Abstract:

Frosting processes on hydrophilic surface,bare aluminum surface and hydrophobic surface were experimentally investigated. The condensate water droplets freezing,frost layer growth,defrosting and water drainage on different surfaces were studied. The experimental results show that the condensate water droplet shape is spherical segment on hydrophobic surface while irregular shape on hydrophilic surface and bare aluminum surface. The condensate water droplets freezing process is delayed and the height of frost layer grows slower on hydrophobic surface. Frosting process on different surfaces are tend to be the same,when the humid air temperature and cooling surface temperature are low enough. The frost distribution is even on hydrophilic surface and bare aluminum surface compared with the hydrophobic surface; the hydrophilic surface has less residual meltwater,thus frost mass is lower on hydrophilic surface in frosting/defrosting circulation.

Key words: phase change, surface, heat transfer, frosting, frost morphology, defrosting and drainage

摘要：

对亲水表面、裸铝表面和疏水表面上结霜和融霜排液过程进行实验研究，分析了表面特性对冷凝水珠冻结、霜层生长和融霜排液的影响。结果表明：疏水表面上冷凝水珠呈规则球缺状、冻结较晚，而亲水表面和裸铝表面上冷凝水珠形状不规则；相比于亲水表面和裸铝表面上平整霜层，疏水表面上霜层不平整，有凹穴和凸起；疏水表面上霜层平均厚度增长较亲水表面和裸铝表面缓慢；在湿空气温度和冷面温度较低的情况下，表面特性对霜层生长的影响减弱；亲水表面具有较好的排液效果，其循环再结霜量最小。

关键词: 相变, 表面, 传热, 结霜, 霜层形貌, 融霜排液