Phase-Resolved Laser Diagnostic Measurements of a Downscaled, Fuel-Staged Gas Turbine Combustor at Elevated Pressure and Comparison to LES Predictions

2006 ◽  
Vol 129 (3) ◽  
pp. 680-687 ◽  
Author(s):  
Klaus Peter Geigle ◽  
Wolfgang Meier ◽  
Manfred Aigner ◽  
Chris Willert ◽  
Marc Jarius ◽  
...  
Keyword(s):  
Gas Turbine ◽  
Combustion Process ◽  
Elevated Pressure ◽  
Air Cooling ◽  
Gas Turbine Combustor ◽  
Image Velocimetry ◽  
Large Eddy ◽  
Laser Diagnostic ◽  
Chemical Scheme ◽  
Pulsating Flames

A technical gas turbine combustor has been studied in detail with optical diagnostics for validation of large-eddy simulations (LES). OH* chemiluminescence, OH laser-induced fluorescence (LIF) and particle image velocimetry (PIV) have been applied to stable and pulsating flames up to 8 bar. The combination of all results yielded good insight into the combustion process with this type of burner and forms a database that was used for the validation of complex numerical combustion simulations. LES, including radiation, convective cooling, and air cooling, were combined with a reduced chemical scheme that predicts NOx emissions. Good agreement of the calculated flame position and shape with experimental data was found.

Phase Resolved Laser Diagnostic Measurements of a Downscaled, Fuel Staged Gas Turbine Combustor at Elevated Pressure and Comparison With LES Predictions

2006 ◽  
Author(s):  
Klaus Peter Geigle ◽  
Wolfgang Meier ◽  
Manfred Aigner ◽  
Chris Willert ◽  
Marc Jarius ◽  
...  
Keyword(s):  
Gas Turbine ◽  
Combustion Process ◽  
Elevated Pressure ◽  
Large Eddy Simulations ◽  
Air Cooling ◽  
Gas Turbine Combustor ◽  
Image Velocimetry ◽  
Large Eddy ◽  
Chemical Scheme ◽  
Pulsating Flames

A technical gas turbine combustor has been studied in detail with optical diagnostics for validation of Large-Eddy Simulations (LES). OH* chemiluminescence, OH laser-induced fluorescence (LIF) and particle image velocimetry (PIV) have been applied to stable and pulsating flames up to 8 bar. The combination of all results yielded a good insight into the combustion process with this type of burner and forms a data base which was used for the validation of complex numerical combustion simulations. Large-Eddy Simulations (LES) including radiation, convective cooling and air cooling were combined with a reduced chemical scheme that predicts NOx emissions. Good agreement of the calculated flame position and shape with experimental data was found.

Flow Field and Structure of Swirl Stabilized Non-Premixed Natural Gas Flames at Elevated Pressure

2004 ◽  
Author(s):  
Bertram Janus ◽  
Andreas Dreizler ◽  
Johannes Janicka
Keyword(s):  
Flow Field ◽  
Gas Turbine ◽  
Elevated Pressure ◽  
Diagnostic Methods ◽  
Computational Grids ◽  
Flow Structures ◽  
Gas Turbine Combustor ◽  
Laser Diagnostic ◽  
Recirculation Zones ◽  
Inflow Conditions

This study reports on measurements in a generic non-premixed gas turbine combustor segment. Flow and scalar field were characterized using advanced laser diagnostic methods. The optically accessible burning chamber allowed for measurement of inflow conditions close-by the nozzle important for comparisons with numerical simulations. The generic nozzle design is sufficiently simplified to be precisely reproduced by block structured computational grids but shows typical features of gas turbine applications. To expose the influence of heat release on the flow field properties both isothermal and combusting conditions were investigated. Striking features of the present configuration are a detached flame, multiple recirculation zones, and complex coherent flow structures.

Towards Improved Prediction of Aero-Engine Combustor Performance Using Large Eddy Simulations

2008 ◽  
Author(s):  
S. James ◽  
M. S. Anand ◽  
B. Sekar
Keyword(s):  
Gas Turbine ◽  
Radial Profile ◽  
Design Tool ◽  
Operating Conditions ◽  
Outlet Temperature ◽  
Gas Turbine Combustor ◽  
Systematic Assessment ◽  
Eddy Simulation ◽  
Large Eddy ◽  
Aero Engine

The paper presents an assessment of large eddy simulation (LES) and conventional Reynolds averaged methods (RANS) for predicting aero-engine gas turbine combustor performance. The performance characteristic that is examined in detail is the radial burner outlet temperature (BOT) or fuel-air ratio profile. Several different combustor configurations, with variations in airflows, geometries, hole patterns and operating conditions are analyzed with both LES and RANS methods. It is seen that LES consistently produces a better match to radial profile as compared to RANS. To assess the predictive capability of LES as a design tool, pretest predictions of radial profile for a combustor configuration are also presented. Overall, the work presented indicates that LES is a more accurate tool and can be used with confidence to guide combustor design. This work is the first systematic assessment of LES versus RANS on industry-relevant aero-engine gas turbine combustors.

