Nucleate Pool Boiling Heat Transfer to Al2O3-Water and TiO2-Water Nanofluids on Horizontal Smooth Tubes with Dissimilar Homogeneous Materials

Sa？etak Nucleate pool boiling heat transfer coefficients of Al2O3-water and TiO2-water nanofluids have been experimentally measured on three horizontal tubes with different materials and similar roughness under atmospheric pressure. Results revealed that the presence of nanoparticles in the base fluid leads to an increase in pool boiling heat transfer coefficients on stainless steel and brass tubes in contrast to copper tube. The effect of different materials on excess temperature around the surface of the tubes has also been investigated. In addition, experimental investigations on the effect of different nanoparticles on nucleate boiling heat transfer have been conducted at volumetric concentrations of 0.1 %, 0.5 %, and 1 % of nanoparticles. Results indicated that the presence of nanoparticles have no effect on the pool boiling heat transfer coefficient for the copper tube. Variations of surface excess temperature for the copper tube were higher in comparison with that of the other tubes tested