Effect of Velocity and Temperature Distribution at the Hole Exit on Film Cooling of Turbine Blades

Garg, Vijay K.; Gaugler, Raymond E.

doi:10.1115/95-gt-002

Cited by 19 publications

(17 citation statements)

References 11 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In this case, as applied also in [92], as could be expected, it has been proved how elm/D = 10 discretization returns results standing between the other two, and so it has been decided to not continue to study this case.…”

Section: Film Cooling Model Implementationmentioning

confidence: 99%

“…Garg and Gaugler [92] conducted RANS simulations of the film and internally cooled C3X vane by prescribing the experimental temperature distribution along the blade surface and velocity/temperature profiles at the hole exits. They noticed that the exit velocity and temperature profiles could result in differences up to 60% in HTC when comparing to experimental data.…”

Section: Literature Reviewmentioning

confidence: 99%

See 1 more Smart Citation

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

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.

show abstract

Section: Film Cooling Model Implementationmentioning

confidence: 99%

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

“…Different velocity and temperature profiles for the injected fluid can be specified at the hole exits. For the present study, polynomial distribution [21] of velocity and temperature of the injectant at the hole exit was specified. The injectant angle was taken to be the same as the hole angle.…”

Section: Boundary Conditionsmentioning

confidence: 99%

Low-Pressure Turbine Separation Control: Comparison With Experimental Data

Garg

2002

Volume 3: Turbo Expo 2002, Parts a and B

Self Cite

View full text Add to dashboard Cite

The present work details a computational study, using the Glenn-HT code, that analyzes the use of vortex generator jets (VGJs) to control separation on a low-pressure turbine (LPT) blade at low Reynolds numbers. The computational results are also compared with the experimental data of Bons et al. [1] for steady VGJs. It is found that the code determines the proper location of the separation point on the suction surface of the baseline blade (without any VGJ) for Reynolds numbers of 50,000 or less. Also, the code finds that the separated region on the suction surface of the blade vanishes with the use of VGJs. However, the separated region and the wake characteristics are not well predicted. The wake width is generally over-predicted while the wake depth is under-predicted.

show abstract

“…Mick and Mayle (1988) showed through experiment that leading edge film cooling, also known as showerhead film cooling, reduces heat flux over the entire flat test body for moderate blowing ratios, despite large increases in heat transfer coefficient in the leading edge region. Garg and Gaugler (1995) computationally demonstrated the profound effect of film hole exit velocity and temperature profile variations on blade surface heat transfer. One of the goals of the present study is thus to accurately describe these profiles for use in new models.…”

Section: Introductionmentioning

confidence: 99%

A Three-Dimensional Coupled Internal/External Simulation of a Film-Cooled Turbine Vane

Heidmann

Rigby²,

Ameri³

1999

Volume 3: Heat Transfer; Electric Power; Industrial and Cogeneration

View full text Add to dashboard Cite

A three-dimensional Navier-Stokes simulation has been performed for a realistic film-cooled turbine vane using the LeRC-HT code. The simulation includes the flow regions inside the coolant plena and film cooling holes in addition to the external flow. The vane is the subject of an upcoming NASA Lewis Research Center experiment and has both circular cross-section and shaped film cooling holes. This complex geometry is modeled using a multi-block grid which accurately discretizes the actual vane geometry including shaped holes. The simulation matches operating conditions for the planned experiment and assumes periodicity in the spanwise direction on the scale of one pitch of the film cooling hole pattern. Two computations were performed for different isothermal wall temperatures, allowing independent determination of heat transfer coefficients and film effectiveness values. The results indicate separate localized regions of high heat flux in the showerhead region due to low film effectiveness and high heat transfer coefficient values, while the shaped holes provide a reduction in heat flux through both parameters. Hole exit data indicate rather simple skewed profiles for the round holes, but complex profiles for the shaped holes with mass fluxes skewed strongly toward their leading edges.

show abstract

Effect of Velocity and Temperature Distribution at the Hole Exit on Film Cooling of Turbine Blades

Cited by 19 publications

References 11 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

Low-Pressure Turbine Separation Control: Comparison With Experimental Data

A Three-Dimensional Coupled Internal/External Simulation of a Film-Cooled Turbine Vane

Contact Info

Product

Resources

About