PARAM, SIGMA

Bulk Data Entry The Stefan-Boltzmann constant used in Radiation Heat Transfer calculations.

Parameter Values Description
SIGMA < Real >

Default = 0.0

$q=\sigma \cdot \text{FAMB}\cdot \left({\epsilon }_{e}{\left({T}_{e}+{T}_{abs}\right)}^{4}-{\alpha }_{e}{\left({T}_{amb}+{T}_{abs}\right)}^{4}\right)$
Where,
$\sigma$
Stefan-Boltzmann constant (PARAM,SIGMA).
$q$
$\text{FAMB}$
Radiation view factor between the element face and the ambient space node. This is defined on the RADBC entry.
${\epsilon }_{e}$
Surface emissivity of the surface element, defined by EMIS1 on the RADM entry.
${\alpha }_{e}$
Surface absorptivity of the surface element, defined by ABSORP field on the RADM entry.
${T}_{e}$
Surface temperature.
${T}_{abs}$
Absolute temperature scale defined via PARAM, TABS.
${T}_{amb}$
Ambient temperature.

The temperatures and SIGMA should be defined in consistent units. Based on the input temperature units, the absolute temperature scale, ${T}_{abs}$ , can be defined via PARAM,TABS. The value of SIGMA in SI units is 5.67E-8 Watts/m2K4.