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An experimental study of falling film evaporation on inclined plates using R-141b and R-134a.

Author(s) : CHIEN L. H., LIN H. T.

Summary

This paper discusses the effects of surface geometries and inclination angle on falling film evaporation performance. Falling film evaporation experiments were conducted on a plain plate and a finned plate using refrigerants R-141b at 15.5°C, plus or minus 0.5°C and R-134a at 10.5°C, plus or minus 0.5°C system temperature. Both plates were tested with an inclination angle between 10 and 40°C, and the heat fluxes were varied between 17.9 and 45.7 kW/m2. The finned surface yielded better falling film evaporation heat transfer performance than the plain surface for both R-141b and R-134a. For R-141b, the finned surface yielded 1.5-1.8 times the heat transfer coefficients of the plain surface. For R-134a, the evaporative heat transfer was enhanced 2.5-4.8-fold with the fins. The visual observation showed that bubble nucleation was more pronounced on the finned surface than on the plain surface. For the Fin-B surface in both R-134a and R-141b, the heat transfer coefficient increased as the inclination angle increased. No significant effect of inclination was found on plain surface for R-141b.

Details

  • Original title: An experimental study of falling film evaporation on inclined plates using R-141b and R-134a.
  • Record ID : 2008-1555
  • Languages: English
  • Source: ASHRAE Transactions. 2007 Annual Meeting, Long Beach, CA. Volume 113, part 2 + CD-ROM.
  • Publication date: 2007/06/23

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