Large-Eddy Simulation of Reacting Turbulent Flows in Complex Geometries

2005 ◽  
Vol 73 (3) ◽  
pp. 374-381 ◽  
Author(s):  
K. Mahesh ◽  
G. Constantinescu ◽  
S. Apte ◽  
G. Iaccarino ◽  
F. Ham ◽  
...  
Keyword(s):  
Large Eddy Simulation ◽  
Gas Turbine ◽  
Turbulent Flows ◽  
Reacting Flows ◽  
Gas Turbine Combustor ◽  
Turbine Engine ◽  
Progress Variable ◽  
Eddy Simulation ◽  
Variable Approach ◽  
Large Eddy

Large-eddy simulation (LES) has traditionally been restricted to fairly simple geometries. This paper discusses LES of reacting flows in geometries as complex as commercial gas turbine engine combustors. The incompressible algorithm developed by Mahesh et al. (J. Comput. Phys., 2004, 197, 215–240) is extended to the zero Mach number equations with heat release. Chemical reactions are modeled using the flamelet/progress variable approach of Pierce and Moin (J. Fluid Mech., 2004, 504, 73–97). The simulations are validated against experiment for methane-air combustion in a coaxial geometry, and jet-A surrogate/air combustion in a gas-turbine combustor geometry.

The Role of the Recirculating Gases at the Mild Combustion Regime Formation

2007 ◽  
Author(s):  
Y. Levy ◽  
V. Sherbaum ◽  
V. Erenburg
Keyword(s):  
Gas Turbine ◽  
Ignition Delay ◽  
Ignition Delay Time ◽  
Combustion Process ◽  
Combustion Regime ◽  
Reaction Products ◽  
Gas Turbine Combustor ◽  
Mild Combustion ◽  
Recirculation Rate ◽  
Co Emission

The present work is concerned with the thermodynamic and chemical kinetics of gas turbine combustor operating in the Moderate or Intense Low-oxygen Dilution (MILD) combustion regime. The objective of the present study is to evaluate analytically the effect of the recirculation rate of combustion products within the FLOXCOM gas turbine combustor on a number of combustion parameters, mainly on the ignition delay time, NOx and CO emission, minimum ignition temperature, rate of pollutant formation and the dilution rate. The study also refers to the mechanism of influence of the recirculation rate on these values. Combustion pressure and inlet air temperature are used as parameters. The gas turbine is fueled with methane. The analysis is mainly based on CHEMKIN simulations where the calculation scheme of the combustion process in the combustor is modeled by a combination of plug reactors and mixers. Due to the unique characteristics of gas turbines, inlet air temperature is directly linked to combustion pressure while assuming conventional adiabatic compression efficiencies. It is shown that free radicals, which are part of the reaction products and exists for only a short period of time within the recirculated gases, decrease ignition delay time. The importance of shortening the ignition delay is further highlighted because of the adverse effect oxygen dilution has on this parameter (dilution of the reactants by the reaction products). It was found that there is an optimal recirculation rate, which corresponds to maximum heat density. In addition, results indicate that CO emission values rise with the recirculation rate, however the NOX values are more complicated. NOX depends on recirculation rate when flame temperatures are kept held constant. The NOX emission increases and the CO emission decreases with compressor pressure ratio. The CO concentration that is evaluated in the combustion process is further reduced during last dilution stage. Finally, basic rules for design optimization of the combustor are drafted. These are based on conventional one-dimensional fluid and thermodynamic relations and on the CHEMKIN simulations.

Idealized gas turbine combustor for performance research and validation of large eddy simulations

2007 ◽  
Vol 78 (3) ◽  
pp. 035114 ◽  
Author(s):  
Timothy C. Williams ◽  
Robert W. Schefer ◽  
Joseph C. Oefelein ◽  
Christopher R. Shaddix
Keyword(s):  
Gas Turbine ◽  
Large Eddy Simulations ◽  
Gas Turbine Combustor ◽  
Large Eddy ◽  
Performance Research
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