Study On The Water And Specific Power Distribution Of The Spray Plate Sprinkler Used In The Moving Sprinkler Machine

With the increasing shortage of water resources and energy, the low pressure sprinkler irrigation machine technology has become one of the focuses in the development of moving sprinkler machine. The sprinkler which was equipped with moving sprinkler machine became the high pressure sprinkler transition to the low pressure. The low pressure spray sprinkler has become the most widely used in the moving sprinkler machine, because it’s excellent performance. In order to select the low pressure sprinkler and configuration problems for the solar moving sprinkler machine, the theoretical simulation, experimental validation and experimental study were used in this article to test and analyze the sprinkling performance of two kinds of spray sprinklers which was widely used in the moving sprinkler machine in China. The main research contents and results were as follows:(1) The Nelson D3000 and Nelson R3000 sprinklers was selected for the spray test in the laboratory, analyzed the relationship between the nozzle pressure and flow rate, compare the throw distances and water distribution curve of the two kind of the sprinkler. The main water of the Nelson D3000 was focus on the one third of the throw distance near the end of the range, the shape of the water distribution curve was like a triangle. The water distribution of Nelson R3000 sprinkler was more uniform than Nelson D3000 sprinkler. The water distribution of single sprinkler of Nelson D3000 sprinkler like a ring distribution, there was no overlap between two adjacent jet. The water distribution of single sprinkler of Nelson R3000 sprinkler like a regular ring.(2) A two dimensional video disdrometer(2DVD) was used to measure drop size, drop velocity and drop angle from Nelson D3000 and Nelson R3000 spray plate sprinklers with operating pressure of 50, 100,150,200 k Pa. The relationship between drop sizes, drop velocity and drop angle were analyzed. The volumetric mean diameter increased with the distances along the sprinkler increased, the change between drop diameter and distances along the sprinkler meets exponential function. Drop velocity increased with the drop diameter increased, the change between drop velocity and drop diameter meets logarithmic function. Drop angle decreased with the increase of drop diameter and divided into three parts. Operating pressure effect on the relationship between drop velocity and drop diameter, drop angle and diameter was not obvious.(3) Based on the water distribution and drop diameter tested, the relationship between drop kinetic energy and drop size, kinetic energy applied per unit drop volume and distances along the sprinkler, specific power and distances along the sprinkler were analyzed, the operating pressure at 50, 100, 150 and 200 k Pa of the Nelson D3000 sprinkler and 100, 150 and 200 k Pa of Nelson R3000 sprinkler. Based on the analyzed, when the sprinkler collocation on the solar moving sprinkler machine, the best water distribution curve of the sprinkler was decreased with the increase of distance from the sprinkler, this kind of water distribution can avoid the peak specific power, reduce the probability of the surface runoff. Compare Nelson D3000 and Nelson R3000 sprinkler, the Nelson D3000 sprinkler is more suit for the solar moving sprinkler machine because of the excellent performance in the low operating pressure.(4) Study on the influence of the combination distance of the Nelson D3000 sprinkler on water distribution and specific power uniformity coefficient in solar moving sprinkler machine. The superposition method was used to simulation the water distribution and specific power distribution when operating pressure at 50, 100, 150 and 200 k Pa, distance between two sprinklers was 2.0, 2.5, 3.0, 3.5, 4.0, 4.5 and 5.0m. Composite water and specific power application rate profile perpendicular to sprinkler lateral for the Nelson D3000 sprinkler was analyzed. When the Nelson D3000 sprinkler was used in the solar moving sprinkler, the best sprinkler distance was 2.5m when operating pressure at 50 k Pa by contrastive analysis.(5) Study on the ballistic theory used in the flight path trajectory of the droplets of the Nelson D3000 sprinkler simulation. A high speed camera was used to measure drop velocity and drop angle when the jet out of the spray plate. The relationship between operating pressure and drop velocity, and drop angle was established. The flight path trajectory of the droplets, drop velocity, drop angle, kinetic energy per unit drop volume and specific power along the distrance from the sprinkler was simulated, and compared with test value which measured by 2DVD. It is found that the simulated and observed values are in good agreement.