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| Numerical simulation and oil film observation on flow field in impeller of screw centrifugal pump with single-blade |
| ZHANG Hua1, CHEN Bin1, SHI Weidong2, WANG Bingqi1, WANG Zhen3 |
| 1.Research Institute of Chemical Machinery, Hefei University of Technology, Hefei, Anhui 230009, China; 2.National Research Center of Pumps, Jiangsu University, Zhenjiang, Jiangsu 212013, China; 3. Lanshen Corp. Ltd., Nanjing, Jiangsu 211500, China |
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Abstract The flow field in a submersible screw centrifugal pump of 240 specific speed with single-blade is studied by using numerical simulation and experimental observation. The pump fluid domains are meshed by using polyhedral cells and the steady turbulent flow in them is calculated by employing the Realizable k-ε turbulence model. The predicted performance curves are compared with measured ones, and the simulated flow field in the impeller is examined against the flow pattern in oil film visua-lization. It is shown that the predicted characteristic curves agree well with the measurements and the calculated streamlines on the impeller flow passage walls are consistent with the oil film observations, suggesting the polyhedral mesh has a better accuracy in flow simulations of the impeller in a screw centrifugal pump. Through an analysis of the internal flow field, a leakage flow around the blade inlet is captured, but it becomes weak gradually with the increase of flow rate. Moreover, under the working conditions of 0.6Qd, 1.0Qd and 1.4Qd, there exists a severe backflow on the hub surface near the blade suction side around the impeller outlet; especially, at 0.6Qd flow rate, the backflow has occupied an area as large as more than 80% the flow channel width. A backflow also exists in the corner between the blade pressure side and the hub; the smaller the flow rate, the more serious the backflow. Under these three working conditions, there exists a larger gradient in the velocity at volute outlet.
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Received: 30 April 2015
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