双齿轮式排肥器设计与试验

为了提高颗粒肥料的施肥均匀性,设计了双齿轮式排肥器。利用离散元软件对排肥过程进行仿真分析,以排肥轮压力角、排肥轮间隙为试验因素,以排肥均匀度变异系数为排肥效果评价指标,分析因素对指标的影响。单因素试验结果表明,排肥轮压力角在15°～25°,排肥轮间隙在4～6 mm,排肥效果较好;通过二次通用旋转组合试验,建立了两个因素与评价指标的回归方程,试验结果表明,随排肥轮压力角、排肥轮间隙的增大,排肥均匀度变异系数均呈现先增大、后减小的趋势,当排肥轮压力角为19. 52°、排肥轮间隙为4. 7 mm时,排肥器具有最优的排肥效果,此时理论计算和仿真试验的排肥均匀度变异系数分别为15. 30%和14. 58%,两者偏差为0. 72个百分点,说明回归模型准确。最优结构参数组合下双齿轮式排肥器的台架试验结果表明,排肥量可通过排肥轮转速线性调节,排肥均匀度变异系数为15. 42%,与仿真值及理论值基本一致;同等条件下外槽轮排肥器的排肥均匀度变异系数为20. 29%,试验排肥器排肥均匀度变异系数提高了31. 58%,排肥均匀性得到明显改善。

Design and Experiment of Double-gear Type Fertilizer Apparatus

In order to improve the fertilizer performance, a double-gear fertilizer apparatus was designed. Aiming to optimize the fertilizer performance, the discrete element simulation technology was used. The pressure angle of gear tooth and the interval of fertilizer wheel were taken as test factors. The coefficient of variation of fertilization uniformity was measured as test indicators, and the influence of various factors on the indicators was obtained and analyzed. The results of single factors simulation test showed that fertilizer apparatus had relatively small coefficient of variation of fertilization uniformity. When pressure angle and fertilizer wheel interval was at 15°~25° and 4~6mm, respectively. According to the results of single factor experiment, a quadratic general rotation unitized design method was conducted, and regression equations of two key structural parameters and coefficient of variation of fertilization uniformity were established. The results showed that coefficient of variation was increased at first, and then decreased with the increase of pressure angle and fertilizer wheel interval. When they were 19.52° and 4.7mm respectively, coefficient of variation of fertilization uniformity was minimum, in this case, the coefficient of variation of theoretical calculation value and simulation test value were 15.30% and 14.58% respectively, and the deviation was only 0.72 percentage point, the regression model was accurate and credible. In order to validate the regression model established by simulation test and optimization effect of structure parameters, a bench test of double-gear fertilizer apparatus with the optimized structure parameters combination of fertilizer wheel was carried out. The results showed that fertilizer discharge flow rate can be adjusted linearly by the speed of fertilizer wheel. The average coefficient of variation was 15.42%, which was basically consistent with simulation test value and theoretical calculation value. Under the same condition, the coefficient of variation of outer groove-wheel fertilizer apparatus was 20.29%. The coefficient of variation of beach test was increased by 31.58%. It obviously improved the fertilization uniformity.