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Publication Citation: Effect of Al2O3 Nanolubricant on a Passively Enhanced R134a Pool Boiling Surface

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Author(s): Mark A. Kedzierski;
Title: Effect of Al2O3 Nanolubricant on a Passively Enhanced R134a Pool Boiling Surface
Published: November 15, 2011
Abstract: This paper quantifies the influence of Al2O3 nanoparticles on the pool boiling performance of R134a/polyolester mixtures on a Turbo-BII-HP boiling surface. An Al2O3 nanolubricant (a lubricant containing dispersed nano-size particles) was made by suspending nominally 10 nm diameter Al2O3 particles in a synthetic polyolester to roughly a 1.6 % volume fraction. The nanoparticles caused, on average, a 12 % degradation in the boiling heat transfer relative to that for R134a/polyolester mixtures without nanoparticles for the three lubricant mass fractions that were tested. The degradation was nearly constant for heat fluxes between 20 kW/m2 and 120 kW/m2. It was speculated that the boiling heat transfer degradation was primarily due to (1) a combination of film boiling in the reentrant cavity rendering the nucleate boiling enhancement mechanism of the nanoparticles ineffective and (2) a reduction in bubble frequency due to the increased surface wetting as caused by the nanoparticles.
Citation: International Journal of Transport Phenomena
Keywords: additives; aluminum oxide; boiling; enhanced heat transfer; nanolubricant; nanotechnology; refrigerants; refrigerant/lubricant mixtures; structured surface
Research Areas: Sustainability, Building Equipment Efficiency
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