Design And Experiment Of Seed Metering Device Of Coated Caragana Seed Sprayer

In order to solve the problems of high crushing rate and large intermittent time of slot wheel seed metering device in 4BQD-40 pneumatic sprayer,this thesis compared and analyzed the structure and working principle of various seed metering devices,and designed a flexible screw conveyor seed metering device suitable for the sprayer.After the determination and calibration of the physical parameters of coated Caragana korshinskii seeds,the discrete element simulation software EDEM was used to select the parameters of the current metering device combined with theoretical and physical experiments.The seed crushing rate and seed spacing time of the current and former metering devices were analyzed,and the feasibility of the current metering device was proved.The main work is as follows:1.The physical properties(size,density,etc.)and contact parameters(static friction coefficient,rolling friction coefficient,etc.)of coated Caragana seeds were determined by physical experiments.The physical test rest angle of coated Caragana seeds was obtained by stacking test.The static friction coefficient and rolling friction coefficient of coated Caragana seeds were 0.285 and 0.6676,respectively.The static friction coefficient between seed plates of coated Caragana seeds was 0.101,and the rolling friction coefficient was 0.218.the repose angle of coated Caragana seeds was 23.47°±0.3.2.According to the design requirements of the seed metering device of 4BQD-40 pneumatic sprayer and the actual situation of the machine,the working parameters and structural parameters of the spiral conveying seed metering device were calculated,and the structural parameters of three groups of spiral conveying seed metering devices meeting the design requirements were obtained.According to the calculated structural parameters,the three-dimensional model of the spiral conveying seed metering device was established.3.According to the physical parameters of the seed particles,the seed model and the geometric model of the metering device were established.The discrete element simulation software was used to analyze the three parameters of the current metering device,and the optimal parameters were determined.The simulation analysis of the seed metering process of the current metering device and the former metering device was carried out.The trajectory,velocity change and stress of the seed particles in the metering process were analyzed.Finally,the stress of the seed in the metering process of the current and former metering devices under five different displacement was obtained.The simulation results showed that the seed force of the former metering device is significantly greater than that of the current metering device,and the intermittent time of the current metering device was shorter than that of the former metering device.4.The broken rate of the current and former metering devices was tested,and the broken rate of the two metering devices was obtained under the same displacement requirements.The crushing rates of the former seed metering device under five kinds of displacement were17.68 %,14.90 %,12.88 %,12.45 % and 11.78 %,respectively.Under the same displacement,the crushing rates of the current metering device were 2.11 %,2.65 %,2.91 %,3.01 % and 3.37 %,respectively.The test results showed that the seed crushing rate of the current metering device was significantly reduced.Through the improved design of the structure,the requirements of the reduction of the broken rate of the seeding and the reduction of the intermittent time of the seeding of the4BQD-40 pneumatic sprayer were realized.The feasibility of the application of the screw conveyor seed metering device in the seeding of the sprinkler was proved.The effectiveness of the screw conveyor seed metering device was analyzed by the discrete element simulation method.The research conclusion provides a reference for the design and research of the sprinkler.