Authors

Abstract

The vacuum seed metering device absorbs seeds by using the negative pressure generated by vacuum air flow. Therefore, it is of great significance to study the variation law of pyrolysis gas flow field to improve its seed metering performance. In this paper, the common disc and composite disc were selected as the research objects and tested on the indoor test-bed. The negative pressure was measured by U-type barometer, and the effects of fan speed, suction hole size, seed hole structure and air chamber thickness on the air flow field were studied. Firstly, the influence of fan rotation frequency on vacuum chamber negative pressure is studied, and the variation law of negative pressure in vacuum chamber and fan port of common disc and composite disc under the same frequency is compared. Secondly, the suction holes in the vacuum chamber were numbered, the negative pressure distribution of the suction holes was measured, and the influence of the number and diameter of the suction holes on the negative pressure of the vacuum chamber was studied. Finally, the negative pressure was measured at the distance of 0 to 10 mm from the suction hole to study the effect of seed hole structure on the air flow field. Moreover, increase the additional thickness of the vacuum chamber from 0 to 40 mm to study the influence of the chamber thickness on the distribution of the gas flow field. This paper makes a comprehensive experimental analysis on the influencing factors of air flow field of air suction seed metering device, necessary for future design of air suction seed metering device.

Abstract in Chinese

气吸式排种器的利用真空气流产生负压吸取种子，了解气流场的变化规律对提高其排种性能具有重要意义。本文选取常规盘和复合盘作为研究对象，在室内试验台上进行试验，利用U型压力计对负压进行测量，对风机转速、吸孔尺寸、取种孔结构、气室的厚度对气流场的影响规律进行研究。首先通过变频器调节风机的转速，研究风机频率对气室负压的影响，对比相同频率下常规盘和复合盘的气室负压及风机口的负压变化；然后，对气室范围内的吸孔编号并测量吸孔的负压分布规律；以常规盘为对象研究吸孔的数量和直径对气室负压的影响；最后分别在距离吸孔0至10mm距离测量负压，研究取种孔结构对气流场的影响；并且增加气室的附加厚度分别为0至40mm，研究气室厚度对气流场的分布影响。本文对气吸式排种器的气流场影响因素进行全面的试验分析，试验结果对气吸式排种器的优化设计具有重要参考价值。