Research On Energy Dissipation Mechanism Of The Open Ditch In Shiplock Chamber

Ship locks are the most ancient navigation facilities in the world, and they are mostwidely used in China. Filling and emptying system is the key part of the ship lockwhich could realize the navigation through filling and emptying water. In the filling andemptying process of ship lock, there is complex flow state in lock chamber. Hydrauliccondition of lock chamber is the key factor on the ship safety. On the one hand, thedesign of filling and emptying system need to meet the require of filling time to ensurethe lock capacity and operation efficiency. On another hand, In the lock filling andemptying process, with the water surface increased or decreased, Ship in ship lock areeffected on the multi-power which are formed by unsteady flow. Ship encounter thesafety problem when the force is too large, for example cable break, collision andcapsize. There for, energy dissipater is important measure to improve the waterconditions in lock chamber. Energy dissipater could achieve better results, which avoidlocal adverse flow pattern and ensure steady flow of water. It could meet the conditionsof the ship moored safety.In this paper, based on the background of Guigang second line lock, Through theestablishment of local physical model and mathematical model, the effect of energydissipation and energy dissipation mechanism of single ditch and multiple ditches areanalyzed and compared. The Lock-scale of Guigang second line lock is280×34×5.6,filling and emptying system is the sidewall corridor branch hole which is simpledispersed delivery. The system applies to middle-low head and deep initial water depth.This system has been immensely applied, for example LeVox and Valeri. Guigang firstline lock adopt this system also in china, and they are well-functioning.The results of this study shows that the same point of the flow field distribution isthe absolute value of the flow field of three ditches increase with the water levelincrease, flow field distribution is uniform on different water level, and not affected bySingle or double valve. The different point is in the progress of the water level rise,apart of underflow point to wall near to lock, the rest point to the middle of lockchamber when valve opening is0.3in single ditch. The most flow point to the middle oflock chamber when valve opening is0.8. Minimax flow velocity appear in the samecross-sectional, flow rate fluctuation large and distribution is uneven, they show that lock chamber appear local irregular surface turbulence. But in three ditches, apart ofunderflow point to wall near to lock, the rest point to the middle of lock chamber. Anyperiod of time in water-filling, flow rate fluctuation don’t appeared and well distributed,this shows that water surface is stable and turbulent motion is small. Double ditches arebetween that single ditch and three ditches.The residual specific energy, kinetic energy and surface fluctuation Eigen value ofsingle ditch, double ditches and three ditches in which the law is accordance with thevelocity field in lock chamber. Indexes of three ditches are optimal, double ditches takesecond place and single ditch is slightly inferior.The mainly energy dissipation of ditches is the energy dissipation of outflow baffleend, a large number of vortex and interblend appear near to the sudden expansion oforifice flow, the energy change between mass, kinetic energy and energy. Because ofinternal and external friction, flow field changes rapidly during the progress of kineticenergy transformed into potential. This lead to violent movement, collision and frictioneffect inner flow. Thus a great part of energy is consumed.