NUCLEATE POOL BOILING AND CONDENSATION HEAT TRANSFER CHARACTERISTICS OF HEXAGONAL BORON NITRIDE/DICHLOROMETHANE NANOFLUID


Çiftçi E. , Sözen A.

HEAT TRANSFER RESEARCH, cilt.51, ss.1043-1059, 2020 (SCI İndekslerine Giren Dergi) identifier identifier

Özet

Boiling and condensation, a kind of convective heat transfer characterized by high heat fluxes, are widely encountered in many engineering applications. Fluids are the main heat carriers in heat transfer applications, and hence performance of a thermal system is remarkably linked with the working fluid's thermophysical properties. In thermal systems, nanofluids have been embarked upon to use as a working fluid because of their improved specifications. Pool boiling and condensation heat transfer characteristics of a new kind nanofluid consisting of hexagonal boron nitride nanoparticles and dichloromethane base fluid were investigated experimentally. Experiments were performed with dichloromethane and hexagonal boron nitride/dichloromethane nanofluid solutions to specify nanoparticles' effect on thermal performance. Nanofluid solutions were prepared at varying volumetric concentrations ranging from 0.5% to 1.5% to analyze the impacts of nanoparticle concentration rate. Experiments were conducted under varying input powers ranging from 50 W to 350 W. Boiling curves, the changes in pressure versus heat flux, heat transfer coefficients both in boiling and condensation processes were determined. Viscosity was also measured for each working fluid. It was figured out that nanoparticle addition to the base fluid dramatically affected thermal characteristics. Some enhancements of 27.6% and 17.65% for boiling and condensation processes have been achieved.