Numerical simulation of excess output condition of a pump-turbine based on compressible calculation
Liu Jintao1, Li Xiaopeng2, Guo Lei3, Wang Leqin3
1.Beijing Institute of Control Engineering, Beijing 100190, China; 2.Central Power Supply Company, Sinopec Shengli Power Management Corporation, Dongying, Shandong 257000, China; 3.Institute of Chemical Machinery Engineering, Zhejiang University, Hangzhou, Zhejiang 310027, China
Abstract：The flow in the runner was speed up at the excess output condition, and flow separation may occur in the runner and the pressure fluctuation was amplified. To study the hydraulic instability of a pump-turbine at excess output condition, a 3D pump-turbine model was set up. Unsteady,incompressible flow was used for numerical simulation using SST k-ω turbulence model under 110% rated power condition. The inner flow as well as the pressure fluctuation in the pump-turbine was analyzed. The law of evolution of pressure fluctuation in the field between the casing and the runner was investigated. Calculation results were compared with the experimental data. The results show that the amplitude of pressure fluctuation increases along the flow direction near the region of vanes. The dominant frequency of pressure fluctuation changes into half of the two times of blade passing frequency between guide vanes and stay vanes. The ratio of the relative amplitude of 9 fn frequency to the amplitude of mixture frequency decreases in the domain of guide vanes. The separation flow at the pressure side in the runner, as well as a large vortex rope in the draft tube, can be found at excess output condition.
刘锦涛, 李晓鹏, 郭雷, 王乐勤. 基于弱可压缩计算的水泵水轮机超出力分析[J]. 排灌机械工程学报, 2013, 31(10): 874-878.
Liu Jintao, Li Xiaopeng, Guo Lei, Wang Leqin. Numerical simulation of excess output condition of a pump-turbine based on compressible calculation. Journal of Drainage and Irrigation Machinery Engin, 2013, 31(10): 874-878.
[1]Hasmatuchi V, Farhat M, Maruzewski P, et al. Experimental investigation of a pump-turbine at off-design o-perating conditions[C]//Proceedings of 3rd Internatio-nal Meeting of the Workgroup on Cavitation and Dyna-mic Problems in Hydraulic Machinery and Systems.Brno, Czech Republic:[s.n.],2009:339-347.[2]Hasmatuchi V, Roth S, Botero F, et al. High-speed flow visualization in a pump-turbine under off-design o-perating conditions [C]//Proceedings of 25th IAHR Symposium on Hydraulic Machinery and Systems. Timisoara, Romania:[s.n.], 2010:1-8.[3]刘锦涛,刘树红,孙跃昆, 等. 水泵水轮机空载开度压力脉动特性预测[J]. 工程热物理学报,2012,33(3):411-414. Liu Jintao, Liu Shuhong, Sun Yuekun, et al. Prediction of pressure fluctuation of a pump-turbine at no-load opening [J]. Journal of Engineering Thermophysics, 2012,33(3): 411-414.(in Chinese)[4]尹俊连,刘锦涛,王乐勤,等. 水泵水轮机泵工况小流量区压力脉动预测[J]. 工程热物理学报,2011,32(7):1141-1144. Yin Junlian, Liu Jintao, Wang Leqin, et al. Prediction of pressure fluctuations of pump-turbine under off-design condition in pump mode [J]. Journal of Engineering Thermophysics,2011, 32(7):1141-1144.(in Chinese)[5]Liu Jintao, Liu Shuhong, Wu Yulin, et al. Numerical investigation of the hump characteristic of a pump-turbine based on an improved cavitation model [J]. Computers and Fluids, 2012, 68:105-111.[6]Yin Junlian, Liu Jintao, Wang Leqin, et al. Perfor-mance prediction and flow analysis in the vaned distributor of a pump turbine under low flow rate in pump mode[J]. Science China Technological Sciences, 2010, 53(12):3302-3309.[7]Menter F R. Two-equation eddy-viscosity turbulence models for engineering applications[J]. AIAA Journal, 1994,32(8):1598-1605.[8]Cable M. An Evaluation of Turbulence Models for the Numerical Study of Forced and Natural Convective Flow in Atria [D]. Kingston: Department of Mechanical and Materials Engineering of Queen′s University, 2009.[9]Yan J,Koutnik J,Seidel U, et al.Compressible simulation of rotor-stator interaction in pump-turbines[C]//Proceedings of 25th IAHR Symposium on Hydraulic Machinery and Systems. Timisoara,Romania:[s.n.],2010: 1-8.[10]Ahujia V, Hosangadi A, Arunajatesan S. Simulations of cavitating flows using hybrid unstructured meshes[J]. Journal of Fluids Engineering, 2001,123(2): 331-334.[11]Venkateswaran S,Lindau J W,Kunz R F, et al. Computation of multiphase mixture flows with compressibility effects[J]. Journal of Computational Physics, 2002,180(1): 54-77.[12]Decaix J, Goncalves E. Compressible effects modeling in turbulent cavitating flows[J]. European Journal of Mechanics, B/Fluids, 2013, 39:11-31.[13]Gatski T, Bonnet J P. Compressibility, Turbulence and High Speed Flow [M]. Amsterdam:Elsevier Science, 2009.[14]Goncalves E, Patella R F. Numerical simulation of cavitating flows with homogeneous models [J]. Computers and Fluids, 2009, 38(9):1682-1696.
