Inzynieria Chemiczna i Procesowa, Vol.15, No.1, 101-113, 1994
GENERATION OF CHARGED AEROSOL BY ELECTRODYNAMIC METHOD
The electrodynamic method of spraying allows generation of charged aerosol in a wide droplet size range. The droplet size distribution can be polydisperse or nearly monodisperse, depending on the applied voltage, its polarity and the volume now rate of liquid. The size of droplets can be controlled by changing these quantities. The following spraying modes of practical importance were observed in the investigations of the dispersion of liquids issuing from a capillary maintained at high potential of positive or negative polarity, in the voltage range of +/-33 kV: microdripping mode, which allows generation of droplets of monodisperse size distribution in the range of 150-300 pm in diameter, sometimes with a few accompanying siblings in the case of tow-viscosity liquids (such as distilled water), precession mode, generating the droplets smaller than 60 pm in diameter, sprayed in a regular spraying cone, cone-jet mode, generating finer aerosol with droplets smaller than 30 mu m in diameter. Other modes known from the literature have also been observed, and they allow us to generate fine droplets, but the liquid stream issuing from the capillary is neither a regular one, nor the sprayed aerosol is spatially distributed in a stable manner. The mode of spraying depends on the physical parameters of the sprayed liquid. Experimental investigations have to be carried out in order to determine the functioning domain of the spraying modes (i.e., the range of voltage and volume flow rate). The paper reports on a new mode of spraying hitherto not known from the literature. This mode can be applied, for example, in electrostatic coating.
Keywords:LIQUIDS