KURENAI : Kyoto University Research Information Repository

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Droplets ejected from the interface have various diameters represented by
droplet size distribution function f(D,jg), which is the fraction of
droplets whose diameter lies between D and D + dD. This function is
considered to depend on the gas velocity. _ Furthermore, f(D,jg) satisfies
the following relation.
ff(D,jg)dD = 1
The initial velocity vi which is
ejected from the interface has its own
g(vi,D,jg). This function represents
velocity lies between vi and vi + dvi
fg(vi ,D,jg)dvi = 1
the velocity of the droplet just
distribution function,
the fraction of droplets whose
at the interface. It also satisfies
In view of the mechanisms of the droplet ejection, this function is
considered to depend on the droplet diameter and gas velocity.
The velocity of a droplet necessary to rise more than h, vh(D,jg,h)
can be obtained by solving the equation of motion of a single droplet with
an appropriate drag coefficient. Thus it should be _a function of the
droplet diameter, gas velocity and height from the interface.
Using the above mentioned statistical parameters, the entrainment at
distance h from the interface can be given by the following integral
Efg(h'jg)
E( J)m
P--------jgJg(vi 99
,D,jg)f(D,jg)dvid0 .
o vh(D,jg,h)
The entrainment given by Eq. (22) consists of two groups of droplets
first group of droplets are the ones whose diameters are larger than
critical droplet diameter Dc. Here Dc is the diameter of a droplet
262
(20)
(21)
(22)
. The
the
whose