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Two-phase frictional pressure drop in U-type wavy tubes subject with and without the presence of lubricant oil.

Author(s) : CHEN I. Y., WU Y. S., HU R., et al.

Summary

The study presents two-phase pressure drop data for R-134a/oil mixture flowing in a wavy tube. Both mixtures have oil concentration for the tests. The ratio between two-phase pressure gradients of U-bend and straight tube is about 2.5-3.5. This ratio is increased with oil concentration and vapour quality. The influence of oil is augmented at a higher mass flux for liquid spreading around the periphery at an annular flow pattern. Moreover, the influence of lubricant becomes more evident in U-bend configurations. This is associated the induced swirled flow motion and an early change of flow pattern from stratified to annular flow pattern. The frictional two-phase pressure gradient for straight tube can be fairly predicted by Friedel correlation with a mean deviation of 17.6%. For the two-phase pressure drop in U-bend, the revised Geary correlation agrees very well with the present data with a mean deviation of 16.4%.

Details

  • Original title: Two-phase frictional pressure drop in U-type wavy tubes subject with and without the presence of lubricant oil.
  • Record ID : 2007-0581
  • Languages: English
  • Subject: HFCs alternatives
  • Source: ACRA-2006. Proceedings of the 3rd Asian conference on refrigeration and air conditioning.
  • Publication date: 2006/05/21

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