0
Research Papers: Flows in Complex Systems

Effect of Axial Clearance on the Efficiency of a Shrouded Centrifugal Pump

[+] Author and Article Information
Cao Lei

State Key Laboratory of Hydroscience and
Engineering and Department of Thermal Engineering,
Tsinghua University,
Beijing 100084, China
e-mail: caolei613@126.com

Zhang Yiyang

China Water Resources Beifang Investigation,
Design and Research Co. Ltd.,
Tianjin 300222, China
e-mail: cherry_33@163.com

Wang Zhengwei

State Key Laboratory of Hydroscience and
Engineering and Department of Thermal Engineering,
Tsinghua University,
Beijing 100084, China
e-mail: wzw@mail.tsinghua.edu.cn

Xiao Yexiang

State Key Laboratory of Hydroscience and
Engineering and Department of Thermal Engineering,
Tsinghua University,
Beijing 100084, China
e-mail: xiaoyex@mail.tsinghua.edu.cn

Liu Ruixiang

CCCC Tianjin Dredging Co. Ltd.,
Binhai New Area,
Tianjin 300042, China
e-mail: yy850319@126.com

1Corresponding author.

Contributed by the Fluids Engineering Division of ASME for publication in the JOURNAL OF FLUIDS ENGINEERING. Manuscript received August 30, 2014; final manuscript received February 4, 2015; published online March 13, 2015. Assoc. Editor: Frank C. Visser.

J. Fluids Eng 137(7), 071101 (Jul 01, 2015) (10 pages) Paper No: FE-14-1482; doi: 10.1115/1.4029761 History: Received August 30, 2014; Revised February 04, 2015; Online March 13, 2015

Clearance always exists between the rotating impeller shrouds and the stationary casing covers in shrouded centrifugal pumps, which affects the pump internal flow and performance. Model tests were conducted for a shrouded centrifugal pump with back blades on the front shroud, and the performance parameters were obtained for three different impeller axial positions. Adjusting the impeller axial position can change the axial size of both the front and back clearances simultaneously. The results show that a tiny variation of the axial clearance size can substantially change the pump performance. A large front clearance reduces the pump efficiency and head with little change in the shaft power. Numerical simulations for a wide range of operating conditions for the three models with different impeller axial positions using the Reynolds-Averaged Navier–Stokes (RANS) with shear stress transport (SST) k–ω turbulence model agree well with the experimental results. The numerical results show how the clearance flow interfere with the main flow as the axial clearance is varied. The change in the pump hydraulic efficiency, volumetric efficiency, and mechanical efficiency was analyzed for various clearances. The hydraulic efficiency is the lowest one of the three kinds of efficiency and changes dramatically as the flow rate increases; thus, the hydraulic efficiency plays a decisive role in the pump performance. The volumetric efficiency is most sensitive to the axial clearance, which obviously decreases as the front clearance is increased. Therefore, the volumetric efficiency is the key factor for the change of the gross efficiency as the axial clearance changes. The mechanical loss varies little with changes in both axial clearance and flow rate so the mechanical efficiency can be regarded as a constant. The effect of axial clearances on the efficiency of shrouded centrifugal pumps should be considered to enable more efficient designs.

Copyright © 2015 by ASME
Your Session has timed out. Please sign back in to continue.

