Simulations of Multiphase Particle Deposition on a Gas Turbine Endwall With Impingement and Film Cooling

2015 ◽  
Vol 137 (11) ◽  
Author(s):  
Amy Mensch ◽  
Karen Thole
Keyword(s):  
Heat Transfer ◽  
Film Cooling ◽  
Gas Turbines ◽  
Particle Deposition ◽  
Transfer Coefficients ◽  
Roughness Effects ◽  
Jet Cooling ◽  
Cooling Hole ◽  
Industrial Gas Turbines ◽  
Molten Particle

Replacing natural gas fuels with coal-derived syngas in industrial gas turbines can lead to molten particle deposition on the turbine components. The deposition of the particles, which originate from impurities in the syngas fuels, can increase surface roughness and obstruct film cooling holes. These deposition effects increase heat transfer to the components and degrade the performance of cooling mechanisms, which are critical for maintaining component life. The current experimental study dynamically simulated molten particle deposition on a conducting blade endwall with the injection of molten wax. The key nondimensional parameters for modeling of conjugate heat transfer and deposition were replicated in the experiment. The endwall was cooled with internal impingement jet cooling and film cooling. Increasing blowing ratio mitigated some deposition at the film cooling hole exits and in areas of coolest endwall temperatures. After deposition, the external surface temperatures and internal endwall temperatures were measured and found to be warmer than the endwall temperatures measured before deposition. Although the deposition helps insulate the endwall from the mainstream, the roughness effects of the deposition counteract the insulating effect by decreasing the benefit of film cooling and by increasing external heat transfer coefficients.

Simulations of Multiphase Particle Deposition on a Gas Turbine Endwall With Impingement and Film Cooling

2014 ◽  
Author(s):  
Amy Mensch ◽  
Karen A. Thole
Keyword(s):  
Heat Transfer ◽  
Film Cooling ◽  
Gas Turbines ◽  
Particle Deposition ◽  
Transfer Coefficients ◽  
Roughness Effects ◽  
Blowing Ratio ◽  
Jet Cooling ◽  
Cooling Hole ◽  
Molten Particle

Replacing natural gas fuels with coal derived syngas in industrial gas turbines can lead to molten particle deposition on the turbine components. The deposition of the particles, which originate from impurities in the syngas fuels, can increase surface roughness and obstruct film cooling holes. These deposition effects increase heat transfer to the components and degrade the performance of cooling mechanisms, which are critical for maintaining component life. The current study dynamically simulated molten particle deposition on a conducting blade endwall with the injection of molten wax. The key non-dimensional parameters for modeling of conjugate heat transfer and deposition were replicated in the experiment. The endwall cooling arrangements included film cooling only as well as internal impingement jet cooling plus film cooling. The distribution of deposition was influenced by the film cooling blowing ratio as well as the surface temperature of the endwall. Increasing blowing ratio mitigated some deposition at the film cooling hole exits and in areas of coolest endwall temperatures. After deposition, the external surface temperatures and internal endwall temperatures were measured and found to be warmer than the endwall temperatures measured before deposition. Although the deposition helps insulate the endwall from the mainstream, the roughness effects of the deposition counteract the insulating effect by decreasing the benefit of film cooling and by increasing external heat transfer coefficients.

Effect of a Ceramic Matrix Composite Surface on Film Cooling

2021 ◽  
Author(s):  
Peter H. Wilkins ◽  
Stephen P. Lynch ◽  
Karen A. Thole ◽  
San Quach ◽  
Tyler Vincent ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Matrix Composite ◽  
Film Cooling ◽  
Gas Turbines ◽  
Ceramic Matrix Composite ◽  
Ceramic Matrix ◽  
Composite Surface ◽  
Minimal Impact ◽  
Cooling Hole ◽  
Adiabatic Effectiveness

Abstract Ceramic matrix composite (CMC) parts create the opportunity for increased turbine entry temperatures within gas turbines. To achieve the highest temperatures possible, film cooling will play an important role in allowing turbine entry temperatures to exceed acceptable surface temperatures for CMC components, just as it does for the current generation of gas turbine components. Film cooling over a CMC surface introduces new challenges including roughness features downstream of the cooling holes and changes to the hole exit due to uneven surface topography. To better understand these impacts, this study presents flowfield and adiabatic effectiveness CFD for a 7-7-7 shaped film cooling hole at two CMC weave orientations. The CMC surface selected is a 5 Harness Satin weave pattern that is examined at two different orientations. To understand the ability of steady RANS to predict flow and convective heat transfer over a CMC surface, the weave surface is initially simulated without film and compared to previous experimental results. The simulation of the weave orientation of 0°, with fewer features projecting into the flow, matches fairly well to the experiment, and demonstrates a minimal impact on film cooling leading to only slightly lower adiabatic effectiveness compared to a smooth surface. However, the simulation of the 90° orientation with a large number of protruding features does not match the experimentally observed surface heat transfer. The additional protruding surface produces degraded film cooling performance at low blowing ratios but is less sensitive to blowing ratio, leading to improved relative performance at higher blowing ratios, particularly in regions far downstream of the hole.

