Combined Eulerian–Eulerian Multiphase Frost model and solidification and melting model to predict the cooling performance of subcooled eutectic plates

Abstract

To limit the environmental footprint of refrigeration, transport of frozen goods based on natural fluids and phase change materials (PCMs) may be a promising solution. However, frost formation on the surface of the PCM encasing might limit the heat exchange and overall efficiency of the frozen food transport. The present work reports the numerical modeling of the heat and mass transfer for a flat plate cooled by a melting PCM located inside an air channel on which frost develops. Eulerian–Eulerian multiphase model is employed in conjunction with the $k-\omega$ Shear Stress Transport (SST) model to simulate the frost formation on the surface of the PCM encasing. It is first favorably validated against a number of published experimental and numerical data. Then the melting model based on the so-called enthalpy-porosity approach is applied as a User-Defined Function (UDF). The solidification and melting model as an applied UDF has been also validated against experimental and numerical works for lauric acid as PCM. The combined Eulerian–Eulerian Multiphase frost model and the solidification and melting model show that the flow must be below the PCM rather than above, in order to promote the formation of the Rayleigh–Bénard convection cells within the PCM when the melting process begins. Otherwise, the heat released from the frost formation on the surface of the PCM encasing and the heat transferred from the high temperature humid air are not effectively diffused within the PCM and results in localized high-temperature zones within the PCM.