Experimental, Numerical, and Theoretical Research on Impeller Diameter Influencing Centrifugal Pump-as-Turbine
Publication: Journal of Energy Engineering
Volume 139, Issue 4
Abstract
One of the limitations of using the pump-as-turbine (PAT) technique is its relatively narrow high-efficiency operating range. When the system pressure head or flow rate decreases, trimming the impeller or replacing the impeller with one of a smaller size is an easy and convenient approach. Therefore, research on the impeller diameter in terms of its influence on PAT is useful. To perform research on how the impeller diameter influences PAT, experimental research was first performed on a single-stage centrifugal PAT with three impellers of different diameters. Experimental results show that PAT flow versus head curve is lessened; its flow versus efficiency and flow versus power curves increased after the best-efficiency point in accordance with increasing impeller diameter. The PAT flow rate, required pressure head, generated shaft power, and efficiency at the best-efficiency point increased in accordance with increasing impeller diameter. Numerical simulation and analysis of the PAT with the three impellers were performed using a verified computational fluid dynamics (CFD) technique. Hydraulic loss and flow field distribution analyses show that the total hydraulic loss within PAT and the hydraulic loss within the radial gap between the rotating impeller and stationery volute decreased in accordance with increasing impeller diameter. Theoretical analysis indicates the PAT theoretical head increased and its required pressure head decreased in accordance with increasing impeller diameter. Theoretical formulas used to predict PAT performances as the impeller diameter changed were verified. Possible reasons for the deviations between the performances predicted by theoretical formulas and test results are explored.
Get full access to this article
View all available purchase options and get full access to this article.
Acknowledgments
Special thanks are given to the project entitled, “Open Research Fund of Key Laboratory of Fluid and Dynamic Machinery (szjj2013-012)”, national science and technology support program entitled “Research on the Key Technology and Engineering Application Project of Typical Centrifugal Pump (2011BAF14B03)” and science and technology support program of Jiangsu Province entitled “Research and application on the key technology of high pressure recovery devices (BE2012150)”.
References
Alatorre-Frenk, C., and Thomas, T. H. (1990). “The pumps-as-turbines approach to small hydropower.” Proc., World Renewable Energy Congress, Pergamon Press, Oxford, UK, 2914–2918.
Ansys CFX 12.0 [Computer software]. Ansys, Cecil Township, PA.
Ansys ICEM CFD 12.0 [Computer software]. Ansys, Cecil Township, PA.
Chapallaz, J. M., Eichenberger, P., and Fischer, G. (1992). Chapter 1, Manual on pumps used as turbines, Friedr. Vieweg & Sohn Verlagsgesellschaft mbH, Braunschweig, 1–12.
Childs, S. M. (1962). “Convert pumps to turbines and recover HP.” Hydrocarb. Process. Pet. Refin., 41(10), 173–174.
Dixon, S. L. (2005). Chapters 2, 6, and 9, Fluid mechanics and thermodynamics of turbomachinery, Elsevier, Oxford, UK.
Fujun, W. (2004). Computational fluid dynamics analysis–CFD principles and application, Tsinghua University Press, Beijing.
Grover, K. M. (1980). Conversion of pumps to turbines, GSA International, Katonah, New York.
Hancock, J. W. (1963). “Centrifugal pump or water turbine.” Pipe Line News, 25–27.
Kline, S. J. (1985). “The purposes of uncertainty analysis.” J. Fluids Eng., 107(2), 153–160.
Lewinsky-Kesslitz, H.-P. (1987). “Pumpen als Turbien fur Klein-kraftwerke.” Wasserwirtschaft, 77(10), 531–537.
Moffat, R. J. (1982). “Contributions to the theory of single-sample uncertainty analysis.” J. Fluids Eng., 104(2), 250–260.
Paish, O. (2002). “Small hydro power: Technology and current status.” Renew. Sustain. Energy Rev., 6(6), 537–556.
Schmiedl, E. (1988). Section A6, Serien-kreiselpumpen im turbinenbetrieb, Pumpentagung, Karlsruhe, Germany.
Shahram, D. H., and Mohammadi, B. (2008). “Incomplete sensitivities for 3D radial turbomachinery blade optimization.” Comput. Fluids, 37(10), 1354–1363.
Shahram, D. H., Mohammadi, B., and Nourbakhsh, A. (2010). “The comparison of incomplete sensitivities and genetic algorithms applications in 3D radial turbomachinery blade optimization.” Comput. Fluids, 39(10), 2022–2029.
Sharma, K. (1985). “Small hydroelectric project–Use of centrifugal pumps as turbines.” Technical Rep., Kirloskar Electric, Bangalore, India.
Singh, P. (2005). “Optimization of the internal hydraulic and of system design in pumps as turbines with field implementation and evaluation.” Ph.D. thesis, Univ. of Karlsruhe, Karlsruhe, Germany.
Singh, P., and Nestman, F. (2009). “Experimental optimization of a free vortex propeller runner for micro hydro application.” Exp. Therm. Fluid Sci., 33(6), 991–1002.
Singh, P., and Nestmann, F. (2011). “Internal hydraulic analysis of impeller rounding in centrifugal pumps as turbines.” Exp. Therm. Fluid Sci., 35(1), 121–134.
Stepanoff, A. J. (1957). Centrifugal and axial flow pumps, Wiley, New York.
Williams, A. A. (1996). “Pump as turbines for low cost micro hydro power.” Renewable Energy, 9(1–4), 1227–1234.
Williams, A. A. (1994). “The turbine performance of centrifugal pumps: A comparison of prediction methods.” J. Power Energy, 208(1), 59–66.
Williams, A. A., and Simpson, R. (2009). “Pico hydro–Reducing technical risks for rural electrification.” Renew. Energy, 34(8), 1986–1991.
Xingfan, G. (1995). Pump handbook, Yu Hang Press, Beijing, 18–21.
Yang, S.-S., Kong, F.-Y., and Chen, B. (2011a). “Research on pump volute design method using CFD.” Int. J. Rotat. Mach., 2011, 7.
Yang, S.-S., Kong, F.-Y., and Chen, B. (2011b). “Research on volute design method of pump as turbine using CFD.” Int. Agr. Eng. J., 20(3), 25–32.
Yang, S.-S., Kong, F.-Y., and Fu, J. H. (2012a). “Numerical research on effects of splitter blades to the influence of pump as turbine.” Int. J., Rotat. Mach., 2012(1), 123093.
Yang, S.-S., Kong, F.-Y., Su, X., and Chen, H. (2012b). “Numerical simulation and performance experiment on pump and pump as turbine.” J. Xi’An Jiaotong Univ., 46(3), 36–41.
Yang, S.-S., Shahram, D. H., and Kong, F.-Y. (2012c). “Theoretical, numerical and experimental prediction of pump as turbine performance.” Renew. Energy, 48(1), 507–513.
Information & Authors
Information
Published In
Copyright
© 2013 American Society of Civil Engineers.
History
Received: May 3, 2012
Accepted: Mar 8, 2013
Published online: Mar 11, 2013
Discussion open until: Aug 11, 2013
Published in print: Dec 1, 2013
Authors
Metrics & Citations
Metrics
Citations
Download citation
If you have the appropriate software installed, you can download article citation data to the citation manager of your choice. Simply select your manager software from the list below and click Download.