Özet:

In this study, the effects of microchannel number, volume concentration, Reynolds number, and nanofluid type on heat transfer and flow characteristics in the heat sink consisting of trapezoidal microchannels are investigated numerically. Governing equations are solved by assuming three-dimensional, incompressible, steady and laminar flow. The channel material is chosen as copper, and a constant heat flux boundary condition is defined on the upper wall of heat sink. For two different nanofluids, CuO-water and Al2O3-water, investigated parameters are the number of trapezoidal channels (n=3-5) in the heat sink, Reynolds number (Re=200-1500), and volume concentration (=0-4%). Results show that using nanoparticles in base fluid causes to increase both heat transfer coefficient and pressure drop. Heat transfer coefficient increases with increasing number of trapezoidal cross-sectional channel in the heat sink, nanofluid volume concentration and Reynolds number. Pressure drop enhances with enhancing Reynolds number and microchannel number in the heat sink. The nanofluid type and volume concentration do not importantly affect the friction factor. According to the performance index, it is seen that adding CuO nanoparticles in water is convenient, but Al2O3 nanoparticles in water is not appropriate. It is observed that volume concentration for CuO-water nanofluid affects the thermal performance, but volume concentration for Al2O3-water nanofluid does not affect.

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