Cableizer ®

Coefficient K in air

Symbol
$K_{A}$
Formulas
$\frac{\pi D_{o} h_{bs}}{1+\lambda_{1}+\lambda_{2}+\lambda_{3}} T_{int}$cables
$\frac{\pi D_{o} h_{bs}}{1+\lambda_{1}} T_{int}$PAC/GIL
$\pi D_{o} h_{bs} T_{hs}$heat sources
$\pi D_{o} h_{bs} T_{fo}$FOC
Related
$D_{o}$
Outer diameter [m]
$h_{bs}$
Heat dissipation coefficient for black surfaces in free air [W/m$^2$/K$^{5/4}$]
$\lambda_{1}$
Loss factor shield (screen/sheath)
$\lambda_{2}$
Loss factor armour
$\lambda_{3}$
Loss factor steel pipe pipe-type cable
$\pi$
Archimedes' constant $\pi$
$T_{fo}$
Thermal resistance FOC [K.m/W]
$T_{hs}$
Thermal resistance heat source [K.m/W]
$T_{int}$
Internal thermal resistance for current losses [K.m/W]
Used in
$\Delta \theta_{s}$
Temperature difference surface—ambient [K]