Experimental study of cooling characteristics of water-based alumina nanofluid in a minichannel heat sink

This paper investigates experimentally the convection heat transfer of Al₂O₃/water nanofluid with 0-8wt% concentrations flowing through a parallel minichannel heat sink. A uniform heat flux in the range of 1.2-6.8W/cm² is applied for heating the heat sink and the Reynolds number is considered in the range of 238-1549. The measured results reveal that the increment of concentration and decrement of flowrate lead to the increase of friction factor. The maximum nanofluid to pure water pressure drop ratio of 1.41 is observed by flowing nanofluid with 8% nanoparticle concentration for Reynolds number of 258. Moreover, it is found that the values of heat transfer effectiveness and figure of merit are more than unity, indicating the beneficial application of Al₂O₃/water nanofluid as the coolant in the heat sink. The maximum values of heat transfer effectiveness and figure of merit are achieved 1.4 and 1.27 by flowing 8wt% nanofluid for Reynolds number of 1549. Furthermore, the addition of nanoparticle content decreased the coefficient of performance and the highest value belongs to the pure water. The increment of Reynolds number and nanoparticle content significantly decrease the thermal resistance.