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Experimental study on flow boiling of CO2-PAG oil mixture in smooth and micro-fin tubes.

[In Japanese. / En japonais.]

Author(s) : KOYAMA S., ITO D., LEE S. M., et al.

Type of article: Article

Summary

In the study, experiments on the flow boiling of nearly pure CO2 and CO2-PAG oil mixture are carried out using a 2.064 m long double-pipe counter-flow heat exchanger, in which the refrigerant flows inside the inner tube and the heat source water flows counter-currently in the outer annulus. A smooth cooper tube and a micro-fin copper tube were used as the inner tube. In the case of nearly pure CO2 the present experimental results of heat transfer coefficients in smooth tubes with a rough surface agree well with the predicted results using the Yu et al. correlation, in which the surface roughness effect is taken into account. It was also confirmed that the values of the heat transfer coefficient for both smooth and micro-fin tubes were almost analogous, while the values of pressure drop for micro-fin tubes were slightly higher than those of smooth tubes. By comparing the experimental results between nearly pure CO2 and CO2-oil mixture, it was confirmed that the oil concentration effects on the heat transfer coefficient and the pressure drop in micro-fin tube have different characteristics from those of smooth tubes.

Details

  • Original title: [In Japanese. / En japonais.]
  • Record ID : 2006-2221
  • Languages: Japanese
  • Source: Transactions of the Japan Society of Refrigerating and Air Conditioning Engineers - vol. 22 - n. 4
  • Publication date: 2005

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