气吸式排种装置排种性能理论分析与试验

为了探讨提高气吸式排种装置排种性能的方法，该文从理论上分析了气吸式排种器的吸附机理，建立了气吸室空气流场方程，并通过对种子在气吸状态下的受力情况及种子脱离吸种孔后的运动进行分析计算，建立了种子运动方程。利用移动式排种器试验台分别以排种盘转速、气吸室真空度为试验因素，对气吸式排种装置排大豆时的影响进行了单因素试验，结果表明：排种盘转速、气吸室真空度对气吸式排种器的排种性能影响显著，与粒距合格率的相关系数均在0.96以上；当排种盘转速为21.7 r/min、气吸室真空度为2.5 kPa时排种效果最好，合格率达到91.26%。

Theoretical analysis and experiments of metering performance of the pheumatic seed metering device

The pheumatic seed metering device is a key component of precision drill, which performance direct affect the quality of seeding. A theoretical analysis was conducted on the adsorption mechanism of the pheumatic seed metering device and an air flow field equation has been derived. An analytical calculation of the state of seed subjected to force under suction effect and the seed motion after breaking away from suction hole was carried out, and a seed motional equation was established. A single factor experimental of the pheumatic seed metering device on the soybean seeding process, taking the rotation speed of seed metering disk and the vacuum degree in suction chamber as experiment factors respectively, was carried out on the experiment stand. The experiment results show that: When the rotation speed of seed metering disk exceeds the one for the vacuum degree to suit for obtained by theoretical calculation, the performance quality gets worse and miss seeding rate evidently increases up to 29.63%; When the vacuum degree in suction chamber is 2.5 kPa, the miss seeding rate will increase up and the seeding rate up to standard appears descending tendency with the rotation speed of seed metering disk increasing; When the rotation speed of seed metering disk is kept at 54 r/min and the vacuum degree in suction chamber is higher than 1.5 kPa, the seeding rate up to standard ranges from 76.11% to 80.65%; When the vacuum degree in suction chamber is lower than 1.5 kPa, the seeding rate up to standard obviously decreases .