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Impingement, coalescence and mixing of micro-droplets on a solid surface
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  • Guina Yi,
  • Ziqi Cai,
  • Zhengming Gao,
  • Jos Derksen
Guina Yi
Beijing University of Chemical Technology

Corresponding Author:2016410004@mail.buct.edu.cn

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Zhengming Gao
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Jos Derksen
University of Aberdeen
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The coalescence of an impinging droplet colliding with a sessile droplet at an angle(θi) is investigated by numerical simulation. The range of θi is 0° - 60° and the surface wettability are set as hydrophilic or hydrophobic, and both of them can affect the droplet mergence behavior. By using a modified mixing function, the dimensionless total mixing time τm can be calculated. The results show that there is no clear effect of θi on τm on a hydrophobic surface, while τm increases as θi increases on the hydrophilic surface. With the Weber number(We) ranging from 5.65 to 22.7 and the Ohnesorge number(Oh) ranging from 0.136 to 0.214, we find τm hardly changes with We and Oh. By dividing the mergence and mixing process in a convection and a diffusion stage, we find that the diffusion is much larger than the convection time.