冲角对轴流泵叶轮水力性能的影响
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摘要
【目的】研究冲角对轴流泵叶轮水力性能的影响。【方法】针对比转数为880的轴流泵叶轮,采用数值模拟方法和数值优化技术,基于儒可夫斯基翼型从3个角度进行冲角对轴流泵水力性能的影响研究。【结果】当设计参数保持不变时,冲角增大,扬程升高,比转数发生变化,最高效率增大,高效区往大流量偏移。为了使翼型处于更高质量区,建议轮缘侧翼型冲角在0～3°之间,且比转数大者取小值。当改变轮毂侧和中间断面翼型冲角时,设计工况下,为了得到较高扬程和较高效率的轴流泵叶轮,可以适当增加中间断面的翼型冲角,同时为了减小叶片扭曲改善非设计工况的水力性能,可以适当减小轮毂侧的翼型冲角。当比转数保持一致时,冲角增大,流量-扬程性能曲线的斜率减小,最高效率值保持相当,高效区范围往大流量偏移且高效区范围变宽。【结论】冲角对轴流泵叶轮水力性能有着重要影响,实际工程应用中,为保证轴流泵叶轮具有较好的水力性能应同时兼顾轮毂和轮缘侧的翼型冲角。
【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 dischargehead 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.
【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 dischargehead 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.
引文
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[13]严敬,王桃,肖国华,等.基于儒可夫斯基变换的轴流叶片翼型设计[J].排灌机械工程学报,2012,30(2):265-269.
[14]汤方平.喷水推进轴流泵设计及紊流数值模拟[D].上海:上海交通大学,2005.
[2]关醒凡.轴流泵和斜流泵水力模型设计试验及工程应用[M].北京:中国宇航出版社,2008.
[3]王勇,刘厚林,袁寿其,等.叶片进口冲角对离心泵空化特性的影响[J].流体机械,2011,39(4):17-20,66.
[4]李大春,杨凌,高宇,等.轴流压气机平面叶栅气动特性的数值研究[J].大连海事大学学报,2017,43(3):71-77.
[5]周逊,王振峰,王祥锋,等.冲角变化对涡轮叶栅内间隙流动的影响[J].实验流体力学,2009,23(3):65-69.
[6]张华良,王松涛,王仲奇.冲角对压气机叶栅内二次涡的影响[J].航空动力学报,2006,21(1):150-155.
[7]周济人,汤方平,石丽建,等.基于CFD的轴流泵针对性设计与试验[J].农业机械学报,2015,46(8):42-47.
[8]YANG Zhengjun,WANG Fujun,ZHOU Peijian.Evaluation of subgrid-scale models in large-eddy simulations of turbulent flow in a centrifugal pump impeller[J].Chinese Journal of Mechanical Engineering,2012,25(5):911-918.
[9]YE Liang,LIU Zhongmin.Design of implantable axial-flow blood pump and numerical studies on its performance[J].Journal of Hydrodynamics,2009,21(4):445-452.
[10]赵敏,崔维成.多学科设计优化研究应用现状综述[J].中国造船,2007(3):63-72.
[11]龙腾,刘建,陈余军,等.基于约束EGO的对地观测卫星多学科设计优化[J].机械工程学报,2018,5(10):133-142.
[12]郑传宇,黄江涛,周铸,等.飞翼翼型高维目标空间多学科综合优化设计[J].空气动力学学报,2017,35(4):587-597.
[13]严敬,王桃,肖国华,等.基于儒可夫斯基变换的轴流叶片翼型设计[J].排灌机械工程学报,2012,30(2):265-269.
[14]汤方平.喷水推进轴流泵设计及紊流数值模拟[D].上海:上海交通大学,2005.