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Heat transfer and pressure drop for flow boiling of non-azeotropic refrigerant mixtures of HFC-32/HFC-125/HFC-134a and HFC-32/HFC-134a in horizontal tubes.

[In Japanese. / En japonais.]

Author(s) : MORI H., YOSHIDA S., OHISHI K.

Type of article: Article

Summary

Experiments were performed on heat transfer and pressure drop for flow boiling of these two non-azeotoropic refrigerant mixtures in horizontal smooth and internally, spirally grooved tubes. Almost the same local heat transfer coefficients were obtained for both the mixtures in each tube. In the smooth tube, in the region where nucleate boiling contributes substantially to the heat transfer, the heat transfer coefficients for the mixtures were reduced down to about two-thirds of the value for HCFC-22, due to the effect of a mass transfer resistance on the heat transfer, while they were approximately equal to those for HCFC-22 in the forced convection dominated region. With the grooved tube, the heat transfer was enhanced over the smooth tube, but the enhancement was smaller than for HCFC-22. In both the tubes, frictional pressure drops for the binary mixture were generally a few to 20 percent higher than those for the ternary mixture and the pure refrigerant, corresponding to the difference in the vapour density.

Details

  • Original title: [In Japanese. / En japonais.]
  • Record ID : 1998-0794
  • Languages: Japanese
  • Source: Transactions of the Japan Society of Refrigerating and Air Conditioning Engineers - vol. 14 - n. 1
  • Publication date: 1997
  • Document available for consultation in the library of the IIR headquarters only.

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