Internal flow characteristics of centrifugal pump at low flow rates
Fu Yanxia1,2, Yuan Shouqi1, Yuan Jianping1, Fu Yuedeng3, Huang Ping1
1.National Research Center of Pumps, Jiangsu University, Zhenjiang, Jiangsu 212013, China; 2.Civil and Industrial Engineering Department, University of Pisa, Pisa, Toscana 56121, Italy; 3.New United Group, Changzhou, Jiangsu 213011, China
Abstract:In order to investigate the performance and internal flow characteristics of centrifugal pump at low flow rates, the type IS160-50-65 end-suction centrifugal pump was selected as computational model. The three-dimensional, steady, turbulent, incompressible fluid flow in the whole pump including a suction pipe, impeller and volute was simulated by means of software Ansys CFX 12.0. Meanwhile the grid independence was checked by employing three sets of mesh to improve the computational accuracy. Finally, both the performance and internal flow characteristics of the pump at low flow rates were analyzed with the mesh just determined. It was shown that the predicted pump head, total efficiency are deviated from the experimental data by 1.47% and 3.61% only under the design condition. As the flow rate is decreased, the predicted head is closer to the tested one to some extent; unfortunately, the estimated efficiency shows increasing disagreement with the experimental value. In addition, the internal flow is quite uniform under the design condition. At low flow rates, however, there is a recirculation in the suction pipe; a reverse flow occurs in the impeller passages as well. The reverse flow is so dominated that it can occupy the entire impeller passages at a certainly low flow rate. At an extreme low flow rate, say 20% design flow rate, the recirculation flow has extended into the whole suction pipe.
[1]黄建德.开式和闭式离心泵进口回流的研究[J].工程热物理学报,1997,18(1):43-47. Huang Jiande. Studies on inlet reverse flow for open-type and closed-type centrifugal pump[J]. Journal of Engineering Thermophysics, 1997, 18(1): 43-47.(in Chinese)[2]李意民,谢和平,李江林,等.离心叶轮入口流动的动力学描述[J].中国矿业大学学报,1998,27(2):132-134. Li Yimin, Xie Heping, Li Jianglin, et al. Dynamic description of flow in centrifugal impeller inlet[J]. Journal of China University of Mining & Technology, 1998, 27(2):132-134.(in Chinese)[3]Brun K, Kurz R. Analysis of secondary flows in centri-fugal impellers[J]. International Journal of Rotating Machinery, 2005, 2005(1):45-52.[4]Cheah K W, Lee T S, Winoto S H, et al. Numerical flow simulation in a centrifugal pump at design and off-design conditions[J]. International Journal of Rotating Machinery, 2007:83641.[5]Tan Lei, Zhu Baoshan, Cao Shuliang, et al. Cavitating flow simulation for a centrifugal pump at a low flow rate[J]. Chinese Science Bulletin, 2013, 58(8):949-952.[6]张金凤,梁赟,袁建平,等.离心泵进口回流流场及其控制方法的数值模拟[J].江苏大学学报:自然科学版,2012,33(4):402-407. Zhang Jinfeng, Liang Yun, Yuan Jianping, et al. Numerical simulation of recirculation control at centrifugal pump inlet[J]. Journal of Jiangsu University:Natural Science Edition, 2012, 33(4):402-407.(in Chinese)[7]Yuan Jianping, Fu Yanxia, Yuan Shouqi. A study of cavitation flow in a centrifugal pump at part load conditions based on numerical analysis[C]//Proceedings of ASME Fluids Engineering Division Summer Meeting, 2012:193-202.[8]谈明高,徐欢,刘厚林,等.基于CFD的离心泵小流量工况下扬程预测分析[J].农业工程学报,2013,29(5):31-36. Tan Minggao, Xu Huan, Liu Houlin, et al. Analysis of head prediction of centrifugal pumps at low flow rate based on CFD[J]. Transactions of the CSAE, 2013, 29(5):31-36.(in Chinese)[9]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,2004:113-158.[10]李晓俊,袁寿其,潘中永,等.离心泵边界层网格的实现及应用评价[J].农业工程学报,2012,28(20):67-72. Li Xiaojun, Yuan Shouqi, Pan Zhongyong, et al. Realization and application evaluation of near-wall mesh in centrifugal pumps[J]. Transactions of the CSAE, 2012, 28(20):67-72.(in Chinese)[11]Zhou Ling, Shi Weidong, Lu Weigang, et al. Numerical investigations and performance experiments of a deep-well centrifugal pump with different diffusers[J]. Journal of Fluids Engineering, 2012, 134(7):071102.[12]Chakraborty S, Pandey K M, Roy B. Numerical analysis on effects of blade number variations on performance of centrifugal pumps with various rotational speeds[J]. Journal of Current Engineering and Technology, 2012, 2(1):143-152.[13]Ding H, Visser F C, Jiang Y, et al. Demonstration and validation of a 3D CFD simulation tool predicting pump performance and cavitation for industrial applications[C]//Proceedings of ASME Fluids Engineering Division Summer Meeting, 2009:1-17.[14]祝磊,袁寿其,袁建平,等.阶梯隔舌对离心泵压力脉动和径向力影响的数值模拟[J].农业机械学报,2010,41(增刊):21-26. Zhu Lei, Yuan Shouqi, Yuan Jianping, et al. Numerical simulation on pressure fluctuations and radial hydraulic forces in centrifugal pump with step-tongue[J]. Transactions of the Chinese Society for Agricultural Machinery, 2010, 41(S1):21-26.(in Chinese)[15]苏铭德,黄素逸.计算流体力学基础[M].北京:清华大学出版社,1997:231-314.[16]赖喜德.叶片式流体机械的数字化[M].成都:四川大学出版社,2007:139-167.[17]关醒凡.泵的理论与设计[M].北京:机械工业出版社,1987:26-51.