Cableizer
Log in

Nusselt number, object to gas

Symbol
$\mathrm{Nu}_{og}$
Formulae
$c_{Nu,r} \left(\mathrm{Gr}_{og} \mathrm{Pr}_{gas}\right)^{n_{Nu,r}}$Riser closed at both ends (Hartlein & Black)
$0.986{\mathrm{Ra}_{int}}^{0.177}$Riser open at both ends, 133 ≤ $Ra$ ≤ 7000 (Hartlein & Black IIa)
$c_{Nu,r} \left(\mathrm{Gr}_{og} \mathrm{Pr}_{gas}\right)^{n_{Nu,r}}$Riser open at both ends, $Ra$ > 7000 (Hartlein & Black IIb)
$c_{Nu,r} \left(\mathrm{Gr}_{og} \mathrm{Pr}_{gas}\right)^{n_{Nu,r}}$Riser open at top and closed at bottom (Hartlein & Black)
$0.797\left(\mathrm{Gr}_{og} \mathrm{Pr}_{gas}\right)^{0.077} \left(\frac{L_d}{\delta_d}\right)^{-0.052} \left(\frac{D_{di}}{D_o}\right)^{0.505}$Riser closed at both ends, $Ra < 363 \cdot K^{0.25}G^{0.76}$ (Anders)
$0.188\left(\mathrm{Gr}_{og} \mathrm{Pr}_{gas}\right)^{0.322} \left(\frac{L_d}{\delta_d}\right)^{-0.238} \left(\frac{D_{di}}{D_o}\right)^{0.442}$Riser closed at both ends, $363 \cdot K^{0.25}G^{0.76} < Ra < 2.3 \cdot 10^6$ (Anders)
$0.1103\mathrm{Gr}_{og} \mathrm{Pr}_{gas}$Riser open at both ends, $Gr \cdot Pr < 10$ (Anders)
$0.62\left(\mathrm{Gr}_{og} \mathrm{Pr}_{gas}\right)^{0.25}$Riser open at both ends, otherwise (Anders)
$c_{Nu,r} \left(\mathrm{Gr}_{og} \mathrm{Pr}_{gas}\right)^{n_{Nu,r}}$Riser open at top and closed at bottom (Anders)
Related
$c_{Nu,r}$
Factor c
$D_{di}$
Inner diameter of duct [m]
$D_o$
Outer diameter [m]
$\delta_d$
Distance between cable and duct [m]
$\mathrm{Gr}_{og}$
Grashof number, object to gas
$L_d$
Length of duct [m]
$n_{Nu,r}$
Factor n
$\mathrm{Pr}_{gas}$
Prandtl number for gas
$\mathrm{Ra}_{int}$
Rayleigh number inside riser
Used in
$h_{conv,og}$
Convection heat transfer coefficient, object to gas [W/(K.m$^2$)]