Modelling frazil and anchor ice on submerged objects

Lasse Makkonen (Corresponding Author), Maria Tikanmäki

    Research output: Contribution to journalArticleScientificpeer-review

    3 Citations (Scopus)

    Abstract

    Frazil and anchor ice cause blockage of water intakes and icing of other type of submerged objects. In this paper, the physical mechanisms that control these phenomena are discussed and analyzed. Our conclusions are somewhat different from the views presented earlier. 1) Ice crystals in water may originate from microbubbles and turbulence, so that nucleation may occur regardless of an external source 2) The number concentration of ice crystals may not necessarily increase much during an active frazil ice event, 3) The heat transfer from a frazil ice crystal is controlled by its relative rise velocity, not by water turbulence, 4) The collision efficiency of frazil ice crystals on grid components is so small that frazil typically causes no blockage of submerged water intakes, and 5) Blockage is largely caused by ice platelets that grow in-situ on the structural components. We model frazil and anchor ice formation theoretically and find that the uncertainty about the concentration of ice crystals is the main obstacle to accurate modelling. Within these limits, our model results agree well with the available experimental data.

    Original languageEnglish
    Pages (from-to)64-74
    Number of pages11
    JournalCold Regions Science and Technology
    Volume151
    DOIs
    Publication statusPublished - 1 Jul 2018
    MoE publication typeA1 Journal article-refereed

    Fingerprint

    ice crystal
    Anchors
    anchor
    Ice
    ice
    modeling
    Crystals
    turbulence
    water
    structural component
    Water
    nucleation
    Turbulence
    heat transfer
    collision
    Platelets
    Nucleation
    Heat transfer

    Keywords

    • Anchor ice
    • Frazil
    • Frazil ice
    • Ice
    • Nucleation
    • Supercooling
    • Water intake

    Cite this

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    title = "Modelling frazil and anchor ice on submerged objects",
    abstract = "Frazil and anchor ice cause blockage of water intakes and icing of other type of submerged objects. In this paper, the physical mechanisms that control these phenomena are discussed and analyzed. Our conclusions are somewhat different from the views presented earlier. 1) Ice crystals in water may originate from microbubbles and turbulence, so that nucleation may occur regardless of an external source 2) The number concentration of ice crystals may not necessarily increase much during an active frazil ice event, 3) The heat transfer from a frazil ice crystal is controlled by its relative rise velocity, not by water turbulence, 4) The collision efficiency of frazil ice crystals on grid components is so small that frazil typically causes no blockage of submerged water intakes, and 5) Blockage is largely caused by ice platelets that grow in-situ on the structural components. We model frazil and anchor ice formation theoretically and find that the uncertainty about the concentration of ice crystals is the main obstacle to accurate modelling. Within these limits, our model results agree well with the available experimental data.",
    keywords = "Anchor ice, Frazil, Frazil ice, Ice, Nucleation, Supercooling, Water intake",
    author = "Lasse Makkonen and Maria Tikanm{\"a}ki",
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    language = "English",
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    Modelling frazil and anchor ice on submerged objects. / Makkonen, Lasse (Corresponding Author); Tikanmäki, Maria.

    In: Cold Regions Science and Technology, Vol. 151, 01.07.2018, p. 64-74.

    Research output: Contribution to journalArticleScientificpeer-review

    TY - JOUR

    T1 - Modelling frazil and anchor ice on submerged objects

    AU - Makkonen, Lasse

    AU - Tikanmäki, Maria

    PY - 2018/7/1

    Y1 - 2018/7/1

    N2 - Frazil and anchor ice cause blockage of water intakes and icing of other type of submerged objects. In this paper, the physical mechanisms that control these phenomena are discussed and analyzed. Our conclusions are somewhat different from the views presented earlier. 1) Ice crystals in water may originate from microbubbles and turbulence, so that nucleation may occur regardless of an external source 2) The number concentration of ice crystals may not necessarily increase much during an active frazil ice event, 3) The heat transfer from a frazil ice crystal is controlled by its relative rise velocity, not by water turbulence, 4) The collision efficiency of frazil ice crystals on grid components is so small that frazil typically causes no blockage of submerged water intakes, and 5) Blockage is largely caused by ice platelets that grow in-situ on the structural components. We model frazil and anchor ice formation theoretically and find that the uncertainty about the concentration of ice crystals is the main obstacle to accurate modelling. Within these limits, our model results agree well with the available experimental data.

    AB - Frazil and anchor ice cause blockage of water intakes and icing of other type of submerged objects. In this paper, the physical mechanisms that control these phenomena are discussed and analyzed. Our conclusions are somewhat different from the views presented earlier. 1) Ice crystals in water may originate from microbubbles and turbulence, so that nucleation may occur regardless of an external source 2) The number concentration of ice crystals may not necessarily increase much during an active frazil ice event, 3) The heat transfer from a frazil ice crystal is controlled by its relative rise velocity, not by water turbulence, 4) The collision efficiency of frazil ice crystals on grid components is so small that frazil typically causes no blockage of submerged water intakes, and 5) Blockage is largely caused by ice platelets that grow in-situ on the structural components. We model frazil and anchor ice formation theoretically and find that the uncertainty about the concentration of ice crystals is the main obstacle to accurate modelling. Within these limits, our model results agree well with the available experimental data.

    KW - Anchor ice

    KW - Frazil

    KW - Frazil ice

    KW - Ice

    KW - Nucleation

    KW - Supercooling

    KW - Water intake

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