Abstract:The internal flow field in a centrifugal pump with specific speed of 84.5 was numerically simulated by using CFD method when it was operated as a pump and run reversely as a hydro-turbine. The Rey-nolds time-averaged Navier-Stokes equations, standard k-ε two-equation turbulence model and SIMPLEC method were adopted in the simulations. The radial thrust was calculated under different flow conditions in that both modes. It was confirmed that the radial thrusts predicted in pump mode is in good agreement with those estimated by means of the Stepanoff empirical correlation, suggesting the flow models adopted are correct and reasonable. It was shown that the best efficiency in turbine mode is lower than the pump mode by about 5.4% and the radial thrust in the turbine mode is always smaller than the pump mode at the same flow rate. In the turbine mode, the radial thrust rises with increasing flow rate. The angle of radial thrust vector measured from the volute tongue is reduced to 125° from 146° as flow rate increase up to 1.1 times the design flow rate in the turbine mode. When flow rate is higher than 1.1 times the design flow rate, however, the angle is increased with increasing flow rate. As a result, the angle is as large as 144° at 1.4 times the design flow rate. The results suggest that the strength of the pump shaft is strong enough and still can meet the requirement of operation in the turbine mode.
杨军虎, 李海龙, 龚朝晖, 夏书强, 罗凯凯. 离心泵反转作液力透平的力学特性[J]. 排灌机械工程学报, 2014, 32(1): 12-16.
Yang Junhu, Li Hailong, Gong Zhaohui, Xia Shuqiang, Luo Kaikai. Radial thrust behavior in centrifugal pump as hydro-turbine. Journal of Drainage and Irrigation Machinery Engin, 2014, 32(1): 12-16.
[1]Himanshu Nautiyal,Varun,Anoop Kumar,et al. Experimental investigation of centrifugal pump working as turbine for small hydropower systems[J]. Energy Science and Technology,2011,1(1):79-86.[2]Shahram Derakhshan,Ahmad Nourbakhsh. Experimental study of characteristic curves of centrifugal pumps wor-king as turbines in different specific speeds[J].Experimental Thermal and Fluid Science,2008,32(1):800-807.[3]Shahram Derakhshan,Ahmad Nourbakhsh. Theoretical,numerical and experimental investigation of centrifugal pumps in reverse operation[J]. Experimental Thermal and Fluid Science,2008,32(1):1620-1627.[4]Sonia Rawal, Kshirsagar J T. Numerical simulation on a pump operating in a turbine mode[C]//Proceedings of the Twenty-third International Pump Users Symposium,2007:21-27.[5]王晓辉.水力透平转轮基本尺寸的确定及其内部流动、力特性研究[D]. 兰州:兰州理工大学能源与动力工程学院,2011.[6]周光坰,严宗毅,许世雄,等.流体力学[M]. 北京: 高等教育出版社, 2009:106-160.[7]王福军.计算流体动力学分析——CFD 软件原理与应用[M]. 北京: 清华大学出版社, 2004:113-143.[8]谢汉龙,赵新宇,张炯明.ANSYS CFX流体分析及仿真[M]. 北京: 电子工业出版社, 2012:32-64.[9]黎义斌,赵伟国,王秀勇,等. 离心泵变工况流场分析及数值模拟[J].兰州理工大学学报,2007,33(6):43-46. Li Yibin, Zhao Weiguo, Wang Xiuyong,et al. Analysis and numeric simulation of off-design flow field in centri-fugal pump[J]. Journal of Lanzhou University of Technology, 2007,33(6):43-46.(in Chinese)[10]Fred Buse.Performance analysis of a centrifugal pump used as a hydro-turbine[J].Chemical Engineering,1981,88(2):113-117.[11]王洋, 张翔, 黎义斌.离心泵变工况流场分析及径向力数值预测[J].排灌机械,2008,26(5):18-22. Wang Yang,Zhang Xiang,Li Yibin. Off-design flow field analysis and radial force prediction of centrifugal pump[J]. Drainage and Irrigation Machinery,2008,26(5):18-22.(in Chinese)[12]赵万勇,荆野,张亮,等.离心泵径向力的数值分析[J].新技术新工艺,2010(5):54-56. Zhao Wanyong,Jing Ye,Zhang Liang,et al. Numerical analysis of radial force on the centrifugal pump[J]. New Technology & New Process,2010(5):54-56.(in Chinese)[13]杨孙圣,孔繁余,张新鹏,等.液力透平非定常压力脉动的数值计算与分析[J].农业工程学报,2012,28(7):67-72. Yang Sunsheng,Kong Fanyu,Zhang Xinpeng,et al. Si-mulation and analysis of unsteady pressure fluctuation in hydraulic turbine[J]. Transactions of the CSAE,2012,28(7):67-72.(in Chinese)[14]关醒凡.现代泵理论与设计[M].北京:中国宇航出版社,2011:596-599.[15]Fernandez J,Blanco E,Parrondo J,et al. Performance of a centrifugal pump running in inverse mode[J]. Journal of Power and Energy,2004,218(4):265-271.