Improving supercritical CO2 cooling using conical tubes equipped with non-uniform twisted inserts

M. Khoshvaght-Aliabadi, P. Ghodrati, S. F. Khaligh, Y. T. Kang

    Research output: Contribution to journalArticlepeer-review

    14 Citations (Scopus)

    Abstract

    Comprehensive understanding of how flow path geometry influences heat transfer and flow characteristics is essential for designing effective heat exchange devices in supercritical Brayton cycles. This study focuses on the numerical investigation of the horizontal flow of supercritical CO2 in conical horizontal tubes (CHTs) equipped with non-uniform structures of twisted inserts (TIs). A meticulously validated numerical model, implemented using the k-omega turbulence model in ANSYS Fluent, is employed to investigate the impact of gravity and operating conditions on the performance of studied models. It is found that in areas characterized by a small tube diameter and a large twist length, the temperature disparity between the top and bottom walls is negligible, indicating a very weak buoyancy effect. Utilizing TIs in diverging CHTs can effectively enhance the heat transfer coefficient and reduce the pressure drop in comparison to uniform and converging cases. Additionally, the combination of diverging CHTs with a TI featuring high-to-low twist lengths results in a maximum percentage enhancement of 43.1% in heat transfer coefficient. Simultaneously, there is an almost 36.7% reduction in pressure drop. This model exhibits the maximum overall performance index value, with approximately a 25% enhancement compared to the reference case.

    Original languageEnglish
    Article number107171
    JournalInternational Communications in Heat and Mass Transfer
    Volume150
    DOIs
    Publication statusPublished - 2024 Jan

    Bibliographical note

    Publisher Copyright:
    © 2023

    Keywords

    • Carbon dioxide (CO)
    • Converging
    • Diverging
    • Supercritical flow
    • Twist length
    • Twisted insert

    ASJC Scopus subject areas

    • Atomic and Molecular Physics, and Optics
    • General Chemical Engineering
    • Condensed Matter Physics

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