Nanometer powders can be produced by an electrohydrodynamic technique. The breakup mechanism of the metal droplets generated by the electrohydrodynamic technique was analysed. It showed that the applied voltage, the e...Nanometer powders can be produced by an electrohydrodynamic technique. The breakup mechanism of the metal droplets generated by the electrohydrodynamic technique was analysed. It showed that the applied voltage, the electric field Btrength, the properties of the molten metal and the volumetric flow rate of the molten metal directly effect the breat-up extent of the metal droplets.展开更多
Electrostatic spraying application is adopted in crop protection to prevent pest infestation,to improve product quality and to maximize yield.It involves a superposition of charges to pesticide spray droplets to attra...Electrostatic spraying application is adopted in crop protection to prevent pest infestation,to improve product quality and to maximize yield.It involves a superposition of charges to pesticide spray droplets to attract substrate ions at obscured surfaces.The droplets wraparound effect reduces off-target deposition,enhances on-target spray and invariably improves spray efficiency.Electrostatic spraying system works effectively at optimum parameters in combination with charging voltages,application pressures,spraying height regimes,flow rate,travel speed,electrode material,and nozzle orientation.Many combinations of the system parameter settings have been systematically used by researchers for the electrostatic application,but there are unknown specific optimum parameters combinations for pesticide spraying.Since droplets chargeability influences the effectiveness of electrostatic spraying system,the parameters that produce ideal charge to mass ratio determine the functionality of the spraying deposition,retention and surface coverage.This article,therefore,analyses electrostatic system parameters that produce suitably charged droplets characteristics for effective impacting behavior of pesticides on substrates.Increasing applied voltages consequently maximizes charge-mass ratio to optimum and starts declining upon further increase in voltages beyond a critical point.This review further proposes the selection of an optimum electrostatic parameters combination that yields optimum droplets chargeability in pesticide application.Also,it is necessary to investigate the charge property of substrates prior to pesticide application in order to superpose the right opposite charge on spray droplets at rupture time during electrostatic spraying system.展开更多
The behavior of particles impacting the surface of a charged droplet involves adhesion, rebound, and submersion. In the present study, a numerical model for simulating particle impacts on charged droplets is presented...The behavior of particles impacting the surface of a charged droplet involves adhesion, rebound, and submersion. In the present study, a numerical model for simulating particle impacts on charged droplets is presented that takes into account the various impact modes. With the droplet considered as a solid boundary, the criterion for rebounding is that the particle's impact angle is 〈85°. The simulated trajecto- ries of the particles are verified by comparing with experimental data for low-velocity particles to assess the reliability of the model. For impact angles 〉85°, particles undergo three distinct modes depending on normal impact velocities. The critical velocity of adhesion/rebound and rebound/submersion is used to identify the mode that the particles are undergoing. The criteria are also verified by comparing with ana- lytical data. The results show that the impact angle of particles increases with increasing Coulomb number and decreases dramatically with increasing Stokes number, both of which lead to a high probability for particle rebound.展开更多
文摘Nanometer powders can be produced by an electrohydrodynamic technique. The breakup mechanism of the metal droplets generated by the electrohydrodynamic technique was analysed. It showed that the applied voltage, the electric field Btrength, the properties of the molten metal and the volumetric flow rate of the molten metal directly effect the breat-up extent of the metal droplets.
基金The authors would like to appreciate the financial support from the funds of the National Key Research and Development Plan of China(grant number 2016YFD0200700)the National Natural Science Foundation of China(grant number 51475215,31601676)the Advanced Talent Research Funding of Jiangsu University(grant number 5501200004).
文摘Electrostatic spraying application is adopted in crop protection to prevent pest infestation,to improve product quality and to maximize yield.It involves a superposition of charges to pesticide spray droplets to attract substrate ions at obscured surfaces.The droplets wraparound effect reduces off-target deposition,enhances on-target spray and invariably improves spray efficiency.Electrostatic spraying system works effectively at optimum parameters in combination with charging voltages,application pressures,spraying height regimes,flow rate,travel speed,electrode material,and nozzle orientation.Many combinations of the system parameter settings have been systematically used by researchers for the electrostatic application,but there are unknown specific optimum parameters combinations for pesticide spraying.Since droplets chargeability influences the effectiveness of electrostatic spraying system,the parameters that produce ideal charge to mass ratio determine the functionality of the spraying deposition,retention and surface coverage.This article,therefore,analyses electrostatic system parameters that produce suitably charged droplets characteristics for effective impacting behavior of pesticides on substrates.Increasing applied voltages consequently maximizes charge-mass ratio to optimum and starts declining upon further increase in voltages beyond a critical point.This review further proposes the selection of an optimum electrostatic parameters combination that yields optimum droplets chargeability in pesticide application.Also,it is necessary to investigate the charge property of substrates prior to pesticide application in order to superpose the right opposite charge on spray droplets at rupture time during electrostatic spraying system.
基金We thank the Natural Science Foundation of China (Grant No. 51376084) and the Postgraduate Scientific Research and Innovation Project of Jiangsu (Grant No. KYLX_1037) for support.
文摘The behavior of particles impacting the surface of a charged droplet involves adhesion, rebound, and submersion. In the present study, a numerical model for simulating particle impacts on charged droplets is presented that takes into account the various impact modes. With the droplet considered as a solid boundary, the criterion for rebounding is that the particle's impact angle is 〈85°. The simulated trajecto- ries of the particles are verified by comparing with experimental data for low-velocity particles to assess the reliability of the model. For impact angles 〉85°, particles undergo three distinct modes depending on normal impact velocities. The critical velocity of adhesion/rebound and rebound/submersion is used to identify the mode that the particles are undergoing. The criteria are also verified by comparing with ana- lytical data. The results show that the impact angle of particles increases with increasing Coulomb number and decreases dramatically with increasing Stokes number, both of which lead to a high probability for particle rebound.