倾斜梯形孔式穴施肥排肥器设计与试验

Design and Experiment of Inclined Trapezoidal Hole Fertilizer Point-applied Discharging Device

为降低肥料施用量、提高肥料利用效率、实现植株根区施肥,设计了一种倾斜梯形孔式定量穴排肥器。阐述了穴排肥器的成穴与工作原理,分析了影响其成穴性能的主要因素,构建了充肥和排肥过程中肥料颗粒群的力学模型;应用离散元软件EDEM和流体分析软件Fluent对穴排肥器的成穴性能进行了仿真分析,研究了作业速度、充肥孔长度和气流速度对穴长、穴排肥量误差的影响,通过全因子试验得到作业速度为3~7 km/h时的较优参数组合为充肥孔长度27.0 mm、气流速度15.0 m/s,对应的穴长和穴排肥量误差分别为62.7~87.5 mm和7.4%~8.9%。台架试验表明,在作业速度为3~7 km/h、充肥孔长度为27.0 mm和气流速度为15.0 m/s条件下,穴长、穴长稳定性变异系数、穴排肥量误差和穴距误差分别为98.5~175.5 mm、7.42%~14.18%、7.60%~15.17%、2.3%~4.7%;田间试验表明,作业速度为3~7 km/h时,穴长、穴长稳定性变异系数、穴排肥量误差和穴距误差分别为104.2~178.4 mm、7.55%~14.56%、7.69%~13.80%、2.1%~4.3%,成穴性能较好。

In order to improve the utilization efficiency of fertilizers,reduce the amount of chemical fertilizers applied,and realize fertilization in the root zone of plants,an inclined trapezoidal hole fertilizer point-applied discharging device was designed.Fertilizer point-applied discharging device can be divided into two categories,the first type was intermittent fertilizer discharge device,and the continuous fertilizer particles were discharged from the fertilizer supplied device and then relied on the intermittent device(duck mouth valve)to open and close to form the hole fertilization;the second type was consequent metering device,the mechanisms combined filling plate and discharging plate continuously and then rotated and extracted fertilizer particles from the filling area,then discharged fertilizer particles from the discharging area.The consequent metering device can reduce the movement time of the fertilizer,offset the forward speed of metering machines,and finally reduce the scattered length of the landing fertilizer particles by the centrifugal force and the initial tangential velocity of the fertilizer.Therefore,a consequent and point-applied fertilization metering device was designed.The centrifugal force of the filling and discharging wheels,the self-gravity of the fertilizer and the assisted pneumatic force were used to discharge the fertilizer,and the performance of the device was improved by reducing the time when the fertilizer particles completely flew out from the hole.The cavitation and working principle of the fertilizer point-applied discharging device were explained,the main influencing factors affecting its fertilizer distribution performance were determined,and the mechanical model of the fertilizer particle group in the process of filling and discharging fertilizer was constructed;the discrete element software EDEM and fluid analysis were used,and the software Fluent was used to carry out a simulation analysis on the fertilizer distribution performance of the fertilizer point-applied device,and the influence of the working speed,length of fertilizer hole and air velocity on the fertilizer distribution length and the error of hole fertilizer amount was studied.The 3-factor 3-level full-factor experimental design method was adopted.The optimized solution showed that when the operating speed,the length of the fertilizer hole and the air velocity were 3~7 km/h,27.0 mm and 15.0 m/s,respectively,the fertilizer distribution length and the hole fertilizer amount were 62.7~87.5 mm and 7.4%~8.9%,respectively.The bench test showed that under the conditions of operating speed of 3~7 km/h,hole length and air velocity of 27.0 mm and 15.0 m/s,respectively,the fertilizer distribution length,the stability coefficient of fertilizer distribution length,the error of fertilizer pointed distance and the error of hole fertilizer discharge the hole distances were 98.5~175.5 mm,7.42%~14.18%,7.60%~15.17%and 2.3%~4.7%,respectively.Field test results showed that when the operating speed was 3~7 km/h,the fertilizer distribution length,the coefficient of variation of the fertilizer distribution length stability,the error of the hole fertilizer amount and the error of the fertilizer pointed distance were 104.2~178.4 mm,7.55%~14.56%,and 7.69%~13.80%,2.1%~4.3%,respectively.The research result can provide equipment support for the popularization and application of fertilizer hole application technology,and provide a theoretical basis for the design and optimization of hole fertilizer device.