叶片包角对混流泵作透平的特性影响
|
摘要
采用数值模拟与试验验证相结合的方法,在保证叶轮其他主要几何参数不变的情况下,分别模拟叶片包角为45°,65°,75°,85°,95°和105°的叶轮模型,并通过试验进行验证,探究叶片包角变化对混流泵作透平性能的影响规律.结果表明:随着叶片包角增大,混流泵作透平流量效率曲线向小流量工况偏移,且高效区间逐渐减小,流量扬程曲线和流量轴功率曲线上升趋势越来越陡峭.随着包角增加,液流流动将更加贴近叶片型线,叶轮流道内部旋涡现象得到一定程度的改善.包角增加使得叶片对液流约束能力加强,旋涡损失减小从而小流量区域水力损失减小;在大流量区域,包角增大使得叶轮流道加长,摩擦损失增加从而流道内的水力损失加大.因此旋涡损失和摩擦损失的共同作用使叶片包角存在一个最佳值使得透平最高,效率最高,对混流泵作透平叶片设计有一定的指导意义.
Numerical simulation was adoped and the blade wrap angles were 45°,65°,75°,85°,95°and 105° when impellers' other geometric parameters remained the same.The influence of blade wrap angles on PATs was studied.The results show that with the increase of the blade wrap angles,the liquid flow is closer to the blade profile.The vortex in the impeller channel inside is improved.The turbine's high-efficiency curves shift toward the small flow rate area,the high efficiency region becomes smaller and the head curve and shaft power curve are getting steeper.The blade's constraint on the flow is enhanced with the increase of blade wrap angles,the hydraulic loss in the small flow area is reduced,but the runner is lengthened,the friction loss is increased.With the augment of the blade wrap angles,the hydraulic loss increases in the mass flow area indicating that there is a best blade wrap angles.This result can provide some guidance to the design of the mixed-flow pump as turbines.
Numerical simulation was adoped and the blade wrap angles were 45°,65°,75°,85°,95°and 105° when impellers' other geometric parameters remained the same.The influence of blade wrap angles on PATs was studied.The results show that with the increase of the blade wrap angles,the liquid flow is closer to the blade profile.The vortex in the impeller channel inside is improved.The turbine's high-efficiency curves shift toward the small flow rate area,the high efficiency region becomes smaller and the head curve and shaft power curve are getting steeper.The blade's constraint on the flow is enhanced with the increase of blade wrap angles,the hydraulic loss in the small flow area is reduced,but the runner is lengthened,the friction loss is increased.With the augment of the blade wrap angles,the hydraulic loss increases in the mass flow area indicating that there is a best blade wrap angles.This result can provide some guidance to the design of the mixed-flow pump as turbines.
引文
[1]闫海成.我国能源发展的现实困境与路径选择[J].资源与产业,2010,12(1):23-27.YAN Haicheng.The realistic dilemma and path choice of China's energy development[J].Resources&industries,2010,12(1):23-27.(in Chinese)
[2]苗森春,杨军虎,王晓晖,等.叶片数对泵作液力透平的性能影响[J].流体机械,2018,46(1):1-5.MIAO Senchun,YANG Junhu,WANG Xiaohui,et al.Effect of blade number on performance of pump as turbine[J].Fluid machinery,2018,46(1):1-5.(in Chinese)
[3]YANG Sunsheng,DERAKHSHAN Shahram,KONGAFanyu.Theoretical,numerical and experimental prediction of pump as turbine performance[J].Renewable energy,2012,48:507-513.
[4]杨军虎,袁亚飞,蒋云国,等.离心泵反转作为能量回收透平的性能预测[J].兰州理工大学学报,2010,36(1):54-56.YANG Junhu,YUAN Yafei,JIANG Yunguo,et al.Performance prediction of centrifugal pump as energy recovery turbine[J].Journal of Lanzhou University of Technology,2010,36(1):54-56.(in Chinese)
[5]杨军虎,雷蕾,张书玮,等.介质黏度对泵作透平时性能换算的影响[J].排灌机械工程学报,2017,35(7):553-557.YANG Junhu,LEI Lei,ZHANG Shuwei,et al.Effect of medium viscosity on performance conversion of pump as turbine[J].Journal of drainage and irrigation machinery engineering,2017,35(7):553-557.(in Chinese)
[6]SINGH P,NESTMANN F.Experimental investigation of the influence of blade height and blade number on the performance of low head axial flow turbines[J].Renewable energy,2011,36(1):272-281.
[7]DERAKHSHAN S,MOHAMMADI B,NOURBAKHSHA.Efficiency improvement of centrifugal reverse pumps[J].Journal of fluids engineering,2009,131(2).
[8]DERAKHSHAN S,NOURBAKHSH A.Experimental study of characteristic curves of centrifugal pumps working as turbines in different specific speeds[J].Experimental thermal&fluid science,2008,32(3):800-807.
[9]SEDLAR M,SOUKAL J,KOMAREK M.CFD analysis of middle stage of multistage pump operating in turbine regime[J].Eng mech,2009,16(9):413.
[2]苗森春,杨军虎,王晓晖,等.叶片数对泵作液力透平的性能影响[J].流体机械,2018,46(1):1-5.MIAO Senchun,YANG Junhu,WANG Xiaohui,et al.Effect of blade number on performance of pump as turbine[J].Fluid machinery,2018,46(1):1-5.(in Chinese)
[3]YANG Sunsheng,DERAKHSHAN Shahram,KONGAFanyu.Theoretical,numerical and experimental prediction of pump as turbine performance[J].Renewable energy,2012,48:507-513.
[4]杨军虎,袁亚飞,蒋云国,等.离心泵反转作为能量回收透平的性能预测[J].兰州理工大学学报,2010,36(1):54-56.YANG Junhu,YUAN Yafei,JIANG Yunguo,et al.Performance prediction of centrifugal pump as energy recovery turbine[J].Journal of Lanzhou University of Technology,2010,36(1):54-56.(in Chinese)
[5]杨军虎,雷蕾,张书玮,等.介质黏度对泵作透平时性能换算的影响[J].排灌机械工程学报,2017,35(7):553-557.YANG Junhu,LEI Lei,ZHANG Shuwei,et al.Effect of medium viscosity on performance conversion of pump as turbine[J].Journal of drainage and irrigation machinery engineering,2017,35(7):553-557.(in Chinese)
[6]SINGH P,NESTMANN F.Experimental investigation of the influence of blade height and blade number on the performance of low head axial flow turbines[J].Renewable energy,2011,36(1):272-281.
[7]DERAKHSHAN S,MOHAMMADI B,NOURBAKHSHA.Efficiency improvement of centrifugal reverse pumps[J].Journal of fluids engineering,2009,131(2).
[8]DERAKHSHAN S,NOURBAKHSH A.Experimental study of characteristic curves of centrifugal pumps working as turbines in different specific speeds[J].Experimental thermal&fluid science,2008,32(3):800-807.
[9]SEDLAR M,SOUKAL J,KOMAREK M.CFD analysis of middle stage of multistage pump operating in turbine regime[J].Eng mech,2009,16(9):413.