Multi-scale Fresh Tea Leaves: Design of Double-Layer Axial Airflow Sorting Equipment and Electronic Control and Regulation Method

Aiming at the problems of material accumulation, screen clogging, and low sorting efficiency in traditional drum screens during multiscale fresh tea leaf sorting, an intelligent electronically controlled sorting system with double-layer axial airflow was designed. The Realizable k-ε turbulence model was adopted to conduct numerical simulation of the internal airflow field inside the drum under different electronic control parameters, and the model accuracy was verified against the detection data from hot-wire anemometers. Independent regulation of wind speeds in the upper and lower layers was realized through electronic control regulating valves, and four groups of working conditions with different electronically controlled wind speed ratios were set to analyze the flow field distribution characteristics. A comprehensive test bench integrating signal acquisition, real-time regulation, and performance detection was built to compare the sorting effects of different electronic control schemes. The results show that the maximum relative error between simulated and measured wind speeds is 3.53%, which confirms that the model can support precise regulation of electronic control parameters. The electronically controlled ratio of upper and lower wind speeds directly determines the longitudinal flow field distribution in the drum. The cross-section uniformity of the flow field reaches the optimal level under the equal wind speed regulation condition, while the working condition with stronger lower-layer wind speed and weaker upper-layer wind speed can significantly improve the suspension effect of bottom materials. Tests verify that the average sorting rate of the double-layer axial airflow electronic control scheme reaches 78.87%, which is 22.7% higher than that of the traditional drum screen and 4% higher than that of the single axial airflow electronic control scheme. The research findings can provide theoretical and experimental basis for the electrification and intelligent upgrading of fresh tea leaf sorting equipment.