Cableizer
Log in

Radiation heat transfer, surface to air

Radiation heat transfer from outer surface to ambient air.

Symbol
$W_{rad,sa}$
Unit
W/m
Formulae
$\sigma \pi D_o K_r \left(\left(\theta_e+\theta_{abs}\right)^4-\left(\theta_{film}+\theta_{abs}\right)^4\right)$surface to air, by Stefan–Boltzmann law
$\pi D_o h_{rad,sa} \left(\theta_e-\theta_{film}\right)$surface to air, using heat transfer coefficient
Related
$D_o$
Outer diameter [m]
$h_{rad,sa}$
Radiation heat transfer coefficient, surface to air [W/(K.m$^2$)]
$K_r$
Radiation shape factor
$\pi$
Archimedes' constant $\pi$
$\sigma$
Stefan Boltzmann constant [W/m$^2$K$^4$]
$\theta_{abs}$
Absolute temperature [K]
$\theta_e$
External temperature of the object [°C]
$\theta_{film}$
Film temperature [°C]
Used in
$T_{4iii}$
Thermal resistance to ambient [K.m/W]
$T_{rad,sa}$
Radiation thermal resistance, surface to air [K.m/W]