F
w
V
=
2
2
and thus
2
2
w
V
F=
.
(26)
The last equation indicates that the most important factor influencing the dynamics
of the interphase surface synthesis is the contact velocity between the gas and liquid
phases. It is important that the technical realization of choosing the w parameter is quite
achievable by choosing the total area of the bubble openings in the aeration system and
the uniform distribution of the gas flow in them.
The total area of the openings
op
f
is determined by the equation:
w
V
f
op
=
.
(27)
The velocity of the gas flow w in bubble
openings should be set within the limits of 25–30
m/s. A circuit is formed by the liquid phase in the
local zones of interphase surface formation
connected to the transient processes of the
dispersed gas phase. Obviously, its direction
coincides with the direction of gas phase
displacement. Since the latter is determined by
the properties of the gravitational field in the
manifestations of the Archimedes law, this means
the technical expediency of organizing counter-
flows of the gas and liquid phases (Fig. 2).
Counter-flows give us:
.
.
.
.
ph
liq
ph
g
w
w
w
+
=
.
(28)
Although the liquid phase velocity
.
.ph
liq
w
is an order of magnitude lower than the gas
phase velocity
ph
g
w
.
, their counter-flows are necessary precisely due to the dispersed gas
phase formation.
Nitrogen as an influential component in aeration modes of culture media. The
process of gas flow transformation and dispersed gas phase formation is an irreversible
thermodynamic process, which does not involve the possibility of returning to the initial
state without changes in the external environment. This real process takes place within a
certain time and speed and it is accompanied by friction, mass transfer, diffusion, and heat
exchange within the initial and final temperatures of the gas and liquid phases. At the same
time, the result of the gas flow interaction with the medium is unbalanced and irreversible,
whereas the question of its transformation needs to be further addressed in relation to the
liquid phase. The physical interaction between the ascending gas flow and the liquid phase
leads to the formation of stochastic circuits, which determine the hydrodynamic state of
the system with interconnected parameters of reduced gas phase velocity and gas retention
Figure 2. Illustration of liquid w
liq.ph.
, gas
w
g.ph.
and gas-liquid w
g.liq.ph
phases, where
BE is the bubble element
BE
w
liq.ph..
w
g.liq.ph.
.
w
g.ph.
BE
BE
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