IIR document

Effect of vapour flow on the falling-film heat transfer of a helical coil.

Author(s) : KWON K., JEONG S.


The flow and heat transfer in the falling film of a heat exchanger can be influenced by the motion of the surrounding refrigerant vapour. In this study, the effect of the vapour flow direction on the condensation and absorption heat transfer has been investigated for a falling-film helical coil which is frequently used as the absorber of ammonia/water absorption refrigerators. The experiments were carried out with pure water and ammonia/water solution, respectively. The heat transfer performance was measured for both parallel and countercurrent flows. It is found that the falling-film heat transfer is deteriorated if the vapour flow is countercurrent and its velocity is high. In the experiments with pure water, whose vapour specific volume is great, the countercurrent flow of vapour resulted in uneven distribution of falling-film and reduced the heat transfer performance of the heat exchanger. For the experiment with ammonia/water, the direction of the vapour flow hardly affected the thermal performance since the specific volume of the ammonia/water vapour was much smaller than that of the water vapour.

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  • Original title: Effect of vapour flow on the falling-film heat transfer of a helical coil.
  • Record ID : 2004-2228
  • Languages: English
  • Source: 21st IIR International Congress of Refrigeration: Serving the Needs of Mankind.
  • Publication date: 2003/08/17


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