Wu Weiwei, Kong Shuaishuai, Xu Xiaoyan, Tao Jin, Li Chuanliang, Wang Jingyi, Su Mingxu, Yang Huinan
School of Energy and Power Engineering, University of Shanghai for Science and Technology, Shanghai 200093, China.
State Key Laboratory of Applied Optics, Changchun Institute of Optics, Chinese Academy of Sciences, Changchun 130033, China.
Spectrochim Acta A Mol Biomol Spectrosc. 2021 Aug 5;257:119804. doi: 10.1016/j.saa.2021.119804. Epub 2021 Apr 9.
The flow and evaporation of liquid films widely exist in various industrial fields. The investigation into liquid films is essential to design and optimize the relevant industrial processes. In this work, a simultaneous measurement method of liquid film thickness and temperature on metal surface based on diode laser absorption spectroscopy (DLAS) was proposed, and a corresponding measurement system was developed. First, static liquid films of 200-800 μm on the horizontal metal plate were studied, ultrasonic pulse-echo method (UPEM) and thermocouple were employed to compare with DLAS data. It revealed that the relative deviations of film thicknesses and temperatures measured by different methods were 3.3% and 2.0%, respectively. Furthermore, the evaporation processes of static liquid films were investigated. For the liquid films with different initial thicknesses (490.0/624.6/744.5 μm), the average relative deviations of the film thicknesses and temperatures measured by different methods were 0.1%/0.8%/4.1% and 0.1%/2.6%/3.0%, respectively. Finally, the flow processes of liquid films at different initial temperatures (40.0/60.0/80.0 °C) on the inclined metal plate were researched. It was found that the variation trends of the liquid film thicknesses and temperatures measured by different methods were in good agreement. In the stable stages of flow processes, the average relative deviations of liquid film thicknesses and temperatures measured by different methods were 9.0%/8.4%/5.1% and 3.6%/1.2%/2.5%, respectively. This work is helpful to understand the heat and mass transfer mechanisms in the evaporation and flow processes of liquid films.
液膜的流动与蒸发广泛存在于各个工业领域。对液膜进行研究对于设计和优化相关工业过程至关重要。在这项工作中，提出了一种基于二极管激光吸收光谱法（DLAS）同时测量金属表面液膜厚度和温度的方法，并开发了相应的测量系统。首先，研究了水平金属板上200 - 800μm的静态液膜，采用超声脉冲回波法（UPEM）和热电偶与DLAS数据进行比较。结果表明，不同方法测量的膜厚和温度的相对偏差分别为3.3%和2.0%。此外，还研究了静态液膜的蒸发过程。对于不同初始厚度（490.0/624.6/744.5μm）的液膜，不同方法测量的膜厚和温度的平均相对偏差分别为0.1%/0.8%/4.1%和0.1%/2.6%/3.0%。最后，研究了倾斜金属板上不同初始温度（40.0/60.0/80.0°C）的液膜流动过程。发现不同方法测量的液膜厚度和温度的变化趋势吻合良好。在流动过程的稳定阶段，不同方法测量的液膜厚度和温度的平均相对偏差分别为9.0%/8.4%/5.1%和3.6%/1.2%/2.5%。这项工作有助于理解液膜蒸发和流动过程中的传热传质机制。
