Analysis Of Droplet Dynamics In An Electric Field With Corona Discharge

At the present stage, the high voltage electrostatic atomization technology had been widely applied to spray pesticides, industrial coating, material preparation, fuel combustion, industrial dust removal and desulfurization, particle coalescence and separation, and other fields. The unstable liquid surface was caused by the use of the interference of electrostatic field, lead to split, refine, and form droplets. By adjusting the size of the spray field controlled the droplets size, atomizing Angle, cloud droplets trajectories under the same control parameters?flow, pressure, electrode diameter, etc.? of atomization device. It was in conformity with the actual needs of droplets size, dispersion effect, the spray density and so on, to achieve purpose of saving raw materials, improving the utilization efficiency of liquidIn this paper, as a place with cavity atomizing electrode electrode, using PCO.Dimax high-speed cameras constantly collected experiment data and various kinds of transient phenomena of atomized droplet movement in the field. By relevant data and phenomenon, it analyzed the forming process of Taylor cone, the fracture process of Taylor cone; the relationship between Taylor cone shape and the cavity size, the applied voltage, fluid properties; the relationship between atomizing angle and the applied voltage; the relationship between the motion trajectory of droplets, velocity, acceleration and the electric field; the broken condition of droplets in the electric field and changes of fog droplets movement state before and after the break; the influence of ion concentration in the liquid on the spray forming process. The results showed that:1. In the cavity atomization device, for atomizing electrode of the same plate spacing, voltage phase at the same time, the size of the current was inversely proportional to the electrode diameter; for the same diameter of the atomizing electrode, voltage phase at the same time, the current varied inversely with the size of the plate spacing; for the same plate spacing and the electrode diameter, the current was proportional to the voltage.2. The experiments showed that: With distilled water as the injection fluid, a smaller diameter cavity atomizing electrode was more prone to form the Taylor cone under low voltage. Under the same parameters of atomizing experimental, the greater atomizing electrode voltage?0-40 kV?, the greater droplet average diameter split out at the end of the Taylor cone, the slower Taylor cone fracture average frequency.3. With the increase of corona voltage?0-40 kV?, Angle of the spray droplets first increased then decreased, the maximum atomizing Angle was 39° when voltage was 20 kV. Atomization angle was associated with Taylor cone fracture, the electric field intensity and the movement time of droplets in electric field.4. In a certain atomization area, the droplet velocity was more and more quick in the electric field. Under the same electric field, the average acceleration of droplet was proportional to the droplet own charge-mass ratio. And droplets instantaneous acceleration was positively related to the intensity of electric field. The plate spacing of 100 mm in the experiment and the voltage of 35-40 kV, the crushing effect of droplet was better.5. For the same atomization parameters, the need applied voltage of Taylor cone fracture during the process of spray, Ca?OH?₂ saturated solution?13 kV? was lower than distilled water?15 kV?. Under the same voltage, the atomization Angle of Ca?OH?₂ solution was bigger than the aqueous solution, with the increase of voltage, the atomization Angle increased first then decreased. In the process of atomization, the Ca?OH?₂ injection rate and the droplet movement speed in the electric field was faster than that of the aqueous solution.In this paper, it analyzed the influence of cavity electrode size of atomization process, applied voltage, droplet ions and other parameters on Taylor cone formation, atomized droplet crushing, movement, summarized the relationship of the various parameters and the atomizing influence of ion; it summed up the atomization rule of cavity atomizing electrode to provide important guiding significance for better applicating cavity atomization device.