Effects of Effusion Cooling Pattern Near the Dilution Hole for a Double-Walled Combustor Liner—Part II: Flowfield Measurements

2018 ◽  
Vol 141 (1) ◽  
Author(s):  
Adam C. Shrager ◽  
Karen A. Thole ◽  
Dominic Mongillo
Keyword(s):  
Leading Edge ◽  
Freestream Turbulence ◽  
Gas Turbine Combustor ◽  
Impingement Cooling ◽  
Cooling Pattern ◽  
Image Velocimetry ◽  
Cooling Hole ◽  
Difficult Challenge ◽  
Combustor Liner ◽  
Double Wall

The complex flowfield inside a gas turbine combustor creates a difficult challenge in cooling the combustor walls. Many modern combustors are designed with a double-wall that contain both impingement cooling on the backside of the wall and effusion cooling on the external side of the wall. Complicating matters is the fact that these double-walls also contain large dilution holes whereby the cooling film from the effusion holes is interrupted by the high-momentum dilution jets. Given the importance of cooling the entire panel, including the metal surrounding the dilution holes, the focus of this paper is understanding the flow in the region near the dilution holes. Near-wall flowfield measurements are presented for three different effusion cooling hole patterns near the dilution hole. The effusion cooling hole patterns were varied in the region near the dilution hole and include: no effusion holes; effusion holes pointed radially outward from the dilution hole; and effusion holes pointed radially inward toward the dilution hole. Particle image velocimetry (PIV) was used to capture the time-averaged flowfield at approaching freestream turbulence intensities of 0.5% and 13%. Results showed evidence of downward motion at the leading edge of the dilution hole for all three effusion hole patterns. In comparing the three geometries, the outward effusion holes showed significantly higher velocities toward the leading edge of the dilution jet relative to the other two geometries. Although the flowfield generated by the dilution jet dominated the flow downstream, each cooling hole pattern interacted with the flowfield uniquely. Approaching freestream turbulence did not have a significant effect on the flowfield.

Effects of Effusion Cooling Pattern Near the Dilution Hole for a Double-Walled Combustor Liner: Part 2 — Flowfield Measurements

2018 ◽  
Author(s):  
Adam C. Shrager ◽  
Karen A. Thole ◽  
Dominic Mongillo
Keyword(s):  
Leading Edge ◽  
Freestream Turbulence ◽  
Gas Turbine Combustor ◽  
Impingement Cooling ◽  
Cooling Pattern ◽  
Image Velocimetry ◽  
Cooling Hole ◽  
Difficult Challenge ◽  
Combustor Liner ◽  
Double Wall

The complex flowfield inside a gas turbine combustor creates a difficult challenge in cooling the combustor walls. Many modern combustors are designed with a double-wall that contain both impingement cooling on the backside of the wall and effusion cooling on the external side of the wall. Complicating matters is the fact that these double-walls also contain large dilution holes whereby the cooling film from the effusion holes is interrupted by the high-momentum dilution jets. Given the importance of cooling the entire panel, including the metal surrounding the dilution holes, the focus of this paper is understanding the flow in the region near the dilution holes. Near-wall flowfield measurements are presented for three different effusion cooling hole patterns near the dilution hole. The effusion cooling hole patterns were varied in the region near the dilution hole and include: no effusion holes; effusion holes pointed radially outward from the dilution hole; and effusion holes pointed radially inward toward the dilution hole. Particle image velocimetry (PIV) was used to capture the time-averaged flowfield at approaching freestream turbulence intensities of 0.5% and 13%. Results showed evidence of downward motion at the leading edge of the dilution hole for all three effusion hole patterns. In comparing the three geometries, the outward effusion holes showed significantly higher velocities toward the leading edge of the dilution jet relative to the other two geometries. Although the flowfield generated by the dilution jet dominated the flow downstream, each cooling hole pattern interacted with the flowfield uniquely. Approaching freestream turbulence did not have a significant effect on the flowfield.

