Design and Optimization of Strength type Negative Pressure Suction Force Pluck Port based on Tesla Valve

Abstract An apple pluck port based on negative pressure suction force can realize contactless apple plucking and also reduce possible damage to the apple. Accordingly, in this study, a strength type pneumatic pluck port was designed on the basis of a Tesla valve. First, a low air pressure block for mechanization of the Tesla valve structure at the intersection between the main and curved air passageway was theoretically modelled and analyzed. Then, the air pressure and the flow speed distribution were analyzed for three different types of structure parameters under various distances of the Tesla pluck port from the apple; on the basis of a fluent simulation, the maximum pressure difference at both sides of the apple was also simulated. Finally, the structure parameters under an optimal negative pressure field according to the simulation analysis were proposed, and a manufactured experimental test was conducted to compare the results with the simulation. The simulation and experimental data prove that when the included angle between the main and curved air passageway of the Tesla pluck port is lower than 45°, the low air pressure block at the intersection between the main and curved air passageway of the Tesla valve affects the flow of the pluck port and extends the length of the low air pressure block. The Tesla pluck port guarantees a flow in the pipe when the pipe port diameter is 10–15 mm larger than the apple diameter, ensuring the negative strengthening effect of the Tesla pluck port. The experiment proves that the Tesla pluck port designed in this study exhibits a better negative pressure strengthening effect than that achieved via previously existing methods, which can strengthen the plucking effect.