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intermediate gas flux regimes given by Eq. (98) or the limit due to CHF given
by Eq. (131).
(4) Entrainment amount in high gas flux regime
At a high gas flux in momentum controlled region, the entrainment
increases rapidly with-jg, as given by Efg4-20.It may be possible to
make a dimensionless correlation based on experimental data for this case.
However, such correlation is not very useful because it may give an
unreasonably high value of entrainment at largejg due to its high power
dependence onjg. Although no data are available, there should be an upper
limit for entrainment in this regime. Here, as a first approximation, it is
assumed that all the droplets produced at the pool surface are carried away.
This limit is also predicted by the basic formulation given by Eq. (83) at jg
m with the condition given by Eq. (122)- Thus, the limit is obtained as
•
8.45 jg-1
lim Jr*1/41/4*-1/4
Efg(hj) *ra(v*
g}°° o
v h
pg
p 0*0.21Pg0.17 1/2
f H Ap
i-22jgNu9D J
x 3.72 x 10pg-1.0~*1.5p*0.5d v~dC*
Ap
-3 p9-1.0
= 4 .84 x 10(135)
Ap
This value is identical to that in the near surface regime which is given by
Eq. (119). Therefore, for practical purposes, the entrainment amount in the
high gas flux might well be estimated by the correlation for the near surface
region.
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