Study On Optimal Design Model Of Pipe-irrigation Network

The shortage of water resources in our country has badly hindered the sustaining development of economy and society. As the most widely used mode of irrigation for conserving water, pipe-irrigation system has grown rapidly in the last two decades. The optimum planning of pipe-net can minimize the investment of pipe-irrigation system and push the development of pipe-irrigation.On the base of analyzed the ordinary design methods and reviewed the optimization theory of optimum planning of pipe-net, the main content of this paper is as following:Firstly, analyzed the conception of optimal design of pipe-irrigation networks and evaluated criterion of optimal design model. On the base of using for reference of models which is founded by elders, through taking annual minimum cost as the objective function, taking the cost formula of pipe network as the foundation, taking diameter as optimization variable, the nonlinear programming models by working in turn is founded. According to the model, the solution of technology & economy and flow bounds approach is detruded.Secondly, stochastic non-linear programming by random irrigating are presented to optimize the diameters of network. In pipe-irrigation ,the mode of working in turn did not concerned the different of crop, so the paper take net benefit as the objective function, a new model for optimal design of pipe-irrigation network by random irrigating is developed, this can be used in choosing reasonable irrigation schedule and saving much more investmentAt last, the author introduced the theory of genetic algorithm and solved the two models which have the characters of many discrete and mixed variables and nonlinear by genetic algorithm. Furthermore, the author took the calculation and analysis by combing each model with living example and get satisfactory result. All these proved that these models and solution had both notable economic benefits and highly practical value.