Experimental study of frost formation on cold surfaces with various fin layouts

Frost formation significantly increases the heat transfer resistance on heat exchangers and the flow resistance in the channels, so there is great interest in understanding the frost formation mechanism on a finned surface. Frost formation was experimentally investigated on several complex finned surfaces, including a single aligned fin, a single angled fin, a single row of aligned fins, a single column of angled fins and five columns of angled fins. The experimental conditions were −2 to 7 °C air temperatures, 80% air relative humidity, 0.3 to 1.1 m/s air velocities and −19 to −10 °C cold surface temperatures. The results show for all the investigated pieces, the frost weight per unit area in the fin region is greater than in the base region at a lower temperature, more frost was observed near the edges than in the middle of the fins, the fins angled with the airflow had more frost than the aligned fins and the multiple lines and columns of fins had the most frost on the frontal fins. A dimensionless empirical correlation for the frost weight in the fin area was developed with 85% of predictions within ±30% of the experimental data.