Numerical study of the influence of changing impeller geometry on improving the performance of a centrifugal pump as a turbine

Document Type : Research Article

Authors

School of Mechanical Engineering, Iran University of Science and Technology, Tehran, Iran

Abstract

The implementation of a pump as a turbine rather than traditional turbines in the soft pressure regulation system reduces the initial costs and construction time of the power plant. However, the significant losses occur under off-design conditions because the pump was not built to work in reverse mode. In this study, the design and simulation of the centrifugal pump as turbine as the most important part of the power plant have been done by CFturbo and CFX software. The discretization of governing equations was done with the help of the finite volume method, and regarding the turbulent nature of flow in the pump as turbine from k-ω SST model was used. The changing trend of the pump as turbine simulation results are basically in acceptable agreement with the experimental results. The impact of changing the parameters of blade thickness, blade inlet width, and splitter blades was numerically investigated in the operating range. Since increasing the efficiency and production capacity of the power plant is considered, the selection of the optimal mode of changes in the geometrical parameters of the impeller was investigated based on the statistical analysis of the flow rate. The results indicated that by simultaneously modifying the parameters, the operating range with high efficiency and electricity production is increased compared to the original impeller. The optimal impeller is better performing in the range of 0.77QBEP to 1.2QBEP, and efficiency at the design point has increased by 1.92%.

