The present study aims to investigate the characteristics of pinning behaviors and local mass flux variations during droplet evaporation at different surface temperatures ranging from 22.5 °C to 80 °C. An evaporating droplet is visualized by a CMOS camera, and the images are analyzed from droplet deposition to completion of evaporation. We measure the contact angle, the contact diameter, the droplet volume, the total evaporation time, and the pinning time during evaporation. The pinning time and Marangoni number increase with surface temperatures in the range from 20 °C to 50 °C; however, they decrease at surface temperatures higher than 50 °C. Moreover, the present study analyzes the local mass flux variation according to the surface temperature, showing the increase in the local mass flux over time. We also consider the change in vapor concentrations for the heated surfaces to estimate the local mass flux. Indeed, the local mass flux at the contact line becomes much higher; it experiences over a 10-fold increase from 0.1t_f to 0.9t_f.

本研究旨在研究在 22.5 °C 至 80 °C 的不同表面温度下液滴蒸发过程中钉扎行为和局部质量通量变化的特征。蒸发的液滴通过 CMOS 相机进行可视化，并分析从液滴沉积到蒸发完成的图像。我们测量接触角、接触直径、液滴体积、总蒸发时间和蒸发过程中的钉扎时间。钉扎时间和马兰戈尼数随着表面温度在 20 °C 到 50 °C 的范围内增加；然而，当表面温度高于 50 °C 时，它们会降低。此外，本研究根据地表温度分析了局部质量通量的变化，显示了局部质量通量随时间的增加。我们还考虑加热表面的蒸汽浓度变化来估计局部质量通量。事实上，接触线上的局部质量通量变得更高；它从 0.1 增加了 10 倍以上t _f到 0.9 t _f。