Development Of Center Pivot Irrigation System Sprinkler Package And Experimental Study On Low Pressure Spray-head

As one of the important mechanized irrigation equipments utilized in the modern agricultural water-saving irrigation, center pivot irrigation system with high irrigation quality, powerful versatility and full automation, has been playing an increasing role in agricultural reconstruction and development of China. The market keeps growing and the demand is rising. But most Chinese center pivot are dependent upon importation from foreign countries for sprinkler packages, which are one of the key components in center pivot irrigation systems. The sprinkler packages are studied in this thesis. Attention is concentrated on the key sprinkler packages, including low pressure spray-head, damping rotator sprinkler, and pressure regulator. This thesis summarizes the developing history and trend of the sprinkler packages. The latest popular structures and corresponding characteristics of the sprinkler packages are introduced. Some experimental research, such as experiment on discharge coefficient, sprinkler range and single spray-head water distribution characteristics, are given, which would promote the development of the sprinkler packages.The main results of this thesis are listed as follow:(1) Based on analyzing the current sprinkler packages on center pivots, compared well with other foreign sprinkler packages, a new series of sprinkler packages is developed. Consideration is given to the general sprinkler performance requirement as well as to cost reduction and water loss reduction. Major obstacles are overcome in developing low pressure spray-head, damping rotator sprinkler and pressure regulator.(2) It also provides the design principle, structure improvement and key processing technic of the sprinkler packages.(3) By ways of theoretical and experimental research on discharge coefficient and sprinkler range of low pressure spray-head normally used in center pivot systems, a proper scope of discharge coefficients and an optimum coefficient value are put forward and a new sprinkler range equation of low pressure spray-head is come up.(4) According to the experimental research, water distribution characteristics of low pressure spray-head are acquired. In the end, optimal sprinkler spacing for low pressure spray-head is put forward. And a computer program for selecting the spray-head nozzle along the lateral and calculating application water depth is presented based on the tested performance data of low pressure sprinklers.