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.

Passive Absorption/Emission Spectroscopy for Gas Temperature Measurements in Gas Turbine Engines

2011 ◽  
Author(s):  
Hejie Li ◽  
Guanghua Wang ◽  
Nirm Nirmalan ◽  
Samhita Dasgupta ◽  
Edward R. Furlong
Keyword(s):  
Gas Turbine ◽  
Emission Spectroscopy ◽  
Gas Absorption ◽  
Temperature Measurements ◽  
Turbine Engines ◽  
Gas Turbine Engines ◽  
Gas Temperature ◽  
Measurement Results ◽  
Passive Absorption ◽  
Hot Surface

A novel technique is developed to simultaneously measure hot surface and gas temperatures based on passive absorption/emission spectroscopy (PAS). This non-intrusive, in situ technique is the extension of multi-wavelength pyrometry to also measure gas temperature. The PAS technique uses hot surface (e.g., turbine blade) as the radiation source, and measures radiation signals at multiple wavelengths. Radiation signals at wavelengths with minimum interference from gas (mostly from water vapor and CO2) can be used to determine the hot surface temperature, while signals at wavelengths with gas absorption/emission can be used to determine the gas temperature in the line-of-sight. The detection wavelengths are optimized for accuracy and sensitivity for gas temperature measurements. Simulation results also show the effect of non-uniform gas temperature profile on measurement results. High pressure/temperature tests are conducted in single nozzle combustor rig to demonstrate sensor proof-of-concept. Preliminary engine measurement results shows the potential of this measurement technique. The PAS technique only requires one optical port, e.g., existing pyrometer or borescope port, to collect the emission signal, and thus provide practical solution for gas temperature measurement in gas turbine engines.

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.

Development and Evaluation of Environmental Barrier Coatings for Si-Based Ceramics

2004 ◽  
Author(s):  
Tania Bhatia ◽  
Venkat Vedula ◽  
Harry Eaton ◽  
Ellen Sun ◽  
John Holowczak ◽  
...  
Keyword(s):  
Silicon Carbide ◽  
Silicon Nitride ◽  
Field Tests ◽  
Turbine Engines ◽  
Gas Turbine Engines ◽  
Barrier Coatings ◽  
Environmental Barrier Coatings ◽  
Environmental Barrier ◽  
And Performance ◽  
Combustor Liner

Environmental barrier coatings (EBCs) are being developed for silicon carbide (SiC) based composites and monolithic silicon nitride (Si3N4) to protect against the accelerated oxidation and subsequent silica volatilization in high temperature, high-pressure steam environments encountered in gas turbine engines. While EBCs for silicon carbide (EBCSiC) have been demonstrated in combustor liner applications, efforts are ongoing in the development of EBC systems for silicon nitride (EBCSiN). The challenges of adapting EBCSiC to monolithic Si3N4 are discussed in this paper. Progress in the area of EBCSiN including development and performance during field tests and tests simulating engine conditions are reviewed.

EBC Protection of SiC/SiC Composites in the Gas Turbine Combustion Environment

2000 ◽  
Author(s):  
Harry E. Eaton ◽  
Gary D. Linsey ◽  
Karren L. More ◽  
Joshua B. Kimmel ◽  
Jeffrey R. Price ◽  
...  
Keyword(s):  
Silicon Carbide ◽  
Gas Turbine ◽  
Department Of Energy ◽  
Turbine Engines ◽  
Gas Turbine Engines ◽  
Barrier Coating ◽  
Temperature Capability ◽  
Pressure Water ◽  
Sic Composites ◽  
Combustor Liner

Silicon carbide fiber reinforced silicon carbide composites (SiC/SiC) are attractive for use in gas turbine engines as combustor liner materials, in part, because the temperature capability allows for reduced cooling. This enables the engine to operate more efficiently and to meet very stringent emission goals for NOx and CO. It has been shown, however, that SiC/SiC and other silica formers can degrade with time in the high steam environment of the gas turbine combustor due to accelerated oxidation and subsequent volatilization of the silica due to reaction with high pressure water (ref.s 1 & 2). As a result, an environmental barrier coating (EBC) is required in conjunction with the SiC composite in order to meet long life goals. Under the U.S. Department of Energy (DOE) sponsored Solar Turbines Incorporated Ceramic Stationary Gas Turbine (CSGT) engine program (ref. 3), EBC systems developed under the HSCT EPM program (NASA contract NAS3-23685) were applied to both SiC/SiC composite coupons and SiC/SiC combustion liners which were then evaluated in long term laboratory testing and in ground based turbine power generation, respectively. This paper discusses the application of the EBC’s to SiC/SiC composites and the results from laboratory and engine test evaluations.