Effects of Effusion Cooling Pattern Near the Dilution Hole for a Double-Walled Combustor Liner—Part 1: Overall Effectiveness Measurements

2018 ◽  
Vol 141 (1) ◽  
Author(s):  
Adam C. Shrager ◽  
Karen A. Thole ◽  
Dominic Mongillo
Keyword(s):  
Momentum Flux ◽  
Freestream Turbulence ◽  
Complex Flow ◽  
Gas Turbine Combustor ◽  
Cooling Pattern ◽  
Cooling Hole ◽  
Cooling Enhancement ◽  
Combustor Liner ◽  
Effusion Hole ◽  
Overall Effectiveness

The complex flow field in a gas turbine combustor makes cooling the liner walls a challenge. In particular, this paper is primarily focused on the region surrounding the dilution holes, which is especially challenging to cool due to the interaction between the effusion cooling jets and high-momentum dilution jets. This study presents overall effectiveness measurements for three different cooling hole patterns of a double-walled combustor liner. Only effusion hole patterns near the dilution holes were varied, which included: no effusion cooling; effusion holes pointed radially outward from the dilution hole; and effusion holes pointed radially inward toward the dilution hole. The double-walled liner contained both impingement and effusion plates as well as a row of dilution jets. Infrared thermography was used to measure the surface temperature of the combustor liners at multiple dilution jet momentum flux ratios and approaching freestream turbulence intensities of 0.5% and 13%. Results showed that the outward and inward geometries were able to more effectively cool the region surrounding the dilution hole compared to the closed case. A significant amount of the cooling enhancement in the outward and inward cases came from in-hole convection. Downstream of the dilution hole, the interactions between the inward effusion holes and the dilution jet led to lower levels of effectiveness compared to the other two geometries. High freestream turbulence caused a small decrease in overall effectiveness over the entire liner and was most impactful in the first three rows of effusion holes.

Effects of Effusion Cooling Pattern Near the Dilution Hole for a Double-Walled Combustor Liner: Part 1 — Overall Effectiveness Measurements

2018 ◽  
Author(s):  
Adam C. Shrager ◽  
Karen A. Thole ◽  
Dominic Mongillo
Keyword(s):  
Momentum Flux ◽  
High Momentum ◽  
Freestream Turbulence ◽  
Gas Turbine Combustor ◽  
Cooling Pattern ◽  
Cooling Hole ◽  
Cooling Enhancement ◽  
Combustor Liner ◽  
Effusion Hole ◽  
Overall Effectiveness

The complex flowfield in a gas turbine combustor makes cooling the liner walls a challenge. In particular, this paper is primarily focused on the region surrounding the dilution holes, which is especially challenging to cool due to the interaction between the effusion cooling jets and high-momentum dilution jets. This study presents overall effectiveness measurements for three different cooling hole patterns of a double-walled combustor liner. Only effusion hole patterns near the dilution holes were varied, which included: no effusion cooling; effusion holes pointed radially outward from the dilution hole; and effusion holes pointed radially inward toward the dilution hole. The double-walled liner contained both impingement and effusion plates as well as a row of dilution jets. Infrared thermography was used to measure the surface temperature of the combustor liners at multiple dilution jet momentum flux ratios and approaching freestream turbulence intensities of 0.5% and 13%. Results showed the outward and inward geometries were able to more effectively cool the region surrounding the dilution hole compared to the closed case. A significant amount of the cooling enhancement in the outward and inward cases came from in-hole convection. Downstream of the dilution hole, the interactions between the inward effusion holes and the dilution jet led to lower levels of effectiveness compared to the other two geometries. High freestream turbulence caused a small decrease in overall effectiveness over the entire liner and was most impactful in the first three rows of effusion holes.

