Cableizer
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Rayleigh number inside riser

Symbol
$\mathrm{Ra}_{int}$
Formulae
$\mathrm{Gr}_{og} \mathrm{Pr}_{gas}$object to gas
$\mathrm{Gr}_{gd} \mathrm{Pr}_{gas}$gas to duct
$\mathrm{Gr}_{int} \mathrm{Pr}_{gas}$object to duct
$\frac{g \mathrm{Pr}_{gas} \beta_{gas} \left(\theta_e-\theta_{di}\right) {\delta_d}^3}{{\nu_{gas}}^2}$Chippendale, IEC 60287
Related
$\beta_{gas}$
Volumetric thermal expansion coefficient for gas [1/K]
$\delta_d$
Distance between cable and duct [m]
$g$
Standard acceleration of gravity [m/s$^2$]
$\mathrm{Gr}_{gd}$
Grashof number, gas to duct
$\mathrm{Gr}_{og}$
Grashof number, object to gas
$\nu_{gas}$
Kinematic viscosity for gas [m$^2$/s]
$\mathrm{Pr}_{gas}$
Prandtl number for gas
$\theta_{di}$
Temperature of duct inner wall [°C]
$\theta_e$
External temperature of the object [°C]
Used in
$h_{conv,int}$
Convection heat transfer coefficient, object to duct [W/(K.m$^2$)]
$\mathrm{Nu}_{int}$
Nusselt number, object to duct
$\mathrm{Nu}_{og}$
Nusselt number, object to gas