A Coupled Heat and Mass Transfer Model of Pure Metal Freezing Using Comsol Multiphysics
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Finite element simulation is a well established technique for simulating melting and freezing behaviour of metals. However, because most methods rely on simulating the phase transition using an empirical method which models the latent heat with a peak in the temperature dependence of the heat capacity, the temperature range of melting/freezing of the material is necessarily large.
For pure metal fixed points containing impurities at the level of less than one part per million, the melting range is of the order of 0.1 mK and alternative means of modelling the phase transition are required.
In this study, Comsol Multiphysics is employed to simulate the freezing of a zinc fixed point for standard platinum resistance thermometer (SPRT) calibrations. The liquid-solid interface is represented by the boundary of an adaptive mesh whose geometry adjusts itself to accommodate the propagating liquid-solid interface.