Page 84 - Packed bed columns for absorption, desorption, rectification and direct heat transfer

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the gas-liquid interfacial area with reduction of the packing size and at high
liquid superficial velocity.
As already mentioned, there are a lot of experimental equations
according to which the effective surface is presented as a function only of Rei.
But there is not any investigation with changing of the liquid viscosity, where
this is experimentally proved. It is noteworthy that these wrong equations are a
result of an incorrect use of dimensional analysis.

1.6.4, Partial mass transfer coefficients

The similarity theory and the dimensional analysis give the following
types of equations for the partial mass transfer coefficients;
for gas phase controlled processes

Sh G=f(Re G,Sc Gl lJJ, (268)

for liquid phase controlled processes

ScJ^lJ, (269)

k d
where: Sh G = G * - Sherwood number for the gas phase;
D G
k d
Sh L = —-— Sherwood number for the liquid phase;

3
«.d
Ga L =^—z—the number of Galilei;
v
i
Sc G — —— - Schmidt number for the gas phase;

Sc L = —^- - Schmidt number for the liquid phase;
Li
v L - the gas kinematic viscosity;
d- the diameter of the packing elements or other characteristic geometrical value
of the packing in m.