（1.Key Laboratory of Ocean Engineering of Shandong Province, Ocean University of China, Qingdao, Shandong 266100, China; 2.College of Engineering, Ocean University of China, Qingdao, Shandong 266100, China)
In order to analyze the discharge energy dissipation of a twostage plug and reveal the influence of its geometrical parameters on the dissipation,a threedimensional RNG k-ε turbulence model was adopted to study discharge in the plug.A physical model of the plug was established to validate the computational results,good agreement has been achieved.The area contraction ratios of both plugs are 0.2,0.3,0.4 and 0.5,respectively,the relative lengths of two plugs are equal to 0.5,1.5 and 3,respe ctively,causing 144 experimental cases.Then the verified mathematical model of energy dissipation was used to estimate the discharge energy loss in the twostage plugs at the 144 conditions.The results showed that the area contraction ratio influences the energy dissipation more significantly than the relative length.The energy dissipation rate and ratio of the first plug were increased,but those of the secondstage were decreased with increasing area contraction ratio of the second plug.The energy dissipation rate and ratio the first plug were decreased,the energy dissipation rate of second plug was varied little,but its energy dissipation ratio was increased with increasing area contraction ratio of the first plug.When the area contraction ratios of the two plugs were optimal,their energy dissipation rates were the largest.
He Yiying,Yang Fan.Application of plug energy dissipater to elimination of bubbles in cooling water occurred to the outlet of power plants[J].Journal of Hydraulic Engineering,2008,39(8):976-981.(in Chinese)
Tian Zhong,Xu Weilin,Wang Wei,et al.Hydraulic characteristics of plug energy dissipater in flood discharge tunnel[J].Journal of Hydrodynamics,2009,21(6):799-806.
Liu Peiqing,Qu Qiulin,Wang Zhiguo,et al.Numerical simulation on hydrodynamic characteristics of bifurcation pipe with internal crescent rib[J].Journal of Hydraulic Engineering,2004,35(3):42-46.(in Chinese)
Mompean G.Numerical simulation of a turbulent flow near a rightangled corner using the speziale nonlinear model with RNG k-ε equations［J］.Computers ＆ Fluids,1998,27(7):847-859.
BazdidiTehrani F,Shahmir A,HaghparastKashani A.Numerical analysis of a single row of coolant jets injected into a heated crossflow[J].Journal of Computational and Applied Mathematics,2004,168(1／2):53-63.