Northern Illinois University
Mechanical Engineering Seminars
Thursday, 01/15/04 at 2:15 PM
Engineering Building (EB 321A--Dean's Conference Room)
Stephen U. S. Choi
Argonne National Laboratory
Energy Technology Division
Many industrial technologies face the challenge of thermal management. The conventional approach for increasing cooling rates is use of extended surfaces such as fins and microchannels. However, current designs have already stretched this approach to its limits. Therefore, a vital need exists for new and innovative concepts to achieve ultra-high-performance cooling. Nanofluids conceived at Argonne are being developed to meet these cooling challenges.
A research team at Argonne National Laboratory has successfully created "nanofluids" by suspending nanoparticles in conventional heat transfer fluids. Nanofluids, stable suspensions of solid nanoparticles with typical length scales on the order of 5 to 50 nm, can conduct heat one order-of-magnitude faster than scientists had predicted possible. Because of their considerable promise, nanofluids have become a rapidly emerging field where nanoscale science and engineering meet.
The realization that nanofluids have fascinating thermal properties promises to bring about a revolution in cooling technologies. However, little is known about the mechanisms of the anomalous thermal behavior of nanofluids. In our pioneering studies, the structure of nanoparticles in nanofluids is being explored experimentally at Argonne’s Advanced Photon Source. In related efforts, Texas A&M University is studying the mobility-enhanced energy transport of nanoparticles, while Rensselaer Polytechnic Institute is undertaking molecular-dynamics simulations of the nanostructure and mobility. From the gathered data, a new model of energy transport in nanofluids, which takes into account the nanoparticle size, structure, and mobility effects on the thermal properties of nanofluids, will be developed at Argonne. This interdisciplinary project presents a great opportunity to explore new frontiers in thermal physics research for the design and engineering of next-generation coolants.
* This work was supported by the U.S. Department of Energy, Office of Basic Energy Sciences and Office of Heavy Vehicle Technologies, under Contract W-31-109-Eng-38.
Dr. Choi joined Argonne National Laboratory in 1983 and has conducted research primarily in advanced fluids. His work on advanced fluids culminated in the invention of nanofluids, probably the world’s most advanced heat transfer fluids. He proposed the concept of nanofluids and has led the nanofluids team to develop stable nanofluids that showed ultra-high thermal conductivities. He is a pioneer in nanofluids and currently serves as the principal investigator of the nanofluids team. In 2001 his team reported making the first nanotube-based nanofluids. Nanofluid technology is currently being applied toward the development of new coolants and the miniaturization of heat exchangers. Recently, he has teamed up with physicists, chemists, material scientists, and engineers to construct a theory of the thermal properties of nanofluids.
Dr. Choi received his bachelor's degree from the Seoul National University, his master’s degree from the University of Texas at Austin, and his doctorate from the University of California, Berkeley, all in Mechanical Engineering. He is the recipient of the Korea Invention Award from Minister of Commerce and Industry in 1972 and Argonne Pacesetter Award in 1999. The nanofluid work was recognized as one of the top 15 research accomplishments in the DOE Basic Energy Sciences Office (BES) in 2002.
He is author or co-author of more than 100 publications and holds 3 U.S. patents, including the one on nanofluids. He wrote the first review article on nanofluids. His pioneering work created a new, active, rapidly expanding area of interdisciplinary research in the field of nanoscale thermal sciences.