Development And Experiment Of Air-assisted Rice Broadcast Sower

Rice direct seeding has been increasingly recognized by countries and regions. It has been a major way of the international rice plant mechanization and the use area increased year by year. As a way of rice direct seeding, rice broadcast spares many fussy processes such as raising seedlings, drawing seedlings and transplanting rice seedlings. Rice direct sowing has a wide development future, with low laboring intensity, little material resuming, high benefit and convenience operation as the simplest planting manner among rice light planting technique.Nowadays, there is no specialized rice seeding machine in China. There are two forms of rice broadcast. One way is to spread the rice out of the sower by centrifugal force, which has the same principle of fertilizer spreading machines. Another way is using the improved rice broadcast sower which is based on knapsack sprayers by the air flow principle, such as convert the mobile dusting(fog) machines to rice broadcast sower. This paper designed an air-assisted rice broadcast sower for sowing rice and other crops, which has a good seed shape adaptability and little damage rate. The whole working process is: concentration sending systems accurately deliver the seeds, discharge the seed into ground through the air delivery system with air as the carrier, and complete the planting.The paper measured the physical properties of wet rice seeds, which contained thousand seed weight, particle size, sliding friction angle, angle of repose, and other related parameters. According to the physical properties of rice and agronomic requirements of rice seeding, the structure of air-assisted rice broadcast sower was determined, including the design of support structure, seed box, seeding system, power transmission system, air delivery system, etc. Using the Solidworks software to complete prototype design and motion simulation; using the ANSYS Workbench software to complete statics simulation of support structure and analyze the structural strength of the machine; designed the seeding system which was easy to operate, meeting the requirements of large quantity and rationed feeding; designed and calculated air delivery system, which have no strict requirements of seed dimensions, low hurt of seeds, high versatility and can meet the high-speed operational requirements; using the Fluent software to simulate the flow field of the air pipe structure and visual displaying the different effects of air pipe structure of the nozzle, and chose the flat nozzle as air pipe structure by comparing velocity and concentration distribution of the three structures.Complete the prototype production and the tests of machine performance based on the theoretical analysis. The tests showed that the results of numerical simulation conform to experimental rule and the flat nozzle can satisfy the uniformity requirement of broadcast. The tests included breakage test and spreading uniformity test. The statistics showed that the damage rate was 0.3713%, less than the standard breakage rate of 0.5%. The standard deviation was 1.49 and the fluctuation was small. The air-assisted rice broadcast sower can improve operational efficiency, meet the requirement of sowing uniformity and decrease the injury of seed.