Analysis of the influence of cooling hole arrangement on the protection of a gas turbine combustor liner

Meccanica ◽  
2018 ◽  
Vol 53 (9) ◽  
pp. 2257-2271 ◽  
Author(s):  
Ahlem Ben Sik Ali ◽  
Wassim Kriaa ◽  
Hatem Mhiri ◽  
Philippe Bournot
Keyword(s):  
Gas Turbine ◽  
Gas Turbine Combustor ◽  
Cooling Hole ◽  
Combustor Liner

Considerations of a Double-Wall Cooling Design to Reduce Sand Blockage

2010 ◽  
Vol 132 (3) ◽  
Author(s):  
Camron C. Land ◽  
Chris Joe ◽  
Karen A. Thole
Keyword(s):  
Film Cooling ◽  
Turbine Engines ◽  
Gas Turbine Engines ◽  
Gas Temperature ◽  
Impingement Cooling ◽  
Large Particles ◽  
Cooling Design ◽  
Size Of Particles ◽  
Combustor Liner ◽  
Double Wall

Gas turbine engines use innovative cooling techniques to keep metal temperatures down while pushing the main gas temperature as high as possible. Cooling technologies such as film-cooling and impingement-cooling are generally used to reduce metal temperatures of the various components in the combustor and turbine sections. As cooling passages become more complicated, ingested particles can block these passages and greatly reduce the life of hot section components. This study investigates a double-walled cooling geometry with impingement- and film-cooling. A number of parameters were simulated to investigate the success of using impingement jets to reduce the size of particles in the cooling passages. Pressure ratios typically ranged between those used for combustor liner cooling and for blade outer air seal cooling whereby both these locations typically use double-walled liners. The results obtained in this study are applicable to more intricate geometries where the need to promote particle breakup exists. Results indicated that ingested sand had a large distribution of particle sizes where particles greater than 150 μm are primarily responsible for blocking the cooling passages. Results also showed that the blockage from these large particles was significantly influenced and can be significantly reduced by controlling the spacing between the film-cooling and impingement-cooling plates.

Considerations of a Double-Wall Cooling Design to Reduce Sand Blockage

2008 ◽  
Author(s):  
Camron C. Land ◽  
Karen A. Thole ◽  
Chris Joe
Keyword(s):  
Film Cooling ◽  
Turbine Engines ◽  
Gas Turbine Engines ◽  
Gas Temperature ◽  
Impingement Cooling ◽  
Large Particles ◽  
Cooling Design ◽  
Size Of Particles ◽  
Combustor Liner ◽  
Double Wall

Gas turbine engines use innovative cooling techniques to keep metal temperatures down while pushing the main gas temperature as high as possible. Cooling technologies such as film-cooling and impingement cooling are generally used to reduce metal temperatures of the various components in the combustor and turbine sections. As cooling passages become more complicated, ingested particles can block these passages and greatly reduce the life of hot section components. This study investigates a double-walled cooling geometry with impingement and film-cooling. A number of parameters were simulated to investigate the success of using impingement jets to reduce the size of particles in the cooling passages. Pressure ratios typically ranged between those used for combustor liner cooling and for blade outer air seal cooling whereby both these locations typically use double-walled liners. The results obtained in this study are applicable to more intricate geometries where the need to promote particle breakup exists. Results indicated that ingested sand had a large distribution of particle sizes where particles greater than 150 μm are primarily responsible for blocking the cooling passages. Results also showed that the blockage from these large particles was significantly influenced and can be significantly reduced by controlling the spacing between the film-cooling and impingement cooling plates.

Turbine Vane Leading Edge Impingement Cooling With a Sweeping Jet

2018 ◽  
Author(s):  
Lucas Agricola ◽  
Mohammad A. Hossain ◽  
Ali Ameri ◽  
James W. Gregory ◽  
Jeffrey P. Bons
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Mass Flow ◽  
Guide Vane ◽  
Internal Heat ◽  
Leading Edge ◽  
Jet Impingement ◽  
Freestream Turbulence ◽  
Impingement Cooling ◽  
Jet Array

A low speed linear cascade was used to investigate sweeping jet impingement cooling in a nozzle guide vane leading edge at an engine-relevant Biot number. Sweeping and steady jets were studied at varying mass flow rates and freestream turbulence intensities. Infrared thermography and a thermal inertia technique were used to determine the overall cooling effectiveness and internal heat transfer coefficients of the impingement cooling configurations. The circular jet array provided higher overall effectiveness values at both freestream turbulence intensities. The sweeping jet array provided a broader heat transfer profile due to the spreading of the jet. Pressure drop was measured for each jet geometry, and the circular jet was found to have less pressure drop than the sweeping jet at a given mass flow rate.

