| LU Xiang-you,PAN Yu-yang,XIE Yuan-lai.Frost Inhibition Characteristics of Superhydrophobic Aluminum Surface of Micro-Nano Composite Structure[J],49(3):106-111 |
| Frost Inhibition Characteristics of Superhydrophobic Aluminum Surface of Micro-Nano Composite Structure |
| Received:June 03, 2019 Revised:March 20, 2020 |
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| DOI：10.16490/j.cnki.issn.1001-3660.2020.03.013 |
| KeyWord:aluminum condensation heat transfer micro-nano structure frost crystal hydrophobic |
| Author | Institution |
| LU Xiang-you |
1.School of Environment and Energy Engineering, Anhui Jianzhu University, Hefei , China |
| PAN Yu-yang |
1.School of Environment and Energy Engineering, Anhui Jianzhu University, Hefei , China |
| XIE Yuan-lai |
2.Institute of Plasma Physics, Chinese Academy of Sciences, Hefei , China |
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| Abstract: |
| The paper aims to profoundly reveal the frost inhibition mechanism of the superhydrophobic surface. The surface of superhydrophobic aluminum with micro-nano composite structure was prepared by chemical etching. The frost formation process of the specimen was observed and the frost crystal evolution of the specimen was analyzed on the refrigerating experiment table. The cold surface temperature of the super hydrophobic aluminum sheet was set at –5 ℃, –10 ℃ and –15 ℃, respectively. The frost formation and frost inhibition mechanism were explained by comparing the frost crystal height and mass on the surface of ordinary aluminum sheet and superhydrophobic aluminum sheet in combination with phase change kinetics, classical nucleation theory, heat and mass transfer theory. It was found that the frost inhibition effect of superhydrophobic aluminum surface was different at different experimental stages and temperatures; but compared with the frost inhibition characteristics of ordinary aluminum surface, the superhydrophobic aluminum surface had a certain frost-inhibition effect, and the frost-formation process lagged behind. The frost height developed relatively slowly. After 10minutes’ of the experiment, the frost height on the superhydrophobic surface was only 35% of that of the ordinary surface. Because condensed-water beads formed Wenzel state on the cold surface, the water droplets were infiltrated in a fine structure. Under certain conditions, the formation of condensed-water beads on the ultra-hydrophobic aluminum surface could be effectively delayed, thereby the frost formation could be inhibited. At the later stage of frosting, when the condensed-water beads froze and there were full of frost crystals on the surface, the frost-inhibition effect was relatively deteriorated. Ordinary aluminum surface also has a certain frost inhibition performance after lauric acid modification, but the effect is obviously weaker than that of the superhydrophobic surface with micro-nano composite structure. It is suggested that when producing material whose surface needs the frost-inhibiting feature, delaying the generation of condensed-water beads can be used as a technological means, for producing the suitable superficial micro-nano structure, so as to achieve the frost-inhibiting purpose most effectively. |
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