Physiochemical Properties of some metal oxides /glycol Nano fluids

Abstract

The thermal properties are a primary indicator in the development of energy efficient heat transfer fluids that is required in numerous industry sectors. Recently nanofluid was introduced into the heat fluids to enhance the thermal conductivity of the resulting nanofluids. The aim of this study is to synthesis, characterization and study of thermal properties of metal oxides of Co, Cu and Fe / glycol nanofluids. Metal oxides nanoparticles were prepared using Sol-Gel method; the nanofluids were obtained via dispersing of nanoparticles powder in 40 ml of ethylene glycol by four concentrations (0. 2 – 0.1 – 0. 05 - and 0.025 g) from nanoparticles at room temperature with mechanical agitation. The structures of the prepared Co3O4, CuO, and Fe2O3/glycol nanoparticles were confirmed using XRD technique and UV absorption spectra. The average crystallite size of nanoparticles obtained was as follows: 41.46 nm, 28, 58 nm, 78, 65 nm for Co3O4, CuO and Fe2O3 respectively. Absorption spectra of Co3O4 nanoparticles are show a strong fundamental absorption, edge approximately 496 nm, The UV- Vis spectra of CuO NPs show peak in the range of 200-350nm, and for Fe2O3 NPs the peak appear between 320 and 420 nm. The density increased with increasing particles concentration in the 12 samples nanofluid. All viscosity measurements were conducted using a capillary viscometer; the viscosity experiment was carried out at wide temperatures ranging between 20 and 80C° to determine their applicability in such range. The viscosity data were collected using a programmable rheometer result, increasing the temperature of nanofluids decreases their viscosity. The Differential Scanning Calorimeter (DSC) instrument was used for the measure of heat flux of the prepared metal oxides /glycol nanofluid in the thermal range between 300-500 °C. It was observed that the heat flux of the synthesized nanocomposites increase with increasing temperature and the rate of increase varies from one oxide to another. And from the heat flux data the thermal conductivity of the samples was calculated using Fourier law: in cobalt oxide nanofluids the thermal conductivity increases with temperature, thermal conductivity oscillates at the beginning of heating but is regulated with continued heating, except the concentration (0.2). For the copper oxide nanofluid and iron oxide nanofluid with their four concentrations their thermal conductivity increases with increase the temperature. The heat capacity of all the prepared samples (which is related to the change in temperature), has been calculated and its values change with the change in temperature and increase with the increase temperature and the concentration of nanoparticles.