Investigations on Viscosity and Thermal Conductivity of Cobalt oxide- water Nano fluid

Abstract

Conventional fluids used for heat transfer applications in solar thermal devices such as solar thermal collectors limit the performance enhancement and compact size preference of the collectors. This limitation can be overcome by using unconventional class of working fluids called nanofluids. The present work aims to prepare nanofluid and study its various thermal and physical properties for use in the solar thermal collectors. Cobalt oxide nanoparticles are added to de-ionized water along with decyl glucoside surfactant and bath sonicated to homogenize the fluid. Concentration of Cobalt oxide nanoparticles varying from 0.1vol% to 0.4vol% are prepared and at different volume fractions the thermo-physical properties of the nanofluid such as relative viscosity, and thermal conductivity are measured over a temperature range limit of 30oC to 60oC. Results showed that relative viscosity values showed a decreasing trend with temperature and increased with the increase in the volume fraction of nanoparticles. The thermal conductivity ratio of the nanofluid increased and showed a maximum value of enhancement up to 25 %.