Overall Effectiveness for a Film Cooled Turbine Blade Leading Edge With Varying Hole Pitch

2010 ◽  
Author(s):  
Thomas E. Dyson ◽  
Dave G. Bogard ◽  
Justin D. Piggush ◽  
Atul Kohli
Keyword(s):  
Turbine Blade ◽  
Hot Spots ◽  
Leading Edge ◽  
Stagnation Line ◽  
Convective Cooling ◽  
Impingement Cooling ◽  
Blowing Ratio ◽  
Cylindrical Holes ◽  
Overall Effectiveness ◽  
Blade Leading Edge

Overall effectiveness, φ, for a simulated turbine blade leading edge was experimentally measured using a model constructed with a relatively high conductivity material selected so that the Biot number of the model matched engine conditions. The model incorporated three rows of cylindrical holes with the center row positioned on the stagnation line. Internally the model used an impingement cooling configuration. Overall effectiveness was measured for pitch variation from 7.6d to 9.6d for blowing ratios ranging from 0.5 to 3.0, and angle of attack from −7.7° to +7.7°. Performance was evaluated for operation with a constant overall mass flow rate of coolant. Consequently when increasing the pitch, the blowing ratio was increased proportionally. The increased blowing ratio resulted in increased impingement cooling internally and increased convective cooling through the holes. The increased internal and convective cooling compensated, to a degree, for the decreased coolant coverage with increased pitch. Performance was evaluated in terms of laterally averaged φ, but also in terms of the minimum φ. The minimum φ evaluation revealed localized hot spots which are arguably more critical to turbine blade durability than the laterally averaged results. For small increases in pitch there was negligible decrease in performance.

Characteristics of a separated flow past a semicircular leading-edge airfoil model under different imposed pressure gradient

2021 ◽  
pp. 095441002110212
Author(s):  
K Anand ◽  
KT Ganesh
Keyword(s):  
Boundary Layer ◽  
Particle Image Velocimetry ◽  
Pressure Gradient ◽  
Particle Image ◽  
Separation Bubble ◽  
Separated Flow ◽  
Leading Edge ◽  
Field Measurements ◽  
Bench Mark ◽  
Image Velocimetry

The effect of pressure gradient on a separated boundary layer past the leading edge of an airfoil model is studied experimentally using electronically scanned pressure (ESP) and particle image velocimetry (PIV) for a Reynolds number ( Re) of 25,000, based on leading-edge diameter ( D). The features of the boundary layer in the region of separation and its development past the reattachment location are examined for three cases of β (−30°, 0°, and +30°). The bubble parameters such as the onset of separation and transition and the reattachment location are identified from the averaged data obtained from pressure and velocity measurements. Surface pressure measurements obtained from ESP show a surge in wall static pressure for β = −30° (flap deflected up), while it goes down for β = +30° (flap deflected down) compared to the fundamental case, β = 0°. Particle image velocimetry results show that the roll up of the shear layer past the onset of separation is early for β = +30°, owing to higher amplification of background disturbances compared to β = 0° and −30°. Downstream to transition location, the instantaneous field measurements reveal a stretched, disoriented, and at instances bigger vortices for β = +30°, whereas a regular, periodically shed vortices, keeping their identity past the reattachment location, is observed for β = 0° and −30°. Above all, this study presents a new insight on the features of a separation bubble receiving a disturbance from the downstream end of the model, and these results may serve as a bench mark for future studies over an airfoil under similar environment.

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