To investigate the characteristics of CHF enhancement in pool boiling of nano-fluids, the pool boiling experiments of nano-fluids are carried out using titania (TiO_(2)) and alumina (Al_(2)O_(3)) nanoparticles. The results show that CHF of nano-fluids is significantly enhanced relative to that of pure water. SEM observation subsequent to the CHF experiment reveals that a nanoparticle surface coating is generated during the pool boiling of nano-fluids. To estimate the role of surface modification due to the nanoparticle surface coating, CHF of pure water is measured on a nanoparticle-coated heater, which is prepared using the pool boiling of nano-fluids. It is found that CHF of pure warer on the nanoparticle-coated heater is not less than that of nano-fluids. The results show that the main reason of the CHF enhancement exists on the heater surface modified by the nanoparticle deposition. To find the mechanism of CHF enhancement due to the nanoparticle coating, the modified surface is chracterized with parameters closely related to CHF: surface wettability, surface roughness, and capillary wicking height. Finally, the contribution of each parameter to CHF enhancement of nano-fluids is discussed.
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