A facile arc impeller with layered-staggered structure to clean cold-proof soil on grapes

Abstract: Cleaning components of cold-proof soil are still lacking for grape production in northern China. In this study, a novel arc impeller was designed to remove the cold-proof soil from the surface of grapes, particularly with low power consumption. Four components were divided, including the spline connection sleeve, impeller shaft, arc impeller blade, and connecting plate of impeller blades. A layered-staggered structure was adopted in the form of a cross arrangement. The external dimension of the arc soil cleaning impeller and the number of impeller blades were determined, according to the agronomic requirements of grape cold-proof soil cleaning in the study areas. Specifically, the rotary diameter and the height of the arc soil cleaning impeller were 600 and 300 mm, respectively, where there were two impeller blades in each layer. The main factors were determined on the power consumption under the movement and force of the arc soil cleaning impeller. The specific range of each factor was determined for the key experimental parameters, according to the actual operation. A three-factor quadratic regression orthogonal rotation center simulation was carried out using an Extended Distinct Element Method (EDEM), where the experimental factors were the forward speed, rotation speed, and bending angle of impeller blade in the soil cleaning impeller, whereas, the indicators were the torque and horizontal forward resistance. Design Expert 8.0.6 software was used to analyze the significance of the regression model on simulation experimental data. A regression model was established between the torque and horizontal forward resistance of the arc soil cleaning impeller and the experiment factors. The results showed that the primary and secondary order of experiment factors affecting the torque and horizontal forward resistance of soil cleaning impeller were the rotation speed, the forward speed, and the bending angle of the impeller blade. An optimal combination of operation parameters was achieved when taking the minimum torque and horizontal forward resistance of the arc soil cleaning impeller as the optimization target. Specifically, when the forward speed was 0.38 m/s, the rotation speed was 450 r/min, and the bending angle of the impeller blade was 18°, the torque and horizontal forward resistance reached the minimum of 9.99 N·m and 27.09 N, respectively. A soil bin verification experiment was carried out using the working parameters of optimization, where the optimized bending angle was processed in the soil cleaning impeller. Correspondingly, the torque and horizontal forward resistance of the arc soil cleaning impeller in soil bin verification experiment were 11.56 N·m and 31.82 N, respectively, while the relative errors between the simulated and experimental values were 13.58% and 14.86%, respectively. It infers that the soil bin verification experiment was basically consistent with the simulation. In any way, the torque and horizontal forward resistance were reduced by 9.40% and 15.37%, respectively, in the arc soil cleaning impeller, compared with the conventional straight-plate soil cleaning impeller.