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Unsteady Flow and Structural Behaviors of Centrifugal Pump under Cavitation Conditions

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Chinese Journal of Mechanical Engineering 2019年第1期32卷 127-141页

作者： Denghao Wu Yun Ren jiegang mou Yunqing Gu Lanfang Jiang College of Mechanical Engineering Zhejiang University of Technology Zhijiang College Zhejiang University of Technology

Cavitation has a significant e ect on the flow fields and structural behaviors of a centrifugal pump. In this study, the unsteady flow and structural behaviors of a centrifugal pump are investigated numerically under di erent cavitation conditions. A strong two-way coupling fluid-structure interaction simulation is applied to obtain interior views of the e ects of cavitating bubbles on the flow and structural dynamics of a pump. The renormalization-group k-ε turbulence model and the Zwart–Gerbe–Belamri cavitation model are solved for the fluid side, while a transient structural dynamic analysis is employed for the structure side. The di erent cavitation states are mapped in the head-net positive suction head(H-NPSH) curves and flow field features inside the impeller are fully revealed. Results indicate that cavitating bubbles grow and expand rapidly with decreasing NPSH. In addition, the pressure fluctuations, both in the impeller and volute, are quantitatively analyzed and associated with the cavitation states. It is shown that influence of the cavitation on the flow field is critical, specifically in the super-cavitation state. The e ect of cavitation on the unsteady radial force and blade loads is also discussed. The results indicate that the averaged radial force increased from 8.5 N to 54.4 N in the transition progress from an onset cavitation state to a super-cavitation state. Furthermore, the structural behaviors, including blade deformation, stress, and natural frequencies, corresponding to the cavitation states are discussed. A large volume of cavitating bubbles weakens the fluid forces on the blade and decreases the natural frequencies of the rotor system. This study could enhance the understanding of the e ects of cavitation on pump flow and structural behaviors.

关键词： Centrifugal pump Cavitation Unsteady flow Structural behaviors Fluid-structure interaction

Influence of the Area of the Reflux Hole on the Performance of a Self-Priming Pumnp

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Fluid Dynamics & Materials Processing 2019年第3期15卷 187-205页

作者： jiegang mou Fengye Zhang Haoshuai Wang Denghao Wu Department of Mechanical Engineering Zhejiang University of TechnologyHangzhou310014China

The self-priming process of a pump involves a complex gas-liquid two-phase *** the distribution of gas and water and the evolution of their flow in the pump is of great importance to optimize this process and shorten the pump self-priming *** the present study,a standard k-εturbulence model and a multiphase flow model have been used to simulate the self-priming pump process considering four different reflux hole areas.A comparison of the distribution of air and water distribution on the axial surface and inside the volume have been carried out for the different considered *** pattern formed by the streamlines at different times during the whole self-priming process has also been *** results show that the velocity at the trailing edge of the impeller outlet is the *** flow in the pump cavity *** by the formation of *** number,shape and location of the vortices change depending on the considered configuration.

关键词： Self-priming pump self-priming process reflux hole numerical simulation

Investigation of Self-Priming Process of a Centrifugal Pump with Double Blades

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Journal of Thermal Science 2021年第3期30卷 849-858页

作者： QIAN Heng mou jiegang REN Yun ZHU Zhibing LIU Nuojia ZHENG Shuihua WU Denghao College of Mechanical Engineering Zhejiang University of TechnologyHangzhou 310014China College of Metrology&Measurement Engineering China Jiliang UniversityHangzhou 310018China Zhijiang College Zhejiang University of TechnologyShaoxing 312030China

The gas-liquid two-phase flow patterns of a centrifugal pump during the self-priming process were investigated numerically and *** Euler-Euler multiphase model and SST k-ω turbulence model were applied for simulating the self-priming ***,the changes of motor speed and self-priming height were considered in the *** overall transient two-phase flow features and water level distributions were *** showed that the self-priming process was divided into three *** liquid level in inlet-pipe rose in oscillation during self-priming *** variations of water level during self-priming process of numerical simulation and test result agreed *** inlet-pipe(Ver)was filled at 22 s and 24 s respectively numerically and *** bubble cloud circulated in the volute during middle stage of self-priming process,and breakup into smaller bubbles by shear force and tongue,and then discharged into *** bubbles in the outlet-pipe mainly included bubbly flow and slug flow at the last stage of self-priming process,which is morphologically consistent with the test ***,during the self-priming process,the reflux liquid was pressed by blades and fully mixed with gas;that is the way to realizing the function of self-priming.