Effects of a Reacting Cross-Stream on Turbine Film Cooling

2010 ◽  
Vol 132 (5) ◽  
Author(s):  
Wesly S. Anderson ◽  
Marc D. Polanka ◽  
Joseph Zelina ◽  
Dave S. Evans ◽  
Scott D. Stouffer ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Film Cooling ◽  
Thermal Protection ◽  
Critical Role ◽  
Cylindrical Hole ◽  
Gas Temperature ◽  
Transfer Coefficients ◽  
Secondary Combustion ◽  
Cooling Hole ◽  
Reactor Operating

Film cooling plays a critical role in providing effective thermal protection to components in modern gas turbine engines. A significant effort has been undertaken over the last 40 years to improve the distribution of coolant and to ensure that the airfoil is protected by this coolant from the hot gases in the freestream. This film, under conditions with high fuel-air ratios, may actually be detrimental to the underlying metal. The presence of unburned fuel from an upstream combustor may interact with this oxygen rich film coolant jet resulting in secondary combustion. The completion of the reactions can increase the gas temperature locally resulting in higher heat transfer to the airfoil directly along the path line of the film coolant jet. This secondary combustion could damage the turbine blade, resulting in costly repair, reduction in turbine life, or even engine failure. However, knowledge of film cooling in a reactive flow is very limited. The current study explores the interaction of cooling flow from typical cooling holes with the exhaust of a fuel-rich well-stirred reactor operating at high temperatures over a flat plate. Surface temperatures, heat flux, and heat transfer coefficients are calculated for a variety of reactor fuel-to-air ratios, cooling hole geometries, and blowing ratios. Emphasis is placed on the difference between a normal cylindrical hole, an inclined cylindrical hole, and a fan-shaped cooling hole. When both air and nitrogen are injected through the cooling holes, the changes in surface temperature can be directly correlated with the presence of the reaction. Photographs of the localized burning are presented to verify the extent and locations of the reaction.

Effects of a Reacting Cross-Stream on Turbine Film Cooling

2009 ◽  
Author(s):  
Wesly S. Anderson ◽  
Marc D. Polanka ◽  
Joseph Zelina ◽  
Dave S. Evans ◽  
Scott D. Stouffer ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Film Cooling ◽  
Thermal Protection ◽  
Critical Role ◽  
Cylindrical Hole ◽  
Gas Temperature ◽  
Transfer Coefficients ◽  
Secondary Combustion ◽  
Cooling Hole ◽  
Reactor Operating

Film cooling plays a critical role in providing effective thermal protection to components in modern gas turbine engines. A significant effort has been undertaken over the last 40 years to improve the distribution of coolant and to ensure that the airfoil is protected by this coolant from the hot gases in the freestream. This film, under conditions with high fuel air ratios, may actually be detrimental to the underlying metal. The presence of unburned fuel from an upstream combustor may interact with this oxygen rich film coolant jet resulting in secondary combustion. The completion of the reactions can increase the gas temperature locally resulting in higher heat transfer to the airfoil directly along the path line of the film coolant jet. This secondary combustion could damage the turbine blade, resulting in costly repair, reduction in turbine life, or even engine failure. However, knowledge of film cooling in a reactive flow is very limited. The current study explores the interaction of cooling flow from typical cooling holes with the exhaust of a fuel-rich well-stirred reactor operating at high temperatures over a flat plate. Surface temperatures, heat flux, and heat transfer coefficients are calculated for a variety of reactor fuel-to-air ratios, cooling hole geometries, and blowing ratios. Emphasis is placed on the difference between a normal cylindrical hole, an inclined cylindrical hole, and a fan shaped cooling hole. When both air and nitrogen are injected through the cooling holes, the changes in surface temperature can be directly correlated to the presence of the reaction. Photographs of the localized burning are presented to verify the extent and locations of the reaction.

scholarly journals Heat Transfer Phenomena in Gas Turbines

1980 ◽  
Author(s):  
J. R. Taylor
Keyword(s):  
Heat Transfer ◽  
Gas Turbine ◽  
Film Cooling ◽  
Gas Turbines ◽  
Turbine Blades ◽  
Gas Turbine Engine ◽  
Transfer Coefficients ◽  
Turbine Engine ◽  
Film Cooling Effectiveness ◽  
Heat Transfer Coefficients

A discussion of the problems encountered in prediction of heat transfer in the turbine section of a gas turbine engine is presented. Areas of current gas turbine engine is presented. Areas of current concern to designers where knowledge is deficient or lacking are elucidated. Consideration is given to methods and problems associated with determination of heat transfer coefficients, external gas temperatures, and, where applicable, film cooling effectiveness. The paper is divided into parts dealing with turbine airfoil heat transfer, endwall heat transfer, and heat transfer in the internal cavities of cooled turbine blades. Recent literature dealing with these topics is listed.

