Characteristics of backflow vortex cavitation in screw centrifugal pump

doi:10.3969/j.issn.1002-6819.2015.01.013

IR > 新能源学院

	Characteristics of backflow vortex cavitation in screw centrifugal pump
	Deng, Yuxuan; Li, Rennian; Han, Wei; Yang, Wenjie; Li, Zhenggui; Zhang, Yipeng
	2015
发表期刊	Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering
ISSN	10026819
卷号	31 期号:1 页码:86-90
摘要	Screw centrifugal pump has swirling backflow under a wide range of flow rates. The backflow vortex structure occurs in the shear layer between the main flow and the swirling backflow. The pressure at the core of a backflow vortex is lower than the ambient pressure due to the centrifugal force on the vertical flow which results in cavitation if the core pressure becomes lower than the vapor pressure. This is called backflow vortex cavitation. In order to study the backflow vortex cavitation, a screw centrifugal pump was designed for experimental studies. The clearance between vane rim and cover plate was 2.9 mm in this screw centrifugal pump. By using the high speed video picture, we observed two backflow vortex cavitation clouds extending upstream from the tip at the screw centrifugal pump inlet, covering a wide range of flow rates. We also found that under a certain net positive suction head (NPSH), i.e., when the flow rate was decreased, the volume of the two backflow vortex cavitation cloud was decreased. Experimental studies on the backflow vortex cavitation from this screw centrifugal pump have provided novel insight of the characteristics of backflow vortex cavitation, but the limited information has not lead to the complete understanding of the phenomena. In addition to blade surface and backflow vortex cavitations, tip leakage cavitation occurred for screw centrifugal pump with tip clearance. With these types of cavitation, the flow in a screw centrifugal pump presented a very complicated three-dimensional structure. Since experiment results give limited information, numerical simulation plays an important role to further understand such complicate flow phenomena. Using the CFD code, the fundamental characteristics of the backflow vortex cavitation was investigated in detail. It was found that the backflow vortices were formed in a circumferentially twisted manner at the boundary between the swirling backflow and the straight inlet flow. When the flow rate was decreased, the screw centrifugal pump inlet flow velocity increased, but the static pressure of fluid at screw centrifugal pump inlet region decreased. As the screw centrifugal pump inlet fluid static pressure was decreased, the static pressure of suction side of vane region near by vane tip at screw centrifugal pump inlet decreased. Meanwhile, the pressure of pressure side of vane region near by vane tip at screw centrifugal pump inlet was about vapor pressure. With the decreased flow rate, the pressure difference of pressure side of vane and suction side of vane reduced. The backflow region reduced upstream due to the decreased pressure difference of pressure side of vane and suction side of vane, which is the main reason of the two backflow vortex cavitation volume decreased with the flow rate decreased in screw centrifugal pump. When the clearance between vane rim and cover plate was less than 1.3 mm in the screw centrifugal pump, the screw centrifugal pump inlet region had no backflow occurred. It indicated that the size of clearance between vane rim and cover plate have influences on backflow vortex cavitation occurred in screw centrifugal pump inlet. The purpose of the present study is to obtain a further understanding of backflow vortex cavitation. ©, 2015, Chinese Society of Agricultural Engineering. All right reserved.
关键词	Cavitation Centrifugal pumps Computational fluid dynamics Computer simulation Flow rate Flow velocity High speed cameras Hydrodynamics Hydrostatic pressure Inlet flow Plates (structural components) Screws Shear flow Backflow Fundamental characteristics Limited information Net positive suction heads Pressure differences Screw centrifugal pumps Three-dimensional structure Tip leakage cavitation
DOI	10.3969/j.issn.1002-6819.2015.01.013
收录类别	EI
语种	中文
出版者	Chinese Society of Agricultural Engineering
EI入藏号	20151000594721
EI主题词	Vortex flow
EI分类号	408.2 Structural Members and Shapes - 605 Small Tools and Hardware - 618.2 Pumps - 631 Fluid Flow - 723.5 Computer Applications - 742.2 Photographic Equipment
来源库	Compendex
分类代码	408.2 Structural Members and Shapes - 605 Small Tools and Hardware - 618.2 Pumps - 631 Fluid Flow - 723.5 Computer Applications - 742.2 Photographic Equipment
引用统计	无
文献类型	期刊论文
条目标识符	https://ir.lut.edu.cn/handle/2XXMBERH/112331
专题	新能源学院能源与动力工程学院
作者单位	School of Energy and Power Engineering, Lanzhou University of Technology, Lanzhou; 730050, China
第一作者单位	新能源学院
第一作者的第一单位	新能源学院
推荐引用方式 GB/T 7714	Deng, Yuxuan,Li, Rennian,Han, Wei,et al. Characteristics of backflow vortex cavitation in screw centrifugal pump[J]. Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering,2015,31(1):86-90.
APA	Deng, Yuxuan,Li, Rennian,Han, Wei,Yang, Wenjie,Li, Zhenggui,&Zhang, Yipeng.(2015).Characteristics of backflow vortex cavitation in screw centrifugal pump.Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering,31(1),86-90.
MLA	Deng, Yuxuan,et al."Characteristics of backflow vortex cavitation in screw centrifugal pump".Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering 31.1(2015):86-90.