Convection heat transfer, gas to duct

Radiation heat transfer from gas in duct to inner wall of the duct used for riser/J-tube.

Symbol
$W_{conv_{gd}}$
Unit
W/m
Formulae
$D_{di} h_{conv_{gd}} \pi \left(- \theta_{di} + \theta_{gas}\right)$
Related
$D_{di}$
$\theta_{gas}$