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Evaporation heat transfer for R22 and R407C refrigerant-oil mixture in a microfin tube with a U-bend.

Author(s) : CHO K., TAE S. J.

Type of article: Article, IJR article

Summary

Evaporation heat transfer experiments for two refrigerants, R407C and R22, mixed with polyol ester and mineral oils were performed in straight and U-bend sections of a microfin tube. Experimental parameters include an oil concentration varied from 0 to 5%, an inlet quality varied from 0.1 to 0.5, two mass fluxes of 219 and 400 kg/(m2.s) and two heat fluxes of 10 and 20 kW/m2. Pressure drop in the test section increased by approximately 20% as the oil concentration increased from 0 to 5%. Enhancement factors decreased as oil concentration increased under inlet quality of 0.5, mass flux of 219 kg/(m2.s), and heat flux of 10 kW/m2, whereas they increased under inlet quality of 0.1, mass flux of 400 kg/(m2.s), and heat flux of 20 kW/m2. The local heat transfer coefficient at the outside curvature of an U-bend was larger than that at the inside curvature of a U-bend, and the maximum value occurred at the 90° position of the U-bend. The heat transfer coefficient was larger in a region of 30 tube diameter length at the second straight section than that at the first straight section.

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Pages: 219-231

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Details

  • Original title: Evaporation heat transfer for R22 and R407C refrigerant-oil mixture in a microfin tube with a U-bend.
  • Record ID : 2000-2452
  • Languages: English
  • Source: International Journal of Refrigeration - Revue Internationale du Froid - vol. 23 - n. 3
  • Publication date: 2000/05

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