方形喷洒域喷灌装置的研制与试验

针对圆形喷洒域喷头导致漏喷、水量重叠和界外喷洒的突出问题,该文研制了一种适用于无风环境的方形喷洒域喷灌装置以提高喷灌均匀度和水资源利用效率。该装置主要由摇臂式喷头、连杆机构和凸轮组成。利用调节喷头仰角的方式改变其射程使摇臂式喷头喷出方形喷洒域,通过凸轮滚子与凸轮接触部分阻力的变化调整喷头转速提高了装置的喷灌均匀度。测试了该装置在工作压力为400 k Pa,喷头仰角变化范围5°~30°,流量4.14 m3/h工作条件下装置的性能,试验结果表明,该装置可喷洒30 m×30 m的正方形区域,其方形喷洒域系数高达92.06%,喷灌均匀度为82.07%,界外喷灌量占总喷灌量的1.32%,喷洒地块边角部分时比圆形喷洒域喷头界外喷洒量减少了13.53%。因此,该装置能较好的实现方形喷洒域、降低了界外喷洒量、减少了多个圆形喷洒域喷头组合灌溉时所产生的重叠,为改善喷灌均匀度和提高水资源利用效率提供了新的思路和方法。

Design and experiment of sprinkler irrigation device with square spray field

Abstract: In this research, the sprinkler for a square spray field was developed to solve the problem of overlapping irrigation and extraterritorial spraying of the circular spray field sprinkler. The device spray field can completely cover the square area of 30 m×30 m. We used the link mechanism and the cam to controls the elevation angle of the sprinkler in order to change the range to form a square area during the sprinkler irrigation. In the design process, we selected 20PY sprinkler, and expanded the sprinkler diameter to 8 mm. We determined the elevation angle of the sprinkler of 5°-30° by the experiment. The results showed that the rotational speed of the sprinkler was linearly related to the velocity of the elevation. We created solid model with solid works, and use solid works motion software to simulate the motion so that we can draw the outline of the cam. In the terms of the spray uniformity, it resulted in uneven spraying that the sprinkler range was constantly changing and the sprinkler unit time was kept constant during the sprinkler process. The device adjusted the sprinkler rotation speed by changing the resistance coefficient between cam roller and cam contact surface so that when the range was far away, the rotation speed was relatively slow, and when the range was closer, the rotation speed was slightly faster to adjust the sprinkler''s shooting time in a variety of range. Thereby the spray uniformity was improved. When we calculated the spray duration, the cam profile was symmetric. As such, we can select a quarter of the cam as the object of study, and divided this part into 18 regions by angle, and the ratio of the sprayed area to the 18 regions was the ratio of these areas'' spray duration. The work of the rocker arm fighting once was relatively stable. The work of the corresponding area was the product of the spray time, rocker strike frequency and the work of the rocker arm fighting once in the area. And we can set the equation with the corresponding regional''s work and resistance coefficient to solve the resistance coefficient of roller and cam contact surface in this area. We took the 1/4 spray field to verify device performance in the experiment. The experimental results verified that the proximity between the spray field and the spray area, and the proximity was 92.06%. The sprinkler uniformity of the device was well, and the Christiansen uniformity of the sprinkler was 82.07% in the uniformity. In addition, the outside spray was also an important indicator of the test, and we regarded 15 m×15 m square outside the area of precipitation as the outside spray. The experiment showed that the ratio of the amount of the outside spray to the total spray was 1.32%. When we irrigated the edge of land, the outside spray amount from the device was decreased by 13.53% than the circular spray domain. The device avoided the overlapping of the circular spray field sprinklers, and the spray uniformity was high. At the same time, the device can effectively avoided the outside spray in the corner of land, thus improved the water use efficiency significantly. Our research provides a new concept and a method for the research and development of new sprinkler. The combined sprinkler and the spray situation in the impact of wind are still variables affecting effectives of sprinkler that needs to be studied.