长短交错叶片对离心泵空蚀特性的影响
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摘要
为了改善离心泵的抗空蚀性能,本文建立3种不同叶片进口形状的叶轮模型。利用数值模拟方法对不同工况下的3种叶轮叶片形状下的离心泵在不同空化余量时内部流动规律进行了研究,分析不同工况下离心泵内部流场特性及空化特性、以及不同空化余量下3种叶片叶轮内的空蚀特性。结果表明:长叶片离心泵最容易发生空化产生空蚀损伤;短叶片和长短交错叶片离心泵较宽的叶轮进口喉部面积改善了泵在叶轮进口处的吸入性能,具有最佳的抗空蚀性能,空蚀损伤区域面积和空蚀强度有显著的减小。由于叶型的不同,短叶片叶轮的扬程与效率有明显的下降,往往达不到设计所需求的扬程和效率。综合比较下,长短交错叶片在不影响离心泵扬程和效率的前提下具有最佳的抗空化效果,有效地改善了离心泵的空蚀性能。
To improve the cavitation erosion performance of centrifugal pumps,this study established three impeller models with different blade inlet shapes. The internal flow pattern of the centrifugal pump with three kinds of impeller blades under different cavitation margins was studied by numerical simulation. The effect of the three kinds of impeller blades in different cavitation margins on the impeller flow and cavitation characteristics was analyzed. The result shows that cavitation erosion is most likely to occur in the centrifugal pump with a long blade. The centrifugal pumps with a short blade and a long-short staggered blade exhibit the best anti-cavitation erosion performance because the wide inlet throat area of the impeller improves the suction performance. The area and erosion strength of the cavitation are significantly reduced with the short blade and the long-short staggered blade of the centrifugal pump. The efficiency and head of the centrifugal pump with a short blade significantly decline,failing to reach the requirements of the design. Hence,the centrifugal pump with a long-short staggered blade exhibits the best anticavitation erosion effect without affecting the head and efficiency. This type of blade effectively improves the cavitation erosion performance of centrifugal pumps.
To improve the cavitation erosion performance of centrifugal pumps,this study established three impeller models with different blade inlet shapes. The internal flow pattern of the centrifugal pump with three kinds of impeller blades under different cavitation margins was studied by numerical simulation. The effect of the three kinds of impeller blades in different cavitation margins on the impeller flow and cavitation characteristics was analyzed. The result shows that cavitation erosion is most likely to occur in the centrifugal pump with a long blade. The centrifugal pumps with a short blade and a long-short staggered blade exhibit the best anti-cavitation erosion performance because the wide inlet throat area of the impeller improves the suction performance. The area and erosion strength of the cavitation are significantly reduced with the short blade and the long-short staggered blade of the centrifugal pump. The efficiency and head of the centrifugal pump with a short blade significantly decline,failing to reach the requirements of the design. Hence,the centrifugal pump with a long-short staggered blade exhibits the best anticavitation erosion effect without affecting the head and efficiency. This type of blade effectively improves the cavitation erosion performance of centrifugal pumps.
引文
[1]卢池.流体机械内部空化流动的数值模拟[D].成都:西华大学,2006.LU Chi. Numerical simulation for cavitations flow inside fluid machinery[D]. Chengdu:Xihua University,2006.
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[4]谢山峰.开缝叶片对低比转速离心泵性能影响的研究[D].镇江:江苏大学,2016.XIE Shanfeng. Study on effect of slotted blades on low specific speed centrifugal pump performance[D]. Zhenjiang:Jiangsu University,2016.
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[9]TAN Lei,ZHU Baoshan,CAO Shuliang,et al. Influence of prewhirl regulation by inlet guide vanes on cavitation performance of a centrifugal pump[J]. Energies, 2014,7(2):1050-1065.
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[11]AN Y J,SHIN B R. Numerical investigation of suction vortices behavior in centrifugal pump[J]. Journal of mechanical science and technology,2011,25(3):767-772.
[12]BIDHANDI M E,RIASI A,ASHJAEE M. The influence of SiO2nanoparticles on cavitation initiation and intensity in a centrifugal water pump[J]. Experimental thermal and fluid science,2014,55:71-76.
[13]王秀礼,袁寿其,朱荣生,等.长短叶片离心泵汽蚀性能数值模拟分析及实验研究[J].中国机械工程,2012,23(10):1154-1157.WANG Xiuli,YUAN Shouqi,ZHU Rongsheng,et al. Numerical simulation and experimental study for cavitations in centrifugal pump impeller with splitters[J]. China mechanical engineering,2012,23(10):1154-1157.
[14]郭晓梅,朱祖超,崔宝玲,等.诱导轮长短叶片位置对高速离心泵汽蚀性能的影响[J].工程热物理学报,2012,33(10):1695-1698.GUO Xiaomei ZHU Zuchao CUI Baoling,et al. InducerShort blade position influence on cavitation performance of high speed centrifugal pump[J]. Journal of engineering thermophysics,2012,33(10):1695-1698.
[15]DRATMAN E,MATERA G. Newton's method and a mesh-independence principle for certain semilinear boundary-value problems[J]. Journal of computational and applied mathematics,2016,292:188-212.