Minimization of Heat Load Due to Secondary Reactions in Fuel Rich Environments

2015 ◽  
Vol 137 (12) ◽  
Author(s):  
Andrew T. Shewhart ◽  
Marc D. Polanka ◽  
Jacob J. Robertson ◽  
Nathan J. Greiner ◽  
James L. Rutledge
Keyword(s):  
Heat Flux ◽  
Film Cooling ◽  
Turbine Blades ◽  
Local Heat ◽  
Turbine Engines ◽  
Inlet Temperature ◽  
Gas Turbine Engines ◽  
Engine Efficiency ◽  
Secondary Reactions ◽  
Local Heat Flux

The demand for increased thrust, higher engine efficiency, and reduced fuel consumption has increased the turbine inlet temperature and pressure in modern gas turbine engines. The outcome of these higher temperatures and pressures is the potential for unconsumed radical species to enter the turbine. Because modern cooling schemes for turbine blades involve injecting cool, oxygen-rich air adjacent to the surface, the potential for reaction with radicals in the mainstream flow, and augmented heat transfer to the blade arises. This result is contrary to the purpose of film cooling. In this environment, there is a competing desire to consume any free radicals prior to the flow entering the rotor stage while still maintaining surface temperatures below the metal melting temperature. This study evaluated various configurations of multiple cylindrical rows of cooling holes in terms of both heat release and effective downstream cooling. Results were evaluated based on net heat flux reduction (NHFR) and a new wall absorption (WA) parameter which combined the additional heat available from these secondary reactions with the length of the resulting flame to determine which schemes protected the wall more efficiently. Two particular schemes showed promise. The two row upstream configuration reduced the overall augmentation of heat by creating a short, concentrated reaction area. Conversely, the roll forward configuration minimized the local heat flux enhancement by spreading the reaction area over the surface being cooled.

EBC Protection of SiC/SiC Composites in the Gas Turbine Combustion Environment: Continuing Evaluation and Refurbishment Considerations

2001 ◽  
Author(s):  
Harry E. Eaton ◽  
Gary D. Linsey ◽  
Ellen Y. Sun ◽  
Karren L. More ◽  
Joshua B. Kimmel ◽  
...  
Keyword(s):  
Silicon Carbide ◽  
Gas Turbine ◽  
Department Of Energy ◽  
Turbine Engines ◽  
Gas Turbine Engines ◽  
Barrier Coating ◽  
Temperature Capability ◽  
Pressure Water ◽  
Sic Composites ◽  
Combustor Liner

Silicon carbide fiber reinforced silicon carbide composites (SiC/SiC CMC’s) are attractive for use in gas turbine engines as combustor liner materials because the temperature capability allows for reduced cooling. This enables the engine to operate more efficiently and enables the design of very stringent emission goals for NOx and CO. It has been shown, however, that SiC/SiC CMC’s and other silica formers can degrade with time in the high steam environment of the gas turbine combustor due to accelerated oxidation and subsequent volatilization of the silica due to reaction with high pressure water (ref.s 1, 2, 3, & 4). As a result, an environmental barrier coating (EBC) is required in conjunction with the SiC/SiC CMC in order to meet long life goals. Under the U.S. Department of Energy (DOE) sponsored Solar Turbines Incorporated Ceramic Stationary Gas Turbine (CSGT) engine program (ref. 5), EBC systems developed under the HSCT EPM program and improved under the CSGT program have been applied to both SiC/SiC CMC coupons and SiC/SiC CMC combustion liners which have been evaluated in long term laboratory testing and in ground based turbine power generation. This paper discusses the continuing evaluation (see ref. 6) of EBC application to SiC/SiC CMC’s and the results from laboratory and engine test evaluations along with refurbishment considerations.

