杂交水稻穗层埋入式管道送风辅助授粉机设计与试验

高地隙杂交水稻制种授粉机在作业过程中，当泥底层高差变化过大时，两侧的授粉器上下颠簸导致授粉器风场脱离父本穗层最佳作用位置，甚至完全脱离父本穗层，从而导致局部区域出现授粉缺失。为解决上述问题，该研究设计了一种杂交水稻穗层埋入式管道送风辅助授粉机，从减轻授粉器质量和增加有效作用深度2个方面进行优化，对授粉器的分流器和授粉管进行分析，并对分流器的气流均布效果和授粉器的气流风场特性进行仿真试验。仿真结果表明：在工作区间内，分流器的气流均布效果与入口风量无关（P>0.05），根据参数优化选出的分流器可使3支授粉管的入口总压平均变异系数仅为1.14%；授粉管的喷孔直径为12 mm时，授粉边界区域风场速度约为1.2 m/s，可保证花粉横向悬浮运送至整个母本区域。根据理论分析和仿真结果试制样机并进行试验，结果表明：授粉机行走速度为1.5 m/s，作业效率约14 hm2/h，在通过200 mm地面高差时依然具有稳定的穗层风场保持能力，授粉管喷孔轴心气流平均速度为34.2 m/s的条件下，母本厢花粉采集点的载玻片单位视野内平均粒数为8.35粒（杂交水稻制种农艺上要求至少有3粒花粉），其中平均花粉粒数多于3粒的采集点数量占比为96.02%，基本解决了局部区域授粉缺失问题。该研究可为杂交水稻制种田间机械化授粉提供参考。

Design and experiments of panicle layer embedded pipeline-airflow auxiliary pollination machine for hybrid rice

Abstract: A pollinator with high-clearance chassis has an excellent performance in hybrid rice beyond artificial pollination with high labor intensity and low efficiency. However, the lack of pollination often occurs when the pollinator is separated from the male parent panicle layer, due to the large size of the left/right trusses swinging in the vertical direction, particularly in the uneven bottom soil. In this study, a pipeline-airflow pollinator was designed to embed panicle layer for the better pollination of hybrid rice. A lightweight vertical pollination tube was adopted, where the effective working length was 60mm. As such, the panicle layer in the local paternal area was effected by the pollination wind field always even if high-clearance chassis shaken when the pollination machine was walking in the field. In addition, the key components were optimized to obtain a uniform airflow field and a suitable velocity of airflow in a pollinator. Firstly, the flow divider was simulated to evaluate the distribution of airflow. Then the circular-hole jets were adopted to adjust the pollination airflow field under the different diameters of the nozzle. Simulation experiments were also conducted on pollination tubes with various nozzle diameters. The simulation results showed that there was no significant effect of inlet Inlet air volume on the airflow distribution of divider in the working range (P> 0.05). An optimal splitter was selected when the average coefficient of variation was only 1.14% at the inlet total pressure in three pollination tubes, indicating a better uniform airflow field. The air velocity along the pollination boundary was 1.2m/s just above the suspended velocity of pollen, when the diameter of the pollination tube nozzle was 12 mm. A prototype was also trial-produced for the field tests. The experiment results showed the simulation data was basically consistent with the actual one. The relative error of airflow between simulation and measurement was ±0.3m/s. The coefficient of variation was only 1.12% for the axial airflow velocity of the nozzle in three pollination pipes, when the diameter of the nozzle was 12 mm, indicating suitable for the design requirements of the uniform wind field. The distance of the pollination tube from the middle of the panicle layer was less than half of the effective working length of the pollination tube when the speed of the pollination machine was 1.5m/s, indicating an effective range of pollination wind field. The pollination experiments were conducted in the paddy field under the condition that the walking speed of the pollination machine was 1.5m/s and the average axis velocity of airflow at the pollination tube nozzle was 34.2 m/s. A total of 80 acquisition points were divided into 5 lines on average in the female compartment area against the male parent. The field experiments showed that the average number of grains in the unit visual field was 8.35 (hybrid rice seed production agronomically requires at least 3 grains of pollen), of which the average number of pollen grains more than 3 grains accounted for 96.02%, indicating the minimum requirement of pollen quantity for hybrid rice seeding and pollination in local areas. This finding can provide a sound reference for the production of hybrid rice seeds in mechanized agriculture.