Evaluation of the thermal performance of hybrid nanofluids in pulsating heat pipe

Abstract

The present article performed experimental and numerical investigations to evaluate the thermal performance of hybrid nanofluids in PHP under heat input and filling ratio of 10 W – 100 W and 50 %-60 %, respectively. The thermal performance results of PHP incorporated with hybrid nanofluids were compared with water. Water has low thermal conductivity value which is not favourable for an efficient heat transfer in a cooling device. Several studies have shown that hybrid nanofluid as a promising working fluid for thermal performance enhancement of the heat transfer device. The present study uses Al2O3-CuO hybrid nanofluid and SiO2-CuO hybrid nanofluid with mass concentration of 0.1 %. The thermal performance of PHP was studied with respect to the start-up mechanism, steady-state evaporator temperature, thermal resistance and the formation of two-phase flow. From the experiment results, PHP filled with SiO2-CuO hybrid nanofluid obtained the lowest thermal resistance value of 0.27 °C/W. Thermal resistance was improved by 55 % when PHP was charged with SiO2-CuO hybrid nanofluid compared to water. The optimal filling ratio of PHP is found to be 60 % at all the heat input and working fluid tested. Incorporating hybrid nanofluids in PHP have seen to expedite the start-up mechanism and also showed lower steady-state evaporator temperature and thermal resistance values. © 2019 PENERBIT AKADEMIA BARU-All rights reserved.