Abstract In this study, sol-gel method and picosecond laser system were used to create surfaces with various roughness and wettability levels. The ranges of contact angle and surface roughness were 0°–125° and 0.121–0.356 μm, respectively. The influence of surface roughness and wettability on bubble dynamics was experimentally investigated by observing droplet evaporation on heated surfaces. The results revealed that not only the surface temperature but also surface characteristics affected bubble behavior and resulted in different evaporation efficiencies. Droplets evaporated most rapidly on the laser-textured copper surface because of its hydrophobicity and enhanced surface roughness, which led to improved liquid–vapor heat transfer in active bubbles behavior. By contrast, silica-coated surfaces exhibited the lowest droplet evaporation efficiency. This evaporation efficiency was attributed to the hydrophilic wetting state and high bubble covering area, which hindered the heat transfer from the heated surface to the liquid droplet. The overall evaporation time on the laser-textured surface was approximately 77% shorter than that on other surfaces for the highest evaluated surface temperature. In addition, the experimental results of the overall evaporation time were compared with the results of the prediction model. With the increase in the temperature of the surface, the hydrophobic wetting state increased, which led to larger differences between the model and experimental results.

中文翻译：

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不同粗糙度和润湿性加热表面水滴蒸发过程中内气泡动力学的实验研究

摘要 在这项研究中，溶胶-凝胶法和皮秒激光系统被用来创建具有各种粗糙度和润湿性水平的表面。接触角和表面粗糙度的范围分别为 0°–125° 和 0.121–0.356 μm。通过观察加热表面上的液滴蒸发，实验研究了表面粗糙度和润湿性对气泡动力学的影响。结果表明，不仅表面温度而且表面特征都会影响气泡行为并导致不同的蒸发效率。由于其疏水性和增强的表面粗糙度，液滴在激光纹理化铜表面上蒸发得最快，从而改善了活性气泡行为中的液-气热传递。相比之下，二氧化硅涂层的表面表现出最低的液滴蒸发效率。这种蒸发效率归因于亲水润湿状态和高气泡覆盖面积，这阻碍了从加热表面到液滴的热传递。对于最高评估的表面温度，激光纹理表面上的总蒸发时间比其他表面上的蒸发时间短约 77%。此外，将整体蒸发时间的实验结果与预测模型的结果进行了比较。随着表面温度的升高，疏水润湿状态增加，导致模型与实验结果存在较大差异。这阻碍了从受热表面到液滴的热传递。对于最高评估的表面温度，激光纹理表面上的总蒸发时间比其他表面上的蒸发时间短约 77%。此外，将整体蒸发时间的实验结果与预测模型的结果进行了比较。随着表面温度的升高，疏水润湿状态增加，导致模型与实验结果存在较大差异。这阻碍了从受热表面到液滴的热传递。对于最高评估的表面温度，激光纹理表面上的总蒸发时间比其他表面上的蒸发时间短约 77%。此外，将整体蒸发时间的实验结果与预测模型的结果进行了比较。随着表面温度的升高，疏水润湿状态增加，导致模型与实验结果存在较大差异。将总蒸发时间的实验结果与预测模型的结果进行了比较。随着表面温度的升高，疏水润湿状态增加，导致模型与实验结果存在较大差异。将总蒸发时间的实验结果与预测模型的结果进行了比较。随着表面温度的升高，疏水润湿状态增加，导致模型与实验结果存在较大差异。