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PUBLICATIONS

Effect of Acoustic Excitation on R134a/Al2O3 Nanolubricant Mixture Boiling on a Reentrant Cavity Surface with Extensive Measurement and Analysis Details

Published

Author(s)

Mark A. Kedzierski, Steven E. Fick

Abstract

This paper quantifies the influence of acoustic excitation of Al2O3 nanoparticles on the pool boiling performance of R134a/polyolester mixtures on a Turbo-BII-HP boiling surface. A nanolubricant with 10 nm diameter Al2O3 nanoparticles at a 5.1 % volume fraction in the base polyolester lubricant was mixed with R134a at a 1 % mass fraction. The study showed that high frequency ultrasound at 1 MHz can improve R134a/nanolubricant boiling on a reentrant cavity surface by as much as 44 %. This maximum enhancement occurred for an applied power level to the fluid of approximately 6 W (39 kW m-2). Applied power levels larger and smaller than 6 W resulted in smaller boiling heat transfer enhancements. In total, five different applied power levels were studied: 0 W, 4 W, 6 W, 8 W, and 12 W. The largest and smallest average enhancement was approximately 15 % and 2.5 % for an applied power level of 6 W and 4 W, respectively. In-situ insonation at 1 MHz resulted in an improved dispersion of the nanolubricant on the test surface. An existing pool boiling model for refrigerant/nanolubricant mixtures was modified to include the effect of acoustic excitation. For heat fluxes greater than 25 kWm-2, the model was within 4.5 % of the measured heat flux ratios for mixtures for all applied power levels. The average agreement between measurements and predictions was approximately 1 % for all power levels.
Citation
Technical Note (NIST TN) - 1836
Report Number
1836
NIST Pub Series
Technical Note (NIST TN)
Pub Type
NIST Pubs

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DOI Link

Keywords

acoustics, additives, aluminum oxide, boiling, enhanced heat transfer, nanolubricant, nanotechnology, refrigerants, refrigerant/lubricant mixtures, structured surface, ultrasound
Buildings and Construction, Building control systems and Energy efficiency

Citation

Kedzierski, M. and Fick, S. (2014), Effect of Acoustic Excitation on R134a/Al2O3 Nanolubricant Mixture Boiling on a Reentrant Cavity Surface with Extensive Measurement and Analysis Details, Technical Note (NIST TN), National Institute of Standards and Technology, Gaithersburg, MD, [online], https://doi.org/10.6028/NIST.TN.1836 (Accessed April 23, 2024)

Created August 6, 2014, Updated November 10, 2018