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Experimental and theoretical investigation of annular film flow reversal in a vertical pipe: application to oil return in refrigeration systems.

Author(s) : MEHENDALE S. S., RADERMACHER R.

Type of article: Article

Summary

The work studied, both experimentally and theoretically, the fundamental mechanism of oil transport by vapour, liquid and two-phase refrigerant through analysis of the characteristic behaviour of several refrigerant-lubricant pairs. Extensive flow visualization experiments were conducted to pinpoint the critical refrigerant flow rate for preventing oil film flow reversal in a vertical pipe with an 8-mm inside diameter for vapour refrigerant with miscible and immiscible lubricants and in the first such study, for two-phase refrigerant with immiscible lubricant. An annular flow model with a vapour core, utilizing an empirical correlation for the interfacial friction factor was also developed to predict the onset of lubricant film flow reversal.

Details

  • Original title: Experimental and theoretical investigation of annular film flow reversal in a vertical pipe: application to oil return in refrigeration systems.
  • Record ID : 2001-0756
  • Languages: English
  • Source: HVAC&R Research - vol. 6 - n. 1
  • Publication date: 2000/01
  • Document available for consultation in the library of the IIR headquarters only.

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