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International Journal of Rotating Machinery
Volume 2013 (2013), Article ID 317473, 12 pages
Research Article

Effects of Flow Rate and Viscosity on Slip Factor of Centrifugal Pump Handling Viscous Oils

Department of Fluid Machinery, Lanzhou University of Technology, 287 Langongping Road, Lanzhou, Gansu 730050, China

Received 14 March 2013; Revised 3 June 2013; Accepted 19 June 2013

Academic Editor: Ryoichi Samuel Amano

Copyright © 2013 Wen-Guang Li. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Slip factor is an important parameter in the hydraulic design of centrifugal pump impeller for handling viscous oils. How to extract the factor from CFD computational results and how flow rate and liquid viscosity to affect it remain unclear. In the present paper, the flip factor was estimated by means of two approaches: one is from the velocity triangles at the impeller outlet and the other is due to the impeller theoretical head of 3D turbulent viscous fluid. The velocity of water and viscous oils in the impeller and volute computed by CFD was validated with LDV measurements at the best efficiency point. The effect of exit blade angle on slip factor was clarified. It was shown that the two approaches result into two different slip factors. The factors are significantly dependent of flow rate; however, the liquid viscosity seems to take less effect on them. Volute is responsible for reduction in tangential velocity of liquid at the outlet of impeller at low flow rates. The slip factor of impeller with large exit blade angle is not sensitive to flow rate.