Numerical study of the thermal performance and pressure drops of water-based Al2O3 - Cu hybrid nanofluids of different compositions in a microchannel heat sink

This paper numerically investigates the effects of hybridization of water-based copper-alumina nanofluid on the thermal performance, pressure drop, and the figure of merit (FOM) inside a three-dimensional microchannel heat sink. The heat sink comprises a copper block with the top covered by a polycarbonate plastic (Lexan) to form a closed microchannel. A constant heat flux of 1.0 MW/m(2) is applied at the base of the heat sink. The Reynolds number is varied between 400 and 1200 for different volume concentrations of alumina and copper nanoparticles of 0.5-3.0% vol. Simulation in ANSYS Fluent is performed with a two-phase Eulerian-Eulerian model using the finite volume approach to solve the conjugate heat transfer problem. Experimental validations of the numerical models are in very good agreement. Furthermore, the result shows that the higher the relative concentration of copper nanoparticles, the better the thermal enhancement and FOM of the hydridized nanofluid. For design and operational conditions, the maximum FOM favour the concentration of copper nanoparticle >= 0.75% for Re of 400 and <0.75% vol. for Re of 1200. [GRAPHICS] .