In order to improve the flow patterns in the vertical well entry / draft tube of pumped storage power stations, both numerical simulations and model experiment investigation were carried out to study the hydrodynamic characteristics. And a 3D RNG k-ε turbulence model was adopted in the numerical efforts. The flow characteristics of two kinds of diffusers, one is ellipse curve and the other one is cone expansion, were mainly compared under pump conditions. The results showed that the flow patterns in the tube with a coneshaped diffuser were better than that with an ellipse one. The flow rate allocation ratios in the tubes with a cone diffuser of 4.3°, 5°, and 7° diffusion angles were simulated and analyzed. The results indicated that the diffusion angle of the cone diffuser installed behind an elbow pipe should be less than 4.5°. The hydraulic model experiments were conducted for the recommended vertical well entry / draft tube. The experimental results showed that there were uniform flow patterns in the models. The loss coefficient of the total head was 0.48 when two units were operated under pump condition while it was 0.33 under turbine condition.
Gao Xueping, Zhang Xiaoxian, Li Changliang, et al. The hydraulic characteristics at vertical pipe intake of Xilongchi pumped storage plant[J]. Journal of Hydroelectric Engineering,2002,21(1):52-60.(in Chinese)
Cheng Weiping, Mao Genhai, Hu Yunjin, et al. Axisymmetric numerical simulation of the vertical pipe inlet／outlet of Mashan pumped storage palnt[J]. Journal of Hydroelectric Engineering, 2005,24(3):56-60.(in Chinese)
Cheng Weiping, Hu Yunjin, Zhang Junjun, et al. Study on hydraulic characteristics of vertical pipe inlet／outlet of pumped storage plants[J]. Journal of Drainage and Irrigation Machinery Engineering, 2010,28(6):537-542.(in Chinese)
Yildirim N, Jain S C. Surface tension effect on profile of a free vortex[J]. Journal of the Hydraulics Division,1981,107(1):132-136.
Quick M C. Efficiency of airentraining vortex formation at water intakes[J]. Journal of the Hydraulics Division,1970,96(7):1403-1416.
Yang Fan, Liu Chao, Tang Fangping, et al. Characteristics of flow in large vertical axial flow pumping system[J]. Transactions of the Chinese Society for Agricultural Machinery, 2011,42(5):40-43.(in Chinese)