7.6.18.12.20. Porous_Emt_Mixture

Syntax

Thermal Conductivity [{of} SpeciesName] = Porous_Emt_Mixture [Liquid_Phase_Name = Liquid_Phase_Name | Gas_Phase_Name = Gas_Phase_Name | Initial_Saturation = Initial_Saturation | Melt_Dt = melt_DT]

Scope

Aria Material

Summary

Thermal conductivity computed effective medium theory model

Description

The effective medium theory model defines a function for averaging the properties of two phases:

\begin{split} \text{EMT}(k_1, k_2, f) &= \frac{1}{4}\left[ x + \sqrt{x^2 + 8 k_1 k_2} \right] \\ x &= (3f-1)k_2 + (3(1-f)-1)k_1 \end{split}

For two-phase porous media problems (solid and liquid phases only):

k = \text{EMT}(k_s, k_l, \phi)

where \phi is the porosity, k_s the solid phase conductivity, and k_l the liquid phase conductivity.

For three-phase porous media problems (solid, liquid, gas):

k = \text{EMT}(k_s, \text{EMT}(k_g, k_l, S_l), \phi)

where S_l is the liquid saturation and k_g the gas phase conductivity.

Note that the optional “liquid_phase_name” and “gas_phase_name” parameters can be used to specify alternate material phase’s supported by Aria for the respective parameters.

The “initial_saturation” and “melt_dt” parameters are for certain thermal battery models, and should be omitted for general use.

Parameter

Value

Default

{of}

{of | species | subindex}

–

SpeciesName

string

–

Liquid_Phase_Name

“string”

–

Gas_Phase_Name

“string”

–

Initial_Saturation

real

1

melt_DT

real

5