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Heat transfer enhancement in evaporation by thermal spray coating.

Author(s) : ASANO H., TOMITA R., SHIGEHARA R., et al.

Summary

Heat transfer enhancement is still required for the compactness and its smaller temperature difference of evaporator. In this study, heat transfer surfaces processed by thermal spraying were examined as a boiling heat transfer enhancement technique. Since the coating has numerous cavities and porous structure, high bubble site density and high wettability is expected. Boiling heat transfer performance was evaluated by pool boiling and forced convective boiling experiments. For pool boiling, the heat transfer performance on horizontal tubes was examined. Vacuum plasma thermal spraying using copper as a coating material was applied to the outside of copper cylinder. As a result, constant heat transfer enhancement ratio to smooth surface could be obtained in entire range of heat flux. Heat transfer coefficient was affected by heating hysteresis. For forced convective boiling, heat transfer performance in a narrow rectangular channel was examined. The effects of channel gap and channel orientation were examined. As a result, the coating using finer particle produced higher heat transfer. The effect of channel orientation was remarkable in the low quality, low mass flux condition.

Details

  • Original title: Heat transfer enhancement in evaporation by thermal spray coating.
  • Record ID : 2011-0090
  • Languages: English
  • Source: Measures to address climate change. 2010 International Symposium on Next-generation Air Conditioning and Refrigeration Technology: February 17-19, Tokyo, Japan.
  • Publication date: 2010/02/17

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