A study on the effect of blade inlet angle, attack angle and the diameter ratio on the efficiency of a Banki Mitchell turbine

Öz

In the present work, a theoretical investigation is presented on how the efficiency of a Banki Mitchell turbine is affected by its design parameters. With the help of general formulation of the control volume theory to the equation of the moment of momentum in the turbine’s runner and considering all assumption regarding the properties of the flow and the design geometry of the runner, a mathematical model has been developed. The water discharge through the turbine is considered incompressible, non-viscous, homogenous and steady flow; The loss due to shock on the inner and outer surface of the runner as well as leakage losses are neglected. As results of the present study, the behaviour of hydraulic efficiency was determined when varying the angle of attack, the blade entry angle as well as the runner diameter ratio, indicating their appropriate values in each different scenario. In this paper critical relationships between design parameters have been disclosed and therefore analysed and simulated using Simulink MATLAB. Furthermore, it was mentioned that for a better performance, the exit angle of the blade should be 90°. At length, an expression was given estimating the turbine’s efficiency at various operating conditions and for calculating the energy contribution per stage, respectively.

Anahtar Kelimeler

• Banki Mitchell Turbine
• Fluid Mechanics Analysis
• Control Volume Theory
• Efficiency.

Destekleyen Kurum

Energy systems engıneeriıng department, Kocaeli Unıversity

Teşekkür

thanks to the department of Energy Systems engineering department, Kocaeli university

Kaynakça

1. Renewables First. Crossflow Turbines [Online]. 2015. https://www.renewablesfirst.co.uk/hydropower/hydropower-learning-centre/crossflow-turbines/. (25th of May 2021)
2. De Andrade, J.; Curiel, C.; Kenyery, F.; Aguillón, O.; Vásquez, A.; Asuaje, M. Numerical investigation of the internal flow in a Banki turbine. Int. J. Rotating Mach. 2011, 2011, 841214.
3. Fukutomi J. Senoo Y. and Nakase Y. 1991. Numerical Method of Flow through a Cross-Flow Runner. JSME International Journal: Series II, Vol. 34, No. 1. Japan. pp 44-51.
4. Fukutomi J., Nakase Y., Ichimiya M. and Ebisu H. 1995. Unsteady Forces on a Blade in a Cross-Flow Turbine. JSME International Journal: Vol. 38, No. 3. Japan. pp 404-410.
5. Yunus A. Çengel and John M. Cimbala; Fluid mechanics: Fundamentals and applications 1st Ed 2006.
6. Durgin, WW., and Fay WK. 1984. Some Fluid Characteristics of a Cross Flow Type Hydraulic Turbine. ASME Small Hydropower Fluid Machinery. USES.
7. Choi, Y-D., Zhao, L. and Kurokawa, J., 2006. A study on the optimal configuration and performance Improvement of a Micro cross flow hydraulic Turbine. Journal of the Korean Society of Marine Engineering Vol 30. No 2. 2006.
8. Mockmore, CA. and Merryfield, F. 1949. The Banki Water Turbine. Engineering Experiment Station. Oregon State College. USES.

9. Desai, V. R. and Aziz, N. M., 1994. An Experimental Investigation of cross flow turbine Efficiency. Journal of Fluids Engineering. Vol 116. Pp 545-550 1944.
10. Desai VR and Aziz NM, 1991. An Experimental Study of the Effect of Some Design Parameters on Crossflow Turbine Efficiency. Engineering Report. Department of Civil Engineering. Clemson University. USES.