Research On Optimization Model And Application Of Long-distance Water Distribution Network Under Demand-side Constraints

Long-distance pipeline has been widely used in many projects because of its advantages of fast and efficient water delivery,less leakage loss,water quality protection,land saving,less environmental impact,easy management and maintenance,safe operation and long service life.However,long-distance pipeline water transportation needs huge one-time project investment,especially in the pipeline sector,which accounts for a relatively high proportion of the total project investment.Therefore,the optimal design of long-distance water pipeline system has important practical significance for saving project investment,reducing system energy consumption and operation and management costs,and improving economic and social benefits.This paper focuses on the optimization of long-distance water delivery system network under demand-side constraints.The guaranteed flow rate and annual pipeline cost are considered comprehensively.A network optimization model of long distance water delivery system is established.Firstly,the hydraulic characteristics of the flow supply side and the structure distribution of the flow demand side of the long distance water conveyance system are analyzed.The flow assurance rate of water conveyance system is analyzed and defined.The expressions of water supply quantity,demand-side water quantity and flow guarantee rate of water delivery system are determined.Secondly,the annual cost of pipeline network,annual power cost,pipeline network investment and overhaul cost are analyzed comprehensively,and the expression of annual cost of pipeline is established.Based on the analysis of reliability and economy of water conveyance system,the objective function of long distance water conveyance network optimization is constructed.Constraints of pipeline network optimization model are established from pipeline path and pipeline diameter.Find the boundary conditions for the optimization of water conveyance system.Then comparing and analyzing the common algorithms of pipe network optimization model.The minimum tree graph algorithm is combined with the hybrid frog leaping algorithm.An optimization model algorithm for long-distance water distribution network is designed,which is suitable for the study in this paper.The minimum tree diagram method is used to solve the pipeline route.At the same time,the hybrid leaping frog algorithm is used to solve the optimal diameter combination.According to the sub-objective multiplication and division of optimization theory,the multi-objective function is transformed into a single objective function.This simplifies the complexity of the optimization model.Entropy theory is introduced into the objective function of the optimization model.The cost of guaranteed rate per unit flow is proposed as a comprehensive evaluation index.Finally,take a specific engineering as a case.By calculating the relevant parameters,the optimal water conveyance path and the optimal pipe diameter combination scheme are determined.From the perspective of demand side constraints,this paper also considers the annual cost of pipelines.The proposed expression method of flow guarantee rate provides a theoretical supplement for the optimal design of pipeline network.It also further enriches the demonstration objectives of relevant schemes.At the same time,it provides reference for pipeline optimization of oil pipeline and gas pipeline projects.