多翼离心风机气动噪声计算与降噪设计研究

Research on Aerodynamic Noise Calculation and Noise Reduction Design of Multi-blade Centrifugal Fans

以船用空调通风系统中多翼离心式风机为对象,建立风机内部流体三维建模,采用CFD软件进行稳态与非稳态计算。将得到的风机内部流场结果导入LMS Virtual. Lab声学软件中进行噪声预估,同时与实验结果对比,验证风机气动噪声计算的准确性。根据分析得知,风机气动噪声主要噪声源位于叶轮处并且与其内部流场分布和自身结构密切相关。对于已经投入生产的风机,很难对其主要结构包括蜗壳、叶轮、叶片尺寸等进行改造,只能对其局部结构进行二次设计以实现降噪的目的。探索采用叶片穿孔设计,通过设置合理穿孔参数,在不改变其性能条件下,减少叶片周围涡流脱落进而使得叶片表面压力脉动降低,达到降低风机气动噪声的目的。

Taking the multi-blade centrifugal fan in a marine air-conditioning and ventilation system as the object,the three-dimensional model for fluid flow analysis inside the fan is established,and the steady state and unsteady state flows are calculated by means of CFD software.The results of the internal flow field of the fan are input into the LMS Virtual.lab software for noise estimation,and the accuracy of the calculation of the aerodynamic noise of the fan is verified by comparison with the experimental results.The analysis shows that the main noise source of the aerodynamic noise of the fan is located at the impeller and is closely related to its internal flow field distribution and its own structure.For a fan that has already been put into production,it is difficult to modify its main structure including volute,impeller,blade size,etc.,and only a secondary design for the local structure improvement is possible to achieve the purpose of noise reduction.This paper explores the blade perforation design.Setting reasonable perforation parameters without changing its performance can reduce the vortex shedding around the blades so as to reduce the pressure pulsation on the blade surface and reduce the aerodynamic noise of the fan.