applications

support

Coupl3: Temperature distribution in an electric wire

Calculate the temperature distribution in a long current carrying wire.

Problem Type:
Axisymmetric problem of electro-thermal coupling.

Geometry:

Given:
Wire diameter d = 0.75";
Resistance ρ = 9.35·10^-8 Ohm/m;
Electric current I = 1000 A;
Thermal conductivity λ = 13 Btu·ft/(h·ft²·°F) = 22.5 W/(K·m);
Convection coefficient α = 5 Btu/(h·ft²°F) = 28.4 W/(K·m²);
Ambient temperature T_o = 70°F = 21.1°C.

Problem:
Calculate the temperature distribution in the wire.

Solution:
We arbitrary chose a 1-foot (12") piece of wire to be represented by the model.
Material electric conductivity is σ = 1/ρ = 1/9.35e-8 = 10.7·10⁶ S·m.
For the conduction problem we specify normal current density at one end j = I /(πd²/4) [A/m²] and zero voltage at another end of the wire, and a zero current condition at its surface.
For heat transfer problem we specify zero thermal flux conditions at the sections of the wire and a convection boundary condition at its surface.

Results:
Temperature distribution in an electric wire:

Center line temperature

Surface temperature

Theory

419.9 F (215.5 °C)

417.9 F (214.4 °C)

QuickField

215.5 °C

214.3 °C

* Reference: W. Rohsenow and H. Y. Choi, "Heat, Mass, and Momentum Transfer", Prentice-Hall, N.J., 1963.