Characterization of Cu-PVA Nanofluids:Ultrasonic and Thermal Properties

Nanofluids have unique features different from conventional solid-liquid mixtures which have millimeter or micrometer sized particles dispersed in some base fluid. Due to their excellent characteristics, these new types of fluids have attracted wide interest in recent years. It is found that nanofluids have significantly higher thermal conductivity than the base fluids. In this work we focus on the ultrasonic and thermal properties of nanofluids. Nanofluids containing copper nanoparticles with base fluid polyvinyl alcohol (PVA) have been developed in our laboratory. These nanofluids are characterized by UV-Visible spectroscopy, X-ray diffraction (XRD) and transmission electron microscopy (TEM). Temperature dependent ultrasonic velocity and ultrasonic attenuation measurements are performed for different concentration of the copper nanoparticles in the PVA. Hot Disk Thermal Constant Analyser is used for the measurement of the thermal conductivity of synthesized nanofluids. Experimental results show that the thermal conductivities of the nanofluids are higher than that of base fluid PVA. The obtained results were analyzed taking into account the ultrasonic and thermal behavior of matrix and particles. Possible mechanism for the enhancement of thermal conductivity of the nanofluids using theoretical model is also discussed.