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在风洞开口实验段,针对不同尖速比应用BSWA VS302USB振动噪声采集分析系统对水平轴风力机叶尖下游4个角度的测试线进行噪声测试。叶尖辐射声中的主要成分是叶片的旋转谐波声,其向风轮下游传播的过程中迅速衰减。在各测试线上,随着测点向风轮下游移动,叶轮辐射声迅速衰减,并在一定距离之后低于背景声,尖速比越高,风轮下游辐射声衰减到背景声级的位置距离风轮越远。风轮旋转过程中,在叶尖后方形成高压力脉动的区域,随着尖速比增加,该区域增大,在向下游扩展的同时影响范围扩大。叶尖区域压力脉动向下游传播的过程中先迅速降低,在一定距离后低于风洞来流的压力脉动,并在更远的下游又高于风洞来流的压力脉动。
In the experimental section of wind tunnel opening, a noise test was carried out on the test lines at four angles downstream of the tip of the horizontal axis wind turbine using the BSWA VS302USB vibration noise acquisition and analysis system with different tip speed ratios. The main component of the sound emitted by the blade tip is the rotational harmonic sound of the blade, which decays rapidly during propagation downstream of the rotor. On each test line, as the measuring point moves downstream of the wind wheel, the radiated sound of the impeller decays rapidly and falls below the background sound after a certain distance, and the higher the tip speed ratio is, the lower the radiating sound of the wind wheel decays to the position of the background sound level The farther away from the wind wheel. During the rotation of the rotor, a region of high pressure pulsation occurs behind the tip of the blade. As the tip-to-tip ratio increases, the region increases and expands downstream as it expands. The pressure pulsation in the tip region propagated downwards rapidly in the process of pressure pulsation, then lower than the pressure pulsation of the wind tunnel flow at a certain distance and higher than the pressure pulsation of the wind tunnel farther downstream.