Page 187 - Packed bed columns for absorption, desorption, rectification and direct heat transfer

177

f%K
0.1 0.433
0.044 TO,71
O .96^ a p L L
e{5a) (sin a)

where a is the average angle of the packing walls which for a random packing
can be taken equal to 45°. For elements with vertical walls it is 90°.
Eq. (24) together with Eq, (259) (Chapter 1) describe all experimental
data as well as Eq. (23). The disadvantage of equation (24) is that it is not
dimensionless, which is owing to the dimensional equation of Hikita and
Kataoka [69].
In later investigations Kolev [34] obtained a dimensionless equation for
using together with the theoretical equation (259), (Chapter 1). This equation is:

J8
0J
u
0M
4 =3.21 Re- L Frl Ed e- . (25)
Ag is the value of ^4 under the loading point;
4L
Re l = is the Reynolds number for the liquid phase;
a.v L
:
Fr L = — — Froude number for the liquid phase;
g
Ed = ' - EStvos number;
era
3
p L - liquid phase density in kg/tn ;
2
v L - liquid phase kinematic viscosity in m /s;
This equation described the experimental data available at that time for
different random packings, presented in Table 7. All the data are under the
loading point.
In Fig. 12 a comparison between the experimental data and date
calculated by Eq. (259), (Chapter 1) and Eq. (25) is presented. All data are for
gas velocity under the loading point.
To calculate the pressure drop also over the loading point, Eqs.(259)
and (260) from Chapter 1, can be used. According to [34] the value of AA in
Eq. (260), Chapter 1, can be calculated by the equation:

M LS l8 10
M = 0.0021 Frl (w 0 / L) Ed e' (26)