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EVAPORATION AND CONDENSATION OF REFRIGERANT-OIL MIXTURES IN A SMOOTH TUBE AND A MICRO-FIN TUBE.

Author(s) : SCHLAGER L. M., PATE M. B., BERGLES A. E.

Summary

EVAPORATION AND CONDENSATION OF REFRIGERANT-OIL MIXTURES WERE STUDIED BOTH INSIDE A SMOOTH TUBE AND A MICRO-FIN TUBE. THE REFRIGERANT WAS R22 AND THE OIL WAS A NAPHTHENIC BASE MINERAL OIL WITH A VISCOSITY OF 150 SUS (ISO 32 OR 4.4 DEG ENGLER). THE OIL AND REFRIGERANT WERE COMPLETELY MISCIBLE FOR THE ENTIRE RANGE OF TEST CONDITIONS. THE MICRO-FIN TUBE INCREASED THE AVERAGE HEAT TRANSFER COEFFICIENTS FOR BOTH EVAPORATION AND CONDENSATION BY AS MUCH AS A FACTOR OF 2.5 FOR REFRIGERANT-OIL MIXTURES AS WELL AS FOR PURE REFRIGERANT. FOR BOTH SMOOTH AND MICRO-FIN TUBES, SMALL QUANTITIES OF OIL WERE FOUND TO ENHANCE EVAPORATION HEAT TRANSFER. ABOVE A THRESHOLD CONCENTRATION, THE ADDITION OF INCREASING QUANTITIES OF OIL CAUSED THE ENHANCEMENT TO DECREASE, BUT FOR THEMICRO-FIN TUBE, THE ENHANCEMENT REMAINED GREATER THAN THE INCREASE IN SURFACE AREA. THE ADDITION OF ANY OIL CAUSED THE CONDENSATION HEAT TRANSFER TO DECREASE FOR BOTH TUBES. THE MICRO-FOR CONDENSATION SHOWED LITTLE DEPENDENCE ON THE OIL CONCENTRATION.

Details

  • Original title: EVAPORATION AND CONDENSATION OF REFRIGERANT-OIL MIXTURES IN A SMOOTH TUBE AND A MICRO-FIN TUBE.
  • Record ID : 1989-0853
  • Languages: English
  • Publication date: 1988
  • Source: Source: ASHRAE Trans.
    vol. 94; n. 1; 149-166; 14 fig.; 4 tabl.; 38 ref.
  • Document available for consultation in the library of the IIR headquarters only.

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