Thermodynamic and heat transfer properties of Al2O3 nanolubricants.

摘要: In vapor compression cycles, a small portion of the oil circulates with refrigerant throughout system components, while most stays in compressors. heat exchangers, lubricant excess penalizes transfer and increases pressure losses: both effects are highly undesired but yet unavoidable. Nanoparticles dispersed expected to provide enhancements transfer. While solubility miscibility refrigerants polyolesters (POE) well established knowledge there is lack information regarding if how nanoparticles affect these two properties. This paper presents experimental data three types Al2O3 nanolubricants R-410A. The were POE by using different surfactants dispersion methods. appeared have slightly lower than that R-410A actually solid did not really interfere characteristics. High viscosity suspensions stabilize avoid clustering. aspect was verified present for long term stability degree agglomeration, when present, measured. identified optimum combinations achieve stable uniform nanolubricant dispersions several months. Surfactants affected thermal conductivity, specific heat, viscosity, properties nanolubricants. heats at temperatures from 0°C 20°C they similar 40°C. Thermal conductivity ranged 1.1 times higher 5°C 1.4 40°C lubricant. nanoparticle concentration 10 wt. % 30 40 percent oil. provided this advance basic understanding interaction mixtures.