腔盘式精量穴施肥装置设计与试验

施肥方式粗放是造成我国肥料利用率低的主要原因之一。与条状施肥相比,穴式施肥可有效提高肥料利用率。本文设计一种用于颗粒状肥料穴式施用的腔盘式精量穴施肥装置,通过理论分析确定了装置的主要结构和工作参数,并探讨了肥腔形状(圆弧型、直线型-钝角、直线型-锐角和抛物线型)对肥料运动的影响。运用离散元法(EDEM)对不同结构和作业参数下的排肥盘充肥性能和肥群运动进行了仿真分析,结果表明:肥腔形状、前进速度和施肥量对各穴排肥量变异系数均有显著影响,随前进速度的增大和施肥量的减少,变异系数增大,且圆弧型肥腔排肥稳定性最好;前进速度和肥腔形状对肥料扰动度有显著影响,排肥盘经过箱体的时间及其对肥料扰动的形式和扰动量是影响排肥量稳定性的主要原因。在前进速度7 km/h、排肥量300 kg/hm~2的条件下,对4种排肥盘进行台架试验,结果表明,圆弧型肥腔性能最优,排肥量合格率为94%,各穴排肥量变异系数为6.5%,与仿真结果呈现相同规律,且满足作业排肥要求。

Design and Experiment of Precision Hole-fertilizing Apparatus with Notched Plate

Extensive fertilization method is one of the main reasons for the low utilization rate of fertilizer in China. Compared with the strip-type fertilization, the hole-type fertilization method can effectively improve the efficiency of fertilizer utilization, but currently there is a lack of mature hole-type fertilization equipment. In view of the above problems, a kind of notched precision hole-fertilizing apparatus was designed, which was used for granular fertilizer. The main structure and working parameters of the device were determined through theoretical analysis, and the analyzing of the shape of fertilizer cavity was focused on. The discrete element method (EDEM) was used to simulate and analyze the filling performance and fertilizer group movements under different conditions. The simulated results showed that the fertilizer cavity shape, operation speed and the fertilizing amount had significant influence on the fertilizing amount coefficient of variation between holes. With the increase of the operating speed and the reduction of fertilizing amount, the variation coefficient of fertilizing amount between holes was increased. Circular-type fertilizer cavity had the best stability in four kinds of shapes. The operating speed and fertilizer cavity shape had significant influence on the fertilizer disturbance coefficient. The time of fertilizer plate passing through the box and the form and size of disturbance on the fertilizer were main reasons affecting the stability of fertilization. Taking the qualified rate of fertilizing amount and coefficient of variation between holes as indicators, four types of fertilizer plates were arranged as verification test of at working speed of 7km/h and fertilizing amount of 300kg/hm2. The results showed that the performance of the circular-type fertilizer cavity was the best with fertilizing amount qualified rate of 94% and the variation coefficient between holes was 6.5%, which satisfied the requirements of hole-fertilizing.