【摘要】 采用高速摄像技术可视化观察10μL液滴在不同固体表面上的蒸发及核化过程,壁面温度110~190℃。通过测量小液滴铺展面积、铺展速率,确认液滴在蒸发沸腾情况下受迫铺展与其内部气泡动态演化关系密切,也受加热板表面特性影响。130℃时液滴最容易铺展,铺展趋势随表面粗糙度增大而加强。160℃时液滴各板面液滴铺展的速度和面积非常相近。160℃以后液滴的铺展趋势与温度较低时相反,金属板越光滑越容易铺展。更多还原

【Abstract】 An experimental investigation was conducted to visually observe the dynamical characteristics of water droplets with evaporation and nucleation on stainless steel and polished silicon surfaces.The water droplet diameter,spreading area and spreading speed were measured using a high-speed CCD camera at the surface temperature ranged from 110 ℃ to 190 ℃.The spreading of water droplets under evaporation and nucleate boiling has a close relationship with the dynamic bubble behaviors in the droplet as well as the surface properties.Both the drag of spreading area and spreading speed are highly dependent upon the surface temperature and surface properties.Water droplets is the easiest to spread at the surface temperature of 130 ℃,and the spreading tendency increased with increasing surface coarseness.Particularly,both bubble volume and bubble interaction have very strong influence on droplet spreading.For the cases with the surface temperature greater than 160 ℃,the spreading tendency increase with increasing surface lubricity,which was opposite to the lower surface temperature.The periodic evaporation and nucleation of a droplet on the polished silicon surfaces was also observed in the experiments.更多还原