The technique of liquid atomization is simply to


 The technique of liquid atomization is simply
to overcome the force of surface tension for a particular liquid. That may have
accomplished by using 3 ways. First, introducing surface tension between moving
liquid and steady air in which it will destabilize the flow and result in its
disintegration into filaments. Secondly, utilizing the centrifugal forces of
swirled liquid jet. As well as, the usage of an outer mechanical and
electrostatic forces and by supersonic phonetic. The fuel atomization features in engine applications
are decisive in setting combustion stability, efficiency, and discharged gas
emissions. Atomization take
place when the magnitude of the disruptive force just overrun the combined
surface tension force. Many of the larger drops produced in the first breakup
of the liquid jet or sheet are unsteady and go through another disintegration
into smaller droplets. Thus, the drop size characteristics of a spray are a
function of the drop sizes generated in the initial atomization as well as the
extent to which the largest of these drops are further disintegrated during
secondary atomization. In 1878, the first study of the disintegration of the
liquid had begun by Silvers Rayleigh when he discovered laminar jet issuing
from a circular orifice and assumed the growth of small disturbances that
produce breakup when the fastest growing disturbance attains a wavelength ?opt of 4.51 d, where d is
the initial jet diameter. Rayleigh’s analysis considers surface tension and
inertial forces but ignored viscosity and the effect of the surrounding air. Weber (1931)
later expanded Rayleigh’s work to include the influence of air resistance on
the disintegration of jets into drops. He found that air friction reduces the
optimum wavelength for drop formation. He used the relative velocity to show
how ?opt is changing and found that when the relative
velocity is equal zero the wavelength will have a value of 4.44d, which is
almost the same as Rayleigh’s result. Then, for higher values of the relative
velocity, Weber demonstrated that the ?opt will
gradually decreases in which for velocity of 15m/s, the wavelength equals to
2.8d and the diameter of the drop is 1.6d. Thus,
the effect of relative velocity between the liquid jet and the surrounding air
is to minimize the optimum wavelength for jet breakup which results in a
smaller drop size.