莲藕施肥机无轴双螺旋供肥装置性能分析与试验

针对藕田施肥过程中存在的劳动强度高、施肥稳定性及均匀性较低的问题，设计了一种水力喷射式莲藕施肥机，其主要分为供肥装置和水肥混合装置，主要对无轴双螺旋供肥装置进行了设计与分析。通过理论分析确定影响供肥性能参数主要为螺旋转速、直径和导程，结合藕田施肥农艺要求确定上述3项参数的取值范围。利用EDEM对无轴双螺旋供肥性能进行离散元仿真分析，以供肥量均值和供肥量稳定性变异系数为评价指标分别进行单因素试验和回归正交旋转组合试验。单因素试验结果表明：供肥量均值随着螺旋转速、直径和导程的增大而增大，并且具有良好的线性关系，因此可通过调节供肥螺旋转速、直径和导程来改变供肥量均值；供肥量稳定性变异系数随着螺旋转速和导程的增大呈现先降低后升高的趋势，而随着直径的增大而减小。运用Design-Expert软件对回归正交旋转组合试验结果进行分析优化，分别开展仿真试验和台架试验对优化后的参数进行验证。结果表明，当螺旋转速为160 r·min^-1，螺旋直径为78 mm，螺旋导程为53 mm时，仿真结果供肥量均值为329.43 g·s^-1，供肥量稳定性变异系数为1.43%，台架试验结果分别为341.32 g·s^-1和2.34%，满足藕田施肥农艺及供肥稳定性要求。该研究可为螺旋式供肥装置的设计优化及藕田机械化施肥提供参考。

Performance analysis and test of shaftless double helix fertilizer feeding device for lotus root fertilizer applicator

In response to the problems of high labor intensity, low fertilization stability and uniformity in the process of lotus root fertilization, a hydro-jet lotus root fertilizer applicator was designed, which was mainly divided into fertilizer supply device and water-fertilizer mixing device, and the shaftless double screw fertilizer supply device was mainly designed and analyzed. The theoretical analysis determined that the main parameters affecting the fertilizer supply performance were screw speed, diameter and pitch, and the range of values of these three parameters was determined according to the agronomic requirements for fertilizer application in root fields. The discrete element simulation analysis of the fertilizer supply performance of the shaftless double helix was carried out by EDEM, and the single-factor test and the regression orthogonal rotating combination test were carried out to evaluate the mean value of fertilizer supply and the coefficient of variation of fertilizer supply stability, respectively. The results of single-factor test showed that: the average value of fertilizer supply increased with the increase of screw speed, diameter and pitch, and had a good linear relationship, so the average value of fertilizer supply could be changed by adjusting the screw speed, diameter and pitch of fertilizer supply; the coefficient of variation of fertilizer supply stability showed a trend of decreasing and then increasing with the increase of screw speed and pitch, and decreasing with the increase of diameter. Design-Expert software was used to analyze and optimize the results of the regression orthogonal rotational combination test, and the optimized parameters were verified by simulation test and bench test, respectively. The results showed that when the screw speed was 160 r·min^-1, the screw diameter was 78 mm and the screw pitch was 53 mm,