Sobac B, Brutin D
Laboratoire IUSTI, UMR 7343 CNRS, Aix-Marseille Université, 5 rue Enrico Fermi, 13453 Marseille cedex 13, France.
Phys Rev E Stat Nonlin Soft Matter Phys. 2012 Aug;86(2 Pt 1):021602. doi: 10.1103/PhysRevE.86.021602. Epub 2012 Aug 20.
We experimentally investigate the behavior of a pinned water droplet evaporating into air. The influence of the substrate temperature and substrate thermal properties on the evaporation process are studied in both hydrophilic and hydrophobic conditions. Our objective is to understand the effect of thermal mechanisms on the droplet evaporation process. The experimental results are compared with the quasisteady, diffusion-driven evaporation model, which is implemented under the influence of the temperature; the model assumes the isothermia of the droplet at the substrate temperature. The results highlight a favorable correlation between the model and the experimental data at ambient temperatures for most situations considered here. The model works to qualitatively describe the influence of the substrate temperature on the evaporation process. However, with an increase in the substrate temperature, the role of the thermal-linked mechanisms becomes increasingly important; this experiment highlights the need for more accurate models to account for the buoyant convection in vapor transport and the evaporative cooling and heat conduction between the droplet and the substrate. Finally, the experimental data reveal the modification of contact angle evolution as the temperature increases and the crucial role played by the nature of the substrate in the evaporation of a sessile droplet. The influence of the substrate thermal properties on the global evaporation rate is explained by the parallel thermal effusivity of the liquid and solid phases.
我们通过实验研究了固定在基底上的水滴在空气中蒸发的行为。在亲水和疏水条件下，研究了基底温度和基底热性质对蒸发过程的影响。我们的目标是了解热机制对液滴蒸发过程的作用。将实验结果与准稳态、扩散驱动的蒸发模型进行了比较，该模型是在温度影响下实现的；该模型假设液滴在基底温度下处于等温状态。结果表明，在此处考虑的大多数情况下，在环境温度下模型与实验数据之间存在良好的相关性。该模型能够定性地描述基底温度对蒸发过程的影响。然而，随着基底温度的升高，热关联机制的作用变得越来越重要；该实验突出表明需要更精确的模型来考虑蒸汽传输中的浮力对流以及液滴与基底之间的蒸发冷却和热传导。最后，实验数据揭示了随着温度升高接触角演变的变化以及基底性质在静态液滴蒸发中所起的关键作用。基底热性质对整体蒸发速率的影响通过液相和固相的平行热扩散率来解释。
