turbulent heat transfer enhancement at the presence of different nanofluid in microchannel

Heat transfer enhancement and it's efficiency, has always been of interest to designers and engineers in different industries# fluids like water, oil and ethylene glycol play an important role in cooling and heating industrial processes# the poor heat transfer properties of these fluids are a major obstacle to increasing heat transfer and more efficient heat exchangers# on the other hand, the thermal conductivity of some solids like metals, is hundreds of times greater than that of conventional energy-consuming fluids# therefore, one of the ways to increase the heat transfer of commonly used fluids is to disperse metallic or nonmetallic particles in the base fluid, which has a higher thermal conductivity than the base fluid# in this study, the effect of adding different nanoparticles of tio2, al2o3, cuo and sio2 with volume fractions of 3% and 5%, inside a tube with a circular cross-section at different reynolds number in turbulent flow was investigated# the average nusselt number was increased by increasing nanoparticles volume fractions# the increase in average nusselt number is more significant in high reynolds numbers# among 4 investigated nanoparticles, tio2 with a volume fraction of 3% by increasing average nusselt number from 8#75% to 16#12% and with volume fraction of 5% by increasing 12#087% to 21#37% (in different reynolds numbers) had the least effect on the heat transfer enhancement#