MODELING THE INFLUENCE OF EXTERNAL FACTORS ON THE HYDRAULIC CHARACTERISTICS OF A CLOSED IRRIGATION SYSTEM

Abstract

An example of a one-sided simplified scheme of the existing sprinkler equipment is considered. The main hydraulic characteristics of pipelines of a closed irrigation system are revealed, namely, water consumption by sprinklers, pressure losses along the length of the pipeline, and specific pressure losses. The physical properties of the liquid (water) have been discovered, which affect the hydraulic characteristics in the system. Examples of calculating the gross water consumption in the irrigation pipeline and in the distribution pipeline, taking into account the efficiency of the pipelines, are given. An example of calculating the diameter of a pipeline in individual sections, taking into account the optimal speed of fluid movement, is given. The formulas are given for calculating the pressure loss along the length and for the specific pressure loss. The tabular data of the physical characteristics of water in the temperature range 0-50 °C are given. Regression models of water density and dynamic viscosity were obtained for the analytical description of the dependences of the physical characteristics of water on temperature. A graph of the dependence of the density of water on temperature was built and it was revealed how much it changes under the influence of temperature. Discovered physical properties of water that most affect the hydraulic performance of the system. It is proved that the density of water under the influence of temperature hardly changes, and the dynamic viscosity of water changes significantly. A graph of the dependence of the dynamic viscosity of water on temperature is plotted with the calculation of the change in the considered range. The values of the kinematic viscosity of water were calculated, from which the function was obtained and a graph of the dependence on temperature was plotted. The Reynolds number is calculated for diameters of 250 mm and 500 mm and a graph of the dependences of its temperature values is built. The coefficients of hydraulic friction are calculated, a graph of their dependence on temperature is built and it is calculated how much they change in the considered temperature range. The values of specific pressure losses and pressure losses along the length are obtained for various sections of the pipeline, graphs of the dependences of pressure losses on temperature are constructed.