Numerical investigation of grid spacer effect on heat transfer of supercritical water flows in a tight rod bundle

Xiaojing Zhu, Shinichi Morooka, Yoshiaki Oka

    Research output: Contribution to journalArticle

    36 Citations (Scopus)

    Abstract

    The numerical investigation was carried out for the effect of grid spacer on the local heat transfer performance of supercritical water flows within the inner sub-channel of a tight, hexagon rod bundle using commercial CFD code STAR CCM+ 6.04. The standard two layer k-epsilon model by Wolfstein with two layer all y+ wall treatment was used as turbulence model. The main objective has focused on the special thermal hydraulic characteristics caused by the standard grid spacer and the grid spacer with split-vanes. The circumferential heterogeneity of heat transfer performance and corresponding mechanism, as well as the effect of heat conduction within the stainless steel cladding, were analyzed in detail. It was found that the local heat transfer within the grid strap is greatly enhanced due to the reduced flow area. In the downstream region of the standard grid spacer, the enlarged circumferential temperature difference and decreased heat transfer near the narrow gap are caused by the aggravated flow choking effect. In the downstream region of the grid spacer with split-vanes, the circumferential distribution of heat transfer performance is greatly changed. The local heat transfer is enhanced just downstream of the grid spacer. However, big circumferential temperature difference and a decreased heat transfer region are also caused by the swirling flow, indicating that the swirling flow has adversely affected the local heat transfer. The improved heat transfer performance downstream of the grid spacer with split vanes is more pronounced for the higher Reynolds number case. The circumferential distribution of cladding temperature is more uniform and the enhanced heat transfer caused by split-vanes is more pronounced when the heat conduction is considered.

    Original languageEnglish
    Pages (from-to)245-257
    Number of pages13
    JournalInternational Journal of Thermal Sciences
    Volume76
    DOIs
    Publication statusPublished - 2014

    Fingerprint

    water flow
    spacers
    bundles
    rods
    heat transfer
    grids
    Heat transfer
    vanes
    Water
    Swirling flow
    swirling
    Heat conduction
    conductive heat transfer
    temperature gradients
    straps
    hexagons
    turbulence models
    high Reynolds number
    charge flow devices
    Turbulence models

    Keywords

    • CFD
    • Grid spacer
    • Heat transfer performance
    • Supercritical water
    • Tight rod bundle

    ASJC Scopus subject areas

    • Engineering(all)
    • Condensed Matter Physics

    Cite this

    Numerical investigation of grid spacer effect on heat transfer of supercritical water flows in a tight rod bundle. / Zhu, Xiaojing; Morooka, Shinichi; Oka, Yoshiaki.

    In: International Journal of Thermal Sciences, Vol. 76, 2014, p. 245-257.

    Research output: Contribution to journalArticle

    @article{fa75c719b84f4aa9be59ead6d2f88485,
    title = "Numerical investigation of grid spacer effect on heat transfer of supercritical water flows in a tight rod bundle",
    abstract = "The numerical investigation was carried out for the effect of grid spacer on the local heat transfer performance of supercritical water flows within the inner sub-channel of a tight, hexagon rod bundle using commercial CFD code STAR CCM+ 6.04. The standard two layer k-epsilon model by Wolfstein with two layer all y+ wall treatment was used as turbulence model. The main objective has focused on the special thermal hydraulic characteristics caused by the standard grid spacer and the grid spacer with split-vanes. The circumferential heterogeneity of heat transfer performance and corresponding mechanism, as well as the effect of heat conduction within the stainless steel cladding, were analyzed in detail. It was found that the local heat transfer within the grid strap is greatly enhanced due to the reduced flow area. In the downstream region of the standard grid spacer, the enlarged circumferential temperature difference and decreased heat transfer near the narrow gap are caused by the aggravated flow choking effect. In the downstream region of the grid spacer with split-vanes, the circumferential distribution of heat transfer performance is greatly changed. The local heat transfer is enhanced just downstream of the grid spacer. However, big circumferential temperature difference and a decreased heat transfer region are also caused by the swirling flow, indicating that the swirling flow has adversely affected the local heat transfer. The improved heat transfer performance downstream of the grid spacer with split vanes is more pronounced for the higher Reynolds number case. The circumferential distribution of cladding temperature is more uniform and the enhanced heat transfer caused by split-vanes is more pronounced when the heat conduction is considered.",
    keywords = "CFD, Grid spacer, Heat transfer performance, Supercritical water, Tight rod bundle",
    author = "Xiaojing Zhu and Shinichi Morooka and Yoshiaki Oka",
    year = "2014",
    doi = "10.1016/j.ijthermalsci.2013.10.003",
    language = "English",
    volume = "76",
    pages = "245--257",
    journal = "International Journal of Thermal Sciences",
    issn = "1290-0729",
    publisher = "Elsevier Masson SAS",

