Nanostructured Surface Significantly Alters Droplet Dynamics and Freezing Behavior

Abstract

Condensation and freezing of water is significant in applications such as refrigeration, HVAC systems, aerospace, and cryogenics. In particular, the formation of amorphous ice is of great interest due its rarity on Earth in comparison to other polymorphs, especially crystalline structures. A surface with nano-sized pillars was used to investigate the effect of nanostructured surfaces on condensation and freezing. These pillars were 0.7 to 1.2 μm in size and spaced about 0.3 μm apart from each other in a repeating hexagonal arrangement, with one pillar on each vertex and one in the center. The experiment was performed in a room with ambient conditions with a relative humidity of 40%, the air temperature ranged from 23°C to 26°C, and the surfaces were cooled using a Peltier device to a temperature of -8°C, with an accuracy of ±0.5°C. When the ice was allowed to condense and freeze on the nano-pillared surface, it was observed to form in clear, dull drops like amorphous ice, versus the clouded, white ice of a crystalline form. The surface took from 24 to 140 seconds to freeze, with an average of 80.4 s. These drops were typically around 50 μm in diameter, with some being as small as 10 μm, and others closer to 100 μm. The growth of the ice appeared to be cubic, growing upward in rectangular columns.

Department(s)

Mechanical and Aerospace Engineering

Keywords and Phrases

Amorphous; Condensation; Cubic; Frost formation; Ice; Low temperature; Nanostructures

International Standard Book Number (ISBN)

978-156700470-0

International Standard Serial Number (ISSN)

2379-1748

Document Type

Article - Conference proceedings

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2024 Begell House Inc., All rights reserved.

Publication Date

01 Jan 2017

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