Local Heat and Mass Transfer in a Counter-current Slug Flow Absorber for Ammonia-water Absorption Heat Pump System

Shigeru Koyama, SAHA Bidyut B., Hyun-Young Kim

    Research output: Contribution to journalArticle


    This study deals with experimental results and data reduction model for a counter-current slug flow absorber working with ammonia-water mixture for significantly low solution flow rate-condition that is required for operating as the GAX cycle. From visualization results of flow pattern, frost flow just after the gas inlet followed by slug flow with well-shaped Taylor bubble are observed, while dry patch on the tube wall are not observed. The local heat flow rate is measured by varying main parameters, namely, pressure, ammonia gas flow rate, solution flow rate, ammonia concentration of inlet solution and coolant inlet conditions. A data reduction model to obtain local heat and mass transfer coefficient on the liquid side is proposed by using the drift flux model to analyze the flow characteristics. Control volume method and heat and mass transfer analogy are employed to solve the combined heat and mass transfer problem. As a result, it is found that the local heat and mass transfer coefficient on the liquid side is greatly influenced by the flow pattern. The heat and mass transfer coefficient at the frost flow region is higher than that at the slug flow region due to flow disturbance and random fluctuation.
    Original languageEnglish
    Pages (from-to)279-286
    Number of pages8
    JournalTransactions of the Japan Society of Refrigerating and Air Conditioning Engineers
    Issue number2
    Publication statusPublished - 2003


    Cite this