TEMPORAL PERFORMANCE EVALUATION OF CuO + GO HYBRID NANOFLUIDS IN HEAT PIPE

Abstract

An experimental investigation was carried focussed on evaluation of the heat transfer characteristics of a cylindrical capillary driven mesh wick heat pipe in horizontal position at a heat load range of 50W to 200W (at steps of 50W each). The heat pipe was tested first with DI water as working fluid followed by CuO mono-nanofluids (0.5%, 1.0%, 1.5% by wt.). Out of all prepared CuO mono-nanofluids, maximum decrement of about 21.56 ºC, 25.24 ºC and 16.57 ºC in adiabatic vapor temperature, evaporator and condenser average temperature respectively was achieved with 1.0% CuO mono-nanofluid in heat pipe relative to that of DI water. Three different hybrid nanofluids namely 1.0% (CuO 75%–GO 25%), 1.0% (CuO 50%–GO 50%) and 1.0% (CuO 25%–GO 75%) hybrid nanofluids respectively were prepared and tested in the heat pipe. Maximum decrement of about 26.71 ºC, 32.58% in the adiabatic vapor temperature, total thermal resistance respectively along with maximum increment of about 48.16%, 26.10% in the effective thermal conductivity, thermal efficiency respectively was attained using 1.0% (CuO 25%–GO 75%) hybrid nanofluid in the heat pipe. 1.0% GO mono-nanofluid was then prepared and tested in the heat pipe and its performance was compared with that of DI water and (CuO+GO) hybrid nanofluid. All the nanosuspensions were prepared following the two step method followed by ultrasonication for 4 hours. The possible reasons and mechanisms responsible for the performance augmentation achieved with hybrid nanofluids were discussed.