Enhanced evaporation from an oscillating liquid in a capillary tube

Abstract

To cite this version:Denis Polezhaev, Paul Duru, Franck Plouraboué. Enhanced evaporation from an oscillating liquid in a capillary tube. a b s t r a c tEnhanced 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. (D. Polezhaev), duru@imft.fr (P. Duru), fplourab@imft.fr (F. Plouraboué).

Measure method of effective diffusion in gas oscillating in channels of variable radius or porous medium

“…An alternative way to increase heat or mass transfer is to excite oscillations of a fluid (or gas) in a stationary container. For example, longitudinal air oscillations increase the mass transfer of a contaminant by several times due to Taylor dispersion in a long straight tube [ 7 , 8 ]. The other direction of research relies on oscillatory fluid (or gas) flow inside a channel of alternating radius.…”

Microcavity-Enabled Local Oscillation of Taylor Bubbles in a Microchannel

“…16 In addition to the extended area at the liquid−gas interface, the microstreaming induced by the ultrasound can greatly increase the convection mass transfer from the bubble body to the liquid slug, which promotes the interface renewal and mass transfer enhancement. 9,21 Therefore, the bubble deformation and local disturbance enabled by the oscillation could overcome the limitations of laminar flow in the microchannel for enhancing the interphase mass-transfer process.…”

“…The uniform surface waves on the bubble body lead to an enlarged interface area for mass transfer. , For a pressure-driven system, bubble oscillation also changes the local flow resistance and feedback to the upstream, further affecting the bubble shape and bubble length . In addition to the extended area at the liquid–gas interface, the microstreaming induced by the ultrasound can greatly increase the convection mass transfer from the bubble body to the liquid slug, which promotes the interface renewal and mass transfer enhancement. , Therefore, the bubble deformation and local disturbance enabled by the oscillation could overcome the limitations of laminar flow in the microchannel for enhancing the interphase mass-transfer process.…”