Electrohydrodynamic atomization in the cone-jet mode physical modeling of the liquid cone and jet

A physical model has been developed which is able to calculate the shape of the liquid cone and jet, the electric fields in and outside the cone, and the surface charge density at the liquid surface. The model also estimates the liquid velocity at the cone surface. The results of this cone-shape model fit well with experimental values with respect to the cone shape, and the current as function of the flow rate, the conductivity, the applied potential, and the electrode configuration. The simulations have shown that a spraying nozzle with a diameter of 1 mm yields a 15% higher current than an 8 mm nozzle. For the 8 mm nozzle the current is almost independent of the applied potential, where for the 1 mm nozzle a stronger relation was found. The space charge due to the charged droplets has an influence of about 5-7% on the electric field at the cone surface. The jet diameter, was calculated and measured as a function of the liquid flow rate, and compared to the droplet size scaling laws. A new derivation of a current scaling law will be given. (C) 1999 Elsevier Science Ltd. All rights reserved.