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| The study on the tip clearance noise in circumferential skewed axial fan under off-designs conditions |
| JIN GuangYuan1, WU Yadong2, OU YANG Hua2, DU Zhaohui2 |
| 1.School of Mechanical Engineering, Jiang Nan University, Wuxi 214122；2.School of Mechanical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China |
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Abstract Tip-clearance noise induced by tip-leakage flow in axial flow fans, with the blades skewed circumferentially at angles of ±8.3°, was investigated under off-design conditions by dynamic pressure experiments in sound near-field and far-field. The characteristics of tip-clearance noise and the effect of circumferential skewed blades on tip-clearance noise are discussed by experimental results. The results reveal that as the flow rate decreases, the strength and transfer of tip leakage flow are changed by circumferntial skewed blades; in frequency domain of the near-field and far-field, the broadband frequency components of tip-clearance noise are observed and tend to increase in the low frequency domain, especially for circumferential forward-skewed blade; the effects of circumferential skewed blades on the directivity patterns of the far-field overall SPL at various flow rates are different; the SPL of forward-skewed blade at all directions distribute well than that of backward-skewed blade.
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Received: 20 July 2012
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2013, Vol. 32 
