Interface Behavior in Functionally Graded Ceramics for the Magnetic Refrigeration: Numerical Modeling

The active magnetic regenerator refrigerator is currently the most common magnetic refrigeration device for near room temperature applications, and it is driven by the magnetocaloric effect in the regenerator material. In order to make this efficient, a graded configuration of the magnetocaloric material is needed. Tape casting is a common process in producing functional ceramics, and it has recently been established for producing side-by-side (SBS) functionally graded ceramics (FGCs). The main goal of the present work is to study the multiple material flows in SBS tape casting and analyze the influence of the different material properties, i.e. the density and the viscosity, on the interface between the flows, since this is highly important for the efficiency of the device. The Newtonian flow behavior with relatively high viscosity is assumed for each fluid and used in the simulation with a commercial CFD code (ANSYS FLUENT). The results show that the density change does not affect the interface between the adjacent fluids. The viscosity of the fluids plays the most important role in the behavior of the interface. Moreover, increasing the viscosity
difference of the adjacent flows, Δμ , leads to increasing the diffusive region between the two fluids.