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where E is given by
For
The
E = tanh
The fully
(7.25 x 10-7We1.25Ref0.25)
developed or over entrained regionis defined by
—E 1 or Reff < Re ff. '
•(1 0.925 .6 x 10-7(RefWe) :1_9)uD= 6 (i - E)0.185
this region the entrainment rate becomes
diffusion based droplet deposition rate
a0 = 0 .022
of
Ref0.74 (u.9 0.26 E0.74
of
It should be noted that there is
which the entrainment mechanism based
stops. Thus one obtains
e = 0 for Reff < 160
u
a
on
0.26 ff
is
cut off film
shearing-off
Reynolds number below
of roll-wave crests
for low viscous fluid such as water.At extremely high gas flux, another en-
trainment mechanism becomes possible, however, for most practical systems
this can be considered as the entrainment shut off point.
The present correlation indicates that the entrainment rate depends on
the total liquid Reynolds number, Weber number, equilibrium entrainment frac-
tion Em and entrainment fraction E or the local film Reynolds number Reff.
These correlations are compared to a number of experimental data both in
terms of the entrainment rate and entrainment fraction. The results are
shown to be satisfactory both in the developing region and fully developed
entrainment region.
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