滚筒集排式油菜精量排种器排种过程分析

摘要

为探明气力滚筒式油菜精量集排器结构与运行参数对排种性能高低的影响，提出了气力滚筒式油菜精量集排器的基本结构组成和工作原理，建立了排种过程中吸种、携种、投种等主要环节的种子运动学和动力学模型，并运用离散元分析软件开展了吸种过程的仿真计算，获得了排种过程中所需的负压值、正压值与结构参数、运行参数的关系模型。利用 JPS-12型排种器性能检测试验台开展了单因素试验研究，试验表明：当滚筒转速20 r/min、正压区压力值2200 Pa、负压区压力值为−2200 Pa时，集排器合格指数可达89.1%以上，变异系数为3.76%。结果表明排种过程力学模型分析计算结果与试验结果一致。该研究为集排器的结构和运行参数优化提供了理论依据。%In order to obtain the relationship model between required negative and positive pressures values and the structural and operating parameters in the main metering processes at the absorbing, retaining and dropping stages,the seeding process of pneumatic cylinder-type centralized rapeseed precision metering device were analyzed. Through analyzing the influence of operational and structural parameters on the performance of pneumatic cylinder-type centralized rapeseed precision metering device, the working principle of the pneumatic cylinder-type centralized precision metering device was summarized, and its basic configuration was designed. Dynamic and kinematics models were established in the main metering processes at the absorbing, retaining and dropping stages, and Extended Discrete Element Method software was used for the simulation and calculation of absorbing process, based on which the relationship model between required negative and positive pressures values and the structural and operating parameters were established in seeding process. The results of extended discrete element method simulation analysis indicated that in order to ensure the reliable work of the metering device, the height of seeds should be limited within the 0.65Dg, which was verified by the results obtained from our preliminary tests. Then the JPS-12 test-rig for the performance of the rapeseed metering device was adopted to conduct the single factor experiments, which showed that the quality index reached above 89.1% and the coefficient variation was 3.76%when the rotational speed was 20 r/min and the positive pressure value was 2 200 Pa and the vacuum was -2 200 Pa. The experimental results were in accordance with the analytical result of dynamic model. The analysis provided theoretical foundation for optimizing the operational and structural parameters of the centralized metering device.