Simulation And Analysis Of Working Process Of Air Suction Seed-metering Device Based On DEM-CFD Coupling Method

Air suction seed-metering device and "Cuilu No.3" Chinese cabbage seeds are considered as the research objects in this paper.The simulation model of air suction seed-metering device is drawn by SolidWorks software.Discrete element method(DEM)is used to simulate the filling process of Chinese cabbage seeds by EDEM software,to solve the motion state of the whole population and single Seed and obtain the curves of population and single seed velocity.At the same time,computational fluid dynamics(CFD)method is used to simulate the flow field distribution of air suction seed-metering device by FLUENT software.By solving the flow field in the whole suction chamber and the seeding tray,the pressure distribution nephogram of the flow field in the suction chamber and the cross-section velocity nephogram of the suction hole are obtained.Finally,DEM-CFD coupling method is used to simulate the seeding process of air suction seed-metering device by EDEM-FLUENT.The performance indexes of seedmetering device under different parameters combination are obtained,and the JPS-12 test-bed test is carried out at the same time.By comparing and analyzing the performance indexes of the seeder obtained from the simulation test and the test-bed test,the following conclusions are drawn.Whether it is a simulation test or a test-bed test,the performance of air suction seedmetering device is better when the vacuum degree is 2-3.5kPa and the speed is 20-30 r/min.When the speed is 20r/min and the vacuum degree is 2.2kPa,the performance of the air suction seed-metering device is the best,the quality of feed index of the test-bed test is 92.75%,the multiples index is 4.38%,and the miss index is 2.87%,the quality of feed index of the simulation test is 91%,the multiples index is 7%,and the miss index is 2%.When the speed is low,the quality of feed index increases slightly with the increase of the speed.When the speed reaches a certain value,the quality of feed index decreases gradually with the increase of the speed,and the influence of the speed on the quality of feed index and the miss index is more significant.The rule of simulation test is consistent with that of test-bed test,and the error is small.The results show that it is feasible and effective to analyze the working process of air suction seed-metering device based on EDEM-FLUENT coupling simulation.