Details
| Original language | English |
|---|---|
| Pages (from-to) | 5871-5895 |
| Number of pages | 25 |
| Journal | Journal of computational physics |
| Volume | 227 |
| Issue number | 11 |
| Early online date | 29 Feb 2008 |
| Publication status | Published - 10 May 2008 |
Abstract
An evaporation model compatible with interface-capturing schemes for vapor-liquid flow is presented. The model formulation is largely independent of the specific realization of interface-capturing and relies on a continuum-field representation of the source terms implementable in a broad class of CFD models. In contrast to most other numerical methods for evaporating interfacial flows, the model incorporates an evaporation source-term derived from a physical relationship for the evaporation mass flux. It is shown that especially for microscale evaporation phenomena this implies significant deviations of the interface temperature from the saturation temperature. The mass source-term distribution is derived from the solution of an inhomogeneous Helmholtz equation that contains a free parameter allowing to tune the spatial localization of the source. The evaporation model is implemented into the volume-of-fluid scheme with piecewise linear interface construction. Results are obtained for three analytically or semi-analytically solvable model problems, the first two being one-dimensional Stefan problems, the third a free droplet evaporation problem. In addition, a two-dimensional film boiling problem is considered. Overall, the comparison between the CFD and the (semi)-analytical models shows good agreement. Deviations exist where convective heat transfer due to spurious currents is no longer negligible compared to heat conduction. With regard to the film boiling problem, a similar evaporation pattern as recently identified using a level-set method is found. A major advantage of the developed evaporation model is that it does not refer to intrinsic details of the interface-capturing scheme, but relies on continuum-field quantities that can be computed by virtually any CFD approach.
Keywords
- Droplet evaporation, Evaporation model, Film boiling, Interfacial flow, Stefan problem, Volume-of-fluid method
ASJC Scopus subject areas
- Mathematics(all)
- Numerical Analysis
- Mathematics(all)
- Modelling and Simulation
- Physics and Astronomy(all)
- Physics and Astronomy (miscellaneous)
- Physics and Astronomy(all)
- General Physics and Astronomy
- Computer Science(all)
- Computer Science Applications
- Mathematics(all)
- Computational Mathematics
- Mathematics(all)
- Applied Mathematics
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In: Journal of computational physics, Vol. 227, No. 11, 10.05.2008, p. 5871-5895.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - Evaporation model for interfacial flows based on a continuum-field representation of the source terms
AU - Hardt, S.
AU - Wondra, F.
PY - 2008/5/10
Y1 - 2008/5/10
N2 - An evaporation model compatible with interface-capturing schemes for vapor-liquid flow is presented. The model formulation is largely independent of the specific realization of interface-capturing and relies on a continuum-field representation of the source terms implementable in a broad class of CFD models. In contrast to most other numerical methods for evaporating interfacial flows, the model incorporates an evaporation source-term derived from a physical relationship for the evaporation mass flux. It is shown that especially for microscale evaporation phenomena this implies significant deviations of the interface temperature from the saturation temperature. The mass source-term distribution is derived from the solution of an inhomogeneous Helmholtz equation that contains a free parameter allowing to tune the spatial localization of the source. The evaporation model is implemented into the volume-of-fluid scheme with piecewise linear interface construction. Results are obtained for three analytically or semi-analytically solvable model problems, the first two being one-dimensional Stefan problems, the third a free droplet evaporation problem. In addition, a two-dimensional film boiling problem is considered. Overall, the comparison between the CFD and the (semi)-analytical models shows good agreement. Deviations exist where convective heat transfer due to spurious currents is no longer negligible compared to heat conduction. With regard to the film boiling problem, a similar evaporation pattern as recently identified using a level-set method is found. A major advantage of the developed evaporation model is that it does not refer to intrinsic details of the interface-capturing scheme, but relies on continuum-field quantities that can be computed by virtually any CFD approach.
AB - An evaporation model compatible with interface-capturing schemes for vapor-liquid flow is presented. The model formulation is largely independent of the specific realization of interface-capturing and relies on a continuum-field representation of the source terms implementable in a broad class of CFD models. In contrast to most other numerical methods for evaporating interfacial flows, the model incorporates an evaporation source-term derived from a physical relationship for the evaporation mass flux. It is shown that especially for microscale evaporation phenomena this implies significant deviations of the interface temperature from the saturation temperature. The mass source-term distribution is derived from the solution of an inhomogeneous Helmholtz equation that contains a free parameter allowing to tune the spatial localization of the source. The evaporation model is implemented into the volume-of-fluid scheme with piecewise linear interface construction. Results are obtained for three analytically or semi-analytically solvable model problems, the first two being one-dimensional Stefan problems, the third a free droplet evaporation problem. In addition, a two-dimensional film boiling problem is considered. Overall, the comparison between the CFD and the (semi)-analytical models shows good agreement. Deviations exist where convective heat transfer due to spurious currents is no longer negligible compared to heat conduction. With regard to the film boiling problem, a similar evaporation pattern as recently identified using a level-set method is found. A major advantage of the developed evaporation model is that it does not refer to intrinsic details of the interface-capturing scheme, but relies on continuum-field quantities that can be computed by virtually any CFD approach.
KW - Droplet evaporation
KW - Evaporation model
KW - Film boiling
KW - Interfacial flow
KW - Stefan problem
KW - Volume-of-fluid method
UR - http://www.scopus.com/inward/record.url?scp=42649137533&partnerID=8YFLogxK
U2 - 10.1016/j.jcp.2008.02.020
DO - 10.1016/j.jcp.2008.02.020
M3 - Article
AN - SCOPUS:42649137533
VL - 227
SP - 5871
EP - 5895
JO - Journal of computational physics
JF - Journal of computational physics
SN - 0021-9991
IS - 11
ER -