Disintegration of water drops in an electric field

Abstract

The disintegration of drops in strong electric fields is believed to play an important part in the formation of thunderstorms, at least in those parts of them where no ice crystals are present. Zeleny showed experimentally that disintegration begins as a hydrodynamical instability, but his ideas about the mechanics of the situation rest on the implicit assumption that instability occurs when the internal pressure is the same as that outside the drop. It is shown that this assumption is false and that instability of an elongated drop would not occur unless a pressure difference existed. When this error is corrected it is found that a drop, elongated by an electric field, becomes unstable when its length is 1.9 times its equatorial diameter, and the calculated critical electric field agrees with laboratory experiments to within 1 %. When the drop becomes unstable the ends develop obtuse-angled conical points from which axial jets are projected but the stability calculations give no indication of the mechanics of this process. It is shown theoretically that a conical interface between two fluids can exist in equilibrium in an electric field, but only when the cone has a semi-vertical angle 49.3°. Apparatus was constructed for producing the necessary field, and photographs show that conical oil/water interfaces and soap films can be produced at the calculated voltage and that their semi-vertical angles are very close to 49.3°. The photographs give an indication of how the axial jets are produced but no complete analytical description of the process is attempted.

Electrospray–differential mobility analysis of bionanoparticles

“…The voltage is then manually modified to create a Taylor cone [21,22] at the tip of the ES capillary. At the tip Columbic repulsion forces the liquid out to form multiple charged droplets.…”

An experimental study of the electrospraying of water in air at atmospheric pressure

“…The order of magnitude of this normal electric field is approximated by a balance between capillary and electrical forces [10],…”

Experimental Study on Repetition Frequency of Drop/Jet Movement in Electro-Spraying of Deionized Water

“…Taylor (1964) was the first to relate the conical shape of the electro-spraying to the hydrostatic balance between electrical force and the surface tension. Cloupeau and Prunet-Foch (1994) introduced the electro-spraying modes classification based on experimental observations.…”