The results of laboratory studies of the proposed drip irrigation system are given. Five different types of droppers have been investigated to quantify the hydraulic characteristics. The dependences of the uniformity of water flow through droppers with a change in the working pressure in the system are obtained. Laboratory studies of the experimental facility were carried out at the training and demonstration center of Kazan State Agrarian University. The experimental installation consists of a storage tank, a submersible pump, five P.V.C. main pipes with a length of 3 m and a diameter of 16 mm, stop valves of a drip line, pressure gauges, a main stop valve, a collector line, a return line, and droppers. Before starting the experiments, air was removed from the system and pressure at the inlet to each main pipe was adjusted to the required value. Immediately under each drip, 500 ml volumetric containers were placed to determine the volume of leaked water in two minutes. Significant uniformity of water consumption and the smallest deviations from the specified nominal flow rate were achieved with type A and C droppers (with pressure compensation) at an operating pressure of 0.2 MPa; with type B droppers (also with pressure compensation), water flow uniformity decreased with increasing pressure. The results of the research show that pressure-compensated droppers are less sensitive to pressure changes with an operating pressure of 0.35 MPa. Water consumption (q) for type A droppers increased by 5.27%, B - by 27.3% and C - by 9.1%. Dropper type D and E have the lowest uniformity of water flow at different pressure levels. Under actual irrigation conditions, it is recommended to install pressure gauges not only in the collector line, but also on the main pipes (preferably at the end of each main pipe) to determine the differential and pressure losses in the system. |
