CFD Modelling of Pump as Turbine with Various Number of Blade for Microhydro System

  • Mohd Azlan Ismail Ismail Faculty of Engineering, University Malaysia Sarawak, Kota Samarahan, Malaysia
  • Al Khalid Othman Faculty of Engineering, University Malaysia Sarawak, Kota Samarahan, Malaysia
  • Hushairi Zen Faculty of Engineering, University Malaysia Sarawak, Kota Samarahan, Malaysia
  • Mohd Suffian Misran Faculty of Engineering, University Malaysia Sabah, Kota Kinabalu, Malaysia
Keywords: microhydro, pump as turbine, blade number, impeller, renewable energy

Abstract

Pump as Turbine is an electromechanically component that is largely used in microhydro system. The main advantages of pump as turbine compared to commercially available turbines are lower cost, easier to maintain and readily available. These key features make them appealing to conditions in many developing countries. However, pump as turbine has poor hydraulic performance and low efficiency thus modifications were applied to improve the performance. The aim of this paper is to study the effect of impeller blade number to the pump as turbine performance. The investigation was carried out by using commercial Computational Fluid Dynamic (CFD) software, ANSYS CFX. A centrifugal pump with a specific speed of 70 with an impeller diameter of 214.0 mm was used to generate the CAD model. The original number of the blade was at 6 and varied to 5, 7 and 8 while other geometric dimensions were kept unchanged. The simulation results reveal that the highest efficiency was attained at 7 blade number with the efficiency recorded at 76.24%. The corresponding pressure was at 20.83 meters. It was found that with increase of blade number, the efficiency and corresponding pressure of the pump as turbine also increases. However, the additional blade number reduce the cross-area flow path, consequently increase the blockage effect thus decrease the net power generated by the rotating impeller.

References

"ASEAN Guideline on Off-grid Rural Electrification Approaches," 2013.

O. A. Jaramillo, M. A. Borja, and J. M. Huacuz, "Using Hydropower to Complement Wind Energy: A Hybrid System to Provide Firm Power," Renewable Energy, vol. 29, pp. 1887-1909, 2004.

https://doi.org/10.1016/j.renene.2004.02.010

S. Chakraborty, K. M. Pandey, and B. Roya, "Numerical Analysis on Effects of Blade Number Variations on Performance of Centrifugal Pumps with Various Rotational Speeds," International Journal of Current Engineering and Technology, vol. 2, 2012.

Liu Houlin, W. Yong, Yuan Shouqi, T. Minggao, and Wang Kai, "Effects of Blade Number on Characteristics of Centrifugal Pumps," Chinese Journal of Mechanical Engineering, vol. 23, 2010.

https://doi.org/10.3901/CJME.2010.06.742

Y. Sun-Sheng, K. Fan-Yu, F. Jian-Hui, and X. Ling, "Numerical Research on Effects of Splitter Blades to the Influence of Pump as Turbine," International Journal of Rotating Machinery, 2012.

https://doi.org/10.1155/2012/123093

S. S. Yang, F. Y. Kong, X. Y. Qu, and W. M. Jiang, "Influence of Blade Number on the Performance and Pressure Pulsations in a Pump Used as a Turbine," Journal of Fluids Engineering, Transactions of the ASME, vol. 134, 2012.

https://doi.org/10.1115/1.4007810

Published
2016-03-31
How to Cite
Ismail, M. A. I., Othman, A. K., Zen, H., & Misran, M. S. (2016). CFD Modelling of Pump as Turbine with Various Number of Blade for Microhydro System. Journal of Applied Science & Process Engineering, 3(1), 17-23. https://doi.org/10.33736/jaspe.171.2016