Abstract
Perfect water application uniformity is a key concern in design and operation of an irrigation system. In this paper, theoretical aspects and experimental validity are presented for ensuring uniform discharge throughout a sprinkler irrigation system. The purpose of this study is to develop a low-cost and easy method to design sprinkler irrigation system in which all sprinklers have the same discharge. An experiment is carried out for different size of orifices by setting them inside of 25-mm diameter pipes and a relationship is found between the orifice diameters and coefficients. Based on the determined relationship, the orifice diameters for simulated risers and the operating pressure head of a sprinkler irrigation system are designed. Different pressure head losses occur at the risers due to the different diameter orifices inside the risers and consequently, a uniform pressure head, which ensures uniform discharges, remains at all the sprinklers. Thus, it is found that the sprinkler flow variation caused by water pressure variation in a sprinkler irrigation system can be controlled by designing proper size of orifices and setting them inside the risers. In addition to designing a sprinkler system for a uniform discharge, the sensitivity that relates the changes of discharges due to an alteration of system operating pressure head at various levels, is analyzed. Further, a proper operating pressure head can be selected for an allowable range of discharge variation.