关键词： self-priming process gas-liquid two-phase flow centrifugal pump gas-liquid mixing and separation transient numerical simulation

Effects of Particle Concentration on the Dynamics of a Single-Channel Sewage Pump under Low-Flow-Rate Conditions

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Fluid Dynamics & Materials Processing 2021年第5期17卷 871-886页

作者： Peijian Zhou Chaoshou Yan Lingfeng Shu Hao Wang jiegang mou Research Center on Levee Safety Disaster Prevention Zhengzhou450003China College of Metrology and Measurement Engineering China Jiliang UniversityHangzhouChina College of Mechanical Engineering Zhejiang University of TechnologyHangzhouChina Power China Huadong Engineering Corporation Limited HangzhouChina

Single-channel sewage pumps are generally used to transport solid-liquid two-phase media consisting of a fluid and solid particles due to the good non-clogging property of such ***,the non-axisymmetric structure of the impeller of this type of pumps generally induces flow asymmetry,oscillatory outflow during operations,and hydraulic *** severe cases,these effects can jeopardize the safety and stability of the overall *** the present study,such a problem is investigated in the framework of a Mixture multiphase flow method coupled with a RNG turbulence model used to determine the structure of the flow field and the related motion of transported *** is shown that under different inlet particle concentrations,the flow field in the pump exhibits periodic variations of the *** volume fraction of solid particles at the trailing edge of the suction surface of the blade is the largest,and solid particles tend to be concentrated at the outer edge of the pump *** a rise in import particle content,the pressure and volume fraction of particles in the sewage pump also increase;for a fixed inlet particle concentration,the pressure pulsation amplitude increases with an increase in the flow *** addition,under small flow conditions,as the inlet particle concentration increases,the flow field leaving the sewage pump diaphragm near the outlet of the volute becomes more turbulent,and even a secondary back-flow vortex appears.

关键词： Single-channel sewage pump numerical simulation solid-liquid two-phase flow particle distribution secondary flow

A Numerical Investigation on the Characteristics of the Radial Force in a Cycloid Gerotor Pump

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Fluid Dynamics & Materials Processing 2020年第5期16卷 1007-1018页

作者： Lingzhi Yu Yunqing Gu jiegang mou Denghao Wu Zhenfu Chen Yun Ren College of Metrology&Measurement Engineering China Jiliang UniversityHangzhou310018China College of Mechanical Engineering Zhejiang University of TechnologyHangzhou310014China Zhijiang College Zhejiang University of TechnologyShaoxing312030China

In order to improve the performances of a cycloid gerotor pump,the variations of the radial force induced by different rotating speeds and outlet pressures are analyzed *** the numerical simulations as a basis,an improved oil inlet and outlet groove structure is *** results show that the radial force decreases with the decrease of the outlet pressure and of the rotor *** with the original model,the large-end oil inlet line and pressure line of the new oil groove are *** configuration can effectively weaken the pressure changes inside the gerotor pump and reduce accordingly the radial force on the inner rotor.

