Numerical analysis of free surface vortices behavior in a pump sump

Asian Working Group- IAHR's Symposium on Hydraulic Machinery and Systems

Amin, A.^1 ; Kim, C.G.^2 ; Lee, Y.H.^3

Department of Mechanical Engineering, Korea Maritime and Ocean University, Busan, Korea, Republic of^1

Brain Korea 21 Plus, Korea Maritime and Ocean University, Busan, Korea, Republic of^2

Divisions of Mechanical Engineering, Korea Maritime and Ocean University, Busan, Korea, Republic of^3

关键词: CFD simulations;    Efficiency and performance;    Free-surface vortices;    Impeller rotation;    Numerical and experimental analysis;    Pumping stations;    Tangential velocities;    Vortex formation;   

Others  :  https://iopscience.iop.org/article/10.1088/1755-1315/163/1/012103/pdf
DOI  :  10.1088/1755-1315/163/1/012103

来源: IOP

【 摘 要 】

Recently, designers and engineers of pump stations realized that the efficiency and performance of a pumping station does not depend only on the performance of selected pumps but also on proper design of intake sumps. Most recurring problems faced in a pumping station are related to the sump design or intake design rather than pump design. Swirl angle parameter and free surface vortex formation are important parameters that determine the quality of flow ingested by sump. For swirl angle parameter, the hydraulic institute prescribes the method that needs to be employed for estimating this parameter. On the other hand, the free surface vortex formation also leads to a decrease in the efficiency of pump intake and pump especially when the vortex rope rotates opposite to impeller rotation. In this study, both numerical and experimental analysis of a rectangular pump sump was carried out to predict swirl angle and free surface vortices formation. The swirl angle experimentally was obtained using a traditional swirl meter installed at the suction pipe in rectangular single pump intake. The objective was to obtain the average tangential velocity at different suction pipe diameter. For free surface vortices the objective was to observe the different vortex formation, air entrance and location. The swirl angle and average tangential velocity estimated by CFD simulation was in agreement with experimental results. The four types of free surface vortices (Surface swirl, Surface dimple, air bubbles and full air core to intake) was also observed clearly in ANSYS CFX.