Page 48 - Geochemical Remote Sensing of The Sub-Surface

Geoelectrochemistry and stream dispersion 25
V/Vo
1.
_-.7 r---
0.8 f
/ n a(1)
0.6 0 a(2)
f I b(1)

0.4 ? 0 ""
9 b(2)
-----3
f
0.2 g El .11
--
0
0 10 20 30 40 50 60 70 80 90 100
r/ro
Fig. 2-5. Dependence of the relative speed of air bubbles v/v0 (ratio of speed of bubbles in porous
system to that in free liquid) on the relative radius of the fraction of particles r/ro (ratio of radius
of particles to that of bubbles): a- front speed; b- rear speed; (1) r0--0.085mm; (2) ro = 0.06mm; (3)
empirical curve.

Vo - kro 2

2(p-Po)g
where, k-
9n

As shown in the experimental results (Fig. 2-5), the relative speed of the front of a
group of bubbles, V/Vo (ratio of speed of bubbles in porous system to that in free liquid),
increases with the relative radius of the fraction of particles, r/r0 (ratio of radius of
particles to that of bubbles), if r/ro >6.4. The relationship may be represented by the
following empirical formula,

v 6.4
= 1 - ~ = 1-6.4(r o /r)
Vo (r / ro)

From this equation it can be seen that if the relative radius of bubbles r0/r < 0.156, the
relative speed of the front of bubbles v/v0 increases with the decrease of relative radius