fore part where flow accelerates and decrease at the rare part where flow decelerates. Flow separation produces pressure fluctuations of large amplitudes, possibly with the dominant frequencies differ from up-stream blade wake passing frequency and its harmonics.