SURFACE TENSION, VISCOSITY, AND THERMAL CONDUCTIVITY OF NANOLUBRICANTS AND VAPOR PRESSURE OF REFRIGERANT/NANOLUBRICANT MIXTURES

摘要

The results of thermophysical properties research of the refrigeration compressor lubricant (mineral oil ISO 9) with nanoparticles of MoS_2 (70 nm) and Cu (50 nm), and measurements of vapor-liquid equilibrium for the refrigerant R600a/nanolubricant mixtures are presented. Series of measurements were completed for surface tension (maximum bubble pressure method), thermal conductivity (steady-state hot-wire method), viscosity (capillary tube method), and saturated vapor pressure (static method). The size and the concentration of nanoparticles in the lubricant were determined by dynamic light scattering (laser correlation spectroscopy). Obtained results (in particular case, decrease in surface tension of nanolubricants, increase the thermal conductivity and vapor pressure of refrigerant/lubricant mixtures) demonstrated a positive effect of nanoparticles to the refrigeration working fluids. Thus, the use of nanorefrigerants could enhance energy efficiency of refrigerating vapor compressor systems.