外凸扰种仿形型孔气吸式水稻芽种精量排种器设计与试验

Design and Experiment of Precision Seed Metering Device for Rice Bud Seed with Protruding Disturbing Species

摘要:

针对水稻芽种播种过程中种群堆积、稻种含水率较高不易被吸附等问题，设计了一种外凸扰种仿形型孔气吸式水稻芽种精量排种器。以南方普遍推广的“Y两优1号”型杂交稻为研究对象，根据其机械物理特性，对外凸扰种仿形型孔结构与几何参数进行了设计；对芽种充种和投种过程进行了动力学和运动学分析，得到了工作转速和工作负压范围；基于CFD-DEM流固耦合理论，将吸附力作为试验指标进行了吸附性能仿真试验，确定吸附力最大的吸孔直径为1.4 mm，同时将水稻芽种平均速度作为评价指标进行了扰种性能仿真试验，当工作转速为10~50 r/min、工作负压为1.2 kPa、吸孔直径为1.4 mm时，具有外凸扰种仿形型孔排种盘扰动能力较强，能有效减少种群堆积现象；以该种吸孔为基础，选取工作转速和工作负压为试验因素，以合格指数X1、重播指数X2和漏播指数X3为评价指标，开展了两因素全因子台架试验。试验结果表明：当工作转速为25 r/min、工作负压为1.24 kPa时，排种器合格指数为92.64%，重播指数为2.57%，漏播指数为4.79%；试制气吸式水稻芽种精量直播机并进行田间播种试验，测得各行合格指数平均值为92.86%，重播指数平均值为2.72%，漏播指数平均值为4.42%，穴距合格率平均值为90.57%，各行排量一致性变异系数为3.12%，总排量稳定性变异系数为1.89%，各项评价指标均满足水稻芽种精量直播种植要求，为水稻芽种播种提供了理论基础。

Abstract:

Aiming at the problems such as population accumulation and high water content of rice seed which are not easy to be adsorbed during seeding process, a kind of airi-suction rice seed precision discharge device with convex and disturbed seed copying hole was designed. According to the mechanical and physical characteristics of Yliangyou No.1 hybrid rice, which is widely used in South China, the structure and geometric parameters of the profile-shaped hole were designed rationally. The dynamic and kinematic analysis of filling and seeding process was carried out, and the range of working speed and working negative pressure was obtained. Based on the fluid-structure coupling theory of CFD-DEM, the adsorption force was taken as the test index, and the adsorption performance simulation tests of seven diameters were carried out. The suction hole diameter with the largest adsorption force was determined to be 1.4 mm. At the same time, the average velocity of rice bud seed was taken as the evaluation index, and the simulation test of disturbed seed performance was carried out. Under the conditions of working speed 10~50 r/min, working negative pressure 1.2 kPa and suction hole diameter 1.4 mm, the disturbance ability of the seed plate with convex species copying hole was strong, which could effectively reduce the population accumulation phenomenon. Based on this suction hole, the working speed and working negative pressure were selected as test factors, and the qualification index X1, replay index X2 and missing sowing index X3 were evaluated. The two-factor full factor bench tests were carried out. The test results showed that when the working speed was 25 r/min and the working negative pressure was 1.24 kPa, the qualified index of the seed feeder was 92.64%, the replay index was 2.57%, and the missing sowing index was 4.79%. The results showed that the average qualified index of each line was 92.86%, the average reseeding index was 2.72%, the average missing sowing index was 4.42%, the average qualified rate of hole distance was 90.57%, and the coefficient of consistency of discharge of each line was 3.12%. The coefficient of variation of total displacement stability was 1.89%, and all the evaluation indexes met the planting requirements of rice bud seed precision direct seeding, which provided a certain theoretical basis for rice bud seed seeding.