Research On Operating State Of Water Distribution Network

The research is mainly about operating state of the water distribution network, experimental model is established convenient for studying. General and leakage operating state are simulated in the experimental model, mathermatics model of the network state estimation is established also, Leakage state is analyzed, pressure distribution model and water quality model are based on experimental model, all of the study providing method and foundation for simulation and control of real water distribution network.First, several different similarity relations between actual network and experimental model are deduced based on distorted similarity theory of pipe liquid, finally, Euler similarity theory is chosen to use. Network simplify theory is used in simplify the complicated network of this area, proper network structure is find for construction of experimental model, possible method and process are put constructing the experimental model of water distribution network, the distorted rate and parameter of experimental model are decided. EPANET software is used for simulating the operating state of water distribution network, well similarity relationship of pipe runoff and flow velocity between the model and the actual network as well as credibility of the simulation method are proved by the operating and monitoring data.Secondly, owing to less monitoring nodes in water distribution network, the collected state variables are limited and can't effectively reflect the operating state of the network, so a BP state estimation model based on particle swarm optimization (PSO) is established. Particle swarm optimization algorithm is a kind of stochastic global optimization based on swarm intelligence, through the interaction of particles,PSO searches the solution space intelligently and finds out the best solution, adopts the particle swarm optimization optimizes the power value of artificial neural network set up PSO-BP network to find the solution of the model. Result of the PSO-BP model shows that PSO-BP network is better in water demand prediction and possesses higher forecasting precision and accuracy.Thirdly,experimentation of leakage and burst in network model are processed,leakage correlative analysis based on the experimental data. Based on the distribution of pressure in water supply network, pressure distribution curve and three dimensional surface model are put forward. Method of solving the model is discussed that has been validated with an example. The result indicated that the model can really carry out the continuous simulation of pressure in network, and provide a new method to resolve technical puzzles of the pressure simulation of network in urban water supply and operation system, and enhance the rationality and veracity of st rategy.In the and, models of residual chlorine decay in network is discussed.The model of first-order decay reaction is adopted for chlorine decay dynamic model. The consumption of chlorine reacting with chemicals and microbes in bulk water, with biofilms on the pipe wall is discussed, besides, the mass transport of chlorine from bulk water to pipe wail is considered too. The pipes simulation software EPANET 2.0 which is developed by national environment protecting bureau of USA is used to solving the model, and the Matlab software is used to simulating the distribution of the chlorine in the network based on the data of experimental model.