An Experimental Study of the Effect of Wake Passing on Turbine Blade Film Cooling

Heidmann, James D.; Lucci, B. L.; Reshotko, Eli

doi:10.1115/1.1354621

Cited by 29 publications

(8 citation statements)

References 28 publications

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“…Not resolving the flow inside the film holes can cause incorrect predictions in the film effectiveness as seen in the numerical data. This is consistent with the research findings by Heidmann et al [22] . The absence of an accurate turbulence model for the computations that can capture the fluid mechanics of the film jet is likely to cause differences between the predictions and experiments.…”

Section: B Comparison With Numerical Datasupporting

confidence: 95%

“…The increased jet mixing with the mainstream in the presence of the wake was reported to be a key factor for decreased film effectiveness with wakes. An experimental and numerical study by Heidmann et al [22] showed that not resolving the flow inside the film holes can cause higher predictions in the film effectiveness. They also showed that the spanwise mixing of the film jet was increased by the passing wake.…”

Section: Review Of Literaturementioning

confidence: 98%

“…Some of the unsteady wake studies on cascade and leading edge geometries include Du et al [14,15] , Han et al [16] , Adami et al [17] , Dullenkopf et al [18] , Teng et al [19] , Funazaki et al [20] , Rodriguez et al [21] , Heidmann et al [22] , O'Brien and Capp [23] , Ou et al [24] , Mehendale et al [25] , and Wright et al [26] . The laminar-turbulent transition for varying mainstream turbulence was observed to be different by Du et al [14] with the trailing edge ejection compensating for the velocity deficit caused by the periodic wakes.…”

Section: Review Of Literaturementioning

confidence: 99%

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Heat Transfer and Film Effectiveness Study on a Pitchwise Curved Surface with Unsteady Wake Interaction

Mahadevan¹,

Kutlu²,

Golsen³

2012

48th AIAA/ASME/SAE/ASEE Joint Propulsion Conference &Amp;amp; Exhibit

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Experiments were performed to measure the heat transfer augmentation and film cooling effectiveness on a film-cooled annular surface subjected to unsteady passing wakes. The wakes can have a profound influence on the effectiveness of film cooling and heat transfer characteristics and it is the objective of an ongoing study to quantify that influence. As part of the study, three blowing ratios (M=0.25, 0.5, 0.75) were tested with discrete film injection (p/D=3) in this paper. The tests were performed for two wake Strouhal numbers (S=0.15, 0.3). The baseline cases involved a steady mainstream flow (S=0). Heat transfer augmentation was measured with passing wakes and with film cooling separately and then with combination of both. A numerical model replicating the annular geometry was used to predict film cooling effectiveness for the steady mainstream cases (S=0) and one transient case was attempted (M=0.5,S=0.3). The computations were performed with pressure-based Reynolds-Averaged Navier-Stokes solver and the realizable k-ε turbulence model. The results from the experiment and computations are compared with relevant published literature. The uncertainties in the experimental values are calculated to be ± 0.03 (absolute) for film cooling effectiveness, ± 3% for velocity measurements, and ± 6.5% for heat transfer coefficient ratio respectively. The passing wakes increased the heat transfer coefficients as high as 11% for the highest wake passing frequency for no film injection (M=0, S=0.3). The influence of the passing wakes was more significant with film injection with a heat transfer augmentation of 37% approximately for M=0.75,S=0.3. The displacement thickness to the film hole diameter ratio at the injection location was observed to be a pertinent parameter that dictates the heat transfer augmentation for the film injection experiments. The centerline film cooling effectiveness was greatly affected by the passing wakes with a maximum decrease of 15% observed for M=0.5,S=0.3. NomenclatureA = area (m 2 ) D = film cooling hole diameter (8mm) D = wake rod diameter (19mm) h = heat transfer coefficient (W/m 2 K) I = momentum flux ratio k = thermal conductivity (W/mK) M = blowing ratio (mass flux ratio) N = angular velocity of wake generator (RPM) n = number of wake generator rods p = pitch (mm) q′′ = heat flux (W/m 2 ) R = resistance of foil heater (ohm) Re = Reynolds number based on entry length; film hole diameter S = wake Strouhal number T = temperature (°C/K) Tu = turbulence intensity U = mean velocity (m/s) V = voltage (V) VR = velocity ratio w = width of heater strip (31 mm)Greek letters α = streamwise inclination angle of film hole (35°) β = compound angle of film hole (0°) δ = disturbance/boundary layer thickness (mm) ε = emissivity η = film cooling effectiveness θ = pitchwise distance θ * = momentum thickness (mm) ρ = density (kg/m 3 ); resistivity of heater material ߢ = ratio of specific heats (c p /c v )

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Section: B Comparison With Numerical Datasupporting

confidence: 95%

Section: Review Of Literaturementioning

confidence: 98%

Section: Review Of Literaturementioning

confidence: 99%

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Heat Transfer and Film Effectiveness Study on a Pitchwise Curved Surface with Unsteady Wake Interaction

Mahadevan¹,

Kutlu²,

Golsen³

2012

48th AIAA/ASME/SAE/ASEE Joint Propulsion Conference &Amp;amp; Exhibit

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“…The deterioration of film cooling effectiveness due to an unsteady wake in the leading edge region was studied (using a spoke wheel) by Funazaki et al (1997) and Heidmann et al (2001). The use of shaped holes to improve film coverage has been studied by Reiss and Bölcs (2000), Falcoz et al (2006) and Gao and Han (2009).…”

Section: Leading Edge Film Coolingmentioning

confidence: 99%

Turbine Blade Film Cooling Using PSP Technique

Han¹,

Rallabandi²

2010

Frontiers in Heat and Mass Transfer

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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“…They found that there is a significant change of film cooling behavior on the suction surface when the simulated NGV unsteady effects are introduced. Heidmann et al [15] studied the effect of passing wakes on showerhead film cooling performance in an annular cascade with a row of upstream rotating cylindrical rods. A high wake Strouhal number is found to decrease effectiveness but it also diverts the coolant towards the pressure side resulting in slightly better cooling on the pressure side.…”

Section: Introductionmentioning

confidence: 99%

Film cooling on a gas turbine blade pressure side or suction side with axial shaped holes

Gao

Narzary

Han

2008

International Journal of Heat and Mass Transfer

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An Experimental Study of the Effect of Wake Passing on Turbine Blade Film Cooling

Abstract: The effect of wake passing on the showerhead film cooling performance of a turbine blade has been investigated experimentally.

Cited by 29 publications

References 28 publications

Heat Transfer and Film Effectiveness Study on a Pitchwise Curved Surface with Unsteady Wake Interaction

Heat Transfer and Film Effectiveness Study on a Pitchwise Curved Surface with Unsteady Wake Interaction

Turbine Blade Film Cooling Using PSP Technique

Film cooling on a gas turbine blade pressure side or suction side with axial shaped holes

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