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ISSN Online: 2377-424X

ISBN Print: 978-1-56700-474-8

ISBN Online: 978-1-56700-473-1

International Heat Transfer Conference 16
August, 10-15, 2018, Beijing, China

EXPERIMENTAL INVESTIGATION ON THE CONDENSATION OF R134A IN MULTIPORT FLAT TUBES

Get access (open in a dialog) DOI: 10.1615/IHTC16.cod.023485
pages 2243-2250

要約

Modern AC systems require a high degree of efficiency to ensure low energy consumption and low emissions. Although numerous investigations regarding the thermohydraulic characteristics of condensing refrigerants have been performed, various influences on the condensation process are not fully understood and therefore negatively affect the aim of developing an efficient design for new and innovative compact heat exchangers for two-phase applications. The channel shape as well as the hydraulic diameter are likely to affect heat transfer characteristics. A test loop facility has been set up to provide high quality measurements for heat transfer and pressure drop inside multiport flat tubes (MPFT). A novel test section design has been developed, which allows the characterization of various flat tube geometries, while maintaining comparability and repeatability. Thus, a fundamental investigation can be performed based on application-oriented conditions. This contribution aims at extending the available data base in the literature regarding the condensation of pure R134a in multiport flat tubes. In addition to the variation of the saturation pressure from 10 to 20 bars, the variation of the mass flux between 200 and 1000 kg/(m²s) and the vapour quality from 10 to 90 %, various channel cross sections have been investigated. The effects of channel shape parameters as well as of the hydraulic diameter have been determined and compared to renowned correlations in the literature. The application of well-known correlations for pure refrigerants, such as the Friedel correlation (1979) regarding the pressure drop or the Koyama correlation (2016) regarding the heat transfer coefficient, will be discussed.