Nanoengineered surfaces for advanced thermal management

Thermal management is a critical challenge for a variety of applications including integrated circuits (ICs) and energy conversion devices. As the heat fluxes exceed 100 W/cm2, novel cooling solutions need to be developed. Thin film evaporation is a promising approach because the large latent heat associated with phase change can be utilized while the thermal resistance associated with the liquid film thickness can be minimized. However, traditional thin film evaporation schemes such as jet impingement and sprays suffer from several limitations, such as high power consumption, complex flow patterns, and localized cooling. In this thesis, micro- and nanostructured surfaces were investigated to enhance fluid and heat transport for thin film evaporation. This thesis includes studies of fluid interactions on surfaces with micro- and nanopillar arrays with diameters and spacings ranging from 500 nm to 10 [mu]m. First, liquid transport studies were performed where a propagating liquid on an array of pillars with scalloped features can separate into multiple layers of liquid films. The scallops were found to act as energy barriers that favored liquid separation into several layers. An analytical model based on surface energy was developed to explain the phenomenon and was validated by experiments on additional tailored pillar geometries. Subsequently, a semi-analytical model was developed to predict the propagation velocity based on Modified Washburn's Model to optimize propagation of the liquid. The results were validated by measurements of liquid propagation velocity on micropillar arrays with various geometries.

Department dc:contributor.department

Massachusetts Institute of Technology. Dept. of Mechanical Engineering.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2009

Author dc:creator

• Xiao, Rong, S.M. Massachusetts Institute of Technology

Advisor dc:contributor.advisor

• Evelyn N. Wang.

• Mechanical Engineering.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/50559

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/50559