xperimental Investigation of the Thermal conductivity of silica nanofluids as a function of nanoparticles size

A large number of studies have been focused on the thermal conductivity of Nano fluids in which SiO2nanoparticles are used as additives to increase thermal conductivity of base fluid. Nanofluids are applied to enhance thethermal conductivity of suspensions compared to the base fluids. There has not been widespread agreement amongdifferent studies and no fully accepted model is also available for the prediction of the relation of thermal conductivityof nanofluids to particle size diameter of suspended particles. In the present study, the aim is to measure the thermalconductivity of different silica nanofluids with different particle sizes, i.e. 10 nm, 20 nm, 40 nm and 54 nm suspended inethanol and different temperatures of 25 ºC, 40 ºC, 55 ºC and 70 ºC. The thermal conductivity of nanofluids with olumefraction up to 1.17 % was measured in a particle size rage between 10 nm, 20 nm, 40 nm and 54nm. The results showthat increase in particle size, nanoparticles volume fraction and temperature increase the relative thermal conductivity ofnanofluid.