For a Francis turbine with a specific speed of just ns=54 used in cooling towers, six design parameters of runner such as β1, β2, b0/D1, Φ/D1, Z and a/D1 which may have effects on the turbine performance are selected, then eight design cases are generated by using orthogonal experimental design array L8(27)in which there are two levels for each factor. The steady 3D turbulent incompressible fluid flow is simulated for each design by means of a CFD package, consequently the hydraulic loss characte-ristics of the runners are analyzed, and the design parameters are optimized. The performance of the optimized runner is predicted and measured. The predicted output power and efficiency of the turbine with the optimized runner are 156.57 kW and 86.51% respectively at the design point(Q=5 000 t/h), showing just 0.11% lower than the measurement of efficiency. This suggests that orthogonal design array combined with CFD technique can help reduce the number of design cases and improve the hydraulic performance of turbine runner effectively so as to realize its hydrodynamics optimization.
CHEN Yang,ZHOU Da-Qing,LI Ling-Yu et al. Numerical simulation and hydrodynamics optimization of direct-drive Francis turbine runner in cooling towers[J]. Journal of Drainage and Irrigation Machinery Engin, 2014, 32(7): 600-605.
Zhang Limin, Zheng Yuan, Zhang Chenghua, et al. Study on francis turbine with super-low specific speed applied in cooling towers[J]. Transactions of the Chinese Society for Agricultural Machinery, 2010,41(S0):39-42.(in Chinese)
Huang Jianfeng, Zhang Lixiang, He Shihua. Numerical simulation of 3-D steady and unsteady flows in whole flow passage of a Francis Hydro-turbine[J]. Procee-dings of the CSEE, 2009,29(2):87-94.(in Chinese)
Khare R, Prasad D V, KUMAR D S. CFD approach for flow characteristics of hydraulic Francis Turbine[J]. International Journal of Engineering Science and Technology, 2010,2(8):3824-3831.
Xin Zhe, Wu Junhong, Chang Jinshi. Flow field analysis and performance prediction of three-dimensional turbulent flow in Francis Turbine[J]. Transactions of the CSAE, 2010,26(3):118-124.(in Chinese)
Laín S, García M, Quintero B, et al. CFD numerical simulations of Francis Turbines[J]. Revista Facultad de Ingenieria Universidad de Antioquia, 2010(51): 24-33.
Jain S, Saini R P, Kumar A. CFD approach for prediction of efficiency of Francis Turbine[EB/OL]. [2014-01-09]. http://www.ahec.org.in/links/IGHEM-2010/Papers/TSF-04.pdf.
Nicolle J, Labbé P, Gauthier G, et al. Impact of blade geometry differences for the CFD performance analysis of existing turbines[C]//Proceedings of IOP Conference Series: Earth and Environmental Science. Bristol, UK: IOP Publishing, 2010,12(1):012028.
Anagnostopoulos J S. A fast numerical method for flow analysis and blade design in centrifugal pump impellers[J]. Computers & Fluids, 2009,38(2): 284-289.
Shen Yanning, Yuan Shouqi, Lu Weigang, et al. Orthogonal test design method based on numerical simulation for non-overload centrifugal pump with complex impeller[J]. Transactions of the Chinese Society for Agricultural Machinery, 2010,41(9):22-26.(in Chinese)
Yuan Shouqi, Zhang Jinfeng, Yuan Jianping, et al. Orthogonal experimental study effect of main geometry factors of splitter blades on pump performance[J]. Drai-nage and Irrigation Machinery, 2008,26(2):1-5.(in Chinese)