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Droplet Evaporation on a Hydrophilic Mesh Considering Their Sunken Shapes in Holes
Author(s) -
Yang Qiang,
Ding Yanliang,
Xu Xiao,
Lu Hao,
Wang Hualin,
Liu Honglai
Publication year - 2020
Publication title -
chemical engineering and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.403
H-Index - 81
eISSN - 1521-4125
pISSN - 0930-7516
DOI - 10.1002/ceat.201900237
Subject(s) - evaporation , darkness , materials science , regular polygon , mechanics , chemistry , chemical engineering , composite material , optics , geometry , thermodynamics , physics , engineering , mathematics
The evolution of droplet shapes on a hydrophilic copper mesh was studied by using high‐speed microscopic imaging technology. When a water droplet wets a hydrophilic mesh, the liquid‐vapor interface initially adopts a convex shape, named as the “first darkness”. Then, as the water evaporates, the liquid‐vapor interface flattens, and then it gradually adopts a concave shape; meanwhile, a “second darkness” forms. Taking the shapes of droplets sunken in holes into consideration, the quantitative liquid‐vapor interface area was acquired. The evaporation coefficient becomes lower and more reasonable when considering the area increase due to the pentahedron sunken liquid in the holes. A speculation was employed to understand the observed evaporation behavior and the overprediction of the evaporation coefficient.