接触面温度对表面液滴蒸发过程的影响

The Effect of Surface Temperature on Droplet Evaporation

摘要:

如今,液滴已被广泛地应用于打印机、微型泵等微流体领域，但是与液滴相关的众多现象，如马兰格尼效应、接触角和蒸发过程等，过去的研究并不充分。本文详细研究了不同接触面温度对液滴蒸发过程的影响。通过分析液滴中间平面的粒子图像，首先阐述了接触面温度对在液滴内漩涡流动的影响，并指出了液滴周围水汽的凝结过程对液滴底部成像的影响。然后计算了不同接触面温度条件下液滴无量纲体积与接触角随时间的变化曲线。结果表明，随着接触面温度的降低，液滴无量纲体积和接触角减少的速度都变慢，在接触面温度较低的时候（例如5°C），液滴无量纲体积和接触角都因空气中水汽凝结过程的影响而增大。

Abstract:

Nowadays, droplets have plenty of applications in the field of microfluids, e.g. inkjet and micropump. However, some phenomena of droplets, such as the Marangoni effect, contact angle and evaporation, are not fully understood. The present paper compressively studied the effect of surface temperature on the evaporation process of droplets. Through analyzing the particle images of droplet middle plane, the effect of surface temperature on vortex flow inside the droplet and the effect of condensation process on contact line at the bottom of droplet ware illustrated. Then, the changing processes of droplet normalized volume and contact angle with time were plotted. The results show that as the decrease of surface temperature, the reducing rates of normalized volume and contact angle become slow. When the surface temperature is relatively low (e.g.5°C), droplet normalized volume and contact angle increase with time due to the condensation process.