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| DOI：10.13522/j.cnki.ggps.20180314 |
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| Impacts of the Angle of Attack on Hydraulic Characteristics over the Axial flow Impeller |
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SHI Lijian, FU Lingling, LIU Chao, TANG Fangping, ZHANG Wenpeng, CHEN Feng
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1.School of Hydraulic Energy and Power Engineering, Yangzhou University, Yangzhou 225100, China; 2. Guangling College, Yangzhou University ,Yangzhou 225100, China；3. Changzhou Changjiang Levee Project Management Office, Changzhou 213000, China
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| Abstract: |
| 【Objective】 This paper presents the results of a study on influence of the angle of attack on hydraulic characteristics of the axial flow impeller. 【Method】 The study was based on numerical simulation and optimization assuming the spinning speed of the impeller was 880. We presumed the impeller was Joukowski airfoil, and compared the impact of the angle of attack in three perspectives. 【Result】 When other design parameters remained the same, increasing the angle of attack increased the lift height and the maximum efficiency of the impeller; it also changed the specific speed, with the high-efficiency area shifting to the large mass flow area. To make the airfoil work at high mass region, the angle of attack on the flange side wing should be in 0°~3° by keeping the larger specific speed as small as possible. Under the design condition, changing the hub side and the middle section of the airfoil angle, in order to get a higher lift and high efficiency axial pump impeller, can be appropriate to increase the middle section of the airfoil angle, at the same time, reducing the attack angle of the wheel side wing can reduce the level of the blade distortion and improve the hydraulic performance under the off-design conditions. When the specific speed remained unchanged and the attack angle increased, the slope of the discharge-head characteristic curve would decrease, the maximum efficiency maintained, the high efficient area was shifted to the large mass flow offset, and the high efficiency area of pump-operation was widened. 【Conclusion】 The attack angle has an important influence on the hydraulic performance of the axial-flow impeller. In order to ensure the better hydraulic performance, the airfoil angle of the hub and rim side of the impeller should be considered at the same time. |
| Key words: attack angle; optimization design; axial-flow impeller; hydraulic performance |
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