车用轴流风机离散噪声与叶片分布特性研究

Study on Discrete Noises and Blade Distribution Characteristics of Vehicle Axial Fans

针对轴流风机离散噪声偏大影响汽车总声压级及声品质问题,采用谐波法相关理论,建立了离散噪声与叶片分布特性关系的理论及仿真模型,结合数值计算、仿真分析分别得到了叶片数量和非等间距的分布特性与噪声、流量、效率的关系。研究表明:7叶片风机在噪声、流量、效率方面的综合性能最佳;利用非等间距理论得出的最大调整角为2.406 rad的方案对于不同数量等间距叶片均可达到最优降噪的效果,并且对流量及效率无明显影响,仿真模拟与实验结果验证了这一结论。基于以上研究提出了一种在满足风机流量及效率前提下有效降低离散噪声的新方法,为叶片分布特性的研究提供了参考。

Aiming at the problems that discrete noises of the axial fans were so big that affected total SPL(sound pressure level) and sound quality of automobiles,a theoretical and simulation model of the relationships between discrete noises and blades distribution characteristics were established by using harmonic correlation theory,and the relationships among the number of blades,the distribution characteristics of the unequal interval and fluxes,efficiency,noise were obtained separately combined with numerical calculations and simulation analyses. The results indicate that 7 blades fan has the best comprehensive performance in flow,efficiency and noise,and the best adjustment angle as 2.406 rad may achieves the effectiveness of optimal noise reduction to different numbers of equal interval blades based on unequal interval theory,and has no obvious effects on the flux and efficiency as well,which is proved by simulations and experiments. Based on the above research,a new method of reducing the discrete noises under the premise of satisfying the flow and efficiency is advanced,which provides references for the studies of the structure distribution characteristics of the blades.