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A COMPARISON OF EVAPORATION HEAT TRANSFER COEFFICIENTS AND PRESSURE DROP IN A HORIZONTAL SMOOTH TUBE FOR HFC-134A AND CFC-12.

Author(s) : TAKAMATSU H., MOMOKI S., FUJII T.

Summary

AN EXPERIMENT IS CARRIED OUT ON THE EVAPORATION OF R12 AND ITS ALTERNATIVE R134A IN A 6 METER-LONG, 7.9 MILLIMETER-INTERNAL DIAMETER SMOOTH TUBE. A DOUBLE PIPE EVAPORATOR, WHERE HEATING WATER FLOWS COUNTERCURRENTLY IN THE OUTER ANNULUS, IS USED AS THE TEST SECTION. A COMPARISON OF MEASURED LOCAL HEAT TRANSFER COEFFICIENT OF R134A AND R12 IS MADE BY ADJUSTING THE HEAT FLUX DISTRIBUTION FOR BOTH FLUIDS. THE HEAT TRANSFER COEFFICIENT VS HEAT FLUX DIAGRAMS SHOWS THAT THE HEAT TRANSFER COEFFICIENT OF R134A IS ABOUT 25% HIGHERTHAN THAT OF R12 FOR THE SAME SATURATION TEMPERATURE, MASS VELOCITY, HEAT FLUX AND QUALITY. THE FRICTIONAL PRESSURE DROP FOR R134A, WHICH IS EVALUATED FROM THE MEASURED STATIC PRESSURE DROP, COINCIDES WITH THAT FOR R12 IN THE RELATIONSHIP BETWEEN TWO-PHASE FLOW PARAMETERS.

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Pages: 444-448

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Details

  • Original title: A COMPARISON OF EVAPORATION HEAT TRANSFER COEFFICIENTS AND PRESSURE DROP IN A HORIZONTAL SMOOTH TUBE FOR HFC-134A AND CFC-12.
  • Record ID : 1992-2131
  • Languages: English
  • Source: New challenges in refrigeration. Proceedings of the XVIIIth International Congress of Refrigeration, August 10-17, 1991, Montreal, Quebec, Canada.
  • Publication date: 1991/08/10
  • Document available for consultation in the library of the IIR headquarters only.

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