Radiation heat transfer, duct to air

Radiation heat transfer from duct outer surface to ambient air.

Symbol
$W_{rad_{da}}$
Unit
W/m
Formulae
$D_{do} \epsilon_{do} \pi \sigma \left(- \left(\theta_{air} + 273\right)^{4} + \left(\theta_{de} + 273\right)^{4}\right)$
Related
$D_{do}$
$\sigma$
$\theta_{air}$
Used in
$T_{4iii}$