Title:
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On the mechanisms of electrohydrodynamic atomisation
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Studies leading to understanding the mechanism of electrohydrodynamic atomisation were carried out. This work involved studying the
behaviour of single drops and liquid flowing through a capillary under
the effect of an electric field in a variety of conditions. Attention
was given to the formation and stability of a single jet in terms of
relevant parameters such as applied potential, liquid conductivity,
flow rate, and capillary diameter.
By inserting tracer particles into the liquid, circulation patterns inside the conical base of the jet were observed and photographed
for the first time. The circulation has provided a major insight into
the mechanism of electrostatic jet formation.
By solving the equation of motion for creep flow in spherical
coordinates, an analytical solution was obtained which predicts the
motion of the liquid near the tip of the cone.
From a knowledge of the jet profile and the current it carries,
the normal and tangential electric fields acting on the cone were calculated and hence the variation of the normal and shear stresses on the
cone surface were monitored as a function of the applied potential.
The results from this study explain the division of a single jet into
multiple jets.
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