Effects of surface roughness and tube materials on the filmwise condensation heat transfer coefficient at low heat transfer rates

Rin Yun, Jaeheok Heo, Yongchan Kim

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6 Citations (Scopus)


The laminar filmwise condensation heat transfer coefficient on the horizontal tubes of copper and stainless steel was investigated. The outside diameter of the tubes was 15.88 mm, and the tube thickness ranged from 1.07 to 1.6 mm. The polished stainless steel tube had an RMS surface roughness of 0.37 μm, and commercial stainless steel tubes had maximum surface roughness of 15 μm. The tests were conducted at saturation temperatures of 20 and 30 °C, and liquid wall subcoolings from 0.4 to 2.1 °C. The measured condensation heat transfer coefficients were significantly lower than the predicted data by the Nusselt analysis when the ratio of the condensate liquid film thickness to the surface roughness, δ/Rp-v, was relatively low. When the condensate liquid film was very thin, tube material affected the condensation heat transfer coefficient in the filmwise condensation.

Original languageEnglish
Pages (from-to)445-450
Number of pages6
JournalInternational Communications in Heat and Mass Transfer
Issue number4
Publication statusPublished - 2006 Apr 1



  • Condensate liquid film thickness
  • Filmwise condensation heat transfer
  • Surface roughness
  • Tube thermal conductivity

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics
  • Chemical Engineering(all)
  • Condensed Matter Physics

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