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Modeling Crystallization and Heat Transfer in an Evaporating Urea-Water Drop

Bender, Achim and Hänichen, Philipp and Stephan, Peter and Gambaryan-Roisman, Tatiana (2018):
Modeling Crystallization and Heat Transfer in an Evaporating Urea-Water Drop.
In: IHTC 16 - International Heat Transfer Conference 16 Digital Libary, August 10-15, Beijing, China, Begellhouse, ISSN 2377-424X, DOI: 10.1615/IHTC16, [Online-Edition: http://dx.doi.org/10.1615/IHTC16.mpf.022242],
[Article]

Abstract

Evaporation and deposit formation of a pinned urea-water drop on an initially smooth surface are modeled. Water evaporates from the two-component drop into the surrounding gas phase containing a non-condensable gas. This leads to an increase of the urea concentration inside the drop. At the three-phase contact line high evaporation rates lead to a significant increase of the urea concentration. As a result, the heterogeneous nucleation and growth of urea crystals take place in the vicinity of the three-phase contact line. The model utilizing the Finite Element Method is implemented in the software COMSOL Multiphysics. The deformation of the liquid-gas interface is resolved using an Arbitrary-Lagrangian-Eulerian Method (ALE) in a moving mesh framework. The deposit shape and the influence of the deposit on the transport processes in the drop are accounted for. The drop volume evolution agrees well with experimental data on urea-water drops evaporating in a controlled environment. A qualitative agreement between model and experiment regarding the deposit formation is achieved. The wall temperature affects the evaporation rate and exerts a strong influence on the time at which the deposit formation is observed. Once the deposit formation has started, the deposit growth rate increases with time.

Item Type: Article
Erschienen: 2018
Creators: Bender, Achim and Hänichen, Philipp and Stephan, Peter and Gambaryan-Roisman, Tatiana
Title: Modeling Crystallization and Heat Transfer in an Evaporating Urea-Water Drop
Language: English
Abstract:

Evaporation and deposit formation of a pinned urea-water drop on an initially smooth surface are modeled. Water evaporates from the two-component drop into the surrounding gas phase containing a non-condensable gas. This leads to an increase of the urea concentration inside the drop. At the three-phase contact line high evaporation rates lead to a significant increase of the urea concentration. As a result, the heterogeneous nucleation and growth of urea crystals take place in the vicinity of the three-phase contact line. The model utilizing the Finite Element Method is implemented in the software COMSOL Multiphysics. The deformation of the liquid-gas interface is resolved using an Arbitrary-Lagrangian-Eulerian Method (ALE) in a moving mesh framework. The deposit shape and the influence of the deposit on the transport processes in the drop are accounted for. The drop volume evolution agrees well with experimental data on urea-water drops evaporating in a controlled environment. A qualitative agreement between model and experiment regarding the deposit formation is achieved. The wall temperature affects the evaporation rate and exerts a strong influence on the time at which the deposit formation is observed. Once the deposit formation has started, the deposit growth rate increases with time.

Journal or Publication Title: IHTC 16 - International Heat Transfer Conference 16 Digital Libary, August 10-15, Beijing, China
Place of Publication: Connecticut
Publisher: Begellhouse
Divisions: 16 Department of Mechanical Engineering
16 Department of Mechanical Engineering > Institute for Technical Thermodynamics (TTD)
Profile Areas
Profile Areas > Thermo-Fluids & Interfaces
Event Location: Connecticut
Date Deposited: 08 Jan 2019 08:49
DOI: 10.1615/IHTC16
Official URL: http://dx.doi.org/10.1615/IHTC16.mpf.022242
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