[16]宫汝志.水轮机水力激振及转子系统振动问题研究[D].哈尔滨:哈尔滨工业大学,2013.GONG Ruzhi. Study on flow induced vibrations and rotor system vibvation in hydro-turbine[D]. Harbin:Harbin Institute of Technology,2013.
[17]BRENNEN C E. Cavitation and bubble dynamics[M].New York:Oxford University Press,1995.
[2]刘宜,张文军,杜杰.离心泵内部空化流动的数值预测[J].排灌机械学报,2008,26(3):19-21.LIU Yi,ZHANG Wenjun,DU Jie. Numerical prediction of cavitation flow in centrifugal pump[J]. Drainage and irrigation machinery,2008,26(3):19-21.
[3]张文军.离心泵全流道内空化流场的数值模拟及预测[D].兰州:兰州理工大学,2008.ZHANG Wenjun. Numerical simulation and prediction of cavitation flow in the whole flow passage of a centrifugal pump[D]. Lanzhou:Lanzhou University of Technology,2008.
[4]谢山峰.开缝叶片对低比转速离心泵性能影响的研究[D].镇江:江苏大学,2016.XIE Shanfeng. Study on effect of slotted blades on low specific speed centrifugal pump performance[D]. Zhenjiang:Jiangsu University,2016.
[5]罗先武,张瑶,彭俊奇,等.叶轮进口几何参数对离心泵空化性能的影响[J].清华大学学报(自然科学版),2008,48(5):836-839.LUO Xianwu,ZHANG Yao,PENG Junqi,et al. Effect of impeller inlet geometry on centrifugal pump cavitation performance[J]. Journal of Tsinghua University(science and technology),2008,48(5):836-839.
[6]王勇,刘庆,刘东喜,等.叶片包角对离心泵空化性能的影响[J].中国农村水利水电,2012,(11):110-113.WANG Yong,LIU Qing,LIU Dongxi,et al. Effects of vane wrap angle on cavitation performance for centrifugal pumps[J]. China rural water and hydropower,2012,(11):110-113.
[7]赵伟国,赵国寿,咸丽霞,等.离心泵叶片表面布置障碍物抑制空化的数值模拟与实验[J].农业机械学报,2017,48(9):111-120.ZHAO Weiguo,ZHAO Guoshou,XIAN Lixia,et al. Effect of surface-fitted obstacle in centrifugal pump on cavitation suppression[J]. Transactions of the Chinese society for agricultural machinery,2017,48(9):111-120.
[8]TAN Lei,ZHU Baoshan,CAO Shuliang,et al. Numerical simulation of unsteady cavitation flow in a centrifugal pump at off-design conditions[J]. Proceedings of the institution of mechanical engineers,part C:journal of mechanical engineering science,2014,228(11):1994-2006.
[9]TAN Lei,ZHU Baoshan,CAO Shuliang,et al. Influence of prewhirl regulation by inlet guide vanes on cavitation performance of a centrifugal pump[J]. Energies, 2014,7(2):1050-1065.
[10]CARIDAD J,ASUAJE M,KENYERY F,et al. Characterization of a centrifugal pump impeller under two-phase flow conditions[J]. Journal of petroleum science and engineering,2008,63(1/2/3/4):18-22.
[11]AN Y J,SHIN B R. Numerical investigation of suction vortices behavior in centrifugal pump[J]. Journal of mechanical science and technology,2011,25(3):767-772.
[12]BIDHANDI M E,RIASI A,ASHJAEE M. The influence of SiO2nanoparticles on cavitation initiation and intensity in a centrifugal water pump[J]. Experimental thermal and fluid science,2014,55:71-76.
[13]王秀礼,袁寿其,朱荣生,等.长短叶片离心泵汽蚀性能数值模拟分析及实验研究[J].中国机械工程,2012,23(10):1154-1157.WANG Xiuli,YUAN Shouqi,ZHU Rongsheng,et al. Numerical simulation and experimental study for cavitations in centrifugal pump impeller with splitters[J]. China mechanical engineering,2012,23(10):1154-1157.
[14]郭晓梅,朱祖超,崔宝玲,等.诱导轮长短叶片位置对高速离心泵汽蚀性能的影响[J].工程热物理学报,2012,33(10):1695-1698.GUO Xiaomei ZHU Zuchao CUI Baoling,et al. InducerShort blade position influence on cavitation performance of high speed centrifugal pump[J]. Journal of engineering thermophysics,2012,33(10):1695-1698.
[15]DRATMAN E,MATERA G. Newton's method and a mesh-independence principle for certain semilinear boundary-value problems[J]. Journal of computational and applied mathematics,2016,292:188-212.
[16]宫汝志.水轮机水力激振及转子系统振动问题研究[D].哈尔滨:哈尔滨工业大学,2013.GONG Ruzhi. Study on flow induced vibrations and rotor system vibvation in hydro-turbine[D]. Harbin:Harbin Institute of Technology,2013.
[17]BRENNEN C E. Cavitation and bubble dynamics[M].New York:Oxford University Press,1995.