关键词: 弯曲/倾斜, 尾迹干涉单音噪声, 位势干涉单音噪声, 二次流, 叶型损失, 干涉强度

Abstract:

The last stage of GE E3 low-pressure turbine is taken as the object of study， and the experimentally validated flow/acoustic field hybrid model is used to investigate the effect of the bend stator （-30°–30°）， the lean stator （-15°–15°）， and the partial combination of the bend/lean stator with serval angles on the aerodynamic performance of the turbine and the influence law of wake interaction tonal noise and potential interaction tonal noise. The physical mechanisms are analyzed in terms of the flow field and the acoustic field. The results are obtained as follows. Isolated large-bending and large-leaning stators are favorable to improving the efficiency of the turbine stage， and the combination may even result in the efficiency gain of “1+1>2”； the potential interaction tonal noise is more affected by the bend or lean of the stator than the wake interaction tonal noise， and the gain of noise reduction is more obvious. Compared to the isolated bend or lean stator， the bend/lean stator can achieve both efficiency and noise gains， and the optimal scheme is the bend 20°/lean 10° stator， which improves the aerodynamic efficiency by 0.16% and obtains a noise reduction gain of 1.84 dB at the same time. The effect of the bend/lean stator on the efficiency is mainly related to the secondary flow and the blade loss， whereas its effect on the noise is mainly related to interaction intensity and phase changes. In conclusion， although the bend/lean stator is not a novel design option， it has the potential to realize a high-efficiency and low-noise design of the turbine； thus， its physical mechanisms and noise reduction laws are still worthy of extensive research， so as to provide theoretical support for future engineering applications.

Key words: bend/lean, wake interaction tonal noise, potential interaction tonal noise, secondary flow, blade loss, interaction intensity