Cylinder Heated by Induction
In this worksheet we consider a long metal cylinder that has a magnetic field applied parallel to the axis and a constraint on the current density at a particular depth. We demonstrate how the temperature depends on time and depth from the surface in a very long cylinder. This is calculated using the current density, the power density and the partial differential equation of heat conduction. In induction, the heating is caused by eddy currents, which themselves give rise to alternating magnetic fields. Because of the skin effect and depending on the frequency of the magnetic field, the highest current density exists directly under the surface of the heated work piece. It decreases rapidly with increasing depth. We calculate the effective magnetic field intensity on the surface required to reach a given temperature in a given time.
