TIPs Laboratory, Université libre de Bruxelles, B-1050, Brussels, Belgium.
Institut de Physique, Université de Liège, B-4000, Liège, Belgium.
Langmuir. 2023 Jul 11;39(27):9343-9357. doi: 10.1021/acs.langmuir.3c00689. Epub 2023 Jun 29.
A benchmark microgravity experiment (dubbed "ARLES") is analyzed. It concerns evaporation of several-μL sessile droplets with a pinned millimetric circular contact line on a flat substrate into a vast calm (here nitrogen) atmosphere at nearly normal conditions. Hydrofluoroether (HFE-7100) is used as a working liquid whose appreciable volatility and heavy vapor accentuate the contrast between the micro- and normal gravity. A possibility of switching on a DC electric field (EF) of several kV/mm orthogonally to the substrate is envisaged. We here focus on the findings intimately associated with the visualization of the vapor cloud by means of interferometry and rationalized by means of extensive simulations. In particular, with different degrees of unexpectedness, we discover and explore a Marangoni jet (without EF) and electroconvection (with EF) in the gas, which would otherwise be masked by buoyancy convection. Using the same tools, we examine some malfunctions of the space experiment.
分析了一项基准微重力实验（称为“ARLES”）。该实验涉及在近乎正常条件下，将具有固定毫米级圆形接触线的几微升贴壁液滴蒸发到平静（此处为氮气）的广阔大气中。使用氢氟醚（HFE-7100）作为工作液体，其明显的挥发性和重蒸汽突出了微重力和正常重力之间的对比。可以设想在基板正交方向上施加几千伏/毫米的直流电场（EF）。我们在这里重点关注通过干涉测量可视化蒸汽云的发现，并通过广泛的模拟进行合理化。特别是，我们以不同程度的意外程度发现并探索了气体中的 Marangoni 射流（无 EF）和电对流（有 EF），否则这些现象会被浮力对流掩盖。我们使用相同的工具检查了空间实验的一些故障。
