TRANSPORT PROPERTIES OF NANOFLUIDS (EXPERIMENT AND CALCULATION METHODS)

Abstract

A review and analysis of experimental studies and methods of calculation of thermal conductivity and viscosity of nanofluids with Al₂O₃ particles are presented. Analysis of published data shows that the results are not consistent. The greatest influence on the thermal conductivity and viscosity of nanofluids make a concentration of the nanoparticles. In addition to concentration, a major factors influencing the transport properties are the following: a method of producing nanofluids and the methods of their preparation for the research; the size and shape of initial nanoparticles; the ability of the nanoparticles to form clusters with different size; temperature and pressure; surface–active substances (surfactants); type and properties of the base fluids; the methodology of the experiment and its adaptation to the specifics of nanofluids. The results of experimental research of thermal conductivity and viscosity for the model system isopropyl alcohol – Al₂O₃ nanoparticles at various nanoparticle concentrations and temperatures are given. Study of thermal conductivity was carried out by two independent methods – stady-state and transient hot wire methods. The viscosity was measured with the capillary viscometers. The influence of nanoparticles additives on the viscosity of refrigeration compressor oil is also studied. The results of the measurements are presented in the form of simple models.