    }

    TY - JOUR

    T1 - Numerical investigation of grid spacer effect on heat transfer of supercritical water flows in a tight rod bundle

    AU - Zhu, Xiaojing

    AU - Morooka, Shinichi

    AU - Oka, Yoshiaki

    PY - 2014

    Y1 - 2014

    N2 - The numerical investigation was carried out for the effect of grid spacer on the local heat transfer performance of supercritical water flows within the inner sub-channel of a tight, hexagon rod bundle using commercial CFD code STAR CCM+ 6.04. The standard two layer k-epsilon model by Wolfstein with two layer all y+ wall treatment was used as turbulence model. The main objective has focused on the special thermal hydraulic characteristics caused by the standard grid spacer and the grid spacer with split-vanes. The circumferential heterogeneity of heat transfer performance and corresponding mechanism, as well as the effect of heat conduction within the stainless steel cladding, were analyzed in detail. It was found that the local heat transfer within the grid strap is greatly enhanced due to the reduced flow area. In the downstream region of the standard grid spacer, the enlarged circumferential temperature difference and decreased heat transfer near the narrow gap are caused by the aggravated flow choking effect. In the downstream region of the grid spacer with split-vanes, the circumferential distribution of heat transfer performance is greatly changed. The local heat transfer is enhanced just downstream of the grid spacer. However, big circumferential temperature difference and a decreased heat transfer region are also caused by the swirling flow, indicating that the swirling flow has adversely affected the local heat transfer. The improved heat transfer performance downstream of the grid spacer with split vanes is more pronounced for the higher Reynolds number case. The circumferential distribution of cladding temperature is more uniform and the enhanced heat transfer caused by split-vanes is more pronounced when the heat conduction is considered.

    AB - The numerical investigation was carried out for the effect of grid spacer on the local heat transfer performance of supercritical water flows within the inner sub-channel of a tight, hexagon rod bundle using commercial CFD code STAR CCM+ 6.04. The standard two layer k-epsilon model by Wolfstein with two layer all y+ wall treatment was used as turbulence model. The main objective has focused on the special thermal hydraulic characteristics caused by the standard grid spacer and the grid spacer with split-vanes. The circumferential heterogeneity of heat transfer performance and corresponding mechanism, as well as the effect of heat conduction within the stainless steel cladding, were analyzed in detail. It was found that the local heat transfer within the grid strap is greatly enhanced due to the reduced flow area. In the downstream region of the standard grid spacer, the enlarged circumferential temperature difference and decreased heat transfer near the narrow gap are caused by the aggravated flow choking effect. In the downstream region of the grid spacer with split-vanes, the circumferential distribution of heat transfer performance is greatly changed. The local heat transfer is enhanced just downstream of the grid spacer. However, big circumferential temperature difference and a decreased heat transfer region are also caused by the swirling flow, indicating that the swirling flow has adversely affected the local heat transfer. The improved heat transfer performance downstream of the grid spacer with split vanes is more pronounced for the higher Reynolds number case. The circumferential distribution of cladding temperature is more uniform and the enhanced heat transfer caused by split-vanes is more pronounced when the heat conduction is considered.

    KW - CFD

    KW - Grid spacer

    KW - Heat transfer performance

    KW - Supercritical water

    KW - Tight rod bundle

    UR - http://www.scopus.com/inward/record.url?scp=84887032410&partnerID=8YFLogxK

    UR - http://www.scopus.com/inward/citedby.url?scp=84887032410&partnerID=8YFLogxK

    U2 - 10.1016/j.ijthermalsci.2013.10.003

    DO - 10.1016/j.ijthermalsci.2013.10.003

    M3 - Article

    AN - SCOPUS:84887032410

    VL - 76

    SP - 245

    EP - 257

    JO - International Journal of Thermal Sciences

    JF - International Journal of Thermal Sciences

    SN - 1290-0729

    ER -