Research On Hydraulic Characteristics Of Siphon Well In Cooling Water System Of Power Plant

It is usually used of dc supply system in cooling water systems of coastal power plant. The commonly water supply process is: Intake—Circulating water pump house—Pressure water supply pipeline—Condenser—Siphon well—Pipe weep—Outfall. What is the very important hydraulic structure is siphon well in dc supply system of power plant, the rationality of the design of siphon well will directly influence the safety, stability and economy of the whole system.On the basis of existing research results, rely on the research project of “The Nuclear PWR Demonstration Project Research on Hydraulic Characteristics of Siphon Well of Nuclear Power plant in Xu Da-pu, Liaoning province”.The main feature of the siphon well is transporting warm water to forebay of pump station through perforated drain-pipe. This method can raise water temperature and prevent ice jam. So the warm water flow need to meet certain conditions. With the specification met, warm water reflux flow under the condition of single unit operation will be met accounted for 20% ~ 40% of total flow in the circulating water. In addition, when the sea water level is low,The weir flow of siphon well is in drop out flow condition, Strong mixing of water and air after the weir siphon Wells will produce a large number of bubbles, If the bubble doesn’t buoyancy and flow into the downstream along with the water, Easily formed pollution zone and salt fog in the sea foam. For the above problem, a physical model of siphon well and perforated drain-pipe were used to study hydraulic characteristics. Optimization scheme was put forward to improve the hydraulic performance of siphon well, to meet requirements of warm water reflux flow and eliminate bubbles. The main contents include:(1)The author refers to lots of literatures and datum on internet to have more comprehensive understanding in research status and research methods of siphon well physical model experiment. Physical model was built based on the similarity theory and experiment;(2)A new method is put forward on the basis of double multi-hole orifices after the weir in siphon well. Double multi-hole orifices are used to short the length of hydraulic jump, dissipate energy and eliminate bubbles(3)It is put forward to seal part of the downstream drainage section to improve the warm water return flow. After sealing part of the downstream drainage section will Increase the water level in weir siphon well, at the same time, hydraulic jump was shot. In prototype what is used to seal part of the downstream drainage section is beam door.In the end, the questions still existing in the researching on mentioned above are revealed. Some author’s suggestions are made of further researching for siphon well.