IMPACT OF EFFECTIVE THERMAL CONDUCTIVITY ON A SINGLE PHASE AMR MODEL

摘要

A simplified AMR model can be created by assuming perfect heat transfer between the working fluid and refrigerant subsequently simplifying the two-phase regenerator into one-phase. In this approach, the impacts of imperfect convective heat transfer can be approximated by post calculating heat leak without impacting the AMR differential equations. This is found to work relatively well over a limited range of operating conditions. Another means of accounting for these losses is converting the convective component into an equivalent thermal conductivity so that it appears within the regenerator energy balance equations. Convective losses can then further influence the shape and magnitude of predicted span and cooling curves. The effects on the predicted AMR performance of combining conduction and convection into a singular effective thermal conductivity are examined. Accounting for convective losses within the energy balance equations is shown to better predict the temperature span of experimental results occurring above the Curie point.