Effectiveness Distributions on Turbine Blade Cascade Platforms Through Simulated Stator-Rotor Seals

Wright, Lesley M.; Blake, Sarah A.; Han, Je-Chin

doi:10.2514/1.30382

Cited by 17 publications

(3 citation statements)

References 27 publications

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“…In a low-speed wind tunnel, Wright et al (2007) compared the film cooling effectiveness downstream of rotor-stator slots with different seal geometries by the PSP technique. Using coolant (at 0.5% to 2% of mainstream passage mass flow rate) with DR = 1.0, it was concluded that using typical advanced rotor-stator seals reduces film cooling effectiveness compared with conventional inclined slots.…”

Section: Endwallmentioning

confidence: 99%

Turbine Blade Film Cooling Using PSP Technique

Han¹,

Rallabandi²

2010

Frontiers in Heat and Mass Transfer

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198

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Film cooling is widely used to protect modern gas turbine blades and vanes from the ever increasing inlet temperatures. Film cooling involves a very complex turbulent flow-field, the characterization of which is necessary for reliable and economical design. Several experimental studies have focused on gas turbine blade, vane and end-wall film cooling over the past few decades. Measurements of heat transfer coefficients, film cooling effectiveness values and heat flux ratios using several different experimental methods have been reported. The emphasis of this current review is on the Pressure Sensitive Paint (PSP) mass transfer analogy to determine the film cooling effectiveness. The theoretical basis of the method is presented in detail. Important results in the open literature obtained using the PSP method are presented, discussing parametric effects of blowing ratio, momentum ratio, density ratio, hole shape, surface geometry, free-stream turbulence on flat plates, turbine blades, vanes and end-walls. The PSP method provides very high resolution contours of film cooling effectiveness, without being subject to the conduction error in high thermal gradient regions near the hole.

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Section: Endwallmentioning

confidence: 99%

Turbine Blade Film Cooling Using PSP Technique

Han¹,

Rallabandi²

2010

Frontiers in Heat and Mass Transfer

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198

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“…They validated the effect of the secondary flows on the endwall heat transfer and the film cooling effectiveness. Wright et al [ 16 ] experimentally analyzed cooling effectiveness distributions on the blade platform with discrete film hole flows. They observed that due to the entrainment of the passage vortex, traces of coolant are weakened.…”

Section: Introductionmentioning

confidence: 99%

Interaction Mechanism and Loss Analysis of Mixing between Film Cooling Jet and Passage Vortex

Mao

Chen

et al. 2021

Entropy

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The interaction between the film-cooling jet and vortex structures in the turbine passage plays an important role in the endwall cooling design. In this study, a simplified topology of a blunt body with a half-cylinder is introduced to simulate the formation of the leading-edge horseshoe vortex, where similarity compared with that in the turbine cascade is satisfied. The shaped cooling hole is located in the passage. With this specially designed model, the interaction mechanism between the cooling jet and the passage vortex can therefore be separated from the crossflow and the pressure gradient, which also affect the cooling jet. The loss-analysis method based on the entropy generation rate is introduced, which locates where losses of the cooling capacity occur and reveals the underlying mechanism during the mixing process. Results show that the cooling performance is sensitive to the hole location. The injection/passage vortex interaction can help enhance the coolant lateral coverage, thus improving the cooling performance when the hole is located at the downwash region. The coolant is able to conserve its structure in that, during the interaction process, the kidney vortex with the positive rotating direction can survive with the negative-rotating passage vortex, and the mixture is suppressed. However, the larger-scale passage vortex eats the negative leg of the kidney vortices when the cooling hole is at the upwash region. As a result, the coolant is fully entrained into the main flow. Changes in the blowing ratio alter the overall cooling effectiveness but have a negligible effect on the interaction mechanism. The optimum blowing ratio increases when the hole is located at the downwash region.

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“…The paper aims to set standard for flat-plate film cooling, be used for calibration with the latest film-cooling measurement techniques, and be a benchmark compared with data of endwall/platform (close to a flat surface) [37,38] film cooling. The primary objective of this research is to provide comprehensive experimental data of typical simple and compound-angled cylindrical holes and advanced simple and compound-angled fan-shaped holes for the flat-plate film cooling.…”

mentioning

confidence: 99%

Film Cooling for Cylindrical and Fan-Shaped Holes Using Pressure-Sensitive Paint Measurement Technique

Chen

Han

2015

Journal of Thermophysics and Heat Transfer

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A systematic study was performed to investigate the combined effects of film-hole geometry, blowing ratio, density ratio, and freestream turbulence intensity on a flat-plate film cooling. Detailed film-cooling effectiveness was obtained using a pressure-sensitive-paint technique. Four common geometries were used in this study: simple-angled cylindrical and fan-shaped holes, and compound-angled (β 45 deg) cylindrical and fan-shaped holes. Each plate contained one row with seven holes, and the hole diameter D and hole-length-to-diameter ratio (L∕D) are 4 mm and 7.5, respectively. The effects of the blowing ratio M, coolant-to-mainstream-density ratio DR, and freestream turbulence intensity Tu were tested within the ranges of 0.3 ∼ 2.0, 1.0 ∼ 2.0, and 0.5 ∼ 6%, correspondingly. Detailed variations of the laterally averaged effectiveness from low to high blowing ratios were obtained for three density ratios. The results indicated that effectiveness increased as increasing density ratio in general for all geometries. Fanshaped holes outweighed cylindrical ones in effectiveness at higher blowing ratios. An additional compound-angle enhanced effectiveness for cylindrical holes. For increasing turbulence intensity, effectiveness decreased for shaped holes but slightly increased for cylindrical ones. The experimental data of simple-angled fan-shaped holes were validated with empirical correlation limited to DR 1.7 ∼ 2.0, and an improved correlation was proposed to predict effectiveness at DR 1.0 ∼ 2.0. NomenclatureAR = area ratio of hole exit and inlet D = diameter of film-cooling hole, mm DR = coolant to mainstream density ratio; ρ c ∕ρ m M = blowing ratio; ρ c v c ∕ρ m v m P = pitch between adjacent holes, mm t = width of hole at trailing edge of hole breakout x = distance from trailing edge of holes, mm α = axial angle to the mainstream, deg β = compound angle to the mainstream, deg η = film-cooling effectiveness η ave = laterally averaged film-cooling effectiveness v = velocity, m∕s ξ = distance scaling parameter used in correlation ρ = density, kg∕m 3 Subscripts air = property with air injection blk = black condition c = coolant f = film fg = property with foreign gas injection m = mainstream ref = reference condition w = wall ∞ = mainstream property

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Effectiveness Distributions on Turbine Blade Cascade Platforms Through Simulated Stator-Rotor Seals

Cited by 17 publications

References 27 publications

Turbine Blade Film Cooling Using PSP Technique

Turbine Blade Film Cooling Using PSP Technique

Interaction Mechanism and Loss Analysis of Mixing between Film Cooling Jet and Passage Vortex

Film Cooling for Cylindrical and Fan-Shaped Holes Using Pressure-Sensitive Paint Measurement Technique

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