Optimization of GAMM Francis Turbine Runner

Authors: Sh. Derakhshan, A. Mostafavi

Abstract:

Nowadays, the challenge in hydraulic turbine design is the multi-objective design of turbine runner to reach higher efficiency. The hydraulic performance of a turbine is strictly depends on runner blades shape. The present paper focuses on the application of the multi-objective optimization algorithm to the design of a small Francis turbine runner. The optimization exercise focuses on the efficiency improvement at the best efficiency operating point (BEP) of the GAMM Francis turbine. A global optimization method based on artificial neural networks (ANN) and genetic algorithms (GA) coupled by 3D Navier-Stokes flow solver has been used to improve the performance of an initial geometry of a Francis runner. The results show the good ability of optimization algorithm and the final geometry has better efficiency with initial geometry. The goal was to optimize the geometry of the blades of GAMM turbine runner which leads to maximum total efficiency by changing the design parameters of camber line in at least 5 sections of a blade. The efficiency of the optimized geometry is improved from 90.7% to 92.5%. Finally, design parameters and the way of selection have been considered and discussed.

Keywords: Francis Turbine, Runner, Optimization, CFD

Digital Object Identifier (DOI): doi.org/10.5281/zenodo.1060223

References:

[1] A. Demeulenaere, Ch. Hirsch,"Application of Multipoint Optimization to the Design of Turbomachinery Blades," ASME Paper GT-2004- 53110.
[2] G.N. Vanderplaats, Numerical optimization techniques for engineering design, McGraw-Hill, 1984.
[3] D.E. Goldberg, Genetic Algorithm, Addison Wesley, 1994.
[4] A. Demeulenaere, A. Purwanto, A. Ligout, C. Hirsch, R. Dijkers, F. Visser, "Design and Optimization of an Industrial Pump: Application of Genetic Algorithm and Neural Network," in Proc of insert Conf. abbreviation, ASME Fluid Engineering Summer Conf., Houston, Texas, June 2005.
[5] A. Alnaga, J.L. Kueny," Optimal Design of Hydraulic Turbine Distributor," WSEAS Transactions on Fluid Mechanics, Issue 2, Volume 3, April 2008.
[6] J.L Kueny, R. Lestriez, A. Helali, and C. Hirsch, "Optimal design of a small hydraulic turbine," 22nd IAHR Symposium on Hydraulic Machinery and Systems, Stockholm, Sweden, 2004.
[7] H. Nilsson, L. Davidson, "A validation of parallel multiblock CFD against the GAMM Francis water turbine runner at best efficiency and off-design operating conditions," Int.rep.01/02, Dept. of Thermo and Fluid Dynamics, Chalmers University of Technology, Gothen-burg, 2001.
[8] F. Avellan , P. Dupont , M. Farhat, B. Gindroz, P. Henry, M. Hussain, E. Parkinson, O. Santal, "Flow survey and blade pressure measurements in a Francis turbine model," Pejovic S. (ed) Proceedings of the 15th IAHR Symposium on Hydraulic Machinery and Cavitation, Belgrade, Yugoslavia, 1990, vol 2, I5, pp 1-14.
[9] S. Derakhshan, B. Mohammadi and A. Nourbakhsh, "Incomplete Sensitivities for 3D Radial Turbomachinery Blade Optimization," Comput. Fluids, 37, pp. 1354-1363, 2008.
[10] S. Derakhshan, B. Mohammadi and A. Nourbakhsh, "Efficiency Improvement of Centrifugal Reverse Pumps," Journal of Fluids Engineering, Vol. 131, 021103-1-9, February 2009.