Cableizer

Grashof number riser/tray—air

Symbol
$\mathrm{Gr}_{ext}$
Formulas
$\frac{g \beta_{gas} {L_{d}}^3}{{\nu_{gas}}^2} \left(\theta_{de}-\theta_{air}\right)$riser
$\frac{g \beta_{gas} {L_{char}}^3}{{\nu_{gas}}^2} \left(\theta_{to}-\theta_{air}\right)$tray
Related
$\beta_{gas}$
Volumetric thermal expansion coefficient gas [1/K]
$g$
Standard acceleration of gravity [m/s$^2$]
$L_{char}$
Characteristic length earth surface
$L_{d}$
Length duct [m]
$\nu_{gas}$
Kinematic viscosity gas [m$^2$/s]
$\theta_{air}$
Ambient air temperature [°C]
$\theta_{de}$
Temperature duct outer surface [°C]
$\theta_{to}$
Temperature wall (outer) [°C]
Used in
$\mathrm{Nu}_{ext}$
Nusselt number riser—air
$\mathrm{Ra}_{ext}$
Rayleigh number riser/tray—air