Heat Transfer With Film Cooling Within and Downstream of One to Four Rows of Normal Injection Holes

Metzger, D. E.; Kuenstler, P. A.; Takeuchi, D. I.

doi:10.1115/76-gt-83

Cited by 6 publications

(2 citation statements)

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“…The resulting sharp temperature gradients present a thermal stress issue and illustrate the advantages of collecting full coverage film cooling data on a local (rather than areaaveraged) basis in order to evaluate variations in hole spacing and blowing ratio. Two studies by Metzger (1973Metzger ( , 1976) pertain specifically to this study as in-line and staggered full coverage film cooling arrangements are compared. See Figure 21 for a depiction of Metzger's test surface.…”

Section: Section 223 Full Coverage Film Cooling Figure 18 Single Romentioning

confidence: 99%

Heat Transfer in a Coupled Impingement-Effusion Cooling System

Miller

Natsui

Ricklick

et al. 2014

Volume 5B: Heat Transfer

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Modern research on gas turbine cooling continues to focus on the optimization of different cooling designs, and better understanding of the underlying flow physics so that cooling schemes can be coupled together. The current study focuses on one particular coupled cooling design: an impingement-effusion cooling system, which combines impingement cooling on the backside of the cooled component and full coverage effusion cooling on the exposed surface. The goal of this study is to explore a wide range of geometrical parameters outside the ranges normally reported in the available literature. Particular attention is given to the total coolant spent per unit surface area cooled. Through determination of impingement heat transfer, film cooling effectiveness, and film cooling heat transfer on the target wall, a simplified heat transfer model of the cooled component is developed to show the relative impact of each parameter on the overall cooling effectiveness. The use of Temperature Sensitive Paint (TSP) for data acquisition allows for high resolution local heat transfer and effectiveness results. Impingement arrays with local extraction of coolant via effusion are able to produce higher overall heat transfer, as no significant cross flow is present to deflect the impinging jets. Low jet-to-target-plate spacing produces the highest yet most non-uniform heat transfer distribution; at high spacing the heat transfer rate is much less sensitive to impingement height. Arrays with high hole-to-hole spacing and high jet Reynold’s number are more effective (per mass of coolant used) than tightly spaced holes at low jet Reynold’s number. On the effusion side, staggered hole arrangements provide significantly higher film cooling effectiveness than their in-line counterparts as the staggered arrangement minimizes jet interactions and promotes a more even lateral distribution of coolant.

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Section: Section 223 Full Coverage Film Cooling Figure 18 Single Romentioning

confidence: 99%

Heat Transfer in a Coupled Impingement-Effusion Cooling System

Miller

Natsui

Ricklick

et al. 2014

Volume 5B: Heat Transfer

View full text Add to dashboard Cite

show abstract

“…Their data show relatively large coefficients near the injection slot; as the downstream distance from the slot increases, hH quickly declines approaching the coefficient obtained without injection. Measurements of heat transfer coefficients averaged across the test surface are reported in some studies of three-dimensional film cooling from a single row and multiple rows of circular holes (Metzger and Fletcher, 1971;Mayle and Camarata, 1975;Liess, 1975;Metzger, Kuenstler and Takeuchi, 1976;Lander, Fish and Suo, 1972;Ligrani and Breugelmans, 1981). Effects of parameters such as injection geometry, blowing rate, pressure gradient, and boundary layer transition on variation of spanwise-averaged coefficients in the mainflow direction were investigated in these studies.…”

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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Full-Coverage Film Cooling With Short Normal Injection Holes

Harrington

McWaters

Bogard

et al. 2001

Journal of Turbomachinery

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An experimental and computational investigation was conducted on the film cooling adiabatic effectiveness of a flat plate with full coverage film cooling. The full coverage film cooling array was comprised of ten rows of coolant holes, arranged in a staggered pattern, with short L/D=1, normal coolant holes. A single row of cooland holes was also examined to determine the accuracy of a superposition prediction of the full coverage adiabatic effectiveness performance. Large density coolant jets and high mainstream turbulence conditions were utilized to simulate realistic engine conditions. High-resolution adiabatic effectiveness measurements were obtained using infrared imaging techniques and a large-scale flat plate model. Optimum adiabatic effectiveness was found to occur for a blowing ratio of M=0.65. At this blowing ratio separation of the coolant jet immediately downstream of the hole was observed. For M=0.65, the high mainstream turbulence decreased the spatially averaged effectiveness level by 12 percent. The high mainstream turbulence produced a larger effect for lower blowing ratios. The superposition model based on single row effectiveness results over-predicted the full coverage effectiveness levels.

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Heat Transfer With Film Cooling Within and Downstream of One to Four Rows of Normal Injection Holes

Cited by 6 publications

References 0 publications

Heat Transfer in a Coupled Impingement-Effusion Cooling System

Heat Transfer in a Coupled Impingement-Effusion Cooling System

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

Full-Coverage Film Cooling With Short Normal Injection Holes

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