The Research On Reliability And Optimal Design Of Water Supply Network

Water supply network is an important underground infrastructure of the city. In the design of water supply network, on the basis of meeting the requirements of water consumption, water pressure and water quality, study of the reliability of the water supply network system and the optimal design method of minimum annual cost is meaningful.The current hydraulic calculation method of water supply network in emergency assumes that node flow is a constant value, that is when the accident happened to the water supply network, no matter how to change node pressure, the node flow can reach 70% of the maximum amount of water. Actually, node flow and node pressure are closely linked, the current method of calculation of water consumption is not agreed with the reality. So, the paper introduced different relationships between node flow and node pressure, at the iterative calculation of solution method with node flow continuity equations, the dynamic relationship between node flow and node pressure as well as the dynamic changes of the pump head with the change of the total supply of water were considered, and the current hydraulic calculation method of water supply network in emergency was improved. on the basis of the improved hydraulic calculation method, the reliability evaluation index of the water supply network was established and the reliability of the water supply network system were calculated.In this paper, the objective function and constraints of the water supply network optimization model were parsed and the water supply network optimization model was established. In the process of solving the water supply network optimization model, minimal path method was set as the allocation methods of initial flow of the water supply network, the main pipe and connecting pipe were distinguished obviously in this method. Monte Carlo pseudorandom number method was adopted in the calculation of pipe diameter standard, this method was easy to understand and it had better practicability.The economy and reliability of the water supply network are two conflicting aspects,. thus economy and reliability should be considered in the optimization of the water supply network. By counting reliability and optimization of a county water supply network and analyzing calculation results, we could find that the optimized network met the reliability requirements, and the decreasing extent of reliability was little, but the economy was better.