Interface dynamics in two-phase flows with diffuse interface methods

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Perustieteiden korkeakoulu | Doctoral thesis (article-based)
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Date

2011

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Degree programme

Language

en

Pages

Verkkokirja (2177 KB, 55 s.)

Series

Aalto University publication series DOCTORAL DISSERTATIONS , 141/2011

Abstract

Diffuse interface methods are an approach to modeling dynamic multiphase systems. The method allows keeping track of domains of phases and assign physical tension to interfaces in between. In this thesis, two diffuse interface methods are applied to study two different kinds of problems. One is a coarse phase field model of slow dynamics on large scales, and the other a hydrodynamics model of fast dynamics on microscopic scales. The basis of the phase field model is slow flow of mass on large scales. The model was considered in relation to the experimental Hele-Shaw cell setup. We studied statistics of a propagating interface as it undergoes kinetic roughening due to disorder. Good match was found between the models and the Hele-Shaw setup, but results from both the models and the experiments suggest against a universality class these minimal model systems would potentially represent. A model of thermal hydrodynamics to study boiling at the microscale was also considered. A method that enables imposing a constant external pressure to the system was developed. The major component of the method is a novel open boundary condition. We verify the method with numerical test cases, and observe the microscale dynamics of nucleate boiling and film boiling under constant pressure. We find a complex flow pattern at the three phase contact line of a growing bubble, which is consistent with the vapor recoil theory of boiling crisis.

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Supervising professor

Ala-Nissilä, Tapio, Prof.

Keywords

diffuse interface, phase field, two-phase flows, kinetic roughening, boiling

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Parts

  • [Publication 1]: T. Laurila, C. Tong, I. Huopaniemi, S. Majaniemi, and T. Ala-Nissila. Dynamics and kinetic roughening of interfaces in two-dimensional forced wetting. European Physical Journal B, Volume 46, pages 553-561, September 2005.
  • [Publication 2]: T. Laurila, C. Tong, S. Majaniemi, and T. Ala-Nissila. Interface equations for capillary rise in random environment. Physical Review E, Volume 74, page 041601, October 2006. © 2006 American Physical Society (APS). By permission.
  • [Publication 3]: T. Laurila, M. Pradas, A. Hernández-Machado, and T. Ala-Nissila. Influence of disorder strength on phase-field models of interfacial growth. Physical Review E, 78, page 031603, September 2008. © 2008 American Physical Society (APS). By permission.
  • [Publication 4]: T. Laurila, A. Carlson, M. Do-Quang, T. Ala-Nissila and G. Amberg. Thermo-hydrodynamics of boiling in a van der Waals fluid. Physical Review E, submitted, September 29th 2011. © 2012 by authors and © 2012 American Physical Society (APS). By permission.

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