Contact person: S. Evgenidis [sevgenid@chem.auth.gr]
Liquid bridges forming between solid surfaces has been the subject of
extensive research due to the large number of applications in which
liquid bridges are encountered. Some examples are the study of the
distribution of phases in porous media with respect to oil recovery
applications, adsorption hysteresis in porous adsorbents, capillary
evaporation/condensation and the binder induced agglomeration of
particles which is of importance in operations such as flotation,
coating, flocculation and granulation.
This work demonstrates how electrical conductance measurements can be employed
for the study of liquid bridges behavior when (a) their length is
altered at constant volume or (b) their volume varies at constant
length, Figure 1. The liquid bridges are confined between two
vertical rods, either edge-pinned at their rim (r-bridges) or simply
wetting them (θ-bridges).
The technique is characterized by satisfactory accuracy and stability
and is particularly sensitive to liquid bridge characteristics. A
major advantage is the simplicity and robustness that makes it
applicable for quick in-situ measurements.
A mathematical framework is developed for the identification of the
geometrical characteristics of liquid bridges explicitly from
conductance data. The role of gravity is demonstrated both in the
experiments and the theoretical analysis. The theoretical predictions
obtained show a close agreement with measurements, Figure 2.
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| Figure 4: Electrical conductance (k) as a function of the è-bridge length (H) for four different liquid volumes (1, 2, 3 & 4 ìL) |
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| Figure 5: Conduct angle (average value of the 4 conduct angles of each liquid bridge) as a function of the è-bridge length (H) for four different liquid volumes (1, 2, 3 & 4 ìL) |
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click to enlarge - 21 KB) |
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