About the project
Frost is a porous medium formed by ice crystals and moist air. Its buildup in evaporators not only lowers the heat transfer rate due to the low thermal conductivity, but also restricts the air passage area, causing a significant loss of load which implies either increasing pumping power or reducing the flow Operation. In both cases, such effects decrease the cooling capacity of the evaporator and consequently cause the energy to be expended to ensure the same refrigerant effect, if compared to a refrigerator without frost formation, is larger, since the compressor needs Act longer.
The computational models developed in POLO to analyze the thermal-hydraulic performance of evaporators in the presence of frost depend on empirical information for both the density and the thermal conductivity of the porous medium, which are restricted to the specific operating conditions in which they were obtained. The present research line is focused not only on the experimental determination of the thermophysical properties of frost but also on the development of physical base correlations, which are applicable to a wide range of operation. Fundamental models for the physical processes that govern the growth and densification of a frost layer are also developed from the diffusion-limited aggregation (DLA) technique.