孔型及倾斜角对穿孔叶片气动和噪声特性的影响

针对叶片尾缘穿孔对气动及噪声特性的影响，基于NACA65019叶片，在雷诺数Re=2×105条件下，采用大涡模拟和FW-H方法研究孔型和倾斜角对叶片气动特性、绕流流场和噪声特性的影响规律，并选择降噪效果较好的穿孔模型应用到小型轴流风机上，对穿孔风机进行试验。结果表明：当穿孔倾斜角为30°时，在一定攻角范围内(α≤10°)，圆柱型穿孔叶片气动性能最接近原始叶片，并且该穿孔叶片总声压级降低可达9 dB。这是由于穿孔叶片有效抑制了涡量沿叶片表面法向的发展，加速了尾缘涡沿流动方向的能量衰减，且穿孔形成的射流使大尺度的涡破碎形成小尺度的涡，衰减波动力，降低了气动噪声。

Influence of hole type and incline angle on the aerodynamic and noise characteristics of perforated blade

Aiming at the impact of blade trailing edge perforation on aerodynamic and noise characteristics, based on NACA65019 blades, under the condition of Reynolds number Re=2×105, large eddy simulation and FW-H method were used to study the influences of hole pattern and inclination angle on blade aerodynamic characteristics and flow field around blade and noise characteristics. The perforation model with better noise reduction effect was chosen to apply to the small axial flow fan. The perforation fan was tested. The results show that when the perforation angle is 30°, the aerodynamic performance of the cylindrical perforated blade is closest to the original blade within a certain angle of attack (α≤10°). In addition, the sound pressure level of the perforated blade can be reduced by 9 dB. This is because the perforated blade effectively reduces the development of vorticity along the normal direction of the blade surface, and accelerates the energy attenuation of the trailing edge vortex along the flow direction. Additionally, the jet formed by the perforation breaks the large-scale vortex to form small-scale vortices, which attenuates the wave power, reducing the aerodynamic noise.