The magnetic refrigeration is an innovative technology of production of cold, which can replace the refrigerants classic compression-relaxation technique. Its principle is based on the magnetocaloric effect which leads to the cooling or the heating of certain materials under the effect of a magnetic field. This thesis work took place within the framework of a project named " CARNOT Energies of future", and turns to the magnetothermal and fluidic study of refrigeration systems. For that purpose, a digital tool was developed using the FLUENT software to describe the thermal behavior of various regenerators, heart of the MR systems. In parallel, two magnetic refrigeration systems were developed and improved, each of them bringing interesting performances. These results allowed to understand and to define the most influential factors on their performances, so as to deduct their optimal operating conditions.
