Characterization of Progeny Droplets Resulting from In-flight Drop Electrospraying

OLEG KIM (1), Patrick Dunn (1)

University of Notre Dame

     Abstract Number: 617
     Last modified: May 14, 2010

Abstract
The results of an experimental study of progeny droplets produced via in-flight parent drop electrospraying is presented. The breakup of the parent drop occurs in applied electric and ion fields that are generated using a DC-corona discharge in a needle-plate configuration. Electric and ion fields are numerically calculated using an electrohydrodynamic model of the corona discharge. Progeny diameter-velocity correlations and diameter distribution functions are measured at different positions from the parent drop using Phase Doppler Anemometry. The progeny charge distributions are determined using droplet mobility analysis. The effects of the applied electric field strength, the ion concentration and the initial drop surface temperature on the parent drop break-up are quantified. The resultant charge of progeny drops is found to vary as d^(3/2), where d is the progeny diameter. It is shown that the production of progenies occurs via a transient cone-jet structure. Experiments reveal that monodisperse, bimodal, and polydisperse progeny distributions can be produced by exposing the parent drop to different corona field intensities.