Study On Optimal Design Of Micro-irrigation Independent Pipe Network For Irrigation Area

Compared with other water-saving irrigation mode, pipeline network sysem have many advantages such as: higher water-saving benefit, higher land utilization rate, better adaptability to the topography, water can be delivered more quickly, irrigate evenly, can save labor and time when pepair and maintenance, can irrigate in time and easy for field management, develop the pipeline network strongly is an important trend of water-saving irrigation in the new trend. Meanwhile, pipeline network system is complex to design and need more materials and equipment, have high requirement on water quality. Therefor,optimizing the pipeline network system in the condition of limited project fund has practical significance for saving the investment, reducing the energy consumption, enhancing the economic and social benefits. The guiding principle of pipeline network system optimization is to seek a project which can satisfy the water volume, water pressure, the lowest cost or the smallest yearly operation expense and the highest system reliability request.The research object is micro-irrigation independent network system. Based on the summarization and analyzation of the domestic and foreign pipe network optimization, in view of the existing problems and shortcomings that the best control area of micro-irrigation independent network system under-reaearched and the layout optimize of tree pipe network can not be used to micro-irrigation network for irrigation area with uniform grade, combing theoretical study with computer simulation and application examples, using matlab genetic algorithm toolbox—gatbx, which exploited by Sheffield university, the minimum investment of unit area pipe network was used as the objective to study the best control area, the layout optimization and optimization design of field pipe netwok and main pipe netwok, the three optimization goal can be obtain at the same time through running the procedure. The results this paper mainly achieved as follows:(1)This paper proposed the optimization deign method of micro-irrigation independent pipe network for irrigation area: optimized the micro-irrigation field pipe network firstly, the results of best control area, the layout optimization and optimization design can be obtained,then optimized the main pipe network on this basis.(2)The minimum investment of unit area field pipe network was used as the objective function to establish optimum design mathematical model of field pipe network with unilateral capillary and field pipe network with paired laterals in the condition of area is not be restricted, using matlab genetic algorithm toolbox similuted calculation, the layout of field pipe network and pipe diameter combination could be optimized at the same time, the best control area of field pipe network could be obtained too. By contrast, field pipe network with paired laterals better than field pipe network with unilateral capillary in control area and minimum investment of unit area, so the project of field pipe network with paired laterals was confirmed and as the basic of main pipe network optimization.(3) The minimum investment of unit area main pipe network was used as the objective function to establish optimum design mathematical model of main pipe network in the condition of area is not be restricted, using matlab genetic algorithm toolbox similuted calculation, the layout of main pipe network and pipe diameter combination could be optimized at the same time, the best control area of main pipe network could be obtained too.(4) Integer and real coding are used in optimal design of diameter selection and aqueduct length respectively in field and main pipe network, optimal result are standard pipe sizes,avoid deviation caused by rouding the contimous diameters and the optimization result can be directly used for construction.