论文标题
在加热的圆柱形细胞中蒸发液层中的热毛细血流过渡
Thermocapillary flow transition in an evaporating liquid layer in a heated cylindrical cell
论文作者
论文摘要
通过最新的基于地面和微重力实验研究了挥发性液体的界面动力学（FC-72，$ PR = 12.34 $），其中包含在加热的圆柱形细胞中，我们在这种蒸发液层中数值研究了热毛细管驱动的流动。当施加温度升高时，特别注意预测轴对称流向完全三维模式的过渡。数值模拟通过通过热传递生物量和蒸发生物数包括热量和通过气相的传播来依赖于改进的蒸发模型。我们呈现轴对称流量特征，显示了这些生物数量的过渡点的变化，更重要的是阐明了潜在蒸发在稳定性中的双重作用。蒸发不仅破坏了流动稳定，而且还可以稳定下来，这取决于蒸发引起的热梯度发挥作用的位置。我们还表明，液态浮力具有稳定作用，尽管其作用微不足道。在高马龙尼数字上，数值模拟揭示了与实验观测的定性一致性，在较薄的蒸发层表面形成了较小的热模式。目前的工作有助于更好地了解相变的作用在蒸发液层的热毛细管不稳定性中。
Motived by recent ground-based and microgravity experiments investigating the interfacial dynamics of a volatile liquid (FC-72, $Pr=12.34$) contained in a heated cylindrical cell, we numerically study the thermocapillary-driven flow in such an evaporating liquid layer. Particular attention is given to the prediction of the transition of the axisymmetric flow to fully three-dimensional patterns when the applied temperature increases. The numerical simulations rely on an improved one-sided model of evaporation by including heat and mass transfer through the gas phase via the heat transfer Biot number and the evaporative Biot number. We present the axisymmetric flow characteristics, show the variation of the transition points with these Biot numbers, and more importantly elucidate the twofold role of the latent heat of evaporation in the stability; evaporation not only destabilizes the flow but also stabilizes it, depending upon the place where the evaporation-induced thermal gradients come into play. We also show that buoyancy in the liquid layer has a stabilizing effect, though its effect is insignificant. At high Marangoni numbers, the numerical simulations revealed smaller-scale thermal patterns formed on the surface of a thinner evaporating layer, in qualitative agreement with experimental observations. The present work helps to gain a better understanding of the role of a phase change in the thermocapillary instability of an evaporating liquid layer.
