KURENAI : Kyoto University Research Information Repository

*
~
• This
Efg(h,jg) = 2.213 N1.5 DH1.25(3,3)-0.31j9h*-1 (97)
lig
In Fig. 19, overall comparisons between the various experimental data and
the above correlations are shown.
From Eqs. (96) and (97) the transition criterion between the low and
intermediate gas flux regimes can be obtained, thus
h
- = 6 .39 x 10-4 .(98)
criterion gives a higher value of j9 than that predicted by Eq. (42)
over the range of h* appeared in the experimental data. This is because
in a boiling or bubbling pool system, the void fraction is generally lower
than those predicted by the standard drift flux model due to the
significant internal circulation of liquid in the pool. Here h* appears
in the criterion due to the fact that the information at the interface to
reach h* requires a certain gas flux.
Figure 20 shows the various experimental data for entrainment in Efg
.10
vs. (jg/h*) N095DH*0.420)-0
plane. The solid line in this figure
represents the correlation given by Eq. (96). This figure indicates that
the correlation generally agrees well with the data, however, there is a
systematic deviation at high values of jg/h*. This actually signifies the
appearance of the high gas flux regime. This transition occurs
approximately at
or at.
()=-
5.7 x 10-4N-0.5p*-0.42 (P9)O.1O(99)
hugH Ap
Efg = 1.0 x 10-3(100)
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