Enhanced evaporation from an oscillating liquid in a capillary tube
Résumé
Enhanced evaporation inside a capillary tube into which the liquid/gas meniscus oscillates is experimentally
studied. It is found that the meniscus oscillation can markedly level-off the evaporation rate, while
keeping an apparent diffusive behaviour. The apparent diffusive coefficient can reach a tenfold increase in
the explored range of parameters. The dependence of the effect is studied by varying the capillary tube
diameter, the frequency and the amplitude of the liquid oscillations. The parametric dependence of the
apparent diffusive coefficient is well captured by the associated dimensionless Péclet number. A nice collapse
of the experimental measurements consistent with a quadratic scaling with Péclet number is found.
Such scaling is suggested by previous theoretical and experimental analysis associated with a Taylor dispersion
transport mechanism. Nevertheless the prefactor of those theory is found to under-predict the
observed effect by a factor three. This deviation from Taylor’s dispersion driven transport predictions
is discussed.
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