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$^2$)]