Study of frost properties and frost melt water drainage on microgrooved brass surfaces in multiple frost/defrost/refrost cycles

摘要

At the end of a defrost, part of the frost melt water is retained on the surface, which freezes in the following frosting cycle. An experimental study is conducted on microgrooved and flat brass surfaces to examine the effects of the variation of the microgroove geometry and frost melt water retention on the cyclical frost growth and on frost properties. It is found that the dimensional variation of the microgroove texture affects these frost properties even in the refrost cycles. Density of the frost layer is increased by about 5-20% in the refrost cycles than in the 1st frost cycle for all the surfaces. The variation of frost properties becomes repeatable and periodic from the 3rd frost cycle. Incorporating microgrooves on a flat surface results in an increase in the frost thickness and a decrease in the frost density in all frosting cycles (by about 5-25%). The possible relationship of the obtained water drainage enhancement from the microgrooved surfaces with the variation of frost properties due to the change in groove dimensions is examined. Findings of this study can provide a more comprehensive idea of the possible effects of incorporating microgrooves on heat transfer surfaces operating under frosting/defrosting conditions.