为研究叶片数对离心泵叶轮失速特性的影响,以4种不同叶片数的离心泵叶轮为研究对象,采用改进的亚格子模型(Sub-grid scale model, SGS)对叶轮的内部流场进行数值模拟,得到不同叶片数的失速团的运动规律,以及失速频率、失速团个数、转速等特性参数。研究表明,叶片数对叶轮内部失速团的类型有显著影响,当叶片数为偶数时,会发生“交替失速”流动现象;当叶片数为奇数时,会发生“旋转失速”流动现象。另外,叶片数对失速团特征参数也有一定影响。当发生“交替失速”时,叶片数增多,失速团的数量也随之增多,失速频率也随之变化,4叶片叶轮失速团的失速频率约是6叶片的2.4倍;而当发生“旋转失速”时,叶片数增多,失速团的数量也随之增多,转速也随之增大,7叶片叶轮失速团的转速约是5叶片的1.8倍,失速频率是它的3.8倍。
In order to investigate the effects of blade number on stall characteristics for a centrifugal pump impeller, a developed Sub-grid scale model is applied to a centrifugal pump impeller with different blade number. The motion rule and characteristic parameters of stall cells are obtained, including the number, stall frequency and rotation speed. The results show that the blade number has significant effects on stall types. As the blade number is even, the alternative stall phenomenon occurs. Otherwise, when it is odd, the rotating stall phenomenon appears. Furthermore, the blade number also has influence on the characteristic parameters of stall cells. Under the alternative stall condition, as the increase of blade number, the number of stall cells increases, while the stall frequency decreases. The stall frequency of 4 blades is 2.4 times as large as that of 6 blades. Under the rotating stall condition, with the increase of blade number, the number of stall cells also increased. The speed of stall cells of the impeller with 7 blades is 1.8 times as fast as that with 5 blades. The stall frequency of 7 blades is 3.8 times as large as that with 5 blades.
[1] FRANCE D. A review of vibration problems in power station boiler feed pumps[C]//NASA C. P.,US,1994：249-276.
[2] LIU H,WANG Y,YUAN S,et al. Effects of blade number on characteristics of centrifugal pumps[J]. Chinese Journal of Mechanical Engineering,2010,23(6)：742-747.
[3] CHAKRABORTY S,CHOUDHURI K,DUTTA P,et al. Performance prediction of centrifugal pumps with variations of blade number[J]. Journal of Scientific & Industrial Research,2013,72(6)：373-378.
[4] ZHANG Z. Rotating stall mechanism and stability control in the pump flows[J]. Proceedings of the Institution of Mechanical Engineers,Part A：Journal of Power and Energy,2011,225(6)：779-788.
[5] BERTEN S,DUPONT P,FABRE L,et al. Experimental investigation of flow instabilities and rotating stall in a high energy centrifugal pump stage[C]//Proceedings of the 2009 ASME Fluids Engineering Division Summer Meetings,Colorado,US,2009：78562.1-78562.6
[6] PACOT O,KATO C,AVELLAN F. High-resolution LES of the rotating stall in a reduced scale model pump-turbine[C]//IAHR Symposium,Canada,2014：22018.1-22018.8.
[7] PEDERSEN N,LARSEN P S,JACOBSEN C B. Flow in a centrifugal pump impeller at design and off-design conditions—Part I：Particle image velocimetry (PIV) and laser Doppler velocimetry (LDV) measurements[J]. Journal of Fluids Engineering,2003,125(1)：61-72.
[8] FENG J,BENRA F K,DOHMEN H J. Unsteady flow visualization at part-load conditions of a radial diffuser pump：By PIV and CFD[J]. Journal of Visualization,2009,12(1)：65-72.
[9] KRAUSE N,ZAHRINGER K,PAP E. Time-resolved particle imaging velocimetry for the investigation of rotating stall in a radial pump[J]. Experiments in Fluids,2005,39(2)：192-201.
[10] ULLUM U,WRIGHT J,DAYI O,et al. Prediction of rotating stall within an impeller of a centrifugal pump based on spectral analysis of pressure and velocity data[C]//Journal of Physics：Conference Series,Denmark,2006：36-45.
[11] BYSKOV R K,JACOBSEN C B,PEDERSEN N. Flow in a centrifugal pump impeller at design and off-design conditions—Part II：Large eddy simulations[J]. Journal of Fluids Engineering,2003,125(1)：73-83.
[12] YANG Z,WANG F,ZHOU P. Evaluation of subgrid-scale models in large-eddy simulations of turbulent flow in a centrifugal pump impeller[J]. Chinese Journal of Mechanical Engineering,2012,25(5)：911-918.
[13] 周佩剑,王福军,姚志峰. 离心泵叶轮旋转失速团特性分析[J]. 水利学报,2015,46(9)：1128-1134.
ZHOU Peijian,WANG Fujun,YAO Zhifeng. Analysis of rotating stall cells in an impeller of a centrifugal pump [J]. Journal of Hydraulic Engineering,2015,46(9)：1128-1134.
[14] YANG Z,WANG F. A dynamic mixed nonlinear subgrid-scale model for large-eddy simulation[J]. Engineering Computations,2012,29(7)：778-791.
[15] LEVY Y,PISMENNY J. The number and speed of stall cells during rotating stall[C]//ASME Turbo Expo,Georgia,USA,2003：889-899.
[16] BRENNEN C E. Hydrodynamics of pumps[M]. Cambridge：Cambridge University Press,2011.
