Computation Model And Test Of Uniformity Of Light And Small Translational Irrigation System

The increasing shortage of water resources makes low-pressure irrigation become the main direction for the development of irrigation technology.At the same time,aiming at the problems existing in the development of domestic and foreign sprinkler units,such as complex equipment,poor adaptability,and heavy structure,a new type of light and small-scale translation type sprinkler was developed.For this type of sprinkler,two commonly low pressure refractions were selected as the research object.Through theoretical analysis and experimental research,the influences of single nozzle,combined nozzle water distribution,operating speed,combination spacing,nozzle installation height and other factors on spray head uniformity were studied.These provided reference for the application of a new type of light and small translational sprinkler.The research content of this article mainly includes the following aspects:(1)A new type of rotary jet refraction nozzle was proposed,which was used with the rotating refraction nozzle Nelson R3000 for indoor spray test.The spray volume distribution of single nozzles with nozzle diameters of 2.98 mm,3.37 mm and 3.77 mm was analyzed.It is concluded that the water distribution curve of the sprinkler is approximately parabolic,with the increase of the working pressure of the sprinkler or the diameter of the nozzle,the spray irrigation intensity increases.(2)Calculating the combined homogeneity coefficient and coefficient of variation in 2m,3m,4m,5m,and 6m stacking cases,according to the single sprinkler's water distribution.It is verified,from the experiment,that the error range of the simulated homogeneity coefficient value was between 0.5% and 11.0%.An empirical formula for calculating the uniformity coefficient based on the working pressure and installation spacing was also proposed.The results show that 4m is the best installation distance.The primary and secondary order of factors that affect the coefficient of uniformity of the combination of rotating refraction nozzles is the nozzle installation spacing,working pressure and nozzle diameter.It is found that the coefficient of variation increases with the increase of the combination spacing.The coefficient of variation was negatively correlated with the coefficient of sprinkler uniformity,and the correlation coefficient of all models was above 0.9.(3)Through the theoretical analysis of the distribution of operating speed and water volume,a calculation model for the operating speed of sprinkler irrigation intensity was established.The experiment was done on several operating speeds which include 15%,30%,45%,60%,75%,and 90% on sprinkler irrigation intensity under three working pressures 0.07 Mpa.,0.1Mpa and 0.14 Mpa.The results show that the operating rate has an influence on the average sprinkler intensity,and the optimal working condition is from 45% to 60%.(4)The experiments and theoretical analysis verify the influence of operating speed and working pressure on the uniformity of unit sprinkler irrigation.The mathematical model of spray irrigation intensity under the influence of two factors and various factors was obtained.The results show that for the operating speed,the pressure has greater influence on the sprinkler intensity,and the operating rate has no regular influence on the uniformity of the spraying.The unit uniform spraying coefficient is above 75% at the test operating rate,which meets the spraying requirements.The fitting coefficients of the various models fitted in the paper are all above 0.85,which can fully meet the actual engineering needs.