Multiphase Interfacial Phenomena for Liquid Manipulation and Defrosting
| dc.contributor.author | Lolla, Venkata Yashasvi | en |
| dc.contributor.committeechair | Boreyko, Jonathan Barton | en |
| dc.contributor.committeemember | Huxtable, Scott T. | en |
| dc.contributor.committeemember | Cheng, Jiangtao | en |
| dc.contributor.committeemember | Yue, Pengtao | en |
| dc.contributor.committeemember | Paul, Mark R. | en |
| dc.contributor.department | Mechanical Engineering | en |
| dc.date.accessioned | 2024-10-08T08:00:34Z | en |
| dc.date.available | 2024-10-08T08:00:34Z | en |
| dc.date.issued | 2024-10-07 | en |
| dc.description.abstract | Interfacial phenomena are prevalent in various natural and engineered systems. A thorough understanding of these phenomena is essential for a complete understanding of processes such as phase transitions and interaction of liquid droplets with different surfaces. The insights gained from understanding interfacial behavior are pivotal in fields such as pharmaceuticals, microfluidics, material sciences, and environmental engineering. This dissertation aims to advance our understanding of interfacial behaviors, thereby facilitating the development of innovative technologies for applications in health, defrosting, and omniphobic surfaces. In Chapters 1 and 2, relevant background information and goals are provided to contextualize the research being presented in this dissertation. Chapter 3 introduces a novel metal-free alternative to conventional antiperspirants (containing aluminum salts and zirconium salts). We leverage the composition of human sweat (97% water and 3% minerals) and employ a hygroscopic substance near the outlet of an artificial sweat duct rig. This leads to complete diffusion and dehydration of sweat, forming a natural mineral plug within the artificial sweat duct that halts the flow. Chapter 4 examines the behavior of room temperature water droplets spreading on a flat icy substrate. The use of flat ice, as opposed to cold substrates, eliminates the nucleation energy barrier, enabling freeze front initiation as soon as the bulk temperature of the spreading drop reaches 0 C. Through scaling analysis, we identify distinct thermo-hydrodynamic regimes with varying Weber numbers. Chapter 5 presents a novel construct for lubricant-impregnated surfaces (LIS). To date, most of the investigations characterizing the wettability of LIS have focused on droplet mobility. We pioneer a lubricant-impregnated fiber (LIF) which exhibits unique droplet dynamics due to simultaneous exploitation of both, high mobility and high adhesion. Chapter 6 proposes an innovative approach for defrosting by exploiting the polarizability and natural thermo-voltage of frost sheets. By placing an actively charged electrode near the frost sheet, we observe that frost dendrites migrate towards the electrode. This technique, termed Electrostatic Defrosting (EDF), effectively removes up to 75% of the frost mass for superhydrophobic surfaces and 50% of the frost mass for untreated surfaces in less than 100 s. | en |
| dc.description.abstractgeneral | Raindrops falling on surfaces, pesticides being sprayed on crops, and frost forming on windshields—these seemingly unrelated phenomena all stem from fundamental water-structure interactions and phase change processes. We encounter these occurrences throughout nature, with some being enchanting, like water dancing on lotus leaves or morning dew sparkling on glass, while others can pose risks, such as condensation impairing visibility while driving. This dissertation aims to enhance our understanding of water-structure interactions by utilizing the phase changes of water (transitioning between vapor and ice). Through this exploration, we seek to develop innovative technologies for health, de-icing, and fog harvesting, highlighting the practical applications of such water-structure interactions. Through four distinct projects, we aim to unlock innovative solutions that enhance everyday life and address pressing environmental challenges. In the first project, we introduce a novel antiperspirant construct that utilizes sweat's own minerals to clog sweat ducts by vaporizing water with a hygroscopic material. The second project investigates droplet dynamics on ice, focusing on how freezing initiates at the contact line when droplets make contact. In the third project, we develop a new design for oil-impregnated surfaces by embedding fibers, characterizing droplet behavior on these curved surfaces. We envision these fibers being utilized in industrial fog harvesting systems, where water can be effectively collected through dropwise condensation. Finally, we present an innovative defrosting method that exploits naturally occurring thermovoltage in frost, using a positively charged electrode to facilitate the removal of frost sheets. Together, these projects illustrate the impact of water-structure interactions on technology and the environment. | en |
| dc.description.degree | Doctor of Philosophy | en |
| dc.format.medium | ETD | en |
| dc.identifier.other | vt_gsexam:41576 | en |
| dc.identifier.uri | https://hdl.handle.net/10919/121295 | en |
| dc.language.iso | en | en |
| dc.publisher | Virginia Tech | en |
| dc.rights | In Copyright | en |
| dc.rights.uri | http://rightsstatements.org/vocab/InC/1.0/ | en |
| dc.subject | Wetting | en |
| dc.subject | Phase Change | en |
| dc.subject | Deicing | en |
| dc.subject | Drop Impact | en |
| dc.subject | Lubricant-Impregnated Surfaces | en |
| dc.title | Multiphase Interfacial Phenomena for Liquid Manipulation and Defrosting | en |
| dc.type | Dissertation | en |
| thesis.degree.discipline | Mechanical Engineering | en |
| thesis.degree.grantor | Virginia Polytechnic Institute and State University | en |
| thesis.degree.level | doctoral | en |
| thesis.degree.name | Doctor of Philosophy | en |
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