Experimental investigation of heat transfer and pressure drop in a straight minichannel heat sink using TiO₂ nanofluid

In this paper, heat transfer and pressure drop characteristic associated with minichannel heat sink is investigated experimentally. TiO₂ nanofluid with 15% weight concentration in water as base fluid is used as a coolant and its performance is compared with the distilled water at heating powers of 100 W, 125 W and 150 W. The results indicate that TiO₂ nanofluid thermal performance is strongly dependent on heating power and its usefulness heat transfer characteristic could be achieved more effectively at lower heating power. However, pressure drop is found to increase with the decrease of heating power and this decrement is more prominent for TiO₂ nanofluid as compared to distilled water due to viscosity variation with temperature. Nusselt number is found invariant with increase or decrease of heating power and hence using distilled water, experimental Nusselt number satisfies Peng and Peterson empirical correlation at all heating powers within 20% accuracy. The lowest wall temperature is measured to be 37.05 °C using TiO₂ nanofluid at Reynolds number of 922 corresponding to heating power of 100 W. Moreover, while passing through the minichannel, an axial rise of base temperature is observed from inlet to outlet of heat sink.