基于流道优化的局部进气高速涡轮机气动噪声控制实验研究

Experimental Study on Aeroacoustics Control for High-Speed Partial Admission Turbine Based on Flow Path Optimal Design

关键词:  涡轮噪声  局部进气  动静叶干涉  流道优化  单音噪声

Key words:  Turbine noise  Partial admission  Rotor-stator interaction  Flow path optimal design  Discrete noise

摘要:

动静叶干涉是涡轮机气动噪声的主要来源之一。针对局部进气高速涡轮机，为了抑制由动静叶干涉引起的单音辐射噪声，提出了增大喷嘴的几何出气角、喷嘴下俯、喷嘴单侧修型和增大动静叶间距的流道优化设计方法以控制涡轮机内的流动状况进而降低噪声辐射，并设计了涡轮机气动噪声测试实验台，测量并分析了优化措施的降噪效果。结果表明，涡轮机流道优化设计方法有效抑制了单音辐射噪声，使各个转子谐频处的离散噪声均得到降低，并在3125Hz处实现了最高达7dB的降噪量；在大部分的三分之一倍频程内，优化设计的涡轮机噪声幅值低于原始设计的涡轮机，最大降噪量为2.1dB。

Abstract:

The rotor-stator interaction is one of the main sources of turbomachine’s aerodynamic noise. For high-speed partial admission turbine，the fluid path optimal design methods including increasing the geometric exit flow angle of nozzle，nozzle pitchdown，sigle-side modification for nozzle，and increasing the distance between rotor and stator were proposed to improve the flow state to control the discrete noise induced by rotor-stator interaction. The test rig for turbine acoustic measurement was designed，and the noise reduction performance was measured and analysed for these optimal design methods. The results show that the distinctive noise is controlled significantly by the adopted optimal design methods，the sound pressure level at every rotating harmonic frequency is decreased，and the maximum reduction is about 7dB at 3125Hz. In most 1/3 octive frequencies，the noise amplitude is lower for optimal turbine，and the maximum decrease is 2.1dB.