Cableizer ®

Thermal resistance of medium in the air-filled pipe with objects

Thermal resistance between ducts and air-filled pipe based on IEC 60287-2-1 for cables in ducts.

Symbol
$T_{4pi}$
Unit
K.m/W
Formulas
$\frac{U_{p}}{1+0.1\left(V_{p}+Y_{p} \theta_{at}\right) D_{eq}}$
Related
$D_{eq}$
Equivalent diameter of a group of round objects [mm]
$\theta_{at}$
Air temperature with load [°C]
$U_{p}$
Constant U for air-filled pipe with objects
$V_{p}$
Constant V for air-filled pipe with objects
$Y_{p}$
Constant Y for air-filled pipe with objects
Used in
$\Delta \theta_{air}$
Temperature increase air [K]
$T_{4db}$
Thermal resistance backfill correction [K.m/W]
$T_{4ss}$
Thermal resistance steady-state [K.m/W]
$\theta_{di}$
Temperature duct inner surface [°C]