Thermal imaging study on the surface wave of heated falling liquid films
Thermal imaging study on the surface wave of heated falling liquid films
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DOI：
10.1016/j.expthermflusci.2008.10.010
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发表时间：
2009-03
影响因子：
3.2
通讯作者：
Feng Zhang;Jin Peng;J. Geng;Zhi‐Xiang Wang;Zhibing Zhang
中科院分区：
文献类型：
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作者：
Feng Zhang;Jin Peng;J. Geng;Zhi‐Xiang Wang;Zhibing Zhang
利用热成像技术和膜厚测量系统，对加热降膜的表面波和膜厚进行了实验研究。加热膜的温度变化引起表面张力梯度和由此引起的试图避免温度变化的Marangoni流。在加热下降液膜中出现了三种形式的Marangoni流。研究发现，横向Marangoni流（MF I）和流向Marangoni流（MF II）使加热膜变厚，而表面波中的Marangoni流（MF III）则使表面波增强，使加热膜变薄。Marangoni流的强度取决于流速和加热条件。MF I和MF II均随液体流量的增加而增强。此外，MF III在中等流量下突出，在高流量下逐渐减弱。MF III开始的距离随着流速的增加而增加，但与加热条件无关。
By using thermal imaging technique and film thickness metering system, the surface wave and film thickness of the heated falling liquid film were experimentally investigated. Temperature variations of the heated film induce surface tension gradient and so-caused Marangoni flow that attempts to avoid the temperature variations. There are three kinds of Marangoni flow appearing in the heated falling liquid film. It is found that the lateral Marangoni flow (MF I) and the streamwise Marangoni flow (MF II) make the heated film thick, while the Marangoni flow in the surface wave (MF III) reinforces the wave and makes the heated film thin. The intensity of Marangoni flow is determined by the flow rate and the heating conditions. MF I and MF II are both enhanced with the increasing liquid flow rate. Moreover, MF III is prominent under moderate flow rates and is gradually weakened at high flow rates. The distance over which MF III starts, increases with a rise in flow rate, but is independent of the heating condition.