Eylül Simsek
Dept. of Mechanical Engineering, Middle East Technical University, Dumlupınar Blv. No 1,
06800, Ankara, Turkey; Mechanical and Aerospace Engineering Department, University of California, Los Angeles, 420 Westwood Plaza 37-132 Engineering IV, Los Angeles, CA 90095-1597
Matthew Redmond
Dept. of Mechanical Engineering, Middle East Technical University, Dumlupinar Blv. No 1, 06800, Ankara, Turkey; George W. Woodruff School of Mechanical Engineering, 801 Ferst Drive, Georgia Institute of Technology, Atlanta, GA 30332-0405, USA
Aziz Koyuncuoglu
Micro and Nanotechnology Program, Graduate School of Arts and Sciences, Middle East
Technical University, Dumlupınar Blv. No 1, 06800, Ankara, Turkey; METU-MEMS Research and Application Center, Middle East Technical University, Dumlupınar
Blv. No 1, 06800, Ankara, Turkey
Tuba Okutucu-Özyurt
Dept. of Mechanical Engineering, Middle East Technical University, Dumlupınar Blv. No 1,
06800, Ankara, Turkey; Micro and Nanotechnology Program, Graduate School of Arts and Sciences, Middle East Technical University, Dumlupınar Blv. No 1, 06800, Ankara, Turkey
Haluk Kulah
Micro and Nanotechnology Program, Graduate School of Arts and Sciences, Middle East
Technical University, Dumlupınar Blv. No 1, 06800, Ankara, Turkey; METU-MEMS Research and Application Center, Middle East Technical University, Dumlupınar Blv. No 1, 06800, Ankara, Turkey; Dept. of Electrical and Electronics Engineering, Middle East Technical University, Dumlupınar
Blv. No 1, 06800, Ankara, Turkey
Heat transfer and pressure drop performance of gold-in-water nanofluids in microchannels are experimentally
investigated. Gold nanoparticles are suspended in de-ionized (DI) water. The nanofluid stability is maintained by
polyvinylpyrrolidone (PVP) for over 4 years. Nanofluids are tested in rectangular, MEMS produced copper microchannels of 70 μm × 50 μm cross-sectional area in a very low Reynolds number range of 30 < Re < 50. The
performances of DI-water, PVP added DI-water, and gold-in-water nanofluid with added PVP are compared. The
nanofluids always yielded a higher heat transfer coefficients than PVP-DI water solution. For occasional
combinations of the particle size, volumetric concentration and flow rate, gold nanofluids yielded higher heat
transfer coefficients compared to DI water as well. The effects of flow rate and particle size on the figure of merit (FM) are presented. The study is rare in dealing with pure metals (gold), and is important in emphasizing the
surfactant effects on stable duration of nanofluids, and their thermal performance.