Numerical simulation of the active magnetic regenerator

A time-dependent one-dimensional model of the active magnetic regenerator (AMR) that takes into account most of the physical and practical design problems for the AMR is developed as a highly nonlinear system of partial differential equations. The adequateness of the model is tested in the case where there is no magnetization or demagnetization, which is the so-called passive regenerator (PR), through numerical experiments and comparison with experimental results. Highly dependable approximation functions for the physical properties of the heat transfer fluid (water) and the heat capacity of the magnetic material (gadolinium) are obtained by using the least squares curve and surface fitting techniques. The technique of calculation of values of the thermo-magnetic function of the magnetic material through the values of the adiabatic temperature change of the material is worked out and an approximation surface for the adiabatic temperature change of the material is obtained. The numerical scheme for the computer simulations of the active magnetic regenerator is developed and its performance analyzed for stability and convergence.