Thermal analysis and thermo-hydraulic characteristics of zirconia-water nanofluid under a convective boiling regime

In this research, flow boiling heat transfer of zirconia-water nanofluid inside a heat exchanger was experimentally investigated. The system was assessed for heat fluxes ranging from 10 to 150 kW m(-2), inlet temperatures of 323 K to 353 K, mass flow rates of 1-10 kg s(-1) and mass concentrations of mass% = 0.1 to 0.3%. Results showed that the boiling thermal performance and heat transfer coefficient of zirconia nanofluid are plausible and this nanofluid can be utilized as a coolant inside the two-phase heat exchanging systems. However, the pressure drop associated with the use of zirconia nanoparticles suppressed the thermal efficiency of the system. Likewise, particulate fouling was not observed during the experiments and bubble formation was not affected by the deposition of nanoparticles on the boiling surface. At mass% = 0.3, the boiling heat transfer coefficient was improved by 35.8%; however, pressure drop value was also augmented. Likewise, temperature increased the heat transfer coefficient slightly which was attributed to the improvement in the thermo-physical properties of nanofluid such as thermal conductivity.