Electric Conduction: solved equations
Introduction
In an Electri c C onduction application the equations used for computation are:
- the corresponding Maxwell's equations for an electrical system, and
- the constitutive equation that characteriz es the conducting materials
The conditions of computation of an Electric Conduction application are the following:
- the computation concerns only the electric field intensity E; the fields D, B and H are not computed. The equations of the electric fields E, D and of the magnetic fields B, H are decoupled.
- the electric field is time independent (steady state): dE/dt =0
Equations and conditions
In the previously defined conditions of computation, the equations are summarized as follows:
|
⇒ |
|
E: electric field (in V/m) V: electric potential (in V) J: current density (in A/m 2 ) |
|
|
⇒ |  |
σ : conductivity (in S) | |
Reminder about the differential operators:
The curl divergence of a field is always null: div [curl (Field)] = 0.
Solved equation
The second order equation solved by the finite elements method in Flux in case of an Electric Conduction application is the following:
where:
- σ is the tensor of the conductivity of the medium (in S)
- V is the electric potential (in V)
State variable
The state variable in the Electric Conduction application is the electric potential V (written Ve in Flux 3D).
The uniqueness condition of the scalar field of the electric potential V requires that the value of this potential be assigned to at least one point of the computation domain.