Library Subscription: Guest
Home Archives Officers Future meetings American Society of Thermal and Fluids Engineering
Second Thermal and Fluids Engineering  Conference

ISSN: 2379-1748
ISBN: 978-1-56700-430-4

NANOSTRUCTURED SURFACE SIGNIFICANTLY ALTERS DROPLET DYNAMICS AND FREEZING BEHAVIOR

Rachel N. Bohm
Kansas State University, Manhattan, KS, 66502, USA

Amy Rachel Betz
Department of Mechanical and Nuclear Engineering, Kansas State University, Kansas 66506, USA

Edward Kinzel
Missouri University of Science and Technology, Rolla, MO, 65409, USA

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.

Purchase $20.00 Check subscription Publication Ethics and Malpractice Recommend to my Librarian Bookmark this Page