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Document IIF

Mesures du transfert de chaleur lors de l'ébullition du R134a et de propane dans des tubes de l'évaporateur lisses et ailetées.

Heat transfer measurements of R134a and propane boiling on evaporation tubes with plain and enhanced finned tubes.

Auteurs : LUKE A., KRUCK O.

Résumé

The influence of micro- and macro-structures on the heat transfer coefficient is investigated with propane and R134a by boiling at low temperatures on surfaces of different roughnesses and on structured surfaces. First, measurements of propane boiling on structured steel-tube surfaces within a recently built up apparatus are presented and compared to the results of a literature survey on propane and R134a boiling with steel tubes. Heat transfer measurements and bubble formation of R134a and propane boiling on plain surfaces with different roughnesses show good correlations. This applies for a wide range of pressures and different surface materials, e.g. steel and copper. Therefore, propane may be used as a replacement for the refrigerant, which has a large GWP. Recent measurements of both fluids at some enhanced tubes presented in this work, show differences in the heat transfer. This may be affected by thermo-physical properties of both fluids which are negligible on plain surfaces but are important for tubes that are optimized for special fluids. The influence of the macrostructure on the heat transfer coefficients of R134a and propane boiling on steel test tubes using different structures at different regimes of boiling will be discussed for a wide pressure range. The heat transfer measurements of the test tubes are carried out in a standard apparatus using electrical heated mild steel test tubes with plain and enhanced structures. The results of the heat transfer measurements are compared to the results of a literature survey. Also the bubble formation of both fluids will be discussed.

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Format PDF

Pages : 2008-2

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  • Prix public

    20 €

  • Prix membre*

    Gratuit

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Détails

  • Titre original : Heat transfer measurements of R134a and propane boiling on evaporation tubes with plain and enhanced finned tubes.
  • Identifiant de la fiche : 2009-0529
  • Langues : Anglais
  • Source : 8th IIR-Gustav Lorentzen Conference on Natural Working Fluids (GL2008)
  • Date d'édition : 07/09/2008

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