Civil Engineering Reference
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transfer for one of the dispersed particles with an endless stream of carrier phase will
be set by the dimensionless parameter of Nusselt
Nu
.
In this work dynamics and heat mass transfer of a steam bubbles in a binary mix-
ture of liquid was studied. On the other hand simultaneously essential thermal, diffu-
sion and ratchet effects were investigated. The dynamics and heat and mass transfer
of vapor bubble in a binary solution of liquids, in [1], was studied for significant ther-
mal, diffusion and inertial effect. It was assumed that binary mixture with a density
ρ
, consisting of components 1 and 2, respectively, the density
ρ
and
ρ
. It was
localized between limiting values for corresponding parameters of pure component.
It showed that pressure differences and accordingly diffusion role were insignificant.
In this work the influence of heat exchange and diffusion on weaken of this process
were investigated.
l
10.2 mAteriAls And metHods
Bubble dynamics described by the Rayleigh equation [2]:
3
pp p
+−−
2/
σ
R
w
•
2
l
Rw
+
w
=
1
2
∞
−
4
n
(1)
l
l
1
2
ρ
R
l
where
p
and
p
--the pressure component of vapor in the bubble,
p
--the pressure
of the liquid away from the bubble,
σ
and
n
--surface tension coefficient of kine-
matic viscosity for the liquid.
Consider the condition of mass conservation at the interface. Mass flow
j
th com-
ponent
(
r
=
in
j
th phase per unit area and per unit of time
and characterizes the intensity of the phase transition is given by:
( )
)
of the interface
i
=
1
2
R
t
•
= −− =
(
)
(2)
j
ρ
Rw w
,
i
1, 2
i
i
l
i
where
w
--the diffusion velocity component on the surface of the bubble.
The relative motion of the components of the solution near the interface is deter-
mined by Fick's law:
∂
k
ρ
w
=
−
ρ
w
=
−
ρ
D
(3)
1
1
2
2
l
∂
r
R
If we add equation (2), while considering that
ρ
+
2
ρ
=
ρ
and draw the equation (3),
1
we obtain
j
1
+
j
•
R
=
w
+
2
(4)
l
ρ
l
Multiplying the first equation (2) on
ρ
, the second in
ρ
and subtract the second
equation from the first. In view of (3) we obtain
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