窗式空调轴流风扇气动噪声研究

Research on Aerodynamic Noise of Axial Flow Fan in Window Air-Conditioners

摘要: 轴流风扇是窗式空调室外部分的主要通风散热元件，其通风量会直接影响窗式空调能否正常工作，而噪声会影响人正常的休息和工作。设计高性能低噪声的轴流风扇成为提高窗式空调市场竞争力的关键问题。本文设计了一种叶片尾缘局部凹陷的轴流风扇。使用流体力学软件Fluent中的大涡模拟(LES)和FW-H方程对优化前后的轴流风扇的气动噪声进行数值模拟，并对两者的气动噪声特性进行实验研究。研究结果表明：轴流风扇的声压级在不同方向并不相同，呈不规则曲线分布，其中正对出风口方向的声压级最大。气动噪声主要沿轴流风机旋转轴线方向传播。叶片尾缘局部凹陷设计可以降低轴流风扇的气动噪声，在出口旋转轴线方向距离轴流风扇1 m处可以降低3~5 dB(A)。

Abstract: Axial flow fan is the main ventilation and heat-dissipating component in the outdoor part of window air-conditioner. Its ventilation volume will directly affect whether the window air-conditioner can work normally. Noise will affect people’s normal rest and work. It has become a key issue for improving the market competitiveness of window air-conditioners to design high-performance and low-noise axial flow fans. An axial flow fan partially depressed at the trailing edge of the blade was designed. A numerical simulation was devised to study the aerodynamic noise of axial flow fans before and after optimization by using LES, FW-H equation in Fluent. An experimental research also was designed to study the aerodynamic noise characteristic of two axial flow fans. The results show that sound pressure levels of axial flow fan are not the same in different directions, it presents irregular curve distribution. Sound pressure level in the direction of the air outlet is the largest. Aerodynamic noise propagates mainly in the direction of the axis of rotation of the fan. The trailing edge local depression can reduce aerodynamic noise of axial flow fan. It can reduce 3 dB(A) to 5 dB(A) at the downstream of axial direction and 1 m away from the axial flow fan.