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Flow visualization of supercritical carbon dioxide entrained with small amount of lubricating oil.

Author(s) : DANG C., IINO K., HIHARA E.

Summary

In order to clarify the heat transfer mechanism of supercritical carbon dioxide flowing with a small amount of lubricating oil, visualization experiments have been conducted using a sight glass in a tube with an inner diameter of 2 mm. This sight glass is made of sapphire crystals in order to withstand pressures of up to 20 MPa. The visualization images were recorded using a high-speed CCD camera, PAG-type oil, which is partially miscible with supercritical carbon dioxide, was used. The experiments were conducted with lubricating oil concentrations of 1 and 5%, pressures between 8 and 10 MPa, and mass fluxes between 800 and 1200 kg/m2s. The visualization images reveal the formation of both oil droplets in the bulk region and the oil film along the inner wall of the tube. The observation results are explained by means of the variation of the density of the supercritical carbon dioxide and solubility of carbon dioxide in lubricating oil with temperature and pressure.

Details

  • Original title: Flow visualization of supercritical carbon dioxide entrained with small amount of lubricating oil.
  • Record ID : 2007-0072
  • Languages: English
  • Source: ACRA-2006. Proceedings of the 3rd Asian conference on refrigeration and air conditioning.
  • Publication date: 2006/05/21

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