A two-dimensional complicated porous media model for an active magnetic regenerator of room temperature magnetic refrigeration was established. In the model
the molecular-field theory was adopted to calculate the temperature and magnetic entropy of magnetic material in magnetization(demagnetization)process and the influence of non-Darcy effect
water stored
thermal dispersion effect
heat flux boundary effect and variable fluid physical properties on numerical results was considered. The finite difference method was used to discretize and solve the two-phase energy equations. The present model was verified by experimental results. The numerical results show that the temperature change of Gd at its Curie temperature was 1.85 K under a magnetic field of 2.18 T; distinct temperature grades and overlapping phenomenon of infinitesimal element cycles existed in the regenerator; heat flux boundary effect reduced the refrigeration performance of the regenerator
and fluid physical properties influenced the refrigeration performance of the regenerator greatly at large fluid flux; the regenerator obtained a maximum refrigeration capacity of 201.8 W with a corresponding coefficient of performance of 4.79.
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references
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