Generalized_Nat_Conv

Syntax

Bc Bar_Flux For Porous_Enthalpy [{of} SpeciesName | {in} MaterialPhaseName | {ls} {a | b | c}] {on} Mesh Extent Name [Touching TouchingMeshExtent | Opposing OpposingMeshExtent] = Generalized_Nat_Conv [Using Data Specification Data Spec Name] [Bar = bar | Hcorr = hcorr | H = h | Bar_Block_Name = bar_block_name | Command_Block_Name = command_block_name | Power_Output = power_output | Flux_Output = flux_output | Multiplier = multiplier]

Summary

This boundary condition couples the 1D advective bar energy equation to the porous enthalpy equation.

Description

For a single temperature porous media problem, the flux applied to the advective bar equation is specified as

-\mathbf{q} \cdot \mathbf{\hat{n}} = -h\left(T_{bar} - T\right)

where h is the heat transfer coefficient, T_{bar} is the bar temperature and T is the temperature of the porous media surface. The heat transfer coefficient is specified through the optional parameters “hcorr” or “h”, where the former must name a heat transfer correlation coefficient block in the input deck and where the latter is a positive constant.

For multi-phase porous flows, the heat flux applied to the advective bar equation will be a weighted sum of the flux applied to each individual phase. For example, applying this flux to both phases in a two-phase porous media (solid and liquid) will result in the following bar flux

-\mathbf{q} \cdot \mathbf{\hat{n}} = -h \left(T_{bar} - T_{l}\right) f_{l} -h \left(T_{bar} - T_{s}\right) f_{s}

where the first term and second term are equal and opposite to the heat flux received by the liquid and solid phases, respectively. Here, f_{l} and f_{s} correspond to the bar flux contribution factors specified in the material block of each phase. If the bar flux contribution factor is not specified, a default weight of one will be used.

The required parameter “bar” must refer to an advective bar specified in the input deck.

The following options are present in most boundary conditions/sources. The meaning of each option is as follows:

Power_Output

If specified, the total (integrated) power of the given BC/Src is calculated and stored into the global variable name specified as the power_output argument.

Flux_Output

If specified, the average flux of the given BC/Src is calculated and stored into the global variable name specified as the flux_output argument.

Parameter

Value

Default

{of}

{of | species | subindex}

–

SpeciesName

string

–

{in}

{in | material_phase}

–

MaterialPhaseName

string

–

{ls}

{levelset_phase | ls}

–

{on}

{@ | at | for | in | on | over}

–

Mesh Extent Name

string

–

TouchingMeshExtent

string

–

OpposingMeshExtent

string

–

Data Spec Name

string

–

bar

“string”

–

hcorr

“string”

–

h

“string”

–

bar_block_name

“string”

–

command_block_name

“string”

–

power_output

“string”

–

flux_output

“string”

–

multiplier

real

1