Contact-line behavior in boiling on a heterogeneous surface: Physical insights from diffuse-interface modeling

Biao Shen, Jiewei Liu, Gustav Amberg, Minh Do-Quang, Junichiro Shiomi, Koji Takahashi, Yasuyuki Takata

研究成果: Contribution to journalArticle

抜粋

Enhancement of boiling heat transfer on biphilic (mixed-wettability) surfaces faces a sudden reversal at low pressures, which is brought about by excessive contact-line spreading across the wetting heterogeneities. We employ the diffuse-interface approach to numerically study bubble expansion on a heating surface that consists of opposing wettabilities. The results show a dramatic shift in the dynamics of a traversing contact line across the wettability divide under different gravities, which correspond to variable bubble growth rates. Specifically, it is found that the contact-line propagation tends to follow closely the rapidly expanding bubble at low gravity, with only a brief interruption at the border between the hydrophobic and hydrophilic sections of the surface. Only when the bubble growth becomes sufficiently weakened at high gravity does the contact line get slowed down drastically to the point of being nearly immobilized at the edge of the hydrophilic surface. The following bubble expansion, which faces strong limitations in the direction parallel to the surface, features a consistent apparent contact angle at around 66.4°, regardless of the wettability combination. A simple theoretical model based on the force-balance analysis is proposed to describe the physical mechanism behind such a dramatic transition in the contact-line behavior.

元の言語英語
記事番号033603
ジャーナルPhysical Review Fluids
5
発行部数3
DOI
出版物ステータス出版済み - 3 2020

All Science Journal Classification (ASJC) codes

  • Computational Mechanics
  • Modelling and Simulation
  • Fluid Flow and Transfer Processes

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