Two problems concerning sessile liquid droplets are considered. First we report the results of physical experiments that demonstrate the strong influence of the thermal conductivity of the substrate and the nature of the atmosphere on the diffusion-dominated evaporation of a pinned sessile liquid droplet without external heating or cooling. We capture this behaviour in a mathematical model including the variation of the saturation concentration with temperature, and hence coupling the problems for the vapour concentration in the atmosphere and the temperature in the liquid and the substrate. Furthermore, we show that including two ad hoc improvements to the model gives excellent quantitative agreement with experiments. We also extend the model to include the effect of reduced atmospheric pressure and different gases, for which we again find good agreement with experiments. We then consider the special case in which both the droplet and the substrate are thin, in the extreme situation in which the substrate has a high thermal resistance relative to the droplet.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:501697 |
| Date | January 2009 |
| Creators | Dunn, Gavin J. |
| Publisher | University of Strathclyde |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
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