International Journal of Air-Conditioning and Refrigeration

The Society of Air-Conditioning and Refrigerating Engineers of Korea (대한설비공학회)
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Forced Convective Boiling of Refrigerant-Oil Mixtures in a Bundle of Enhanced Tubes Having Pores and Connecting Gaps

  • Park, Ji-Hoon (Department of Mechanical Engineering, University of Incheon) ;
  • Kim, Nae-Hyun (Department of Mechanical Engineering, University of Incheon) ;
  • Kim, Do-Young (Department of Mechanical Engineering, University of Incheon) ;
  • Byun, Ho-Won (Department of Mechanical Engineering, University of Incheon) ;
  • Choi, Yong-Min (Department of Mechanical Engineering, University of Incheon) ;
  • Kim, Soo-Hwan (Department of Mechanical Engineering, University of Incheon)
  • Published : 2009.09.30
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Abstract

The effect of oil on convective boiling of R-123 in an enhanced tube bundle is experimentally investigated at $26.7^{\circ}C$ saturation temperature. The enhanced tube had pores (0.23 mm diameter) and connecting gaps (0.07 mm width), which had been optimized using pure R-123. The effects of oil concentration (0 to 5%), heat flux (10 to $40\;kW/m^2$), mass velocity (8 to $26\;kg/m2^s$) and vapor quality are investigated. The oil significantly reduces the bundle boiling heat transfer coefficient. With 1% oil, the reduction is approximately 35%. Further addition of oil further reduces the heat transfer coefficient. The data are also compared with the pool boiling counterpart. The reduction in the heat transfer coefficient is smaller in a bundle (convective boiling) than in a pool (single-tube pool boiling), with larger difference at a smaller heat flux. Similar to pure R-123 case, the effects of mass velocity and vapor quality are negligible for the convective boiling of R-123/oil mixture.

Keywords

References

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