Abstract This paper reports an experimental and theoretical study of sessile water droplet evaporation during depressurization. During the experiments, three kinds of surfaces were used: copper, slide glass and Teflon. The change in droplet shape with ambient pressure was recorded. The experimental results showed that the water droplet evaporated the fastest on the slide glass surface and the lowest on the Teflon surface, due to the different wettability of substrates. Bubbles were easily formed on the Teflon surface, and the existence of bubbles hindered the contraction of the contact line. A mathematical model was then developed to simulate droplet evaporation on the copper surface and the slide glass surface during depressurization, which combined the effects of air flow, the substrate thermal properties, evaporative cooling, internal circulation and the Stefan flow for the first time. The calculated results matched well with the experimental results, and the deviations between them were within 30%. A significant difference between sessile droplet evaporation under reduced pressure and under atmospheric pressure was that the droplet height did not follow the linear change with time, which was related to the change of droplet surface temperature. And then, the changes of droplet surface temperature and substrate surface temperature with time were analyzed based on calculations. Finally, the main factors affecting the accuracy of present model were proposed.

中文翻译：

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减压过程中固着水滴的蒸发

摘要 本文报道了减压过程中固着水滴蒸发的实验和理论研究。在实验过程中，使用了三种表面：铜、载玻片和特氟龙。记录液滴形状随环境压力的变化。实验结果表明，由于基材的润湿性不同，水滴在载玻片表面蒸发最快，在聚四氟乙烯表面蒸发最低。特氟龙表面容易形成气泡，气泡的存在阻碍了接触线的收缩。然后开发了数学模型来模拟减压过程中铜表面和载玻片表面上的液滴蒸发，该模型结合了气流、基板热性能、蒸发冷却、内循环和 Stefan 流是第一次。计算结果与实验结果吻合良好，偏差在30%以内。减压和常压下固着液滴蒸发的显着差异在于液滴高度不随时间线性变化，这与液滴表面温度的变化有关。然后，在计算的基础上分析了液滴表面温度和基板表面温度随时间的变化。最后，提出了影响现有模型精度的主要因素。减压和常压下固着液滴蒸发的显着差异在于液滴高度不随时间呈线性变化，这与液滴表面温度的变化有关。然后，在计算的基础上分析了液滴表面温度和基板表面温度随时间的变化。最后，提出了影响现有模型精度的主要因素。减压和常压下固着液滴蒸发的显着差异在于液滴高度不随时间呈线性变化，这与液滴表面温度的变化有关。然后，在计算的基础上分析了液滴表面温度和基板表面温度随时间的变化。最后，提出了影响现有模型精度的主要因素。