Keywords

Main Subjects

References

[1] H. Ramos, A. Borga, Pumps as turbines: an unconventional solution to energy production, Urban Water, 1(3) (1999) 261-263.
[2] J. Fernández, E. Blanco, J. Parrondo, M. Stickland, T. Scanlon, Performance of a centrifugal pump running in inverse mode, Proceedings of The Institution of Mechanical Engineers Part A-journal of Power and Energy - PROC INST MECH ENG A-J POWER, 218 (2004) 265-271.
[3] H. Nautiyal, V. Goel, A. Kumar, S. Yadav, Experimental Investigation of Centrifugal Pump Working as Turbine for Small Hydropower Systems, Energy Science and Technology, 1 (2011).
[4] T. Agarwal, Review of Pump as Turbine (PAT) for Micro-Hydropower, International Journal of Emerging Technology and Advanced Engineering, 2 (2012) 163-169.
[5] S. Derakhshan, A. Nourbakhsh, Theoretical, numerical and experimental investigation of centrifugal pumps in reverse operation, Experimental Thermal and Fluid Science, 32(8) (2008) 1620-1627.
[6] S. Derakhshan, B. Mohammadi, A. Nourbakhsh, Efficiency Improvement of Centrifugal Reverse Pumps, Journal of Fluids Engineering, 131(2) (2009).
[7] A. Bozorgi, E. Javidpour, A. Riasi, A. Nourbakhsh, Numerical and experimental study of using axial pump as turbine in Pico hydropower plants, Renewable Energy, 53 (2013) 258-264.
[8] T.N. Edessa Dribssa, Bazen Tsegaye, Performance Analysis of Centrifugal Pump Operating as Turbine for Identified Micro/Pico Hydro Site of Ethiopia, International Journal of Engineering Research and General Science, 3(3) (2015) 6-19.
[9] S.S. Yang, F.Y. Kong, J.H Fu, L. Xue, Numerical Research on Effects of Splitter Blades to the Influence of Pump as Turbine, International Journal of Rotating Machinery, 2012 (2012), 26-34.
[10] S.V. Jain, A. Swarnkar, K.H. Motwani, R.N. Patel, Effects of impeller diameter and rotational speed on performance of pump running in turbine mode, Energy Conversion and Management, 89 (2015) 808-824.
[11] S. Huang, G. Qiu, X. Su, J. Chen, W. Zou, Performance prediction of a centrifugal pump as turbine using rotor-volute matching principle, Renewable Energy, 108 (2017) 64-71.
[12] J.W. Li, Y.N. Zhang, K.H. Liu, H.Z. Xian, J.X. Yu, Numerical simulation of hydraulic force on the impeller of reversible pump turbines in generating mode, Journal of Hydrodynamics, Ser. B, 29(4) (2017) 603-609.
[13] M.H. Shojaeefard, S. Saremian, Effects of impeller geometry modification on performance of pump as turbine in the urban water distribution network, Energy, 255 (2022).
[14] F. Shi, J. Yang, X. Wang, Analysis on the effect of variable guide vane numbers on the performance of pump as turbine, Advances in Mechanical Engineering, 10 (2018).
[15] L. Wang, S.N. Asomani, J. Yuan, D. Appiah, Geometrical Optimization of Pump-As-Turbine (PAT) Impellers for Enhancing Energy Efficiency with 1-D Theory, Energies, 13(16) (2020).
[16] Z. Qian, F. Wang, Z. Guo, J. Lu, Performance evaluation of an axial-flow pump with adjustable guide vanes in turbine mode, Renew. Energy, 99 (2016) 1146-52.
[17] B. Qi, D. Zhang, L. Geng, R. Zhao, B.P.M. van Esch, Numerical and experimental investigations on inflow loss in the energy recovery turbines with back-curved and front-curved impeller based on the entropy generation theory, Energy, 239 (2022).
[18] M.H. Shojaeefard, M. Tahani, M.B. Ehghaghi, M.A. Fallahian, M. Beglari, Numerical study of the effects of some geometric characteristics of a centrifugal pump impeller that pumps a viscous fluid, Computers & Fluids, 60 (2012) 61-70.
[19] F. Menter, Two-equation eddy-viscosity turbulence models for engineering applications, AIAA Journal, 32 (1994) 1598-1605.
[20] M.H. Shojaeefard, S. Saremian, Studying the impact of impeller geometrical parameters on the high-efficiency working range of pump as turbine (PAT) installed in the water distribution network, Renewable Energy, 216 (2023).
[21] M. Tahani, S. Saremian, H. Yousefi, Y. Noorollahi, R. Fahimi, Investigation Effect of Type and Diameter of Volute on the Efficiency of Centrifugal Reverse Pump at Different Operating Conditions, Journal of Mechanical Engineering, 49 (2019) 229–238.
[22] H. Yousefi, Y. Noorollahi, M. Tahani, R. Fahimi, S. Saremian, Numerical simulation for obtaining optimal impeller’s blade parameters of a centrifugal pump for high-viscosity fluid pumping, Sustainable Energy Technologies and Assessments, 34 (2019) 16-26.
[23] M.M. Ghorani, M.H. Sotoude Haghighi, A. Maleki, A. Riasi, A numerical study on mechanisms of energy dissipation in a pump as turbine (PAT) using entropy generation theory, Renewable Energy, 162 (2020) 1036-1053.
[24] Z. Hu, Y. Cheng, D. Liu, H. Chen, B. Ji, J. Ding, Broadening the operating range of pump-turbine to deep-part load by runner optimization, Renewable Energy, 207 (2023) 73-88.
[25] M. Tahani, S. Saremian, Investigation Effect of Changes Geometry of Impeller on Turbine Mode Performance of the Centrifugal Pump at the Governing Condition of the Urban Water Distribution Network. Modares Mechanical Engineering, 18 (2018) 11-9. (In Persian)
[26] M.H. Shojaeefard, S. Saremian, Analyzing the impact of blade geometrical parameters on energy recovery and efficiency of centrifugal pump as turbine installed in the pressure-reducing station, Energy, 289 (2024).
[27] A. Maleki, M.M Ghorani, M.H.S Haghighi, A. Riasi, Numerical study on the effect of viscosity on a multistage pump running in reverse mode. Renewable Energy, 150 (2020) 234-54.
[28] R.J. Moffat, Contributions to the Theory of Single-Sample Uncertainty Analysis, Journal of Fluids Engineering, 104(2) (1982) 250-258.
Amirkabir Journal of Mechanical Engineering
Volume 56, Issue 1
2024
Pages 103-124

Files

Share

How to cite

Statistics