References

Gülich, J. F., 2008, Centrifugal Pumps, Springer, Berlin.
Gülich, J. F., 2003, “Disk Friction Losses of Closed Turbomachine Impellers,” Forsch. Ingenieurwes., 68(2), pp. 87–95. [CrossRef]
Kaupert, K. A., and Staubli, T., 1999, “The Unsteady Pressure Field in a High Specific Speed Centrifugal Pump Impeller—Part I: Influence of the Volute,” ASME J. Fluids Eng., 121(3), pp. 621–626. [CrossRef]
Pedersen, N., Larsen, P. S., and Jacobsen, C. B., 2003, “Flow in a Centrifugal Pump Impeller at Design and Off-Design Conditions—Part I: Particle Image Velocimetry (PIV) and Laser Doppler Velocimetry (LDV) Measurements,” ASME J. Fluids Eng., 125(1), pp. 61–72. [CrossRef]
González, J., and Santolaria, C., 2006, “Unsteady Flow Structure and Global Variables in a Centrifugal Pump,” ASME J. Fluids Eng., 128(5), pp. 937–946. [CrossRef]
Liu, H., Wang, K., Yuan, S., Tan, M., Wang, Y., and Dong, L., 2013, “Multicondition Optimization and Experimental Measurements of a Double-Blade Centrifugal Pump Impeller,” ASME J. Fluids Eng., 135(1), p. 011103. [CrossRef]
Stel, H., Amaral, G. D. L., Negrao, C. O. R., Chiva, S., Estevam, V., and Morales, R. E. M., 2013, “Numerical Analysis of the Fluid Flow in the First Stage of a Two-Stage Centrifugal Pump With a Vaned Diffuser,” ASME J. Fluids Eng., 135(7), p. 071104. [CrossRef]
Gao, Z., Zhu, W., Lu, L., Deng, J., Zhang, J., and Wang, F., 2014, “Numerical and Experimental Study of Unsteady Flow in a Large Centrifugal Pump With Stay Vanes,” ASME J. Fluids Eng., 136(7), p. 071101. [CrossRef]
Pei, J., Yuan, S., Benra, F. K., and Dohmen, H. S., 2012, “Numerical Prediction of Unsteady Pressure Field Within the Whole Flow Passage of a Radial Single-Blade Pump,” ASME J. Fluids Eng., 134(10), p. 101103. [CrossRef]
Daily, J. W., and Nece, R. E., 1960, “Chamber Dimension Effects on Induced Flow and Frictional Resistance of Enclosed Rotating Disks,” ASME J. Basic Eng., 82(1), pp. 217–230. [CrossRef]
Launder, B., Poncet, S., and Serre, E., 2010, “Laminar, Transitional, and Turbulent Flows in Rotor–Stator Cavities,” Ann. Rev. Fluid Mech., 42(1), pp. 229–248. [CrossRef]
Piesche, M., 1989, “Investigation of the Flow in the Impeller-Side Space of Rotary Pumps With Superimposed Throughflow for the Determination of Axial Force and Frictional Torque,” Acta Mech., 78(3-4), pp. 175–189. [CrossRef]
Will, B. C., Benra, F. K., and Dohmen, H. J., 2012, “Investigation of the Flow in the Impeller Side Clearances of a Centrifugal Pump With Volute Casing,” J. Therm. Sci., 21(3), pp. 197–208. [CrossRef]
Xia, P., Liu, S., Wu, Y., and Zhang, L., 2005, “Study on Flow Field of Impeller Tip Clearance in the Double Suction Pump,” ASME Paper No. FEDSM2005-77409. [CrossRef]
Chua, L. P., Song, G., Yu, S. C. M., and Tau, M. L., 2005, “Computational Fluid Dynamics of Gap Flow in a Biocentrifugal Blood Pump,” Artif. Organs, 29(8), pp. 620–628. [CrossRef] [PubMed]
Chan, W. K., and Wong, Y. W., 2006, “A Review of Leakage Flow in Centrifugal Blood Pumps,” Artif. Organs, 30(5), pp. 354–359. [CrossRef] [PubMed]
Teo, J. B., Chan, W. K., and Wong, Y. W., 2010, “Prediction of Leakage Flow in a Shrouded Centrifugal Blood Pump,” Artif. Organs, 34(9), pp. 788–791. [CrossRef] [PubMed]
Wu, D., Yang, S., Xu, B. J., Liu, Q., Wu, P., and Wang, L., 2014, “Investigation of CFD Calculation Method of a Centrifugal Pump With Unshrouded Impeller,” Chin. J. Mech. Eng., 27(2), pp. 376–384. [CrossRef]
Engeda, A., 1995, “Correlation and Prediction of Efficiency of Centrifugal Pumps Due to Tip Clearance Effects,” Proc. Inst. Mech. Eng., Part A, 209(2), pp. 111–114. [CrossRef]
Shukla, S. N., and Kshirsagar, J., 2007, “Numerical Simulation of Tip Clearance Flow in Semi-Open Impeller Pump,” ASME Paper No. FEDSM2007-37355. [CrossRef]
Park, S. H., 2009, “The Effects of the Back Clearance Size and the Balance Holes on the Back Clearance Flow of the Centrifugal Pump With Semi-Open Impeller,” Ph.D. thesis, Texas A&M University, College Station, TX.
Park, S. H., and Morrison, G. L., 2009, “Analysis of the Flow Between the Impeller and Pump Casing Back Face for a Centrifugal Pump,” ASME Paper No. FEDSM2009-78185. [CrossRef]
Zhu, B., Chen, H. X., Wei, Q., and Zhang, R., 2012, “The Analysis of Unsteady Characteristics in the Low Specific Speed Centrifugal Pump With Drainage Gaps,” Conf. Ser.: Earth Environ. Sci., 15(3), p. 032049. [CrossRef]
Li, W. G., 2012, “An Experimental Study on the Effect of Oil Viscosity and Wear-Ring Clearance on the Performance of an Industrial Centrifugal Pump,” ASME J. Fluids Eng., 134(1), p. 014501. [CrossRef]
Li, W. G., 2013, “Model of Flow in the Side Chambers of an Industrial Centrifugal Pump for Delivering Viscous Oil,” ASME J. Fluids Eng., 135(5), p. 051201. [CrossRef]
Zhao, W. G., Li, Y. B., Wang, X. Y., Sun, J. P., and Wu, G. X., 2012, “Research on the Effect of Wear-Ring Clearance to the Performance of Centrifugal Pump,” Conf. Ser.: Earth Environ. Sci., 15(7), p. 072018. [CrossRef]
Zhao, W. G., He, M. Y., Qi, C. X., and Li, Y. B., 2013, “Research on the Effect of Wear-Ring Clearances to the Axial and Radial Force of a Centrifugal Pump,” IOP Conf. Ser.: Mater. Sci. Eng., 52(7), p. 072015. [CrossRef]
Uy, R. V., Bircumshwa, B. L., and Brennen, C. E., 1998, “Rotordynamic Forces From Discharge-to-Suction Leakage Flows in Centrifugal Pumps: Effects of Geometry,” JSME Int. Conf. Fluid Eng., 41(1), pp. 208–213. [CrossRef]
Oh, H. W., Yoon, E. S., and Chung, M. K., 1997, “An Optimum Set of Loss Models for Performance Prediction of Centrifugal Compressors,” Proc. Inst. Mech. Eng., Part A, 211(4), pp. 331–338. [CrossRef]

