Sturgess, GJ
1994
Observations of Flame Behavior from a Practical Fuel Injector Using Gaseous Fuel in a Technolgoy Combustor
Hedman, P.O.; Sturgess, G.J.; Warren, D.L.; Goss, L.P. and Shouse, D.T.
Transactions of the ASME, 1994 (in press). (Also presented at the ASME International Gas Turbine and Aeroengine Congress and Exposition, The Hague, Netherlands, June 1994. Funded by ACERC, Wright Patterson Air Force Base and Air Force Office of Scientific Research.
This paper presents results from an Air Force program being conducted by researchers at Brigham Young University (BYU), Wright-Patterson Air Force Base (WPAFB), and Pratt and Whitney Aircraft Co. (P&W). This study is part of a comprehensive effort being supported by the Aero Propulsion and Power Laboratory at Wright-Patterson Air Force Base, and Pratt and Whitney, Inc. in which simple and complex diffusion flames are being studied to better understand the fundamentals of gas turbine combustion near lean blowout. The program's long-term goal is to improve the design methodology of gas turbine combustors.
This paper focuses on four areas of investigation: 1) digitized images from still film photographs to document the observed flame structures as fuel equivalence ratio was varied, 2) sets of LDA data to quantify the velocity flow fields existing in the burner, 3) CARS measurements of gas temperature to determine the temperature field in the combustion zone, and to evaluate the magnitude of peak temperature, and 4) two-dimensional images of OH radical concentrations using PLIF to document the instantaneous location of the flame reaction zones.
Aspects of Flame Stability in a Research Dump Combustor
Sturgess, G.J.; Hedman, P.O.; Sloan, D.G. and Shouse, D.T.
Transactions of the ASME, 1994 (in press). (Also presented at the ASME International Gas Turbine and Aeroengine Congress and Exposition, The Hague, Netherlands, June 1994. Funded by ACERC, Wright Patterson Air Force Base and Air Force Office of Scientific Research.
The lean blowout process is studied in a simplified, nominally diffusion flame, research combustor that incorporates the essential features of the combustor primary zone for an aircraft gas turbine engine. The research combustor is provided with extensive optical access. To investigate the blowout, a variety of diagnostic techniques are employed, including direct flame observation, laser-Doppler anemometry, spontaneous OH-imaging, thin-filament pyrometry, laser-induced fluorescence OH imaging, coherent anti-Stokes Raman spectroscopy, and computational fluid dynamics. Lean blowouts in the research combustor are related to well-stirred reactor blowout. A blowout sequence is found to be initiated by the loss of a key flame structure in the form of an attached pilot flame. The behavior of this attached flame is investigated. It is concluded that a major contribution to the existence of the attached flame is near-field, non-stationary radial transport of reactants directly into the recirculation zone, rather than by mean flow recirculation of hot products. "Lift" of the attached flame is the reason that lean blowout in the research combustor is related to well-stirred reactor blowout since it allows at least partial premixing of reactants to take place.
1991
Flame Stability and Lean Blowout
Sturgess, G.J.; Sloan, D.G.; Roquemore, W.M.; Reddy, V.K.; Schouse, D.; Lesmerises, A.L.; Ballal, D.R.; Heneghan, S.P.; Vangsness, M.D. and Hedman, P.O.
10th International Society of Air Breathing Engines, Nottingham, England, September 1991. Funded by US Air Force.
A progress report is presented on a comprehensive research program aimed at improving the design and analysis capabilities for flame stability and lean blowout in the combustors of aircraft gas turbine engines. The motivation and aims of the program are reviewed, and the unusual approach adopted to address the research issues is outlined. The supporting experimental program and the test vehicles involved are described, together with some major results obtained to date. The modeling techniques that are being explored are summarized. Their potential and limitations are highlighted. Although much work remains yet to be done, the progress made thus far gives rise to reasonable optimism for achieving the program objectives.
