叶片穿孔数对冷却风扇气动性能和噪声性能的影响研究

Influence of blade perforation number on aerodynamic performance and noise performance of cooling fan

为了降低车用环形冷却风扇的气动噪声,以某款环形冷却风扇叶片结构作为研究对象,设计了叶片穿孔结构,并且采用数值模拟的方法,研究了叶片穿孔数对车用环形冷却风扇气动性能和噪声性能的影响规律。首先,建立了冷却风扇气动及噪声性能计算模型,采用了大涡模拟与福克斯·威廉姆斯和霍金斯(FW-H)方程对其进行了仿真计算,并对结果进行了试验验证;然后,设计了叶片穿孔定位方式,得到了三种叶片穿孔模型,并对其气动及噪声性能进行了计算;最后,对原风扇模型和叶片穿孔模型的流场与声场进行了分析,获得了不同穿孔数对环形冷却风扇性能的影响规律。研究结果表明:穿孔结构可有效降低环形冷却风扇离散频率噪声和总声压级,其中模型B效果最好,其较原风扇模型的A计权总声压级降低4 dB;风量和静压效率随穿孔数量增加而相应降低;分析环形冷却风扇流场及声场分布情况可知,穿孔结构能够有效减少叶尖低速回流区的产生,并且在一定程度上抑制了叶片尾涡脱落,从而降低了穿孔结构风扇的噪声。该研究结果可为后续车用环形冷却风扇的性能优化设计提供新思路。

In order to improve the aerodynamic noise of an automotive annular cooling fan,the blade structure of an annular cooling fan was taken as the research object,and the influence of blade perforation numbers on the aerodynamic and noise performance of automotive annular cooling fans was studied using numerical simulation methods.Firstly,the aerodynamic and noise performance calculation model of the cooling fan was established,and the large eddy simulation and the Ffowcs Williams and Hawkings(FW-H)equation were used to simulate and verify the calculation results.Then,the blade perforation positioning method was designed,and three perforation models were obtained and their aerodynamic and noise performance were simulated and calculated.Finally,the flow and sound fields of the original fan model and the blade perforation model were analyzed,the influence of different perforation numbers on the performance of annular cooling fan was obtained by analyzing the calculation results.The research results show that the perforated structure can effectively reduce the discrete frequency noise and total sound pressure level of the annular cooling fan,and the model B has the best effect,which is 4 dB lower than the A-weighted total sound pressure level of the original fan model.Air volume and static pressure efficiency decrease with the increase of the number of perforations.By analyzing the flow field and sound field distribution of the annular cooling fan,it can be seen that the perforated structure can effectively reduce the generation of the low-speed recirculation zone at the tip of the blade,and inhibit the vortex shedding of the blade to a certain extent,thereby reducing the noise of the perforated structure fan.It can provide a new idea for the performance optimization design of the subsequent automotive annular cooling fan.