University of Illinois Urbana-Champaign

Natural and engineered surfaces for enhanced phase change heat transfer

Oh, Junho

Content Files
OH-DISSERTATION-2019.pdf

Permalink

https://hdl.handle.net/2142/105931

Description

Title
Natural and engineered surfaces for enhanced phase change heat transfer
Author(s)
Oh, Junho
Issue Date
2019-07-12
Director of Research (if dissertation) or Advisor (if thesis)
Miljkovic, Nenad
Doctoral Committee Chair(s)
Miljkovic, Nenad
Committee Member(s)
  • Jacobi, Anthony M
  • Braun, Paul V
  • Cropek, Donald M
  • Alleyne, Marianne
Department of Study
Mechanical Sci & Engineering
Discipline
Mechanical Engineering
Degree Granting Institution
University of Illinois at Urbana-Champaign
Degree Name
Ph.D.
Degree Level
Dissertation
Date of Ingest
2019-11-26T20:59:44Z
Keyword(s)
  • Condensation
  • Phase change heat transfer
  • Nanoengineering
  • Superhydrophobic
Abstract
Phase change of water is a ubiquitous process that occurs throughout nature and in a wide range of engineering systems. Over the last century, many researchers have studied the effect of surface wettability on the enhancement of phase change heat transfer. Interestingly, interfacial phenomena tailored for the manipulation of water can be found in nature. Many natural plant and insect surfaces have evolved to repel or attract water in order to adapt to external evolutionary pressures and to help them survive. This dissertation focuses on nature-inspired surfaces with desirable wettability characteristics that can enhance phase change heat transfer. We begin by investigating the wettability of natural surfaces to understand why and how hydrophobicity is achieved. We reveal that hydrophobicity of cicada wings, stemming from both chemistry and structure, is governed by life history and reproductive strategy, rather than habitat. We utilize the knowledge of natural surface chemistries to develop hydrophobic materials for environmentally friendly superhydrophobic coatings. Furthermore, we answer a key scientific controversy regarding the wettability of rare earth oxides by conclusively showing that hydrophobicity is driven by hydrocarbon adsorption. The findings were leveraged to design, develop, and demonstrate a novel concepts of condensation heat transfer capable of enhancing performance of state-of-the-art sytems by leveraging thin film condensation and jumping-droplet induced localized hot spot cooling.
Graduation Semester
2019-08
Type of Resource
text
Permalink
http://hdl.handle.net/2142/105931
Copyright and License Information
Copyright 2019 Junho Oh

Owning Collections

Dissertations and Theses - Mechanical Science and Engineering
Graduate Dissertations and Theses at Illinois PRIMARY
Graduate Theses and Dissertations at Illinois