Experimental and Theoretical Studies in a Gas-Fueled Research Combustor
Roquemore, W.M.; Reddy, V.K.; Hedman, P.O.; Post, M.E.; Chen, T.H.; Goss, L.P.; Trump, D.; Vilimpoc, V. and Sturgess, G.J.
AIAA 29th Aerospace Sciences Meeting, Reno, NV, January 1991. Funded by US Air Force.
This paper reports the results of an investigation to determine the flow and flame characteristics of a burner which has been carefully designed to "specifically reproduce recirculation patterns and lean-blow-out (LBO) processes that occur in a real gas turbine combustor." When operated in a fuel rich mode, the flame is very stable and is anchored in the jet shear layer by a pilot flame attached to the step, near the outer edge of the air supply tube. As the equilivalence ratio is reduced, the flame becomes less stable, and eventually reaches a point where the pilot flame becomes detached (lifts) from the base region, and the entire flame structure becomes stabilized downstream. Thus, there are two distinct operating modes for the combustor: a fully attached flame and a lifted flame. As the fuel equivalence ratio is further reduced, the flame becomes progressively less stable in its lifted condition, and eventually blows out. Photographs of the flame clearly illustrate the attached and lifted flame operational regimes of the combustor. However, visual observation and conventional photographic techniques are unable to quantify the precise details of the flame transition from an attached to a lifted condition. A Computational Fluid Dynamics (CFD) model with one step chemistry was used to investigate the time-averaged features of the reacting and non-reacting flow fields. The difficulties of predicting the characteristics of the attached flame with a time averaged CFD type model are discussed. Measurements, using OH emissions and gray body radiation from 14 µm diameter filaments located near the base of the flame, clearly indicate the dynamic or intermittent nature of both the attached and lifted flames. It is theorized that unburned hydrocarbon combustion products are transported into the recirculation zone by the intermittent process; and it is these products that provide the fuel needed for the flame to attach to the outer edge of the step.
Sturgess, GJ
1994
Observations of Flame Behavior from a Practical Fuel Injector Using Gaseous Fuel in a Technolgoy Combustor
Hedman, P.O.; Sturgess, G.J.; Warren, D.L.; Goss, L.P. and Shouse, D.T.
Transactions of the ASME, 1994 (in press). (Also presented at the ASME International Gas Turbine and Aeroengine Congress and Exposition, The Hague, Netherlands, June 1994. Funded by ACERC, Wright Patterson Air Force Base and Air Force Office of Scientific Research.
This paper presents results from an Air Force program being conducted by researchers at Brigham Young University (BYU), Wright-Patterson Air Force Base (WPAFB), and Pratt and Whitney Aircraft Co. (P&W). This study is part of a comprehensive effort being supported by the Aero Propulsion and Power Laboratory at Wright-Patterson Air Force Base, and Pratt and Whitney, Inc. in which simple and complex diffusion flames are being studied to better understand the fundamentals of gas turbine combustion near lean blowout. The program's long-term goal is to improve the design methodology of gas turbine combustors.
This paper focuses on four areas of investigation: 1) digitized images from still film photographs to document the observed flame structures as fuel equivalence ratio was varied, 2) sets of LDA data to quantify the velocity flow fields existing in the burner, 3) CARS measurements of gas temperature to determine the temperature field in the combustion zone, and to evaluate the magnitude of peak temperature, and 4) two-dimensional images of OH radical concentrations using PLIF to document the instantaneous location of the flame reaction zones.
Aspects of Flame Stability in a Research Dump Combustor
Sturgess, G.J.; Hedman, P.O.; Sloan, D.G. and Shouse, D.T.
Transactions of the ASME, 1994 (in press). (Also presented at the ASME International Gas Turbine and Aeroengine Congress and Exposition, The Hague, Netherlands, June 1994. Funded by ACERC, Wright Patterson Air Force Base and Air Force Office of Scientific Research.
