# Convection heat transfer coefficient, gas to duct

Symbol
$h_{conv,gd}$
Unit
W/(K.m$^2$)
Formulae
 $\frac{h_{conv,og} D_o}{D_{di}}$ Riser closed at both ends (Anders) $\frac{\left(\frac{0.6D_o}{D_{di}}+0.4\right) k_{gas} \mathrm{Nu}_{gd}}{\delta_d}$ Riser open at both ends (Anders) $\frac{k_{gas} \mathrm{Nu}_{gd}}{D_{di}}$ Riser open at top and closed at bottom (Anders/Hartlein & Black) $h_{conv,og}$ Riser closed at both ends (Hartlein & Black) $h_{conv,og}$ Riser open at both ends (Hartlein & Black IIa) $\frac{k_{gas} \mathrm{Nu}_{gd}}{\delta_d}$ Riser open at both ends, 0.1 ≤ $Ra$ < 10^5 (Hartlein & Black IIb)
Related
$D_{di}$
$D_o$
$\delta_d$
$k_{gas}$
$\mathrm{Nu}_{gd}$
Used in
$W_{conv,gd}$