Criterion similarity equation for determining the drops diameter of artificial rain

Development and implementation of water-saving technologies into irrigation agriculture aimed at increasing the efficiency of irrigation water use, is one of the priorities for achieving guaranteed and stable yields of agricultural crops. Study of parameters of artificial rain is one of the key moments in design of irrigation equipment. Research of the rain formation process is necessary in order to avoid negative effect on soil cover and vegetation, and also to increase efficiency of artificial irrigation, also reducing the power consumption. At the same time, one of the key characteristics is the diameter of drops created by rain-forming devices, which directly affects the other main characteristics of artificial rain and depends on the physical and mechanical properties of water, parameters of working fluid flow and geometric parameters of rain- forming devices. Based on the theoretical studies, a criterion similarity equation was obtained, allowing to calculate the drop diameter using parameters characterizing the process of artificial rain formation, to predict the size of drops when designing sprinkling equipment. The parameters having greatest effect on drop diameter are determined. It was revealed that, in accordance with the criterion equation obtained, the process of formation of artificial rain drops can be characterized by a geometric similarity criterion, as well as by Ohnezorge and Froude number. Calculations on the proposed formulas are well correlated with the results of other authors’ experiments. The studies conducted further allow to significantly improve the accuracy of determining the diameter of drops for various types of sprinkling nozzles, match design parameters and operating fluid flow parameters for the specified conditions.

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