Falling film evaporation of pure refrigerant HCFC123 in a vertical rectangular minichannele consisting of offset strip fins

Junichi Ohara, Shigeru Koyama, Ken Kuwahara

    Research output: Chapter in Book/Report/Conference proceedingConference contribution

    Abstract

    In the present study, the characteristics of heat transfer and flow patterns are experimentally investigated on the falling film evaporation of pure refrigerant HCFC123 in a vertical rectangular minichannel consisting of offset strop fins. The refrigerant liquid is supplied to the channel through 37 holes of a distributor. The liquid flowing down vertically is heated electrically from the rear wall of the channel and evaporated. To observe the flow patterns during the evaporation process directly, a transparent vinyl chloride resin plate is placed as the front wall. The experimental parameters are as follows: the mass velocity G = 28-70 kg/(m2s), the heat flux q = 20-50 kW/m2 and the pressure P ≈ 100 kPa. It is clarified that the heat transfer coefficient α depends on G and q in the region of vapor quality x ≥ 0.3 while there is little influence of G and q in the region x ≤ 0.3 . From the direct observation using a high speed video camera and a digital still camera, flow patterns are classified into five typical ones: plane liquid film, wavy liquid film, liquid film accompanied with dry patch, liquid film accompanied with dripping and liquid film accompanied with mist. Then the relation between heat transfer and flow pattern is clarified. The results of heat transfer characteristics are also compared with some previous correlation equations.

    Original languageEnglish
    Title of host publicationProceedings of the 3rd International Conference on Microchannels and Minichannels, 2005
    Pages49-56
    Number of pages8
    Publication statusPublished - 2005
    Event3rd International Conference on Microchannels and Minichannels, ICMM2005 - Toronto, ON, Canada
    Duration: Jun 13 2005Jun 15 2005

    Publication series

    NameProceedings of the 3rd International Conference on Microchannels and Minichannels, 2005
    VolumePART B

    Other

    Other3rd International Conference on Microchannels and Minichannels, ICMM2005
    CountryCanada
    CityToronto, ON
    Period6/13/056/15/05

    All Science Journal Classification (ASJC) codes

    • Engineering(all)

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  • Cite this

    Ohara, J., Koyama, S., & Kuwahara, K. (2005). Falling film evaporation of pure refrigerant HCFC123 in a vertical rectangular minichannele consisting of offset strip fins. In Proceedings of the 3rd International Conference on Microchannels and Minichannels, 2005 (pp. 49-56). [ICMM2005-75128] (Proceedings of the 3rd International Conference on Microchannels and Minichannels, 2005; Vol. PART B).