Influence of Coolant Density on Turbine Blade Film-Cooling With Axial Shaped Holes

Liu, Kevin; Yang, Shang-Feng; Han, Je-Chin

doi:10.1115/ht2012-58144

Cited by 3 publications

(4 citation statements)

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“…2, the PSP response, upon normalization by the appropriate condition, is independent of temperature. A similar feature of the PSP calibration curves was also found by Liu et al [23].…”

Section: Fig 1 Schematic Layout For Psp Calibration Setupsupporting

confidence: 86%

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Measurement Uncertainty Analysis in Determining Adiabatic Film Cooling Effectiveness by Using Pressure Sensitive Paint Technique

Johnson

2016

Journal of Turbomachinery

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While pressure sensitive paint (PSP) technique has been widely used to measure adiabatic film cooling effectiveness distributions on the surfaces of interest based on a mass transfer analog to traditional thermal-based measurements, very little can be found in literature to provide a comprehensive analysis on the uncertainty levels of the measured film cooling effectiveness distributions derived from PSP measurements. In the present study, a detailed analysis is performed to evaluate the effects of various associated uncertainties in the PSP measurements on the measured film cooling effectiveness distributions over the surfaces of interest. The experimental study is conducted in a low-speed wind tunnel under an isothermal condition. While airflow is used to represent the “hot” mainstream flow, an oxygen-free gas, i.e., carbon dioxide (CO2) gas with a density ratio of DR = 1.5 for the present study, is supplied to simulate the “coolant” stream for the PSP measurements to map the adiabatic film cooling effectiveness distribution over a flat test plate with an array of five cylindrical coolant holes at a span-wise spacing of three diameters center-to-center. A comprehensive analysis was carried out with focus on the measurement uncertainty and process uncertainty for the PSP measurements to determine the film cooling effectiveness distributions over the surface of interest. The final analysis indicates that the total uncertainty in the adiabatic film cooling effectiveness measurements by using the PSP technique depends strongly on the local behavior of the mixing process between the mainstream and coolant flows. The measurement uncertainty is estimated as high as 5% at the near field behind the coolant holes. In the far field away from the coolant holes, the total measurement uncertainty is found to be more uniform throughout the measurement domain and generally lower than those in the near field at about 3%.

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“…2, the PSP response, upon normalization by the appropriate condition, is independent of temperature. A similar feature of the PSP calibration curves was also found by Liu et al [23].…”

Section: Fig 1 Schematic Layout For Psp Calibration Setupsupporting

confidence: 86%

“…which closely resembles the calibration curve reported in Ref. [23], though the calibration coefficients are rather dissimilar.…”

Section: Fig 1 Schematic Layout For Psp Calibration Setupsupporting

confidence: 85%

Measurement Uncertainty Analysis in Determining Adiabatic Film Cooling Effectiveness by Using Pressure Sensitive Paint Technique

Johnson

2016

Journal of Turbomachinery

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“…The different camera framings do not allow to cover the whole vane surface; nevertheless, the investigated areas are wide enough to characterize the behaviour of the film-cooling holes on the different surfaces. At a first sight it is possible to note, for the suction side results, a strong effect of the secondary flows, as the coolant traces are driven away from the endwalls towards the midspan; this well-known effect [10,11] determines the presence of uncovered areas close to the endwalls, in the region between rows SS2 and SS3 and close to the trailing edge. In the latter location, this phenomenon also creates two areas (h/H = 65%-80% and 20%-35%) where the effectiveness is slightly higher than at midspan, due to the superposition of the converging coolant traces.…”

Section: Experimental Technique and Data Reductionmentioning

confidence: 99%

“…For convex surfaces, on the other hand, effectiveness is generally higher than for flat plates, but an important drop-off in performance occurs as the momentum ratio overcomes threshold values; the adiabatic effectiveness is always higher in the proximity of the holes, as the surface curvature works against the reattachment. More recent studies focused on the analysis of cylindrical [8,9] and shaped holes [10,11] on actual turbine vane/blade geometries. Despite their conclusions were often qualitatively similar to the ones of the previous base studies, the quantitative behaviour could significantly deviate.…”

Section: Introductionmentioning

confidence: 99%

Flat Plate and Turbine Vane Film-Cooling Performance with Laid-Back Fan-Shaped Holes

Bacci

Picchi

Facchini

2019

IJTPP

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Shaped holes are considered as an effective solution to enhance gas turbine film-cooling performance, as they allow to increase the coolant mass-flux, while limiting the detrimental lift-off phenomena. A great amount of work has been carried out in past years on basic flat plate configurations while a reduced number of experimental works deals with a quantitative assessment of the influence of curvature and vane pressure gradient. In the present work PSP (Pressure Sensitive Paint) technique is used to detail the adiabatic effectiveness generated by axial shaped holes with high value of Area Ratio close to 7, in three different configurations with the same 1:1 scale: first of all, a flat plate configuration is examined; after that, the film-cooled pressure and suction sides of a turbine vane model are investigated. Tests were performed varying the blowing ratio and imposing a density ratio of 2.5. The experimental results are finally compared to the predictions of two different correlations, developed for flat plate configurations.

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An Experimental Study on Film Cooling Effectiveness by Using PIV and PSP Techniques

2013

51st AIAA Aerospace Sciences Meeting Including the New Horizons Forum and Aerospace Exposition

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An experimental study was conducted to investigate the performance of film cooling injection from a row of circular holes spaced laterally across a flat plate. A highresolution PIV system was used to conduct flow field measurements to reveal the tendencies of the coolant stream to remain attached to the test plate or to separate from it, and a Pressure Sensitive Paint (PSP) technique was used to map the distribution of the corresponding adiabatic cooling effectiveness on the surface of the test plate based on a mass-flux analog to traditional thermal effectiveness measurements. The effects of the density ratio between the cooling jet stream and mainstream flows, P, are investigated by performing isothermal experiments at fixed mass-flux ratios but using coolant streams of N 2 (P=0.97), air (P=1.00), and CO 2 (P=1.53). An accompanying analysis of alternative parametric scaling quantities, such as the momentum flux ratio I and bulk coolant-to-mainstream velocity ratio V r , is performed to illuminate the extent to which this flow scenario can be described using purely kinematic means. It was found that those quantities that give more weight to P (M and then I) have more success to collapse data from varying P flows for relatively low coolant flow rates, while the bulk velocity ratio V r may be used with some success to scale the effectiveness from jets of higher bulk velocity ratio.

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Influence of Coolant Density on Turbine Blade Film-Cooling With Axial Shaped Holes

Cited by 3 publications

References 0 publications

Measurement Uncertainty Analysis in Determining Adiabatic Film Cooling Effectiveness by Using Pressure Sensitive Paint Technique

Measurement Uncertainty Analysis in Determining Adiabatic Film Cooling Effectiveness by Using Pressure Sensitive Paint Technique

Flat Plate and Turbine Vane Film-Cooling Performance with Laid-Back Fan-Shaped Holes

An Experimental Study on Film Cooling Effectiveness by Using PIV and PSP Techniques

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