Research On The Hydraulic Characteristic Of The Siphon Outlet With Long Straight Conduit After The Roof

Siphon outlet conduit has many advantages such as the smaller loss of the water power, lower consumption of the electric power, lower costs for operation, less maintenance work, easier of the flow cut off and safer for operation. So the large pumping stations in our country use such outlet conduits forms. Because of the limitations of the terrain conditions, construction conditions and engineering costs ,conventional forms of the Siphon outlet conduit can no longer meet the full requirements of pumping stations, the siphon outlet conduit with long and straight conduit after the roof comes into being. The paper combines with the study of the hydraulic models of pumping stations in Shanghai to get the water from the Yangtze River and explores hydraulic characteristics of such a special form of Siphon outlet conduit.The main problem of the siphon outlet conduit with a long and straight conduit after the roof is that the time to form the siphon is too long or the siphon can not be formed as a result of the irrational structure. The paper combines with the study of the hydraulic models, researches factors which affect the form of the siphon, and educes the main factors that affects the form of the siphon, which are the water level of outlet sump and the going of the vent at the roof of the siphon.Hydraulic model test is widely used to solve hydraulics problems, which has visual, simple and reliable advantages. However, because of the experimental limitations, it also has its limitations. The paper discusses the problems about the similarity of the prototype and the model, and obtains the conclusions and measures, to some extent, which have some guidance and operation.