An Experimental and Numerical Investigation of Near Cooling Hole Heat Fluxes on a Film-Cooled Turbine Blade

1989 ◽  
Vol 111 (1) ◽  
pp. 63-70 ◽  
Author(s):  
C. Camci
Keyword(s):  
Heat Transfer ◽  
Film Cooling ◽  
Internal Heat ◽  
External Heat ◽  
Heat Fluxes ◽  
Temperature Gradients ◽  
Transfer Coefficients ◽  
External Heat Transfer ◽  
Heat Transfer Coefficients ◽  
Cooling Hole

Discrete hole film cooling on highly curved surfaces of a gas turbine blade produces very significant wall temperature gradients and wall heat flux variations near downstream and upstream of rows of circular cooling holes. In this study a set of well-defined external heat transfer coefficient distributions in the presence of discrete hole film cooling is presented. Heat transfer coefficients are measured on the suction side of an HP rotor blade profile in a short-duration facility under well-simulated gas turbine flow conditions. The main emphasis of the study is to evaluate the internal heat flux distributions in a detailed way near the cooling holes by using a computational technique. The method uses the measured external heat transfer coefficients as boundary conditions in addition to available internal heat transfer correlations for the internal passages. The study shows the details of the near hole temperature gradients and heat fluxes. The convective heat transfer inside the circular film cooling holes is shown to be very significant even with their relatively small diameter and lengths compared to the chord length. The study also indicates a nonnegligible wall temperature reduction at near upstream of discrete cooling holes. This is explained with the elliptic nature of the internal conduction field of the blade and relatively low coolant temperature levels at the exit of a film cooling hole compared to the mean blade temperature.

scholarly journals Internal Aerodynamics and Heat Transfer Problems Associated to Film Cooling of Gas Turbines

1979 ◽  
Author(s):  
Emile Le Grivès ◽  
J.-J. Nicolas ◽  
Jeanne Génot
Keyword(s):  
Heat Transfer ◽  
Film Cooling ◽  
Gas Turbines ◽  
Flow Distribution ◽  
Transfer Coefficients ◽  
Pressure Losses ◽  
Effects Of Rotation ◽  
Transient Thermal ◽  
Turbine Airfoils ◽  
Transfer Problems

Heat transfer and aerodynamic processes within coolant ducts and film emission holes of high temperature gas turbine components have been investigated at ONERA by means of specially devised test rigs affording an adequate similitude of geometrical or aerothermal parameters. Results obtained in tests at steady or transient thermal regime are reported for several points of interest concerning internal coolant circuits: • Heat transfer through multihole parts of turbine airfoils • Aerodynamics of flows within perforated ducts, with special attention to coolant mass flow distribution, to pressure losses and heat transfer coefficients in small or scaled up turbine blade models • Heat transfer over a perforated wall, with mass transfer of the coolant flow through holes of various patterns and pitch-to-diameter ratio. Experimental data are discussed in regard to desired accuracy for the analysis of heat transfer in air-cooled gas turbines, except for the effects of rotation.

Full-Coverage Film Cooling: Film Effectiveness and Heat Transfer Coefficients for Dense Hole Arrays at Different Hole Angles, Contraction Ratios, and Blowing Ratios

2013 ◽  
Vol 135 (3) ◽  
Author(s):  
Phil Ligrani ◽  
Matt Goodro ◽  
Mike Fox ◽  
Hee-Koo Moon
Keyword(s):  
Heat Transfer ◽  
Film Cooling ◽  
Test Surface ◽  
Transfer Coefficients ◽  
Heat Transfer Coefficients ◽  
Blowing Ratio ◽  
Full Coverage ◽  
Contraction Ratio ◽  
Cooling Hole ◽  
Film Cooling Holes

