Numerical Simulation of Internal Flow Field in Air Suction Grafting Rootstock Clamping Device for Melon Vegetables

The existing rootstock clamping device for melon vegetables is easy to cause damage to the rootstock seedling stems due to its high rigidity. In order to improve the success rate and safety of grafting, an air suction type rootstock clamping device was designed in this paper. Using computational fluid dynamics(CFD) method to numerically simulate the internal flow characteristics of the clamping device, the influence of different suction hole diameters and different pressure values on the clamping effect was obtained, and the simulation results were verified by experimental data. Simulation results showed that the flow velocity in the suction hole diminished with the increase of the suction hole diameter, while negative pressure decreased. When suction hole diameter increased to 3 mm, the pressure drop was obvious, which was not advantageous for adsorption of the cotyledons. The flow velocity in the suction hole progressively increased with an increase of the negative pressure. When negative pressure was 8 kPa, the air flow in the suction hole was exacerbated with unstable flow field, which easily caused cotyledons damage and reduced the adsorption effect. This research will be a useful reference for the design and applications of grafting machine components.