| In order to solve the problems of short spraying radius,insufficient water fragmentation and low uniformity of combined spraying under low-pressure conditions,this study uses Nelson R55 rotary refracting nozzle as a prototype and designs a series of rotary refracting end nozzles based on the working principles of secondary fragmentation,face slot diversion,rotary jet and non-full circle restricted spraying.Using Creo modeling and laser modeling,actual measurement tests,model calculations and multi-objective comprehensive evaluation,we completed the physical fabrication of the nozzle,hydraulic performance testing and evaluation,and determined the optimal design parameters of the nozzle.The primary research contents and conclusions of this paper are listed below.(1)Optimize the design of the rotating nozzle structure parameters,and put forward the concept of "face-to-slot ratio".Nelson R55 type rotary refractive nozzle on the original structure,the end of the nozzle near the distal end of the water distribution and the combination with the central nozzle spraying uniformity as the goal,by adjusting the spray disc surface and groove diversion ratio to regulate the near and distal water distribution,the design of the rotating spray disc flow channel outlet cross-sectional shape of V-shaped and semicircular,nozzle outlet outer ring radius r2 for 14 mm,the inlet cross-sectional radius r3 is 23.9mm,the addition of a speed adjustment device based on excitation damping,the use of Creo software to build a three-dimensional model of the nozzle,and finally by laser rapid prototyping to establish the nozzle solid.(2)To carry out a single end nozzle fixed spraying hydraulic performance testing,the calculation of multi-nozzle combination of mobile spraying water distribution.Spray disc "plane-groove" diversion design can effectively reduce the peak,optimize the water distribution: the proportion of the proximal water distribution increases with the increase in plane diversion;the proportion of the distal water distribution increases with the increase in groove diversion;plane part and the flow channel groove part of the diversion ratio is equal to the "surface groove ratio " for 1:1,mobile spraying radial water distribution is more uniform,the curve is a good triangle.Semi-circular compared with the V-shaped runner cross-section design,reducing the peak sprinkler intensity of 21.82%,a single nozzle uniformity of 21.33% improvement.(3)Calculate the superimposed moving water distribution of the central sprinkler head and the end sprinkler combination,establish a comprehensive evaluation model of sprinkler performance,and compare the hydraulic characteristics of the end sprinkler head with similar products in the market.Based on the existing sprinkler configuration for the combination of superposition calculation,the radial water distribution curve of the unit combination superposition analysis,found that the working pressure of 0.2MPa,"flat slot ratio" of 1:1,the flow channel cross-sectional form of semi-circular when the overall radial water distribution curve of the unit is more uniform,the highest uniformity of mobile irrigation,the main component analysis results show that the flat slot ratio of 0.2MPa,"flat slot ratio" of 1:1,when the flow channel cross-sectional form of semi-circular radial water distribution curve of the unit is more uniform.Component analysis results show that the flat slot ratio of1:1,matching the semi-circular runner disc of the rotary nozzle composite score is the highest,the final optimization results of this study.Comparison of optimization results with the existing end of the market nozzle,the results show that the improvement of the end of the nozzle can improve the unit spray width of 38.5%,flow rate of 5.2m3 /h,spraying uniformity of more than 85%,low-pressure conditions far better than similar products on the market,indicating that by regulating the spray disc "face slot ratio",the form of runner cross-section can effectively optimize the nozzle water distribution. |
PDF Full Text Request