Effects of Hot Streaks on Adiabatic Effectiveness for a Film Cooled Turbine Vane

2004 ◽  
Author(s):  
Krishnakumar Varadarajan ◽  
David G. Bogard
Keyword(s):  
Film Cooling ◽  
Field Measurements ◽  
Suction Side ◽  
Experimental Program ◽  
Turbine Engines ◽  
Gas Turbine Engines ◽  
Turbine Vane ◽  
Adiabatic Effectiveness ◽  
Hot Streak ◽  
Effectiveness Data

Turbine guide vanes in gas turbine engines are typically subjected to localized “hot streaks” emanating from the combustor. This experimental program examined how these hot streaks affect the film cooling performance for these vanes. Adiabatic effectiveness tests were conducted on the showerhead and suction side regions of the vane. Particular attention was placed on how to scale that adiabatic effectiveness data obtained with a hot streak to correctly predict the adiabatic effectiveness. Thermal field measurements were made to determine the temperature gradients for the hot streak near the wall. These experiments showed that the effect of the hot streak on the adiabatic effectiveness could be accounted for by using an “adjusted” mainstream temperature equal to the hot streak temperature at the wall of the vane.

Simulation of a Multi-Stage Cooling Scheme for Gas Turbine Engines: Part I

2007 ◽  
Author(s):  
M. Ghorab ◽  
I. Hassan ◽  
M. Beauchamp
Keyword(s):  
Gas Turbine ◽  
Film Cooling ◽  
Lateral Spreading ◽  
Turbine Engines ◽  
Gas Turbine Engines ◽  
Cooling Effectiveness ◽  
Film Cooling Effectiveness ◽  
Multi Stage ◽  
Gap Height ◽  
Internal Gap

This paper presents heat transfer characteristics for a Multi-Stage Cooling Scheme (MSCS) design applicable to high temperature gas turbine engines in aerospace and electric power generation. The film cooling and impingement techniques are considered concurrently throughout this study. The proposed design involves passing cooling air from the inside of the turbine blade to the outside through three designed stages. The coolant air is passed through a circular hole into an internal gap creating an impingement of air inside the blade. It then exits through a sequence of two differently shaped holes onto the blade’s external surface. The film cooling effectiveness is enhanced by increasing the internal gap height and offset distance. This effect is significantly diminished however by changing the inclination angle from 90° to 30° at large gap height. The coolant momentum became more uniform by creating the internal gap consequently the coolant air is spread closer to the external blade surface. This reduces jet liftoff as the air exits its hole and also provides internal cooling for the blade. The hole exit positioned on the outer surface of the blade is designed to give a positive and a wide downstream lateral spreading. The MSCS demonstrates greater film cooling effectiveness performance than traditional schemes.

Minimization of Heat Load due to Secondary Reactions in Fuel Rich Environments

2014 ◽  
Author(s):  
Andrew T. Shewhart ◽  
Marc D. Polanka ◽  
Jacob J. Robertson ◽  
Nathan J. Greiner ◽  
James L. Rutledge
Keyword(s):  
Film Cooling ◽  
Turbine Blades ◽  
Local Heat ◽  
Turbine Engines ◽  
Inlet Temperature ◽  
Gas Turbine Engines ◽  
Engine Efficiency ◽  
Secondary Reactions ◽  
Local Heat Flux ◽  
Metal Melting

The demand for increased thrust, higher engine efficiency, and reduced fuel consumption has increased the turbine inlet temperature and pressure in modern gas turbine engines. The outcome of these higher temperatures and pressures is the potential for unconsumed radical species to enter the turbine. Because modern cooling schemes for turbine blades involve injecting cool, oxygen rich air adjacent to the surface, the potential for reaction with radicals in the mainstream flow and augmented heat transfer to the blade arises. This result is contrary to the purpose of film cooling. In this environment there is a competing desire to consume any free radicals prior to the flow entering the rotor stage while still maintaining surface temperatures below the metal melting temperature. This study evaluated various configurations of multiple cylindrical rows of cooling holes in terms of both heat release and effective downstream cooling. Results were evaluated based on a new Wall Absorption parameter which combined the additional heat available from these secondary reactions with the length of the resulting flame to determine which schemes protected the wall more efficiently. Two particular schemes showed promise. The two row upstream configuration reduced the overall augmentation of heat by creating a short, concentrated reaction area. Conversely, the roll forward configuration minimized the local heat flux enhancement by spreading the reaction area over the surface being cooled.

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