The magnetic filtration of small paramagnetic particles consists in making a high static magnetic field, which is created by a supraconductor inductor and magnetizes many iron wires that are embedded in a fluid flow. The magnetic field, in the vicinity of the iron wires, comports high gradients that trap the paramagnetic particles carried by the fluid. The modelling of the magnetic filtration is very complex1 because the fluid flow must be computed accurately at both the scale of the iron wires and particles to take into account the many interactions. Moreover the interaction between the fluid and particles is difficult to state. The magnetic analysis is also complex even if we only treat the 2D problem, which is issued from the assumption that the iron wires are infinite cylinders. In fact the magnetic field can be computed by using its scalar potential as state variable, and the magnetic force is proportional to a double derivative of this potential whose values are difficult to obtain numerically2. The aim of this paper is to show the results that we have obtained by using a re-interpolation of the double derivative of the potential on a triangular mesh that is generated from the finite element mesh from which we compute the potential.
