The Study Of Branch Pipe Network Optimal Design In Hongwushan High Efficient Water-saving Irrigation Project

Compared with the traditional irrigation technology, pipe irrigation technology can useefficiency of earth, reduce water loss, accommodate to all kinds of topographical andgeological conditions, develop tractor-ploughing and extend the farmland irrigation areaeasily. At the same time, it’s complex to plan and design a piping system. Besides, a pipingsystem which need large number of materials an equipment would demand a big one-offinvestment. Therefore it’s valuable to optimize layout and design of pipe network, which cansave investment, reduce energy intensity and promote the development of irrigation theoryand technology.Aiming at optimization layout of single resource and gravity type irrigation pipe network,an optimal method is proposed, in which at first I generalize pipe network as a directiveconnection diagram, then I use integer coding to express the layout of irrigation pipe networkand standard pipe size, design corresponding Genetic Algorithm, including: coding, decoding,objective function, fitness function, method of ascertaining flow in all or different levels pipesand designing genetic operator. In the end, this method is used to optimize layout of pipenetwork on No.2zone which is one zone among two zones in Hong Wu Shan high efficientwater-saving irrigation project, objective function is minimum pipe network investment. Bycomparing with the original designing scheme, this method is proved useful, and theinvestment is reduced5.7%.On the other hand, the study combining optimal designing pipe network and workingsystem of rotation flow is aim at optimal design method used in condition of machinepressure pipe network. I attempt to minimize pipe network investment in different scheme ofrotation flow. First I scheme original rotation flow manually, then code original rotation flowand different levels pipe size using integer coding. At last, I attempt to optimize differentlevels pipe size under different scheme of rotation flow by means of genetic algorithm. Aim atreduce the number of non-feasible solution when optimizing, I design special crossover and mutation operators, which ensure individual of population could be feasible solution whenusing genetic algorithm. In the end, this method is used in optimizing pipe size on zone Ⅱ-5in Hong Wu Shan irrigation project, the result show that this optimal method could reduceinvestment9.1%and optimize scheme of rotation flow at the same time when objectivefunction is minimizing pipe investment.