基于离散元法高垄膜上覆土装置设计与试验

Design and Experiment of Covering Soil on Plastic-film Device for High Ridge Based on Discrete Element Method

摘要:

针对丘陵地区高垄作物覆膜后易造成大风揭膜的问题，结合高垄膜上覆土农艺要求，设计了一种高垄膜上覆土装置。根据阿基米德螺旋线在圆台的成线原理，设计了覆土滚筒螺旋叶片，对土壤在覆土滚筒中的运动进行动力学分析，确定了影响膜上覆土量和土堆聚拢值的主要因素;使用EDEM软件建立了覆土装置和土壤交互作用仿真模型，以螺旋线结束角、机具前进速度和出土口对应圆周角度为试验因素，以覆土量和土堆聚拢值为试验指标开展单因素和三因素三水平正交试验，确定了影响因素范围并建立了响应面模型。正交试验结果表明，螺旋线结束角和前进速度对覆土量影响极显著，前进速度和出土口对应圆周角度对土堆聚拢值影响极显著，最佳作业参数为螺旋线结束角57.44°、前进速度3.82 km/h、出土口对应圆周角度32.02°。根据最佳作业参数完成样机试制并开展田间试验，结果表明膜边覆土宽度90.2 mm，膜边覆土厚度35.7 mm，膜上土堆质量545.2 g，地膜透光面占比72.25%，满足丘陵地区高垄覆膜和膜上覆土农艺要求。

Abstract:

Aiming to address the problem of plastic-film lifting caused by strong winds after mulching on high ridges in hilly areas, a covering soil on plastic-film device was designed according to the agronomic requirements of high ridge mulching. Based on the generating principle of the Archimedean spiral line on a truncated cone, a spiral blade of the overlying drum was designed. The dynamics of soil movement within the drum were analyzed to determine the main factors affecting the soil pile mass and the soil pile convergence value. Using EDEM, a simulation model of the interaction between the covering device and soil was established. Taking the spiral end angle, forward velocity, and circumferential angle corresponding to the soil discharge port as experimental factors, the soil pile mass and soil convergence value as evaluation indices, single-factor and three-factor three-level orthogonal experiments were carried out to determine the factor ranges and establish a response surface model. The orthogonal test results showed that the spiral end angle and forward velocity had a highly significant effect on the soil pile mass, while the forward velocity and circumferential angle corresponding to the soil discharge port had a highly significant effect on the soil pile convergence value. The optimal operating parameters were determined as follows: spiral end angle was 57.44°, forward velocity was 3.82 km/h, and circumferential angle corresponding to the soil discharge port was 32.02°. A prototype was manufactured based on the optimized parameters, and field experiment was conducted. The field experiment results showed that the soil pile mass on the film was 545.2 g, the lighting-struck ratio of the plastic-film was 72.25%, the soil wide on film side was 90.2 mm, and the soil depth on film side was 35.7 mm, all meeting the agronomic requirements of film mulching and covering soil on plastic-film for high ridge in hilly areas.