基于交错叶轮技术的横流风机气动声学特性研究

为了有效降低空调器室内机横流风机离散频率噪声,采用试验和理论分析方法研究交错叶轮技术对空调器室内机横流风机气动及声学性能的影响。对节间交错角度分别为0°、3.50°、4.00°和5.14°的横流风机气动声学试验结果显示,节间交错叶轮可在不影响横流风机气动性能的基础上,有效降低离散频率噪声,但对宽频噪声影响不大。建立基于Lighthill声类比理论以及傅里叶变换性质的横流风机离散频率噪声预测模型,用于分析不同叶轮交错角对横流风机离散频率噪声的影响。理论分析结果与试验测量结果吻合较好,该模型可有效地分析横流风机节间交错叶轮交错角度与叶片通过频率及其谐波分量处噪声的关联。以此为基础,进一步探讨横流风机节间交错叶轮最佳交错角的设计方法。

Aerodynamic and Aeroacoustic Study on the Cross Flow Fan with Block Stagger Impeller

In order to reduce discrete frequency noise of cross flow fan (CFF) of indoor unit of air-conditioner, both aerodynamic and aeroacoustic performance of CFF with block stagger impeller is investigated by using experimental and theoretical method. Four CFF impellers with block stagger angle of 0°, 3.50°, 4.00° and 5.14° are adopted as research objects. It can be shown that the block stagger technique has little influence on the aerodynamic performance of CFF. However, the discrete tone noise levels could be effectively reduced, even though the broadband noise level is also kept constant. Based on the Lighthill's acoustic analogy theory and Fourier transform character, discrete frequency noise prediction model of CFF is built and used to analyze the influence of different block stagger angles on the discrete frequency noise of CFF. Theoretical analysis results agree well with experimental results. The model can be used to analyze the relationship between stagger angle impeller and BPF noise together with its harmonics of CFF. Meanwhile, the design method of optimum stagger angle of block stagger impeller is also discussed.