Effect of a crossflow at the entrance to a film-cooling hole

Karen Ann Thole, M. Gritsch, A. Schulz, S. Wittig

    Research output: Contribution to journalArticle

    104 Citations (Scopus)

    Abstract

    Understanding the complex flow of jets issuing into a crossflow from an inclined hole that has a short length-to-diameter ratio is relevant for film-cooling applications on gas turbine blades. In particular, this experimental study focused on the effect of different velocities in a coflowing channel at the cooling hole entrance. Flows on both sides of the cooling hole (entrance and exit) were parallel and in the same direction. With the blowing ratio and the mainstream velocity at the hole exit remaining fixed, only the flow velocity in the channel at the hole entrance was varied. The Mach number at the hole entrance was varied between 0 < Mac< 0.5, while the Mach number at the hole exit remained constant at Ma= 0.25. The velocity ratio and density ratio of the jet were unity giving a blowing ratio and momentum flux ratio also of unity. The single, scaled’up film-cooling hole was inclined at 30 deg with respect to the mainstream and had a hole length-to-diameter ratio of L/D = 6. Flowfield measurements were made inside the hole, at the hole inlet and exit, and in the near-hole region where the jet interacted with the crossflow at the hole exit. The results show that for entrance crossflow Mach numbers of Mac= 0 and 0.5, a separation region occurs on the leeward and windward side of the cooling hole entrances, respectively. As a result of this separation region, the cooling jet exits in a skewed manner with very high turbulence levels.

    Original languageEnglish (US)
    Pages (from-to)533-540
    Number of pages8
    JournalJournal of Fluids Engineering, Transactions of the ASME
    Volume119
    Issue number3
    DOIs
    StatePublished - Jan 1 1997

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    Cooling
    Mach number
    Blow molding
    Flow velocity
    Turbomachine blades
    Gas turbines
    Momentum
    Turbulence
    Fluxes

    All Science Journal Classification (ASJC) codes

    • Mechanical Engineering

    Cite this

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    abstract = "Understanding the complex flow of jets issuing into a crossflow from an inclined hole that has a short length-to-diameter ratio is relevant for film-cooling applications on gas turbine blades. In particular, this experimental study focused on the effect of different velocities in a coflowing channel at the cooling hole entrance. Flows on both sides of the cooling hole (entrance and exit) were parallel and in the same direction. With the blowing ratio and the mainstream velocity at the hole exit remaining fixed, only the flow velocity in the channel at the hole entrance was varied. The Mach number at the hole entrance was varied between 0 < Mac< 0.5, while the Mach number at the hole exit remained constant at Ma∞= 0.25. The velocity ratio and density ratio of the jet were unity giving a blowing ratio and momentum flux ratio also of unity. The single, scaled’up film-cooling hole was inclined at 30 deg with respect to the mainstream and had a hole length-to-diameter ratio of L/D = 6. Flowfield measurements were made inside the hole, at the hole inlet and exit, and in the near-hole region where the jet interacted with the crossflow at the hole exit. The results show that for entrance crossflow Mach numbers of Mac= 0 and 0.5, a separation region occurs on the leeward and windward side of the cooling hole entrances, respectively. As a result of this separation region, the cooling jet exits in a skewed manner with very high turbulence levels.",
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    Effect of a crossflow at the entrance to a film-cooling hole. / Thole, Karen Ann; Gritsch, M.; Schulz, A.; Wittig, S.

    In: Journal of Fluids Engineering, Transactions of the ASME, Vol. 119, No. 3, 01.01.1997, p. 533-540.

    Research output: Contribution to journalArticle

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