Investigation of the pool boiling heat transfer enhancement of nano-engineered fluids by means of high-speed infrared thermography

A high-speed video and infrared thermography based technique has been used to obtain detailed and fundamental time- and space-resolved information on pool boiling heat transfer. The work is enabled by recent advances in heat transfer diagnostics and motivated by increased interest in the enhancement of heat transfer for applications such as micro-electronics, space heat-transfer systems, and advanced nuclear reactors. This study critically examined the fundamental processes occurring during nucleate boiling, critical heat flux, and rewetting on thin-film heating elements. A significant focus of the work was to investigate and explain the modification of these heat transfer phenomena through the addition of silica and diamond nanoparticles to the working fluid. Bubble departure diameter and frequency, growth and wait times, and nucleation site density were measured for every nucleation site during nucleate pool boiling at multiple superheats. The data were compared with decades-old and poorly-validated models and correlations, and were used to evaluate the relative contribution of the superheated liquid layer and microlayer evaporation to bubble growth. Deterioration in nucleate boiling heat transfer of water-based nanofluids was observed. It was determined that a reduction in the static contact angle, caused by nanoparticle deposition on the surface during boiling, created a larger energy barrier for nucleation, which in turn reduced bubble departure frequency and nucleation density, thus resulting in a reduced heat transfer coefficient.

Department dc:contributor.department

Massachusetts Institute of Technology. Dept. of Nuclear Science and Engineering.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2009

Author dc:creator

• Gerardi, Craig Douglas

Advisor dc:contributor.advisor

• Jacopo Buongiorno, Lin-wen Hu and David Cory.

• Nuclear Science and 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/1721.1/52793

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/52793