Experimental investigation of TiO₂–water nanofluid flow and heat transfer inside wavy mini-channel heat sinks

The present study comprises experimental investigation on heat transfer and hydrodynamic characteristics of TiO₂ nanofluid as coolant in wavy channel heat sinks having three different channel configurations. The performance of TiO₂ nanofluids having concentrations of 0.006, 0.008, 0.01 and 0.012 vol% is compared with that of distilled water under laminar regime at heating powers of 25 W, 35 W and 45 W. Results indicated that for all heat sinks, nanofluids showed better heat transfer characteristics than distilled water. With an increase in heating power, TiO₂ nanofluid thermal performance was decreased. Using 0.012% TiO₂ nanofluids, minimum wall base temperature and maximum enhancement in Nusselt number are noted as 33.85 °C and 40.57%, respectively, for heat sink with wavelength of 5 mm and amplitude of 0.5 mm corresponding to Reynolds number of 894 at heating power of 25 W. Pumping power requirement is function of flow rate and pressure drop, and its maximum value of 0.0284 W is associated with heat sink with minimum wavelength. Moreover, variation in wavelength of channel is found to have dominating effect on heat transfer performance of heat sink as compared to the width of channel.