关键词： Cycloid gerotor pump radial force oil groove structure pressure distribution

LES Analysis of the Unsteady Flow Characteristics of a Centrifugal Pump Impeller

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Fluid Dynamics & Materials Processing 2022年第5期18卷 1349-1361页

作者： Ting Zhang Denghao Wu Shijun Qiu Peijian Zhou Yun Ren jiegang mou School of Metrology and Measurement Engineering China Jiliang UniversityHangzhouChina Leo Group Pump Co. Ltd.TaizhouChina Zhijiang College Zhejiang University of TechnologyHangzhouChina

Stall phenomena increase the complexity of the internal flow in centrifugal pump *** order to tackle this problem,in the present work,a large eddy simulation(LES)approach is applied to determine the characteristics of these unstable ***,a vorticity identification method is used to characterize quantitatively the vortex position inside the impeller and its influencing *** comparing the outcomes of the numerical simulations and experimental results provided by a Particle Image Velocimetry(PIV)technique,it is shown that an apparent“alternating stall”phenomenon exists inside the impeller when relatively small flow rate conditions are *** stall is generated near the suction side of the blade inlet,grows towards the high-pressure side of the blade in the circumferential direction,and gradually *** the flow rate decreases,the number of stalls remains unchanged,while the related influencing area and strength gradually increase and the circumferential velocity increases.

关键词： Centrifugal pump impeller large eddy simulation unsteady flow stalls vorticity

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射流表面射流孔菱形排布减阻特性实验分析

华中科技大学学报（自然科学版） 2015年第1期43卷 16-20页

作者：谷云庆牟介刚郑水华赵刚浙江工业大学机械工程学院浙江杭州310014 哈尔滨工程大学机电工程学院黑龙江哈尔滨150001

针对射流表面流场特性,以回转体的U-PVC管为实验样件载体,在其表面上加工出按菱形排布的射流孔结构.在射流表面减阻测试实验平台上,对光滑表面和不同射流孔排布方式的射流表面所受摩擦扭矩进行模型实验,分析射流孔排布、射流速度、旋转... 详细信息

针对射流表面流场特性,以回转体的U-PVC管为实验样件载体,在其表面上加工出按菱形排布的射流孔结构.在射流表面减阻测试实验平台上,对光滑表面和不同射流孔排布方式的射流表面所受摩擦扭矩进行模型实验,分析射流孔排布、射流速度、旋转速度等因素对射流表面减阻率的影响,研究射流孔不同排布方式下射流表面减阻特性.结果表明:不同排布方式的实验样件射流表面具有较好减阻效果,射流孔菱形排布的两个对角线均能影响射流表面减阻特性.

关键词：射流表面减阻摩擦扭矩射流孔菱形排布模型实验

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多级冲压泵固液两相流冲蚀特性

振动与冲击 2020年第9期39卷 214-220页

作者：郑水华牟成琪张文奇张冯烨牟介刚浙江工业大学机械工程学院杭州310014

基于离散相模型和标准k-ε湍流模型,对多级冲压泵首级和次级流场进行数值模拟。计算不同固相颗粒质量浓度时的外特性和过流部件冲蚀特性,分析颗粒体积分数分布、流场速度和颗粒运动轨迹,研究其对冲蚀特性的影响。结果表明:随着颗粒浓度... 详细信息

基于离散相模型和标准k-ε湍流模型,对多级冲压泵首级和次级流场进行数值模拟。计算不同固相颗粒质量浓度时的外特性和过流部件冲蚀特性,分析颗粒体积分数分布、流场速度和颗粒运动轨迹,研究其对冲蚀特性的影响。结果表明:随着颗粒浓度的上升,冲压泵的单级扬程和效率线性衰减,当颗粒质量浓度为90 kg/m^3时,单级扬程下降6.89%,效率下降6.95%;叶轮和导叶的冲蚀率与颗粒质量浓度指数正相关,叶片与后盖板的连接处、导叶叶片转弯部分的磨损率最高;较高的颗粒浓度与冲击速度、更为频繁的颗粒冲击是造成上述区域较高的冲蚀率的主要原因。

关键词：冲压泵固液两相流冲蚀颗粒轨迹

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长短交错叶片对离心泵空蚀特性的影响

哈尔滨工程大学学报 2019年第3期40卷 593-602页

作者：牟介刚施郑赞谷云庆王浩帅浙江工业大学机械工程学院浙江杭州310014

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... 详细信息

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。

关键词：离心泵长短交错叶片数值模拟空泡空蚀强度空蚀区域