Figures

Grahic Jump Location
Fig. 2

Parts of the mesh in the impeller region and around the tongue of the volute casing

Grahic Jump Location
Fig. 4

Experimental performance curves for Cf0.22, Cf0.42, and Cf0.62

Grahic Jump Location
Fig. 5

Comparison of experimental and numerical results for the three models: (a) Cf0.22, (b) Cf0.42, (c) Cf0.62, and Cf0

Grahic Jump Location
Fig. 6

Meridional velocity distributions on section B for: (a) section illustration, (b) Cf0.62, and (c) Cf0

Grahic Jump Location
Fig. 7

Velocity distributions on the symmetry plane of the volute casing for: (a) Cf0.62 and (b) Cf0

Grahic Jump Location
Fig. 8

Meridional velocity distribution on section B: (a) Cf0.22, (b) Cf0.42, and (c) Cf0.62

Grahic Jump Location
Fig. 9

Detailed views of the meridional velocity distributions on section B: (a) a_Cf0.22, (b) a_Cf0.42, (c) a_Cf0.62, (d) b_Cf0.22, (e) b_Cf0.42, (f) b_Cf0.62, (g) c_Cf0.22, (h) c_Cf0.42, and (i) c_Cf0.62

Grahic Jump Location
Fig. 10

Velocity distribution on the symmetry plane of the volute casing: (a) Cf0.22, (b) Cf0.42, and (c) Cf0.62

Grahic Jump Location
Fig. 12

Hydraulic efficiency

Grahic Jump Location
Fig. 14

Volumetric efficiency

Grahic Jump Location
Fig. 16

Mechanical efficiency

Grahic Jump Location
Fig. 17

Comparison of hydraulic efficiency, volumetric efficiency, and mechanical efficiency

Tables

Errata

Discussions

Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related Journal Articles
Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In