The effect of wall thickness and material on Marangoni driven convection in capillaries
The effect of wall thickness and material on Marangoni driven convection in capillaries
复制标题
壁厚和材料对毛细管中马兰戈尼驱动对流的影响
DOI：
10.1016/j.colsurfa.2015.05.050
复制
发表时间：
2015
期刊：
影响因子：
--
通讯作者：
C. Minetti
中科院分区：
文献类型：
--
作者：
C. Buffone;K. Sefiane;C. Minetti
我们提出的Marangoni对流的实验研究结果的蒸发弯月面在开放的空气钉在毛细管的嘴。研究了四种不同的液体：乙醇、甲醇、丙酮，并首次研究了FC-72。这种实验配置已经研究了本作者和其他人。然而，这是第一次，毛细管的厚度和材料的影响进行了实验研究。特别是，该研究考虑了所有管的相同内径（1 mm）和三种硼硅酸盐外径（1.4、2和3 mm）以及一种聚碳酸酯（1.25 mm）和一种蓝宝石（3 mm）。选择这三种管材料是因为它们具有非常不同的热性能和光学透明度。蒸发率是通过跟踪第二个弯月面在毛细管内后退而第一个弯月面固定在管口来测量的。结果表明，蒸发速率受管壁导热系数的影响大于管壁厚度的影响。还采用红外相机来测量固定在管口处的弯月面处以及沿着靠近管口的管壁的界面温度。此外，传热分析已被执行在管口沿着与传质分析，允许的弯月面界面的温度和蒸发速率的评估，分别，并比较这些结果与测量的。发现的偏差是最大的65%之间的测量和计算的壁面和弯月面之间的温差和6.7%的蒸发率。根据蒸发固着液滴获得的结果进行定性评估，发现趋势相似。
We present results of an experimental investigation of Marangoni convection for an evaporating meniscus in open air pinned at the mouth of a capillary tube. Four different liquids have been studied: ethanol, methanol, acetone and, for the first time, also FC-72. This experimental configuration has been studied before by the present authors and others. However, it is the first time that the effect of the capillary tube thickness and material is experimentally investigated. In particular, the study considered the same internal diameter for all the tubes (1 mm) and three borosilicate external diameters (1.4, 2, and 3 mm) as well as one polycarbonate (1.25 mm) and one sapphire (3 mm). These three tube materials were chosen for their very different thermal properties and their optical transparency. The evaporation rate is measured by tracking the second meniscus receding inside the capillary tube while the first one is pinned at the tube mouth. It was found that the evaporation rate is influenced more by the thermal conductivity of the tubes than the wall thickness. An infrared camera has also been employed to measure the interfacial temperature at the meniscus pinned at the tube mouth and also along the wall of the tube close to the tube mouth. In addition, a heat transfer analysis has been performed at the tube mouth along with a mass transfer analysis which allowed the evaluation of the temperature of the meniscus interface and the evaporation rate, respectively, and comparing these results with the measured ones. The deviation found is maximum 65% between measured and calculated temperature differences between wall and meniscus and 6.7% for the evaporation rate. The results are qualitatively assessed in the light of those obtained for evaporating sessile drops and the trends found are similar.