Effect of Al2O3 Nanolubricant on a Passively Enhanced R134a Pool Boiling Surface
Mark A. Kedzierski
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.
Effect of Al2O3 Nanolubricant on a Passively Enhanced R134a Pool Boiling Surface, International Journal of Transport Phenomena, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=907104
(Accessed June 10, 2023)