Acquired Electronics360

Materials and Cost Benchmarking

Magnetic Nanoparticles Could Prevent Hotspots in Systems and Electronics

22 November 2013

Researchers at the Massachusetts Institute of Technology (MIT) and the University of Newcastle in Australia have found a new method of enhancing heat transfer by using magnetic fields to prevent hotspots that lead to system failures. The method could be applied to cooling everything from electronic devices to advanced fusion reactors.

In a system, the method relies on a slurry of tiny particles of magnetite, a form of iron oxide, where the magnetite nanofluid flows through tubes and is manipulated by magnets placed on the outside of the tubes.

The results of the experimental system are the culmination of several years of research on nanofluids, which are nanoparticles dissolved in water, according to Lin-Wen Hu, associate director of MIT's Nuclear Reactor Laboratory.

Hu explained that the magnets "attract the particles closer to the heated surface" of the tube, greatly enhancing the transfer of heat from the fluid, through the walls of the tube and into the outside air. Without the magnets in place, the fluid behaves just like water, with no change in its cooling properties.

With the magnets, the heat transfer coefficient is higher—in the best case, about 300 percent better than with plain water. "We were very surprised" by the magnitude of the improvement, said Hu.

Conventional methods to increase heat transfer in cooling systems rely on features such as fins and grooves on the surfaces of the pipes, increasing their surface area. While these features improve heat transfer, they do not approach the results of using magnetic particles, according to Hu. Also, she pointed out these conventional features are expensive to fabricate.

In the improved new system, the magnetic field tends to cause the particles to clump together, thus possibly forming a chainlike structure on the side of the tube closest to the magnet, disrupting the flow there and increasing the local temperature gradient, according to Hu.

"This is the first work we know of that demonstrates this experimentally," Hu said.

"It's a neat way to enhance heat transfer," said Jacopo Buongiorno, a co-author of the paper and an associate professor of nuclear science and engineering at MIT. "You can imagine magnets placed at strategic locations. When you want to turn the cooling up, you turn up the magnets and get a very localized cooling there."

Buongiorno suggested numerous applications where systems 'require not necessarily system-wide cooling, but localized cooling,' such as microchips and other electronic systems in which local areas are subject to strong heating.

The research was performed by the teams at MIT and in Australia and was supported by the University of Newcastle, Granite Power Ltd., the Australian Research Council and King Saud University in Saudi Arabia.

The method is described in the International Journal of Heat and Mass Transfer.

Related stories:



Powered by CR4, the Engineering Community

Discussion – 0 comments

By posting a comment you confirm that you have read and accept our Posting Rules and Terms of Use.
Engineering Newsletter Signup
Get the Engineering360
Stay up to date on:
Features the top stories, latest news, charts, insights and more on the end-to-end electronics value chain.
Advertisement
Weekly Newsletter
Get news, research, and analysis
on the Electronics industry in your
inbox every week - for FREE
Sign up for our FREE eNewsletter
Advertisement

CALENDAR OF EVENTS

Date Event Location
30 Nov-01 Dec 2017 Helsinki, Finland
23-27 Apr 2018 Oklahoma City, Oklahoma
18-22 Jun 2018 Honolulu, Hawaii
Find Free Electronics Datasheets
Advertisement