Jul 2026· International Conference on Control, Decision and Information Technologies· pp. 2879-2884· 0 citations· 19 references
Abstract
Traditional tea harvesting methods often lack precision, leading to significant leaf damage and reduced operational efficiency. To address these limitations, this paper proposes an airflow-driven end-effector designed for selective tea harvesting, utilizing pneumatic transport to move harvested leaves from the shearing interface to storage. A theoretical model based on force equilibrium was developed to determine the critical transport velocity (CTV), calculated to be approximately 3.6 m/s. The theoretical prediction was further evaluated through CFD analysis using ANSYS Fluent with a k–ω Shear Stress Transport (SST) turbulence model across inlet velocities ranging from 2.5 m/s to 4.5 m/s. Simulation results indicate that inlet velocities at or above 3.6 m/s provide airflow conditions favourable for sustained pneumatic leaf transport, with 4.5 m/s achieving outlet velocities up to 6.586 m/s and mass flow rates of approximately 1.59×10−3 kg/s, while lower velocities fail to maintain sufficient transport momentum. Despite considerable velocity decay along the transport path, adequate velocity is retained in critical regions for sustained pneumatic conveyance. These findings demonstrate the feasibility of airflow-based transport for selective harvesting and provide a quantitative basis for optimizing end-effector design.
Physical control technology as an alternative to chemical pesticides is of great significance for modern sustainable agriculture. However, small pests such as tea green leafhoppers and tea thrips possess sensitive aerodynamic receptors that easily perceive disturbances generated by suction airflow and initiate stress-induced escape behavior. The current bottleneck in the state of the art is that conventional straight tube capture devices generate severe airflow pulsations and turbulence near the intake which act as alarm signals causing pests to escape before entering the effective capture zone. To resolve this trade-off, this study developed and validated a variable cross-section wind-suction channel based on the principle of biological behavioral suppression. This design incorporates a three-stage functional structure consisting of a flow-stabilizing intake section a guided acceleration section and a high negative-pressure throat to achieve a synergistic balance between low disturbance induction and strong aerodynamic confinement. Numerical simulations and prototype experiments show that this design establishes a stable rectified environment at the intake with relative wind speed deviations within 5%. Under controlled laboratory conditions, the average capture rate for target pests exceeded 85% within an effective operating radius of 20 cm. Comparative biological validation further confirms that the capture efficiency of this design is improved by more than 32 percentage points compared with a conventional straight-tube benchmark device. Furthermore, the critical stress-response distance was reduced by approximately 50%, significantly enhancing the concealment of the capture process. These findings elucidate the critical role of channel geometry in resolving the conflict between suction intensity and environmental disturbance providing a theoretical foundation and technical support for the development of high efficiency and precision plant protection equipment.
Qiang Wu, Zhu Chen, Huihua Ji et al.· Agronomy· 0 citations
To promote the mechanization of the tobacco industry, a self-propelled tobacco stem harvester was designed in this study. To improve harvesting efficiency under varying terrain and planting conditions, the machine integrates key functional components, including a chain-clamp conveyor and a loosening shovel with optimized structural parameters. The performance of these core components was analysed using 3D modelling and finite element simulations conducted in ANSYS. Field experiment optimization indicated that the optimal operating parameters were a clamping chain speed of 0.7 m/s, a forward travel speed of 0.4 m/s, and a clamping chain gap of 12 mm. Experimental results showed that the harvester achieved a leakage rate of 3% and a breakage rate of 7%. Overall, the machine demonstrated reliable performance and satisfied practical operational requirements. This study provides an effective technical solution for the mechanization of tobacco stem harvesting, contributing to reduced production costs and the advancement of agricultural modernization.
Liquan Yang, G. Yin, Rui Feng et al.· INMATEH Agricultural Enginee...· 0 citations
The convective drying of agricultural materials is an energy-intensive process, and optimizing dryer design is critical for improving efficiency and product quality. This study presents a comprehensive heat and mass transfer model for the convective drying of alfalfa leaves in a rotary drum dryer. Freshly harvested leaves with an initial moisture content of approximately 70% (w.b.) were used as the test material. The proposed system features a simplified drum design aimed at enhancing process efficiency while reducing equipment complexity. The primary objective was to reduce the moisture content of alfalfa leaves to below 50% to ensure their quality during subsequent storage and transportation. To determine the optimal operating conditions, the kinematics of leaf motion inside the rotating drum and the associated heat and mass transfer phenomena were investigated through analytical modeling, numerical simulation, and experimental studies on a laboratory-scale physical model. An analytical model was developed to establish relationships between transverse kinematic characteristics (detachment condition, Froude number, drum inclination angle), average longitudinal velocity, and residence time. Numerical simulations based on the Navier–Stokes equations (continuity, momentum, and energy) provided detailed moisture content distributions within individual leaves under varying airflow orientations and drying durations. The novelty of this work lies in the integrated determination of optimized operating parameters through combined analytical, numerical, and experimental approaches. A regression model relating final moisture content to key process variables (air velocity, temperature of 60 °C, drum rotation frequency and mass of loaded material) was developed from experimental data, yielding practical recommendations for the design and operation of rotary drum dryers for alfalfa and similar agricultural materials.
