비등점의 가열 표면에서 나노유체 액적의 증발 특성

Abstract

This study aims to investigate evaporation characteristics of nanofluid droplet on heated surface at boiling temperature of DI-water. At the initial stage of evaporation process, dynamic contact angle (DCA) of nanofluid droplet with 0.01 vol.% on the textured surface rapidly increased over its ECA by generated large bubble inside the droplet due to lower wettability. However, contact angle of nanofluid droplet with higher concentration on textured surface decreased with the surface tension. After that, DCA gradually decreased until dried out, and total evaporation time was significantly delayed in the case of textured surface. In addition, the evaporation rate of droplet was estimated by using droplet contact angle and diameter through image processing. The evaporation characteristics were highly affected by the nanofluid concentration and surface wettability.l.% on the textured surface rapidly increased over its ECA by generated large bubble inside the droplet due to lower wettability. However, contact angle of nanofluid droplet with higher concentration on textured surface decreased with the surface tension. After that, DCA gradually decreased until dried out, and total evaporation time was significantly delayed in the case of textured surface. In addition, the evaporation rate of droplet was estimated by using droplet contact angle and diameter through image processing. The evaporation characteristics were highly affected by the nanofluid concentration and surface wettability.