The lean blowout process is studied in a simplified, nominally diffusion flame, research combustor that incorporates the essential features of the combustor primary zone for an aircraft gas turbine engine. The research combustor is provided with extensive optical access. To investigate the blowout, a variety of diagnostic techniques are employed, including direct flame observation, laser-Doppler anemometry, spontaneous OH-imaging, thin-filament pyrometry, laser-induced fluorescence OH imaging, coherent anti-Stokes Raman spectroscopy, and computational fluid dynamics. Lean blowouts in the research combustor are related to well-stirred reactor blowout. A blowout sequence is found to be initiated by the loss of a key flame structure in the form of an attached pilot flame. The behavior of this attached flame is investigated. It is concluded that a major contribution to the existence of the attached flame is near-field, non-stationary radial transport of reactants directly into the recirculation zone, rather than by mean flow recirculation of hot products. "Lift" of the attached flame is the reason that lean blowout in the research combustor is related to well-stirred reactor blowout since it allows at least partial premixing of reactants to take place.
1991
Flame Stability and Lean Blowout
Sturgess, G.J.; Sloan, D.G.; Roquemore, W.M.; Reddy, V.K.; Schouse, D.; Lesmerises, A.L.; Ballal, D.R.; Heneghan, S.P.; Vangsness, M.D. and Hedman, P.O.
10th International Society of Air Breathing Engines, Nottingham, England, September 1991. Funded by US Air Force.
A progress report is presented on a comprehensive research program aimed at improving the design and analysis capabilities for flame stability and lean blowout in the combustors of aircraft gas turbine engines. The motivation and aims of the program are reviewed, and the unusual approach adopted to address the research issues is outlined. The supporting experimental program and the test vehicles involved are described, together with some major results obtained to date. The modeling techniques that are being explored are summarized. Their potential and limitations are highlighted. Although much work remains yet to be done, the progress made thus far gives rise to reasonable optimism for achieving the program objectives.
Experimental and Theoretical Studies in a Gas-Fueled Research Combustor
Roquemore, W.M.; Reddy, V.K.; Hedman, P.O.; Post, M.E.; Chen, T.H.; Goss, L.P.; Trump, D.; Vilimpoc, V. and Sturgess, G.J.
AIAA 29th Aerospace Sciences Meeting, Reno, NV, January 1991. Funded by US Air Force.
This paper reports the results of an investigation to determine the flow and flame characteristics of a burner which has been carefully designed to "specifically reproduce recirculation patterns and lean-blow-out (LBO) processes that occur in a real gas turbine combustor." When operated in a fuel rich mode, the flame is very stable and is anchored in the jet shear layer by a pilot flame attached to the step, near the outer edge of the air supply tube. As the equilivalence ratio is reduced, the flame becomes less stable, and eventually reaches a point where the pilot flame becomes detached (lifts) from the base region, and the entire flame structure becomes stabilized downstream. Thus, there are two distinct operating modes for the combustor: a fully attached flame and a lifted flame. As the fuel equivalence ratio is further reduced, the flame becomes progressively less stable in its lifted condition, and eventually blows out. Photographs of the flame clearly illustrate the attached and lifted flame operational regimes of the combustor. However, visual observation and conventional photographic techniques are unable to quantify the precise details of the flame transition from an attached to a lifted condition. A Computational Fluid Dynamics (CFD) model with one step chemistry was used to investigate the time-averaged features of the reacting and non-reacting flow fields. The difficulties of predicting the characteristics of the attached flame with a time averaged CFD type model are discussed. Measurements, using OH emissions and gray body radiation from 14 µm diameter filaments located near the base of the flame, clearly indicate the dynamic or intermittent nature of both the attached and lifted flames. It is theorized that unburned hydrocarbon combustion products are transported into the recirculation zone by the intermittent process; and it is these products that provide the fuel needed for the flame to attach to the outer edge of the step.