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Two-phase flow heat transfer during NH3 vaporization in horizontal smooth minichannels.

Author(s) : CHOI K. I., RIFALDI M., OH J. T., et al.

Summary

An experimental study of convective boiling heat transfer was conducted with NH3 in horizontal smooth minichannels. The experimental facilities were used to collect data with rigorous study and development. The test section is made of stainless steel tubes with inner diameters of 1.5 and 3.0 mm; the length is 2000 mm each. The minichannels are uniformly heated by applying an electric current directly to the single tubes; all components are well insulated to prevent heat loss. Local heat transfer coefficients are obtained for a heat flux of 10-80 kW/m2, a mass flux of 50-800 kg/m2.s, saturation temperatures of 0, 5, and 10°C and quality of up to 1.0. Nucleate boiling heat transfer contributions are predominant, especially at the low quality region. The reduction of heat transfer coefficients occurred at areas of lower vapor quality with a rise of heat flux, mass flux and saturation temperature, and with smaller inner tube diameters. Laminar flow appears in minichannel flows. A new boiling heat transfer coefficient correlation for NH3 was developed with 9.79% MD and -3.57% AD.

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Details

  • Original title: Two-phase flow heat transfer during NH3 vaporization in horizontal smooth minichannels.
  • Record ID : 30002840
  • Languages: English
  • Source: 4th Conference on Ammonia Refrigeration Technology. Proceedings: Ohrid, North Macedonia, April 14-16, 2011.
  • Publication date: 2011/04/14

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