EXPERIMENTAL STUDY ON AL2O3/H2O NANOFLUID FLOW BOILING HEAT TRANSFER UNDER DIFFERENT PRESSURES

In present work, Al2O3/H2O nanofluid was prepared by ultrasonic oscillation. Furthermore, nanofluid flow boiling heat transfer in a vertical cube is experimentally studied, with 0.1% and 0.5% volume concentration and 20nm diameter. Some factors are under consideration, including heat flux on the seating surface (48 similar to 289kW.m(-2)), pressure (0.2 similar to 0.8MPa) and mass flow rate (400 similar to 1100 kgm(2)s(-1)). The results confirm that the flow boiling heat transfer of Al2O3/H2O nanofluid is improved mostly about 86% compared with pure water. And the average Nusselt number enhancement rate of nanofluid compared with deionized water is 35% in the range of this work. Moreover, the heat transfer capacity of nanofluid Increase with the heat flux on the heating surface, pressure and the volume concentration. of nanoparticle. It is proved that nanoparticle deposited on the heating surface by SEM Observation, and TEM observations for nanoparticle confirm that nanoparticle have not obviously changed after boiling. In addition, the enhancement rate of nanofluid flow boiling heat :ransfer capacity increase with the pressure, and the influence of mass flow rate is negligible. In conclusion, this work is a supplement for nanofluid flow boiling heating transfer, especially for the influence of pressure.