7.6.20.15.11. From_Thermal_Expansion

Syntax

Volume Fraction Gas [{of} SpeciesName] = From_Thermal_Expansion ([Phi0 = phi0] | [Rhob0 = rhob0] | [Rhoc0 = rhoc0] | [Beta0 = beta0] | [Beta1 = beta1] | [T0 = t0])

Scope

Aria Material

Summary

Gas volume fraction from thermal expansion of the condensed phase

Description

This model calculates volume fraction of a porous material where the condensed phase has linear thermal expansion

$\phi = 1 - \frac{\rho}{\rho_c}$

The value is clipped to be between 1e-16 and 1, but generally for this model to be relevant the density ( $\rho$ ) should be less than the condensed density ( $\rho_c$ ). The condensed density is calculated from

$\rho_c = \rho_{c,0} \left( 1 - \beta \left( T - T_0 \right) \right)$

$\beta = \beta_0 + \beta_1 T$

If $\rho_{c,0}$ is not provided, it is calculated from

$\rho_{c,0} = \frac{\rho_{b,0}}{1 - \phi_0}$

Note

This model does not account for changes in gas volume fraction due to reactions that convert solids to gasses. It only includes thermal expansion.

Parameter	Value	Default
{of}	{of \| species \| subindex}	–
SpeciesName	string	–
phi0	real	-1
rhob0	real	-1
rhoc0	real	-1
beta0	real	0
beta1	real	0
t0	real	300