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Electrostatic spraying is considered an effective means to improve the efficacy of pesticide application and reduce pesticide consumption. However, the effectiveness of electrostatic spraying needs further validation in greenhouse environments, especially in long-range air-assisted spraying scenarios. A waist-shaped charging device has been improved to obtain a maximum charge-to-mass ratio of 4.4 mC/kg at an applied voltage of 6 kV in a laboratory setting, representing an increase of approximately 84.9% compared to a commercial circular charging electrode with a fan-shaped nozzle. A comparative air-assisted spray test between electrostatic deactivation (EDAS) and electrostatic activation (EAAS) was conducted on greenhouse tomato crops using a single hanging track autonomous sprayer equipped with a pair of waist-shaped charging devices. The results showed that EAAS yielded an overall average coverage of 28.4%, representing a significant 10.9% improvement over the 25.6% coverage achieved with EDAS. The overall coefficient of variation (CV) for EDAS and EAAS was 62.0% and 48.0%, respectively. Within these, the CV for the average coverage of the sample set reflecting axial distribution uniformity was 33.4% and 31.4%, respectively. Conversely, the CV for the average coverage of the sample group reflecting radial distribution uniformity was 33.7% and 17.9%, respectively. The results indicate that the waist-shaped charging device possesses remarkable charging capabilities, presenting favorable application prospects for long-range air-assisted spraying in greenhouses. The electrostatic application has a positive effect on enhancing the average coverage and improving the overall distribution uniformity. Notably, it significantly improves the radial distribution uniformity of the air-assisted spray at long range, albeit with limited improvement in the axial distribution uniformity. [ABSTRACT FROM AUTHOR]

Cavitation happening inside an inclined V-shaped corner is a common and important phenomenon in practical engineering. In the present study, the lattice Boltzmann models coupling velocity and temperature fields are adopted to investigate this complex collapse process. Based on a series of simulations, the fields of density, pressure, velocity and temperature are obtained simultaneously. Overall, the simulation results agree with the experiments, and they prove that the coupled lattice Boltzmann models are effective to study cavitation bubble collapse. It was found that the maximum temperature of bubble collapse increases approximately linearly with the rise of the distance between the single bubble center and the corner. Meanwhile, the velocity of the micro-jet increases and the pressure peak at the corner decreases correspondingly. Moreover, the effect of angle of the V-shaped wall on the collapse process of bubbles is similar to the effect of distance between the single bubble center and the corner. Moreover, with the increase in bubble radius, the maximum temperature of bubble collapse increases proportionally, the starting and ending of the micro-jet are delayed and the pressure peak at the corner becomes larger and also is delayed. In the double bubble collapse, the effect of distance between two bubble centers on the collapse process of bubbles is discussed in detail. Based on the present study, appropriate measures can be proposed to prevent or utilize cavitation in practical engineering. [ABSTRACT FROM AUTHOR]