Experimental results are presented for a full-coverage film cooling arrangement which simulates a portion of a gas turbine engine, with appropriate streamwise static pressure gradient. The test surface utilizes varying blowing ratio (BR) along the length of the contraction passage which contains the cooling hole arrangement. For the different experimental conditions examined, film cooling holes are sharp-edged and streamwise inclined either at 20 deg or 30 deg with respect to the liner surface. The film cooling holes in adjacent streamwise rows are staggered with respect to each other. Data are provided for turbulent film cooling, contraction ratios of 1, 3, 4, and 5, blowing ratios (at the test section entrance) of 2.0, 5.0, and 10.0, coolant Reynolds numbers Refc of 10,000–12,000, freestream temperatures from 75 °C to 115 °C, a film hole diameter of 7 mm, and density ratios from 1.15 to 1.25. Nondimensional streamwise and spanwise film cooling hole spacings, X/D and Y/D, are 6, and 5, respectively. When the streamwise hole inclination angle is 20 deg spatially averaged and line-averaged adiabatic effectiveness values at each x/D location are about the same as the contraction ratio varies between 1, 3, and 4, with slightly higher values at each x/D location when the contraction ratio Cr is 5. For each contraction ratio, there is a slight increase in effectiveness when the blowing ratio is increased from 2.0 to 5.0 but there is no further substantial improvement when the blowing ratio is increased to 10.0. Overall, line-averaged and spatially averaged-adiabatic film effectiveness data, and spatially averaged heat transfer coefficient data are described as they are affected by contraction ratio, blowing ratio, hole angle α, and streamwise location x/D. For example, when α = 20 deg, the detrimental effects of mainstream acceleration are apparent since heat transfer coefficients for contraction ratios Cr of 3 and 5 are often higher than values for Cr = 1, especially for x/D > 100.

Full-Coverage Film Cooling: Film Effectiveness and Heat Transfer Coefficients for Dense Hole Arrays at Different Hole Angles, Contraction Ratios, and Blowing Ratios

2012 ◽  
Author(s):  
Matt Goodro ◽  
Phil Ligrani ◽  
Mike Fox ◽  
Hee-Koo Moon
Keyword(s):  
Heat Transfer ◽  
Film Cooling ◽  
Test Surface ◽  
Transfer Coefficients ◽  
Heat Transfer Coefficients ◽  
Blowing Ratio ◽  
Full Coverage ◽  
Contraction Ratio ◽  
Cooling Hole ◽  
Film Cooling Holes

Experimental results are presented for a full coverage film cooling arrangement which simulates a portion of a gas turbine engine, with appropriate streamwise static pressure gradient. The test surface utilizes varying blowing ratio along the length of the contraction passage which contains the cooling hole arrangement. For the different experimental conditions examined, film cooling holes are sharp-edged and streamwise inclined either at 20° or 30° with respect to the liner surface. The film cooling holes in adjacent streamwise rows are staggered with respect to each other. Data are provided for turbulent film cooling, contraction ratios of 1, 3, 4, and 5, blowing ratios (at the test section entrance) of 2.0, 5.0, and 10.0, coolant Reynolds numbers Refc of 10,000 to 12,000, freestream temperatures from 75°C to 115°C, a film hole diameter of 7 mm, and density ratios from 1.15 to 1.25. Non-dimensional streamwise and spanwise film cooling hole spacings, X/D and Y/D, are 6, and 5, respectively. When the streamwise hole inclination angle is 20°, spatially-averaged and line-averaged adiabatic effectiveness values at each x/D location are about the same as the contraction ratio varies between 1, 3, and 4, with slightly higher values at each x/D location when the contraction ratio Cr is 5. For each contraction ratio, there is a slight increase in effectiveness when the blowing ratio is increased from 2.0 to 5.0 but there is no further substantial improvement when the blowing ratio is increased to 10.0. Overall, line-averaged and spatially-averaged adiabatic film effectiveness data, and spatially-averaged heat transfer coefficient data are described as they are affected by contraction ratio, blowing ratio, hole angle α, and streamwise location x/D. For example, when α = 20°, the detrimental effects of mainstream acceleration are apparent since heat transfer coefficients for contraction ratios Cr of 3 and 5 are often higher than values for Cr = 1, especially for x/D > 100.

Adiabatic and Overall Effectiveness for a Film Cooled Blade

2004 ◽  
Author(s):  
Jason E. Albert ◽  
David G. Bogard ◽  
Frank Cunha
Keyword(s):  
Heat Transfer ◽  
Film Cooling ◽  
Internal Heat ◽  
Leading Edge ◽  
Test Case ◽  
Test Model ◽  
Transfer Coefficients ◽  
Cooling Effectiveness ◽  
Cooling Hole ◽  
Adiabatic Effectiveness

Laboratory studies of film cooling performance for turbine section airfoils typically quantify adiabatic effectiveness and occasionally the heat transfer coefficient for the film cooling configuration. In this study the normalized airfoil metal surface temperatures are obtained directly by using a test model that has a material conductivity scaled to the external and internal heat transfer coefficients so that the Biot number for the model is similar to that for the actual airfoil. These results provide an experimental test case of the conjugate heat transfer involved in turbine airfoil cooling. In this study, conventional adiabatic effectiveness and the overall cooling effectiveness (normalized surface temperature for the matched Biot model) were measured for a generic blade leading edge using three rows of shaped holes. Distinct differences were found between the adiabatic effectiveness and overall cooling effectiveness. Also included is a practical application of this experimental method for which the degradation of overall cooling effectiveness due to a plugged cooling hole is examined.

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