| Water supply project is an important one for the people’s livelihood in China, being of momentous significance in improving the living standards of countryside residents, ensuring rural area drinking water safety and promoting construction of harmony society construction. With the rapid development of new countryside and the continual process of urbanization, and the aggravating environment and water pollution in rural area, to develop rural water supply and ensure rural drinking water safety have become an important task in all-round building of the new socialist countryside. Water supply pipelines are vital components of rural drinking water safety project, bearing the task of carrying water to users safely and reliably and meeting the needs of water quality, water quantity and water pressure. Whether the water supply pipelines can operate well will affect directly the water safety of social production and people’s living. Hence, an important issue that we are facing to is to optimize the rural water supply pipeline networks reasonably and ensure sustainable operation of rural water supply projects and bring into maximum engineering benefits.On the basis of summering theoretic achievements at home and abroad in optimization of pipeline networks, taking the optimization of centralized water supply pipe network for rural drinking water safety project as the research object, aiming at the optimization of pipeline systems, tree-type water supply networks and mixed water supply networks, a series of optimization mathematical models and solution methods were proposed respectively in this thesis. The main research contents and achievements are as follows:(1) Aiming at the optimization of water supply route for rural water supply project, a wandering mathematician optimization mathematical model with constraint was established. The model was solved by using the wandering mathematician thoughts, in which the scheme of different segment of the water supply pipeline was taken as decision variable, the minimum total investment of the water supply project as the objective function, the permitted hydraulic loss at the end of the pipeline as constraint. The application range of wandering mathematician thought will be extended by using the optimization model and the relevant solution method, and the optimization problem in the water supply network for rural drinking water supply project can be solved in a certain degree, where there were several route schemes to be selected between distribution nodes, providing references for qualitative optimization of such pipelines.(2) Aiming at the optimization of water supply pipe diameter for rural water supply project, a nonlinear optimal mathematical model was established when the type, pipe material, route and length of the pipeline was known in advance. The complex nonlinear model was solved by using a large system decomposition-dynamic programming aggregation method, in which the diameter of different segment of the water supply pipeline was taken as decision variable, the minimum total investment of the water supply project as the objective function, the permitted hydraulic loss for each segment and the total water supply pipeline as constraints. The method makes use of the overall optimization ability of dynamic programming while the scheme obtained was a best one with standard diameter, which is of universal guide effect for the optimal design of such pipeline systems.(3) Aiming at the optimization of pipeline route and pipe diameter for rural water supply project, an integrated optimal, qualitative and quantitative, mixed nonlinear mathematical model was established. The nonlinear optimization model was solved by using an integrated optimization method, i.e. using the orthogonal experiment method to optimize the route of pipeline segments qualitatively, and using the dynamic programming method to optimize the diameter of the pipeline quantitatively, where the pipeline route and the diameter of different segment were taken as decision variables, the minimum total investment of the water supply project as the objective function, the permitted hydraulic loss for each segment and the total water supply pipeline as constraints. The optimization method can solve qualitative and quantitative nonlinear mathematical model that cannot be solved by other existing optimization methods, providing theoretic support for optimal study of qualitative and quantitative complicated nonlinear system in gas and oil supply pipeline projects.(4) Aiming at the optimization of pumping pressured pipeline for rural water supply project, and based on the optimal design model of gravity water supply pipeline, a nonlinear optimal design mathematical model was established. The complex nonlinear mathematical model was solved by using the large system decomposition-dynamic programming aggregation method, in which the diameter of different segment of the water supply pipeline and pumping head were taken as decision variables, the minimum annual discount cost of the water supply pipeline system as the objective function, the permitted hydraulic loss for each segment and the total water supply pipeline as constraints. The optimization method is obviously effective in reducing construction investment, cutting down operation cost and increasing water supply benefit, and be referenced in the optimal design of other type pipelines.(5) Aiming at the optimization of tree-type gravity water supply pipeline network for rural water supply project, a nonlinear optimal design mathematical model was established when the type of water supply network, pipe material, route and length of the pipeline were known in advance. The complex nonlinear model was solved by using the large system double decomposition-dynamic programming aggregation method, in which the pipe diameters of main pipeline and sub-main pipeline were taken as decision variables, the minimum total investment of the water supply pipeline network as the objective function. Optimal schemes of pipe diameter for each pipeline segment can be obtained by adopting the optimization method, a new way for the optimal design of tree-type gravity water supply pipeline network.(6) Aiming at the optimization of pumping pressured tree-type water supply pipeline network for rural water supply project, and based on the optimal design model of tree-type gravity water supply pipeline network, a nonlinear optimal design mathematical model was established. The complex nonlinear problem was solved by using the large system double decomposition-dynamic programming aggregation method, in which the pipe diameters of main pipelin(?)dd sub-main pipeline and the pumping head were taken as decision variables, the mini(?) total investment of the water supply pipeline network as the objective function. Optimal schemes of pipe diameter for each pipeline segment and pumping head can be obtained, being of universal guide meaning to decision-making of quantitative issues in gas and oil supply pipeline network.Living examples were employed to verify the reasonableness of those mathematical models and solution methods, and a series of optimization theory and method were established for centralized water supply pipe network for rural drinking water safety project, all of which will provide effective theoretic support and application reference for the optimization design and operation management of rural drinking water safety project. |
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