Design,Development And Numerical Simulation Analysis Of Air Suction Rice Precision Direct Seed Metering Device

Rice is one of the most important food crops in my country.Optimizing rice planting patterns and improving new varieties to increase its yield are of great significance for ensuring my country’s food security.Rice varieties directly affect the yield of rice.The selection of new varieties needs to be carried out under the same natural conditions and the same agronomic planting model.The existing rice seed breeding model under artificial sowing conditions cannot meet this requirement.Compared with traditional rice breeding operations such as artificial sowing,seedling raising,seedling pulling,and seedling transplanting,the use of rice dry field direct seeding technology for sowing operations can not only improve breeding efficiency and reduce costs,but also effectively ensure the accuracy and consistency of seeding operations,and eliminate human intervention.Factors interfere to improve the accuracy and credibility of the test results.The core equipment of rice dryland direct seeding technology is rice breeding and metering device,but at this stage,there are few researches on rice dryland direct seeding metering device in my country,and the technology is not mature enough.Therefore,this article aims to design and develop an air suction that can meet the agronomy of direct seeding in dry land by studying the working principle of the metering device,the adsorption/carrying movement of rice seeds,the fluid simulation of the suction hole,and the bench test.Type rice precision breeding and metering device.The main research contents are as follows:(1)Analysis of research status at home and abroadOn the basis of fully studying the relevant documents and patents of seed metering devices at home and abroad,combined with market visits and investigations,we analyze the current functional requirements of rice breeding seed metering devices,compare existing domestic products and equipment,and clarify the design goals.The required numerical simulation method is analyzed,and the design scheme of the air suction type breeding seed metering device is proposed.(2)Rice seeds calibration by testCarry out direct measurement test of seed physical parameters to obtain seed physical parameters such as density,moisture content,shear modulus,geometric size and sliding friction coefficient;adopt the method of combining discrete element simulation test and direct measurement test to take the natural seed The angle of repose is a control parameter,and the material contact parameters of rice seeds are systematically calibrated.(3)Structure Design of Rice Seed Metering DeviceAccording to the physical parameters of rice seeds(3-axis size,sliding friction coefficient,etc.),combined with the functional requirements of the rice breeding seed metering device in the breeding experiment,a suction type rice precision breeding seed metering device is designed,and the seed metering device is pre-designed.The structure and function analysis of the planting mechanism,the structure of the seed cleaning room and the structure of the seeding tray are carried out.By analyzing the stress of rice seeds during sucking,carrying and dropping,the principle of seed metering and the main factors affecting the performance of sucking and carrying are clarified.(4)Optimal Design and Simulation Test of Seed Metering Device StructureDesign three kinds of seeding disc disturbing groove structure,and determine the best parameter of seeding disc disturbing groove through discrete element simulation.Establish a fluid model for the seed-suction hole of the seed-metering plate,conduct a simulation analysis on the flow field of the seed-suction hole,determine the structure of the seed-suction hole and key working parameters,and combine the simulation analysis results to optimize the structure of the seed-suction hole.The fluid-solid coupling numerical simulation is used to verify whether the structure of the seed metering device clearing room meets the requirements of the breeding seed metering device’s seed clearing function.(5)Experimental Research on the Performance of Seed Metering DeviceUsing a decelerated stepper motor as the power source of the seed metering device,and a variable frequency fan as a negative pressure supply system,a rice breeding seed metering device test bench was established,and the working speed and air chamber pressure of the seed metering device were used as the main tasks of the seed metering performance of the seed metering device.Parameters,a series of bench tests are performed on the seed metering device,including a single factor test of the seed metering device’s working speed and air chamber air pressure,and a 2-factor 3-level test that considers the seed metering device’s working speed and air chamber air pressure at the same time.Using single and double factor experiments to study the working parameters of the seed meter,analyze the test results,obtain the best working parameters of the pressure value and speed of the seed meter,and carry out the impact test of the seed meter leakage rate and the adaptability test of the seed meter.To verify the working performance of the seed metering device.