  Film boiling has practical applications in the current technology including
steam power plants, cooling of electronic devices and emergency cooling
systems. A finite difference/front tracking method is used to simulate film
boiling at high density ratios on a horizontal plate subject to a constant wall
heat flux. The grid resolution is relatively high (768 grids per width of the
domain). The flow is dominated by Rayleigh-Taylor instability as well as
Kelvin-Helmholtz instability. The flow structure includes the roll up of the
interface between the gas and liquid. This happens at high density ratio (1000)
where the difference between the gas and the liquid velocities across the
interface is large. The jump in tangential velocity is an order of magnitude
smaller at a lower density ratio (100). Hence, there is no roll up at lower
density ratio. The flow is also influenced by vortex development as a result of
the baroclinic term in the vorticity transport equation. The density gradient
is large at the interface at high density ratio which tends to increase the
baroclinic term. The plot of pressure gradient and density gradient shows that
they are not parallel in the roll up regions. As a result, vortices in small
scales develop that shed in the gas phase. The plot of the enstrophy with time
shows that it shows smooth variation that match for two grid resolutions,
however at a specific time enstrophies become spiky, and they depart from each
other at two grid resolutions. The spiky behavior of enstrophy is due to vortex
shedding in the roll up region.
