Analysis of picking characteristics of blueberry by air blowing

Abstract Aiming at the possible damage to blueberry trees and fruits caused by existing contact vibration picking devices, this study focused on the principle of air blowing picking technology and the flow rate and distance of the air. By applying the theory of fluid mechanics, the attenuation characteristics of free jet in blueberry tree canopy were analyzed, and the related factors affecting the length of jet core region and the attenuation of air velocity in canopy were revealed. A numerical simulation method was used to establish the relationship between the length of the jet core region and the diameter of the outlet, and experimental evidence was verified by the free jet velocity attenuation, the velocity change of the blueberry tree canopy and the gas blowing picking test platform to ensure the accuracy of the numerical simulation results. In this study, fluid-structure coupling numerical simulation under the action of air flow was carried out, and the motion characteristics of the hanging branches and main branches of blueberry under the action of air flow were obtained, and the effective range of air flow parameters for realizing the non-contact shedding of blueberry fruit was preliminarily determined. Finally, this paper successfully completed the picking characteristics and numerical simulation of the air blowing blueberry picking process, and determined that the optimal picking of blueberries can be effectively achieved when the flow rate is 60m/s and the operating distance is between 100mm and 400mm. These research results provide important theoretical guidance and experimental parameters for the design of air-blown blueberry pickers in the future.