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

Abstract

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.

Influence of Balance Hole Diameter on Leakage Flow of the Balance Chamber in a Centrifugal Pump

“…is demonstrates the existence of turbulent boundary layers near the outer wall of the impeller back cover plate and the fixed inner wall. In addition, a core flow area can be found between two layers, with the core velocity varying slightly along the axial direction [19][20][21][22][23][24]. erefore, the flow field distribution at the axial center of the balance chamber reflects the overall distribution of flow in the core flow area of the balance chamber.…”

Design Optimization of the Centrifugal Pumps via Low Fidelity Models

“…This phenomenon is severe at off-design working condition of a centrifugal pump [1][2][3][4][5][6][7]. The flow physics inside the blade passage can be analyzed by simulating the complex pump domain either experimentally or computationally which help to understand the performance of the impeller at both design and off-design conditions [8][9][10][11][12][13][14][15][16].…”

Analysis of effect of impeller geometry including blade outlet angle on the performance of multi-pressure pumps: Simulation and experiment

“…Using tests and LDV measurements along with CFD techniques, Wen-Guang [13] determined fluid (water and oil) velocity in the impeller as well as volute casing of a centrifugal pump. He proved the slip factor to be a very important factor when hydraulically designing impellers of centrifugal pumps intended to work with oil.…”