RADM

Bulk Data Entry Defines the radiation material properties of a surface element for heat transfer analysis.

Format

(1)	(2)	(3)	(4)	(5)	(6)	(7)	(8)	(9)	(10)
RADM	`RMID`	`ABSORP`	`EMIS1`

(1)	(2)	(3)	(4)	(5)	(6)	(7)	(8)	(9)	(10)
RADM	24	0.2	1.0

Field	Contents	SI Unit Example
`RMID`	Radiation material property entry identification number. No default (Integer > 0)
`ABSORP`	Surface absortivity. No default (0.0 ≤ Real ≤ 1.0)
`EMIS1`	Surface emissivity. No default (0.0 ≤ Real ≤ 1.0)

The RADM entry can be referenced by a CHBDYE Bulk Data Entry.
The Radiation Heat Flux is calculated as follows, between the surface element and the black-body space node.(1)
$q = σ \cdot FAMB \cdot (ε_{e} {(T_{e} + T_{a b s})}^{4} - α_{e} {(T_{a m b} + T_{a b s})}^{4})$ $q = σ \cdot FAMB \cdot (ε_{e} {(T_{e} + T_{a b s})}^{4} - α_{e} {(T_{a m b} + T_{a b s})}^{4})$

Where,

$q$ $q$

Radiation heat flux.

$σ$ $σ$

Stefan-Boltzmann constant defined via PARAM, SIGMA.

$FAMB$ $FAMB$

Radiation view factor between the element face and the ambient space node.

$ε_{e}$ $ε_{e}$

Surface emissivity of the surface element, defined by EMIS1 on the RADM entry.

$α_{e}$ $α_{e}$

Surface absorptivity of the surface element, defined by ABSORP field on the RADM entry.

$T_{e}$ $T_{e}$

Surface temperature.

$T_{a b s}$ $T_{a b s}$

Absolute temperature scale defined via PARAM, TABS.

$T_{a m b}$ $T_{a m b}$

Ambient temperature.
For a Heat Transfer Analysis via Radiation, PARAM,TABS can be used to define the absolute temperature scale, and PARAM,SIGMA is used to specify the Stefan-Boltzmann constant. Additionally, a RADBC entry can be used to define radiation boundary conditions.