Characteristics of frost formation on two-dimensional fins and its empirical correlations

Frosting experiments were conducted to analyze the characteristics of frost formation on a two-dimensional fin with a non-uniform temperature distribution. The local temperature distribution and the characteristics of frosting formation were analyzed parallel and normal to the airflow for various fin thickness and frosting parameters (air temperature, air velocity, absolute humidity, and fin base temperature). It was found that the frost behavior on the fin was closely related to the fin conductivity. Correlations of local frost thickness and frost surface temperature are proposed as functions of the Reynolds number, Fourier number, humidity ratio, dimensionless temperature, dimensionless fin thickness, dimensionless fin thermal conductivity, and measurement position. When the correlations were compared with the measured local frost properties, the maximum error was 14% for frost thickness and the maximum difference in the frost surface temperature was 1.1 °C. Correlations of average frost properties are suggested based on these results.