Gani Zhumatay, O. Zhortuylov, K.A. Moshanov et al.· Applied Sciences· 0 citations
To address the problems of low sorting accuracy and poor operation stability caused by physical leaf entanglement in traditional drum screening of fresh tea leaves, a multiscale fresh tea leaf sorting system with drum-axial airflow coupling based on intelligent control was designed. The axial moving distances of fresh tea leaves of different scales at wind speeds of 5, 7, and 9 m/s were calibrated through bench tests, and the optimal wind speed parameter for secondary fine screening was determined. A numerical model of the axial airflow field inside the drum was established via Fluent software, and a coupled sorting test platform was built to compare the sorting performance of the traditional pure drum screening mode and that of the coupled intelligent sorting mode. The results showed that 7 m/s is the optimal axial airflow velocity for secondary fine screening of multiscale fresh tea leaves during this test, which can realize effective back-blowing of small-scale materials and accurate screening of large-scale materials. At this velocity, the flow field is evenly distributed, and the effective thrust area highly matched the sorting demand. The average sorting efficiency of the coupled intelligent sorting mode reached 84.8%, which is 25.6% higher than that of traditional pure drum screening, with favorable sorting accuracy and operation stability. These findings can provide a theoretical basis and technical reference for the optimization, upgrading, and intelligent transformation of high-efficiency fresh tea leaf sorting equipment.
To address uneven air supply among multiple needle tubes during the drying of high-density forage bales, this study investigated the airflow characteristics and structural optimization of the upper and lower air distribution chambers of a needle-type forage dryer. A three-dimensional CFD model was established, and airflow performance was evaluated using the velocity non-uniformity coefficient M and the inlet-to-outlet total pressure drop Δp. Response surface methodology was used to optimize the key structural parameters. For the upper chamber, installation of a T-shaped baffle and optimization of the cavity height Hc, diffuser angle α, and top-plate opening area ratio Ra yielded an optimal combination of Hc = 133.29 mm, α = 12.51°, and Ra = 1.12, reducing M from 11.2264% to 3.3886%. For the lower chamber, a strip-perforated airflow equalizing plate with Hb = 74.82 mm, D = 23.79 mm, and W = 25.03 mm reduced M from 9.8772% to 1.5484%, with Δp of approximately 130 Pa. Mesh-refinement and turbulence-model sensitivity analyses supported the robustness of the numerical predictions. Repeated outlet-velocity measurements yielded mean absolute relative errors of 3.09%–4.58%. Smoke visualization and grayscale analysis further indicated that the optimized structures enhanced airflow diffusion and redistribution. The results provide guidance for air distribution chamber design in needle-type forage dryers.
Freshwater scarcity is a critical global challenge, driving the development of high‐efficiency atmospheric water harvesting technologies. While fog collection is a sustainable solution for arid regions, conventional passive systems are often limited by poor droplet interception and slow surface renewal. This work proposes a synergistic fog‐harvesting strategy combining biomimetic cactus spines (BCS) with electrostatic and aerodynamic regulation: corona charging, airflow guidance, and Laplace pressure‐driven transport on cones, which shortens shedding cycles and greatly improves harvesting efficiency. Systematic experiments and fluid dynamic simulations evaluated the influence of applied voltage, wind speed, windward angle, and geometry. The BCS achieved a peak collection rate of 390 mg/min at 18 kV and a wind speed of 2 m/s, representing a substantial enhancement over passive designs. Furthermore, the performance of longitudinal and radial BCS arrays was quantitatively analyzed, leading to a modified saturation model that accounts for airflow interference between adjacent units. The results further determine the optimal working parameters and array layout, which can parametrically adjust aerodynamic airflow regulation and improve droplet transport efficiency. This multi‐field coupled design offers a feasible strategy for high‐efficiency electric‐assisted fog harvesting under complex practical environmental conditions.
Ying Yang, Lei Zhang, Yikai Zhu et al.· Advanced Materials & Technol...· 0 citations
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