DROPLET DIAMETER, FLUX, AND TOTAL CURRENT MEASUREMENTS IN AN ELECTROHYDRODYNAMIC SPRAY

The measured diameter and flux distributions and total current of ethanol droplets generated electrohydrodynamically from a single hypodermic needle at two different spray charge densities are presented and discussed. The resultant droplet diameter and droplet flux distributions reveal a progressive production of an increasing number of smaller diameter droplets with increasing spray charge density. These are consistent with observations made of the filament breakup-to-droplet process in this region. The droplet flux distributions are used to construct droplet charge flux distributions by assuming various models of the droplet charging process. The resultant charge fluxes are logarithmically related to lateral position, regardless of the droplet charging model assumed. The integrals of the various charge flux profiles are compared to the measured total current. This approach reveals the best agreement between measured and predicted total droplet currents when an equilibrium end-state process for droplet charging is assumed.