Description🔗

The compressible::alphatWallBoilingWallFunction is a boundary condition that provides A thermal wall function for simulation of boiling wall.

This alpha wall function can handle the following regimes:

• single phase
• sub-cooled nucleate wall boiling
• transitional boiling
• film boiling

The wall function uses a partition method to transfer heat either to the liquid or vapor phase. At the moment, this function works in a wall temperature fixed mode, i.e. there is no consideration for the sudden change of heat transfer coefficient (htc) after reaching TDBN (deviation from nucleate boiling temperature).

For the single phase non-boiling regime the standard JayatillekeWallFunction is used.

For the sub-cool nucleate boiling regime the following runtime selectable submodels are used:

• nucleation site density
• bubble departure frequency
• bubble departure diameter

Implements a version of the well-known RPI wall boiling model (Kurul & Podowski, 1991). The model implementation is similar to the model described by Peltola & Pättikangas (2012) but has been extended with the wall heat flux partitioning models.

Alternatively a correlation can be used instead of the RPI wall boiling model. If the keyword nucleatingModel a model is provided the BC uses it instead of the RPI model.

The transition boiling regime flux (TBF) is modelled following a temperature based linear interpolation between the critical heat flux (CHF) and the minimum heat flux (MHF) in such a way that when the wall temperature is between the range of TDBN and the Leidenfrost temperature (TLeiden) a linear interpolation is used between CHF and MHF.

Thus, the following models are required:

• LeidenfrostModel
• CHFModel
• CHFSubCoolModel
• MHFModel
• TDNBModel
• filmBoilingModel

The linear interpolation is as follows:

$TBF = CHF*\phi + (1 - \phi)*MHF$

with:

$\phi = w_p*(T_w - T_{DNB})/(T_{Leiden} - T_{DNB})$

where:

Property Description
$$w_p$$ Model constant
$$T_w$$ Wall temperature [K]

References

Srinivasan, V., Moon, K. M., Greif, D.,
Wang, D. M., & Kim, M. H. (2010).
Numerical simulation of immersion quenching
process of an engine cylinder head.
Applied Mathematical Modelling, 34(8), 2111-2128.
DOI:10.1016/j.apm.2009.10.023

Kurul, N., & Podowski, M. Z. (1991).
On the modeling of multidimensional effects in boiling channels.
Proceedings of the 27th National Heat Transfer Conference.
Minneapolis, Minn, USA, July 28-31, 1991.
ISBN: 0-89448-162-1, pp. 30-40

Peltola, J., & Pättikangas, T. (2012).
Development and validation of a boiling model
for OpenFOAM multiphase solver.
Proceedings of the CFD4NRS-4. p. 59.
Daejeon, Democratic People's Republic of Korea, September 10-12, 2012.


Usage🔗

The condition requires entries in both the boundary and field files.

Boundary file🔗

<patchName>
{
type            patch;
...
}


Field file🔗

<patchName>
{
type            compressible::alphatWallBoilingWallFunction;
phaseType       <word>;
otherPhase      <word>;
relax           <Function1<scalar>>;

partitioningModel
{
type        Lavieville;
alphaCrit   0.2;
}

// Conditional entries

// Option-1: phaseType=vapor

// Optional entries
LeidenfrostModel
{
type        Spiegler;
Tcrit       647;
}

filmBoilingModel
{
type        Bromley;
}

// Option-2: phaseType=liquid
nucleationSiteModel
{
type        LemmertChawla;
}

departureDiamModel
{
type        TolubinskiKostanchuk;
}

departureFreqModel
{
type        Cole;
}

// Optional entries
LeidenfrostModel
{
type        Spiegler;
Tcrit       647;
}

CHFModel
{
type        Zuber;
}

CHFSubCoolModel
{
type        HuaXu;
Kburn       0.5;
}

MHFModel
{
type        Jeschar;
Kmhf        1;
}

TDNBModel
{
type        Schroeder;
}

filmBoilingModel
{
type        Bromley;
}

dDep    <scalarField>;
K       <scalar>;
wp      <scalar>;
qQuenching <scalarField>;

// Optional entries
alphatConv      <scalarField>;

//Inherited entries
...
}


where:

Property Description Type Required Default
type Type name: compressible::alphatWallBoilingWallFunction word yes -
phaseType Name of phase type word yes -
otherPhase Name of other phase word yes -
relax Relaxation factor for dmdt Function1<scalar> yes -
alphatConv Convective turbulent thermal diffusivity scalarField no 0
partitioningModel Run-time selected heat flux partitioning model dict yes -

Options for the phaseType and otherPhase entries:

Property Description
vapor Vapor phase
liquid Liquid phase

when phaseType=liquid:

Property Description Type Required Default
nucleationSiteModel Nucleation site density model dict yes -
departureDiamModel Bubble departure diameter model dict yes -
departureFreqModel Bubble departure frequency model dict yes -
LeidenfrostModel Leidenfrost temperature model dict no -
CHFModel Critical heat flux model dict no -
CHFSubCoolModel CHF sub-cool model dict no -
MHFModel Minium heat flux model dict no -
TDNBModel Departure from nulceate boiling model dict no -
filmBoilingModel Film boiling model dict no -
K Model constant for area of bubbles scalar no 4.0
wp Wetting parameter for transient boiling scalar no 1.0

The inherited entries are elaborated in:

• alphatPhaseChangeJayatillekeWallFunctionFvPatchScalarField.H

Further information🔗

Tutorial:

Source code:

API:

History:

• Introduced in version v2012