Vanessa Egan

Bio: Vanessa Egan is an academic researcher from University of Limerick. The author has contributed to research in topics: Heat transfer & Heat sink. The author has an hindex of 16, co-authored 40 publications receiving 825 citations.

Transient natural convection in a conducting enclosure heated from above

Abstract: Graphical Abstract

Design and Fabrication of a Hybrid Superhydrophobic-Hydrophilic Surface That Exhibits Stable Dropwise Condensation.

Abstract: Condensation of water vapor is an essential process in power generation, water collection, and thermal management. Dropwise condensation, where condensed droplets are removed from the surface before coalescing into a film, has been shown to increase the heat transfer efficiency and water collection ability of many surfaces. Numerous efforts have been made to create surfaces which can promote dropwise condensation, including superhydrophobic surfaces on which water droplets are highly mobile. However, the challenge with using such surfaces in condensing environments is that hydrophobic coatings can degrade and/or water droplets on superhydrophobic surfaces transition from the mobile Cassie to the wetted Wenzel state over time and condensation shifts to a less-effective filmwise mechanism. To meet the need for a heat-transfer surface that can maintain stable dropwise condensation, we designed and fabricated a hybrid superhydrophobic–hydrophilic surface. An array of hydrophilic needles, thermally connected t...

An Experimental Study on the Design of Miniature Heat Sinks for Forced Convection Air Cooling

Abstract: An experimental study is performed on one of the smallest commercially available miniature fans, suitable for cooling portable electronic devices, used in conjunction with both finned and finless heat sinks of equal exterior dimensions. The maximum overall footprint area of the cooling solution is 534 mm 2 with a profile height of 5 mm. Previous analysis has shown that due to fan exit angle, flow does not enter the heat sinks parallel to the fins or bounding walls. This results in a nonuniform flow rate within the channels of the finned and finless heat sinks along with impingement of the flow at the entrance giving rise to large entrance pressure losses. In this paper straightening diffusers were attached at the exit of the fan, which resulted in aligning the flow entering the heat sinks with the fins and channel walls. Detailed velocity measurements were obtained using particle image velocimetry, which provided a further insight into the physics of the flow in such miniature geometries and in designing the straightening diffusers. The thermal analysis results indicate that the cooling power of the solution is increased by up to 20% through the introduction of a diffuser, hence demonstrating the need for integrated fan and heat sink design of low profile applications.

Bioinspired Special Wettability Surfaces: From Fundamental Research to Water Harvesting Applications

Abstract: Nowadays, the pollution of water has become worse in many parts of the world, which causes a severe shortage of clean water and attracts widespread attention worldwide. Bioinspired from nature, i.e. spider silk, cactus, Namib desert beetle, Nepenthes alata, special wettability surfaces have attracted great interest from fundamental research to water-harvesting applications. Here, recently published literature about creatures possessing water-harvesting ability are reviewed, with a focus on the corresponding water-harvesting mechanisms of creatures in dry or arid regions, consisting of the theory of wetting and transporting. Then a detailed account of the innovative fabrication technologies and bionic water-harvesting materials with special wetting are summarized, i.e. bio-inspired artificial spider silk, bio-inspired artificial cactus-like structures, and bio-inspired artificial Namib desert beetle-like surfaces. Special attentions are paid to the discussion of the advantages and disadvantages of the technologies, as well as factors that affect the amount of water-harvesting. Finally, conclusions, future outlooks and the current challenges for future development of the water-harvesting technology are presented and discussed.

Review of micro- and mini-channel heat sinks and heat exchangers for single phase fluids

Abstract: Depleting energy resources have become the driving force for their conservation. Increasing the system efficiencies is one method by which sustainability of energy may be ensured, for which miniaturization has successfully provided solutions. Miniature heat exchangers, owing to their high thermal performance, have the potential to provide energy efficient systems. In addition, their characteristics of compactness, small size and lesser weight have attracted widespread applications. Various works on micro- and minichannel heat exchangers as heat sinks and heat exchangers have been reviewed in this paper. Currently employed fabrication techniques and different applications have been summarized. An overview of the single-phase thermo-hydraulic studies in micro- and minichannel heat sinks has been presented. Literatures related co-current, counter-current and cross-current micro- and minichannel heat exchangers have been discussed. Finally, the persisting lacunae of this technology drawn from the review have been pointed out.

Bioinspired Surfaces with Superwettability for Anti-Icing and Ice-Phobic Application: Concept, Mechanism, and Design

Abstract: Ice accumulation poses a series of severe issues in daily life. Inspired by the nature, superwettability surfaces have attracted great interests from fundamental research to anti-icing and ice-phobic applications. Here, recently published literature about the mechanism of ice prevention is reviewed, with a focus on the anti-icing and ice-phobic mechanisms, encompassing the behavior of condensate microdrops on the surface, wetting, ice nucleation, and freezing. Then, a detailed account of the innovative fabrication and fundamental research of anti-icing materials with special wettability is summarized with a focus on recent progresses including low-surface energy coatings and liquid-infused layered coatings. Finally, special attention is paid to a discussion about advantages and disadvantages of the technologies, as well as factors that affect the anti-icing and ice-phobic efficiency. Outlooks and the challenges for future development of the anti-icing and ice-phobic technology are presented and discussed.