摘要
隔舌结构参数对泵和透平的性能有着显著影响。为了研究隔舌安放角变化对泵作透平正反模式下水力性能的影响规律,本文对4种隔舌安放角的低比转速离心泵正反模式运行的内流场进行了数值模拟,并通过实验验证了模拟结果的可靠性。结合熵产诊断以及损失功率计算,分析了不同泵模型在正反模式下扬程(泵模式)、必需水头(透平模式)、效率以及内流损失的变化情况。结果表明,适当增加安放角可以使泵扬程增加,透平必需水头减小,两种模式的效率提高,效率-流量曲线右移,最佳效率点对应的流量值增大。但角度增加超出一定范围后,泵效率降低。两种模式的水力损失都集中在蜗壳区域,与转轮内水力损失相比,其受隔舌安放角角度变化影响更为显著。当隔舌安放角角度增加时,泵效率增大的主要原因在于蜗壳出口区域水力损失的减小。对于透平模式,尽管转轮内分离涡结构在较大隔舌安放角情况下受到抑制,但其变化对效率影响较小,透平效率提升的主要原因是隔舌与转轮间隙以及蜗壳壁面附近的水力损失降低。
The volute tongue could markedly influence the performance of pump and turbine.In order to study the hydraulic characteristic of pump as turbine with the variance of volute tongue angle under the direct and reverse modes,a numerical simulation is carried out to analyze the inner flow of low specific speed centrifugal pump with four volute types of different tongue angle,which is validated by experiment.Combining the entropy generation analysis and loss calculation,the change laws of pump head,required head of turbine,efficiency and internal loss are investigated.The results show that an increase of volute tongue angle could improve the pump head,reduce the turbine required head,and make both efficiencies rise,and the efficiency-discharge curves move to the right with the discharge of the best efficiency point increasing,while the pump efficiency decreases when the angle value exceeds a certain range.The loss in the volute region accounts for the major part of hydraulic loss under both modes,and the loss is more likely to be affected by angle changing than it in the runner.As the angle increasing,the pump efficiency rise is attributed to the loss decrease in the outlet region of volute,while the loss reduction in the gap between runner and volute tongue,and the area near volute wall is the main cause instead of the restricted separation in the runner for the improvement of the turbine efficiency.
作者
袁志懿
张永学
祁紫伟
YUAN Zhiyi;ZHANG Yongxue;QI Ziwei(College of Mechanical and Transportation Engineering,China University of Petroleum(Beijing),Beijing 102249,China;School of international education,Hainan medical university,Haikou 571199,Hainan,China)
出处
《储能科学与技术》
CAS
CSCD
北大核心
2021年第5期1777-1787,共11页
Energy Storage Science and Technology
基金
国家自然科学基金项目(51876220)。
关键词
泵作透
平隔舌安放角
正反模式
熵产诊断
内流分析
pump as turbine
volute tongue angle
direct and reverse modes
entropy generation diagnose
inner flow analysis
