KURENAI : Kyoto University Research Information Repository

In the regime where (jg/h*) exceeds the value given by Eq. (99), the
entrainment increases with (j9/h*) very rapidly as given by
Efg (j 9/h*)7--20(101)
The transition from the intermediate to high gas flux regime may be
attributed to a flow regime transition in the liquid pool. The transition
from churn-turbulent to annular, pseudo jet or fountain flow [2,73,74] is
indicated.
Now, based on the above analysis and correlation development, some of
the underlining assumptions are reexamined. First, from Eqs. (95) and
(96), the various constants in the correlation are now identified as
and
C = 21.86(102)
n2 = 0.279(103)
n3 = -0.0693 .(104)
When these values are compared to the results from the void fraction
correlations given by Eq. (62), interesting observations can be made. The
value of n2 from Eq. (103) almost coincides with that given in Eq. (62),
whereas the value of n3 is quite different from that given in Eq. (62).
This discrepancy should come from neglecting the effect of the density
ratio (pg/ip) in some of the correlations used to develop Eq. (95).
A careful reexamination of Eqs. (40), (65), and (80) leading to Eq.
(95), indicates that Eq. (40) should have an additional (pg/op) term which
reflects the effects of the pressure. Note that Eq. (40) is obtained from
a simple model and the experimental data of steam-water system at 1 atm.
There are no experimental data available at elevated pressures for this
correlation. Thus Eq. (40) should be modified to account for the pressure
effects as
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