Asymptotic analysis of evaporating droplets

This paper was presented at the 4th Micro and Nano Flows Conference (MNF2014), which was held at University College, London, UK. The conference was organised by Brunel University and supported by the Italian Union of Thermofluiddynamics, IPEM, the Process Intensification Network, the Institution of Mechanical Engineers, the Heat Transfer Society, HEXAG - the Heat Exchange Action Group, and the Energy Institute, ASME Press, LCN London Centre for Nanotechnology, UCL University College London, UCL Engineering, the International NanoScience Community, www.nanopaprika.eu.We consider the evaporation dynamics of a two-dimensional, partially-wetting sessile droplet of a volatile liquid in its pure vapour, which is supported on a smooth horizontal superheated substrate. Assuming that the liquid properties remain unchanged, we utilise a one-sided lubrication-type model for the evolution of the droplet thickness, which accounts for the effects of evaporation, capillarity, slip and the kinetic resistance to evaporation. We follow an asymptotic approach, which yields a set of coupled evolution equations for the droplet radius and area, estimating analytically the evaporation-modified apparent angle when evaporation effects are weak. The validity of our matching procedure is verified by numerical experiments, obtaining also an estimate for the evaporation time

Stability analysis of the evaporation of a binary liquid into an inert gas, considering solute/thermal and gravity/surface tension effects

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A comprehensive analysis of the evaporation of a liquid spherical drop

International audienc

Time-dependent Marangoni-Bénard instability of an evaporating binary-liquid layer including gas transients

info:eu-repo/semantics/publishe

Nonmonotonic Rayleigh-Taylor Instabilities Driven by Gas–Liquid CO₂ Chemisorption

Density variations induced by gas absorption in reactive aqueous solutions often trigger buoyancy-induced motions, generally in the form of plumes monotonically sinking into the bulk liquid and enhancing the absorption rate. Here, we contrast two types of CO₂-absorbing alkaline solutions, studying their dynamics inside a vertical Hele-Shaw cell by interferometry. While the first one indeed behaves as expected, the second one leads to a quite unusual oscillatory (phase-slipping) dynamics of convective plumes, which moreover does not lead to a significant transfer enhancement. Thanks to a simplified model of momentum and species transport, we show that this particular dynamics is related to a nonmonotonic density stratification, resulting in a stagnant layer close to the interface. Conditions for this to occur are highlighted in terms of the ratios of species’ diffusivities and their contribution to density, a classification deemed to be useful for optimizing chemisorption (e.g., for CO₂ capture or sequestration) processes

Influence of a nonlinear reference temperature profile on oscillatory Benard-Marangoni convection.

We analyze oscillatory instabilities in a fluid layer of infinite horizontal extent, heated from above or cooled from below, taking into account the nonlinearity of the reference temperature profile during the transient state of heat conduction. The linear stability analysis shows that a nonlinear reference temperature profile can have a strong effect on the system, either stabilizing or destabilizing, depending on the relative importance of buoyancy and surface tension forces. For the nonlinear analysis we use a Galerkin-Eckhaus method leading to a finite set of amplitude equations. In the two-dimensional (2D) case, we show the solution of these amplitude equations are standing waves