Cableizer ®

Thermal resistance jacket

Symbol
$T_{3}$
Unit
K.m/W
Formulas
$\frac{\rho_{j}}{2\pi} \ln\left(\frac{D_{j}}{D_{j}-2t_{3}}\right)$general case
$1.6T_{3}$single-core cables, part-metallic sheathed/metallic sheathed, trefoil
$T_{scs}+T_{dsh}+T_{ab}+T_{j}+T_{jj}$CIGRE TB 880 Guidance Point 15, cables without armour/sheath, with screen
$T_{ab}+T_{j}+T_{jj}$CIGRE TB 880 Guidance Point 15, cables without armour, with sheath5
$T_{j}+T_{jj}$CIGRE TB 880 Guidance Point 15, cables otherwise
Related
$D_{j}$
Diameter over jacket [mm]
$\pi$
Archimedes' constant $\pi$
$\rho_{j}$
Thermal resistivity jacket material [K.m/W]
$t_{3}$
Thickness armour—surface [mm]
$T_{ab}$
Thermal resistance armour bedding [K.m/W]
$T_{dsh}$
Thermal resistance corrugation filling [K.m/W]
$T_{j}$
Thermal resistance jacket [K.m/W]
$T_{jj}$
Thermal resistance additional layer [K.m/W]
$T_{scs}$
Thermal resistance screen serving [K.m/W]
Used in
$\delta \theta_{c}$
Ohmic steady-state temperature rise [K]
$I_{c}$
Conductor current [A]
$Q_{B,ab}$
Thermal capacitance B transient thermal circuit, armour bedding [J/(m.K)]
$Q_{B,f}$
Thermal capacitance B transient thermal circuit, filler [J/(m.K)]
$Q_{B,j}$
Thermal capacitance B transient thermal circuit, jacket [J/(m.K)]
$T_{B}$
Thermal resistance B transient thermal circuit [K.m/W]
$T_{d}$
Internal thermal resistance for dielectric losses [K.m/W]
$T_{eq}$
Thermal resistance, equivalent [K.m/W]
$T_{int}$
Internal thermal resistance for current losses [K.m/W]
$T_{r}$
Thermal resistance, total [K.m/W]
$T_{tot}$
Thermal resistance, transient [K.m/W]
$\theta_{c,z}$
Temperature conductor z [°C]
$\theta_{e}$
External temperature object [°C]
$U_{wall}$
OHTC pipe wall [W/(K.m$^2$)]