Modeling of Transient Heat Transfer in Temperature Fixed Points: Indium Cell Design

Laboratoire national de métrologie et d’essais has recently constructed a new device to realize the indium fixed point adiabatically. In parallel, a numerical heat transfer model has been developed as an aid to understanding its thermal behavior. This transient axially symmetric two-dimensional (2D) model simulates the melting process using the apparent specific heat method; the effects of mixing and convection within the liquid phase of indium are not taken into account. The thermal parameters, the nonuniformity of the furnace, and the thermal control of the surroundings were assessed with the aim of reducing parasitic heat exchanges. The results of the modeling are in good agreement with the measurements and clarify the parasitic heat flux observed during the phase transition. This article describes the model and the first results obtained. The model is a helpful tool in evaluating future technical improvements of the enclosure used to realize the indium fixed point.