叶片圆形尾缘对微型轴流风扇气动噪声的影响

Effects of the Circular Trailing Edge on the Aerodynamic Noise of the Micro Axial Flow Fan

摘要: 为降低微型轴流风扇气动噪声，将原型风扇直线形叶片尾缘设计成圆弧形，采用大涡模拟(LES)结合FW-H声类比方法对原型及改型风扇进行气动性能和噪声计算，并对两款风扇进行气动性能与噪声试验。数值模拟结果显示改型后的叶轮对降低风扇气动噪声有积极作用，风扇压力会有所下降；试验结果表明：在0.84~1.37 qvs流量区间内，改型风扇较原型相比，静压降低2.5%~4.3%，静压效率最多提升1.9%；改型后的叶轮可使风扇比A声级下降0.63~2.32 dB；在设计工况下，风扇静压下降3%，静压效率提高1.8%，比A声级降低2.3 dB；对两种风扇A计权1/3倍频程图分析发现，圆形叶片尾缘对800~5000 Hz频段的高频尾迹涡流噪声有明显抑制作用。研究结果对微型轴流风扇的气动设计、优化具有一定程度的参考价值。

Abstract: In order to reduce the aerodynamic noise of the micro axial flow fan, the linear blade trailing edge of the prototype fan was designed into a circular arc shape, and the large eddy simulation (LES) combined with the FW-H sound analog method was used to calculate the aerodynamic performance and noise of the prototype and modified fans, and conduct aerodynamic performance and noise tests on two fans. Numerical simulation results show that the modified impeller has a positive effect on reducing the aerodynamic noise of the fan, but the fan pressure will be reduced. The test results show that: In the flow range of 0.84 qvs to 1.37 qvs, the modified fan has a static pressure compared to the prototype reduced by 2.5% to 4.3%, and increases static pressure efficiency by up to 1.9%; the modified impeller can reduce the specific A-weighted sound level of the fan by 0.63 dB to 2.32 dB; under design conditions, the static pressure of the fan is reduced by 3%, and the static pressure efficiency is improved 1.8%, the specific A-weighted sound level is decreased by 2.3 dB. The analysis of the A-weighted 1/3 octave diagram of the two fans found that the trailing edge of the circular blade has a significant inhibitory effect on the high-frequency wake eddy current noise in the frequency range of 800 Hz to 5000 Hz. The research results have a certain degree of reference value for the aerodynamic design and optimization of micro-axial fans.