GENERATION OF MICRON-SIZED DROPLETS FROM THE TAYLOR CONE

The development of an aerosol generator is reported. It makes use of a strong electric field, in which a pendular droplet deforms into a conical shape. This cone shaped droplet is known as the Taylor cone. From the tip of the cone droplets are generated at a frequency of about 10(8)-10(10) Hz. The initially highly charged droplets repel each other thus preventing coalescence but can be neutralized by use of a strategically-placed needle of opposite polarity. In this study droplets of ethylene glycol were produced, whose modal diameter varied with increasing potential between 1.33 and 1.55-mu-m. Their standard deviation decreased from 0.3 to 0.2-mu-m. By using mixtures of DOP and ethanol, droplets of DOP as small as 0.08-mu-m were produced by evaporation of the ethanol. A calibration curve for the droplets produced before and after evaporation is given for this particular apparatus configuration. The Taylor cone exhibits current-voltage characteristics which are analogous to those of a corona discharge. Other phenomena characterizing corona discharge are also found.