DESIGN AND OPTIMIZATION OF AIR-ASSISTED SPIRAL SEED-SUPPLY DEVICE FOR HIGH SPEED DENSE PLANTING MAIZE SEEDER

In order to improve the seed supply performance of seed-supplying link of high-speed dense planting seeder of maize, an air-assisted spiral seed-supply device was designed and optimized. The kinetic model of maize seeds in the migration zone was established. Based on computational fluid dynamics (CFD) simulation, the pressure and velocity distribution in the axial plane were explored when the blower pressure was 4.0, 4.5, 5.0, 5.5, 6.0 kPa, respectively. A two-factor, five-level central composite design (CCD) experiment was conducted using blower pressure and rotational speed of spiral shaft as test factors and seed supply rate, coefficient of variation of seed supply rate stability and seed breakage rate as seed supply performance indicators. Explored the impact trend of interaction terms of factors on seed supply performance indicators. Based on the multi-objective variable optimization method, the optimal working parameter combination of the air-assisted spiral seed-supply device was determined and verified by bench experiments. The results showed that the optimal combination of working parameters was the blower pressure of 6.0 kPa and the rotational speed of spiral shaft of 80 r/min. Under the verification test, the seed supply rate, the coefficient of variation of seed supply rate stability and the seed breakage rate were 2933.21 g/min, 1.87% and 1.69%, respectively, and the relative error was within 5.5% compared with the optimized results. This study can provide a reference for the optimal design of the seed-supply device of the high-speed dense planting seeder.