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Boiling heat transfer on a high temperature silver sphere in nanofluid

Lotfi, H ; Sharif University of Technology

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  1. Type of Document: Article
  2. DOI: 10.1016/j.ijthermalsci.2009.04.009
  3. Abstract:
  4. To investigate boiling heat transfer characteristics of nanofluids, transient quenching experiments of a high temperature silver sphere in water-based nanofluids with Ag and TiO2 nanoparticles were performed. A silver sphere with a diameter of 10 mm and an initial temperature of 700 °C was quenched in these nanofluids at a temperature of 90 °C. The results showed a considerable reduction in the quenching ability of nanofluids compared to that of pure water. The presence of nanoparticles in water caused the film boiling mode to vanish at lower temperatures depending on the mixture concentration. Calculated heat transfer rates in nanofluids were lower than those in pure water. In the quenching experiments with an unwashed heated sphere, the film boiling mode did not appear and the hot sphere quenched more rapidly through nucleate boiling. In this case the sphere surface was covered by a thin layer of nanoparticles. It was evident that nanoparticle deposition on the sphere surface prevented vapor film from forming around it and resulted in quick quenching of the hot sphere. © 2009 Elsevier Masson SAS. All rights reserved
  5. Keywords:
  6. Boiling ; Boiling heat transfer ; Film boiling ; Heat transfer rate ; Heated spheres ; High temperature ; Mixture concentration ; Nanoparticle deposition ; Pure water ; Silver spheres ; Sphere surfaces ; Thin layers ; TiO ; Vapor films ; Water based ; Evaporation ; Heat exchangers ; Heat transfer ; Nanoparticles ; Nucleate boiling ; Quenching ; Silver ; Spheres ; Nanofluidics
  7. Source: International Journal of Thermal Sciences ; Volume 48, Issue 12 , 2009 , Pages 2215-2220 ; 12900729 (ISSN)
  8. URL: http://www.sciencedirect.com/science/article/pii/S1290072909000969