Simulation and experiment of air-blowing precision seed-metering device for Panax notoginseng

Objective  A novel kind of air-blowing precision seed-metering device was designed in order to fulfill the mechanized planting needs of Panax notoginseng and reduce seed damage in the process of mechanical seeding.

Method  The main structural parameters of the seed-metering device were determined. The mechanical model in seed clearing process was established. The internal flow field model of the seed-metering device was established, Fluent software was used to simulate the flow field under different air-blowing pressure, and the range of air-blowing pressure for seed clearing was verified. We used orthogonal design and performed bench test to further examine the feasibility of the range of air-blowing pressure and find out the optimal combination of working parameters. Eligible index, leakage sowing index and repeat sowing index were selected as experimental indexes. Operating speed, seed layer height and air-blowing pressure were selected as the influencing factors in the test.

Result  The optimal combination of parameters was the operating speed of 0.6 m/s, seed layer height of 90 mm and air-blowing pressure of 0.5 kPa. Under these conditions, the qualified index was 90.48, the leakage sowing index was 4.24, and the repeat sowing index was 5.28.

Conclusion  The air-blowing seed-metering device can meet the requirements of Panax notoginseng seeding. This study provides a theoretical basis for the field experiment of the seed-metering device. Comparison between the test results and the simulation analysis indicates that the influence of air-blowing pressure changes on the filling performance of the seed-metering device is consistent, and Fluent simulation is feasible for determining the air-blowing pressure for seed clearing.