Numerical Simulation of Single, Double, and Multiple Row Film Cooling Effectiveness and Heat Transfer

Miller, K.; Crawford, Michael E.

doi:10.1115/84-gt-112

Cited by 16 publications

(10 citation statements)

References 7 publications

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“…[77] and Miller and Crawford [78]: they implemented a model for the coolant injection in a 2D boundary layer code. More recently, approaches in 3D-CFD have been presented.…”

Section: Literature Reviewmentioning

confidence: 99%

Film Cooling Modelling for Gas Turbine Nozzles and Blades: Validation and Application

Andrei

Innocenti

Andreini

et al. 2015

Volume 5B: Heat Transfer

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The use of Computational Fluid Dynamics (CFD) for modern turbine blade design requires the accurate representation of the effect of film cooling. However, including complete cooling hole discretization in the computational domain requires a substantial meshing effort and leads to a drastic increase in the computing time. For this reason, many efforts have been made to develop lower order approaches aiming at reducing the number of mesh elements and therefore computational resources. The simplest approach models the set of holes as a uniform coolant injection, but it does not allow an accurate assessment of the interaction between hot gas and coolant. Therefore higher order models have been developed, such as those based on localized mass sources in the region of hole discharge. It is here proposed an innovative injection film cooling model (FCM), embedded in a CFD code, to represent the effect of cooling holes by adding local source terms at the hole exit in a delimited portion of the domain, avoiding the meshing process of perforations. The goal is to provide a reliable and accurate tool to simulate film-cooled turbine blades and nozzles without having to explicitly mesh the holes. The validation campaign of the proposed model is composed of two phases. During the first one, results obtained with the film cooling model are compared to experimental data and to numerical results obtained with the full meshing of the cooling holes on a series of test cases, ranging from single row to multi row flat plate, at varying coolant conditions (in terms of blowing and density ratio). Though details of the flow structure downstream of the holes cannot be perfectly captured, this method allows an accurate prediction of the overall flow and performance modifications induced by the presence of the cooling holes, with a strong agreement to complete hole discretization results. In the second phase, a complete film-cooled vane test case has been studied, in order to consider a real injection system and flow conditions. In this case, film cooling model predictions are compared to an in-house developed correlative approach and full CHT 3D-CFD results. Finally, a comparison between film cooling model predictions and experimental data was performed on an actual nozzle of a GE Oil & Gas heavy-duty gas turbine as well, in order to prove the feasibility of the procedure. The presented film cooling model proved to be a feasible and reliable tool to evaluate adiabatic effectiveness, simplifying the design phase avoiding the meshing process of perforations. Also, refining the mesh near the hole exit, FCM results well approximate the solution coming from a full CHT calculation.

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“…[77] and Miller and Crawford [78]: they implemented a model for the coolant injection in a 2D boundary layer code. More recently, approaches in 3D-CFD have been presented.…”

Section: Literature Reviewmentioning

confidence: 99%

Film Cooling Modelling for Gas Turbine Nozzles and Blades: Validation and Application

Andrei

Innocenti

Andreini

et al. 2015

Volume 5B: Heat Transfer

View full text Add to dashboard Cite

show abstract

“…The present computer program is a derivative of STAN-5 [14] and equations (9)(10)(11) are similar to those used by [7,8] and Uj e t.. Unlike in [7,8], no ad hoc adjustments are necessary to determine these values and this feature provides the present injection model with a wider range of applicability, which is so important in any prediction scheme.…”

Section: The 2-d Jet Enthalpy Is Assumed To Be Equal To the Injectionmentioning

confidence: 99%

“…Crawford et al [7] and subsequently other workers [8] have used the STAN-5 boundary layer code [9] to predict the Stanton numbers for full-coverage film cooling and η for one and two rows of injection, respectively. The effect of injection is introduced in the calculation procedure by using an injection model along with an augmented mixing length.…”

mentioning

confidence: 99%

Prediction of Heat Transfer Characteristics for Discrete Hole Film Cooling - One Row of Injection Into a Turbulent Boundary Layer

Tafti

Yavuzkurt²

1991

International Journal of Turbo and Jet Engines

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A two-dimensional (2-D) injection model for the discrete hole film cooling process is developed. The injection model is used with a low Reynolds number k -e turbulence model to predict the spanwise averaged effectiveness (η) and the heat transfer coefficient (hf) for one row of injection into a turbulent boundary layer.The three-dimensional effect of discrete hole injection is introduced in the prediction scheme by developing the concept of "entrainment fraction" and "entrainment enthalpy." The "entrainment fraction" replaces a fraction of the jet fluid by entrained boundary layer fluid. The "entrainment fraction" is correlated with the injection parameter χ = UjStna 0 /U e and the pitch to diameter ratio of the holes, where Uj is the jet velocity, U e is the local free stream velocity, and a 0 is the angle of injection.Predictions of velocity and temperature profiles, η and hf are in good agreement with experimental data for one row of injection into a turbulent boundary layer. Brought to you by | University of Arizona Authenticated Download Date | 7/22/15 4:30 PM 237

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“…In various studies (Metzger and Fletcher, 1971, Miller and Crawford, 1984, and Ligrani and Camci, 1985 values of hH and rl were approximated from h' and 8 * data using a linear extrapolation based on Eq. (6).…”

Section: Introductionmentioning

confidence: 99%

Surface Injection Effect on Mass Transfer From a Cylinder in Crossflow: A Simulation of Film Cooling in the Leading Edge Region of a Turbine Blade

Karni

Goldstein

1990

Journal of Turbomachinery

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A naphthalene sublimation technique is used to study the effect of surface injection on the mass (heat) transfer from a circular cylinder in crossflow. Using a heat/mass transfer analogy the results can be used to predict film cooling effects in the leading edge region of a turbine blade. Air injection through one row of circular holes is employed in the stagnation region of the cylinder. Streamwise and spanwise injection inclinations are studied separately, and the effects of blowing rate and injection location relative to the cylinder front stagnation line are investigated. Streamwise injection produces significant mass transfer increases downstream of the injection holes, but a relatively small increase is observed between holes, normal to the injection direction. The mass transfer distribution, measured with spanwise injection through holes located near the cylinder front stagnation line, is extremely sensitive to small changes in the injection hole location relative to stagnation. When the centers of the spanwise injection holes are located 5 deg or more from the stagnation line, the holes lie entirely on one side of the stagnation line and the injection affects the mass transfer only on that side of the cylinder, approaching the pattern observed with streamwise injection.

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Numerical Simulation of Single, Double, and Multiple Row Film Cooling Effectiveness and Heat Transfer

Cited by 16 publications

References 7 publications

Film Cooling Modelling for Gas Turbine Nozzles and Blades: Validation and Application

Film Cooling Modelling for Gas Turbine Nozzles and Blades: Validation and Application

Prediction of Heat Transfer Characteristics for Discrete Hole Film Cooling - One Row of Injection Into a Turbulent Boundary Layer

Surface Injection Effect on Mass Transfer From a Cylinder in Crossflow: A Simulation of Film Cooling in the Leading Edge Region of a Turbine Blade

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