高水头水泵水轮机空化特性分析
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摘要
为探究多工况下水泵水轮机空化特性,选取5个典型工况,采用Rayleigh-Plesset空化模型对水泵水轮机进行三维定常数值模拟。结果表明:在水轮机工况,伴随空化数减小,大、中流量下长叶片吸力面靠近下环根部的空化程度逐渐加重,沿下环线形成类似鱼尾拖拽区,而小流量空化区域则沿长叶片吸力面出口的中部向来流方向蔓延。在水泵高、低扬程工况,空化区域位于长叶片不同部位,空化严重时易引起叶片表面流体脱流及流道漩涡现象,导致扬程急剧下降。
In order to investigate the cavitation characteristics of pump turbine with splitter blades under multi-condition,three turbine and two pump operating conditions are selected. The Rayleigh-Plesset cavitation model is used to simulate the three-dimensional constant values of a pump turbine. The calculated results are in good agreement with the measured data of the flow field,and the variation of energy characteristics and cavitation performance under different working conditions are predicted. The results show that in the turbine mode,as the cavitation number decreases,the degree of cavitation of the root of suction surface of long blade near the lower ring increases gradually under large and medium flow conditions,and a dragging area similar to fish tail is formed along the lower ring line,the cavitation area spreads to the inlet along the middle of the outlet of the suction surface of the long blade,which is significantly enlarged. Under the low head condition of the pump mode,cavitation mainly occurs on the long blade pressure surface. However,the suction surface of the long blade is susceptible to serious cavitation at the high head condition,and the front edge of the pressure is only slightly cavitated. When cavitation is serious,it is easy to cause fluid flow off the surface of the blade and vortex in the flow channel and a sharp drop in head.
In order to investigate the cavitation characteristics of pump turbine with splitter blades under multi-condition,three turbine and two pump operating conditions are selected. The Rayleigh-Plesset cavitation model is used to simulate the three-dimensional constant values of a pump turbine. The calculated results are in good agreement with the measured data of the flow field,and the variation of energy characteristics and cavitation performance under different working conditions are predicted. The results show that in the turbine mode,as the cavitation number decreases,the degree of cavitation of the root of suction surface of long blade near the lower ring increases gradually under large and medium flow conditions,and a dragging area similar to fish tail is formed along the lower ring line,the cavitation area spreads to the inlet along the middle of the outlet of the suction surface of the long blade,which is significantly enlarged. Under the low head condition of the pump mode,cavitation mainly occurs on the long blade pressure surface. However,the suction surface of the long blade is susceptible to serious cavitation at the high head condition,and the front edge of the pressure is only slightly cavitated. When cavitation is serious,it is easy to cause fluid flow off the surface of the blade and vortex in the flow channel and a sharp drop in head.
引文
[1]袁丹青,陈向阳,白滨,等.水力机械空化空蚀问题的研究进展[J].排灌机械,2009,27(4):269-272.
[2]阮辉,廖伟丽,罗兴锜,等.叶片低压边的轴面位置对高水头水泵水轮机空化性能的影响[J].农业工程学报,2016,32(16):73-81.
[3]阮辉,廖伟丽,罗兴锜,等.叶片低压边厚度对水泵水轮机空化性能与强度的影响[J].农业工程学报,2015,31(15):32-39.
[4]杜荣幸,王庆,榎本保之,等.长短叶片转轮水泵水轮机在清远抽水蓄能电站中的应用[J].水电与抽水蓄能,2016,2(5):39-44.
[5]王焕茂,覃大清,魏显著,等.哈电混流式水泵水轮机长短叶片转轮水力研发及进展[J].水电与抽水蓄能,2016,2(3):38-43.
[6]杜荣幸,陈梁年,德宫健男,等.清远长短叶片水泵水轮机水力研究及模型试验[J].水电站机电技术,2015,38(2):12-15,84.
[7]KUBOTA Kazumasa,Watanabe.The advantage for the application of splitter blades runner in super high head large capacity pump turbine[C]∥23th IAHR Symposium,2006:55-58.(下转第124页)
[8]Lin Hao,Brian D Storey,Andrew J Szeri.Inertially driven inhomogeneities in violently collapsing bubbles:the validity of the RayleighPlesset equation[J].Journal of Fluid Mechanics,2002,452(452):145-162.
[9]Romeo S R,Sebastian M,Ioan A.Numerical analysis of cavitation inception in Francis turbine[C]∥Lausanne:21st IAHR Symposium on Hydraulic Machinery and Systems,2002.
[10]X D Lai,Q W Liang,X M Chen,et al.Experimental investigation of flows in a high-head pump-turbine draft tube at turbine mode[C]∥IOP Conference Series:Earth and Environmental Science,2018.
[11]李琪飞,张建勋,刘萌萌,等.水泵水轮机泵工况下内部空化特性分析[J].热能动力工程,2017,32(10):84-89,144.
[12]罗丽,赖喜德,赵玺,等.不同比例长短叶片对混流式水轮机内部流场的影响[J].中国农村水利水电,2016(7):180-183,186.
[2]阮辉,廖伟丽,罗兴锜,等.叶片低压边的轴面位置对高水头水泵水轮机空化性能的影响[J].农业工程学报,2016,32(16):73-81.
[3]阮辉,廖伟丽,罗兴锜,等.叶片低压边厚度对水泵水轮机空化性能与强度的影响[J].农业工程学报,2015,31(15):32-39.
[4]杜荣幸,王庆,榎本保之,等.长短叶片转轮水泵水轮机在清远抽水蓄能电站中的应用[J].水电与抽水蓄能,2016,2(5):39-44.
[5]王焕茂,覃大清,魏显著,等.哈电混流式水泵水轮机长短叶片转轮水力研发及进展[J].水电与抽水蓄能,2016,2(3):38-43.
[6]杜荣幸,陈梁年,德宫健男,等.清远长短叶片水泵水轮机水力研究及模型试验[J].水电站机电技术,2015,38(2):12-15,84.
[7]KUBOTA Kazumasa,Watanabe.The advantage for the application of splitter blades runner in super high head large capacity pump turbine[C]∥23th IAHR Symposium,2006:55-58.(下转第124页)
[8]Lin Hao,Brian D Storey,Andrew J Szeri.Inertially driven inhomogeneities in violently collapsing bubbles:the validity of the RayleighPlesset equation[J].Journal of Fluid Mechanics,2002,452(452):145-162.
[9]Romeo S R,Sebastian M,Ioan A.Numerical analysis of cavitation inception in Francis turbine[C]∥Lausanne:21st IAHR Symposium on Hydraulic Machinery and Systems,2002.
[10]X D Lai,Q W Liang,X M Chen,et al.Experimental investigation of flows in a high-head pump-turbine draft tube at turbine mode[C]∥IOP Conference Series:Earth and Environmental Science,2018.
[11]李琪飞,张建勋,刘萌萌,等.水泵水轮机泵工况下内部空化特性分析[J].热能动力工程,2017,32(10):84-89,144.
[12]罗丽,赖喜德,赵玺,等.不同比例长短叶片对混流式水轮机内部流场的影响[J].中国农村水利水电,2016(7):180-183,186.
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