Frost nucleation and growth on hydrophilic, hydrophobic, and biphilic surfaces

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dc.contributor.author Van Dyke, Alexander Scott
dc.date.accessioned 2015-04-24T20:05:08Z
dc.date.available 2015-04-24T20:05:08Z
dc.date.issued 2015-04-24
dc.identifier.uri http://hdl.handle.net/2097/19105
dc.description.abstract The purpose of this research was to test if biphilic surfaces mitigate frost and ice formation. Frost, which forms when humid air comes into contact with a surface that is below the dew point and freezing temperature of water, hinders engineering systems such as aeronautics, refrigeration systems, and wind turbines. Most previous research has investigated increasingly superhydrophobic materials to delay frost formation; however, these materials are dependent on fluctuating operating conditions and surface roughness. Therefore, the hypothesis for this research was that a biphilic surface would slow the frost formation process and create a less dense frost layer, and water vapor would preferentially condense on hydrophilic areas, thus controlling where nucleation initially occurs. Preferential nucleation can control the size, shape, and location of frost nucleation. To fabricate biphilic surfaces, a hydrophobic material was coated on a silicon wafer, and a pattern of hydrophobic material was removed using photolithography to reveal hydrophilic silicon-oxide. Circles were patterned at various pitches and diameters. The heat sink was comprised of two parts: a solid bottom half and a finned upper half. Half of the heat sink was placed inside a polyethylene base for insulation. Tests were conducted in quiescent air at room temperature, 22 °C, and two relative humidities, 30% and 60%. Substrate temperatures were held constant throughout all tests. All tests showed a trend that biphilic surfaces suppress freezing temperature more effectively than plain hydrophilic or hydrophobic surfaces; however, no difference between pattern orientation or size was noticed for maximum freezing temperature. However, the biphilic patterns did affect other aspects such as time to freezing and volume of water on the surface. These effects are from the patterns altering the nucleation and coalescence behavior of condensation. en_US
dc.description.sponsorship National Science Foundation en_US
dc.language.iso en_US en_US
dc.publisher Kansas State University en
dc.subject Frost formation en_US
dc.subject Biphilic en_US
dc.subject Nucleation en_US
dc.subject Phase change heat transfer en_US
dc.subject Surface enhancement en_US
dc.title Frost nucleation and growth on hydrophilic, hydrophobic, and biphilic surfaces en_US
dc.type Thesis en_US
dc.description.degree Master of Science en_US
dc.description.level Masters en_US
dc.description.department Department of Mechanical and Nuclear Engineering en_US
dc.description.advisor Amy R. Betz en_US
dc.subject.umi Mechanical Engineering (0548) en_US
dc.date.published 2015 en_US
dc.date.graduationmonth May en_US


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