Lenz Law to the Contactless Heating

Any electrically conductive material immersed in a variable magnetic field is the seat of electrical or induced currents.

Lenz law – the basic principles of induction heating

This law is the basis of many applications. Among these applications is induction heating whose the principle is the flowing of the current through the coils which generates an alternating magnetic field. This field induces current in the electric conductor (eddy current). These eddy currents are fluent against electrical resistivity of the metal and generate heat without any direct contact between the work-piece and the inductor.
Induction heating causes successively the following three physical phenomena:

  • Transferring energy electromagnetically
  • Transformation of this energy into heat (Joule effect)
  • Diffusion of the heat by thermal conduction

Several methods exist to model this process:

  • Analytical method: based on solving mathematical equations and simplifying assumptions
  • Finite element method: based on the determination of the vector potential (scalar potential). The advantages of using the FEM method to model the process:
    Analysis: Flux makes visible what once was hidden to all but a few experts
    Design: to reduce time to market. Virtual prototyping allows reducing the size and the number of costly mock-ups
    Optimization: improves the efficiency of your devices
    Teaching: things are easier to understand when you can see them

Among of tools based on the finite element method we find Flux (2D and 3D) developed by CEDRAT. The advantage of Flux in this application offers an easy way to take into account of the fast decrease of the temperature corresponding to the forced cooling (shower).

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