The Hydraulic Performance Evaluation Of Drainage System At The Old Town In Chaohu City

Based on the survey of the current drain network of the old town in Chaohu City, and certain simplified principles, this paper plans to establish a simplified model of drain network of the old town. Drainage network of the old town is divided into the1st and2st pipe system, and with the simplified model analyze the hydraulic characteristics of the drainage system of the old town under the dry-weather sewage condition on sunny days and that of pipeline system under the rainy working condition.Under the dry-weather sewage working condition on sunny days, with basic hydraulic computing formula in the field of drain and the average daily sewage quantity of the old town, stimulates the operation in the old town under the dry-weather sewage condition, and with an analysis of hydraulic factors of pipeline network evaluates the hydraulic performance of pipelines of the old town under the dry-weather sewage working condition.Based on the local rainfall data, the results indicate that the simulation with SWMM is an effective way by which the hydraulic performance and the bottleneck pipelines that affect the drainage network of the Old Town can be seek out correctly. Finally, the optimized proposal can be obtained through solving the model, which will optimize the operating conditions greatly.Finally concluded that:1. Through monitoring many group of24h changes in the quantity of sewage and calculated it, obtains the Kh of dry-weather sewage in the old town of Chaohu City is1.31.2. Through monitoring the quantity and quality of sewage under the dry-weather sewage working condition on sunny days, obtains the quantity of1st pipe system change in the range of10.46m3/h～56.2m3/h; the quantity of2st pipe system change in the range of5.31m3/h～21.75m3/h. After simulation,the h/D of the1st and2st sewer system change in the range of0.01to0.3. The flow rate of the majority pipes being smaller than the0.6m/s, only a small number of pipes’flow rate is greater than or equal to0.6m/s.3. Through monitoring the rainfall intensity, the sewer system of the old town reflects that the transfer of local sewer system is poor, when the rainfall intensity is greater than or equal to50.13mm/h,about89.3%nodes have the ground water. In the all monitoring time, the1st and2sewer system have about290min and255min in a paralyzed state, about80.5%and70.8%. Be optimized by the local drainage system to improve the overall water delivery performance of the pipeline, reduce the nodes of the water time, enhance the storage capacity of the pipeline in rainfall. After adjusted, the1st and2sewer system have about240min and225min in a paralyzed state, about80.5%and70.8%.