Investigation of a Gas Turbine Model Combustor by means of High-Speed Laser Imaging

2009 ◽  
Author(s):  
Isaac Boxx ◽  
Ralf Blumenthal ◽  
Michael Stöhr ◽  
Wolfgang Meier
Keyword(s):  
Gas Turbine ◽  
High Speed ◽  
Laser Imaging ◽  
Turbine Model

scholarly journals High-speed laser diagnostics for the study of flame dynamics in a lean premixed gas turbine model combustor

2010 ◽  
Vol 52 (3) ◽  
pp. 555-567 ◽  
Author(s):  
Isaac Boxx ◽  
Christoph M. Arndt ◽  
Campbell D. Carter ◽  
Wolfgang Meier
Keyword(s):  
Gas Turbine ◽  
High Speed ◽  
Laser Diagnostics ◽  
Flame Dynamics ◽  
Lean Premixed ◽  
Turbine Model

Predicting Flashback Limits of a Gas Turbine Model Combustor Based on Velocity and Fuel Concentration for H2-Air-Mixtures

2016 ◽  
Author(s):  
Matthias Utschick ◽  
Daniel Eiringhaus ◽  
Christian Köhler ◽  
Thomas Sattelmayer
Keyword(s):  
Combustion Chamber ◽  
Gas Turbine ◽  
High Speed ◽  
Air Flow ◽  
Turbulent Flame ◽  
Flame Speed ◽  
Fuel Injector ◽  
Trailing Edge ◽  
Fuel Concentration ◽  
Turbine Model

This study investigates the influence of the fuel injection strategy on safety against flashback in a gas turbine model combustor with premixing of H2-air-mixtures. The flashback propensity is quantified and the flashback mechanism is identified experimentally. The A2EV swirler concept exhibits a hollow, thick walled conical structure with four tangential slots. Four fuel injector geometries were tested. One of them injects the fuel orthogonal to the air flow in the slots (jet-in-crossflow-injector, JICI). Three injector types introduce the fuel almost isokinetic to the air flow at the trailing edge of the swirler slots (trailing edge injector, TEI). Velocity and mixing fields in mixing zone and combustion chamber in isothermal water flow were measured with High-speed-Particle-Image-Velocimetry (PIV) and Highspeed-Laser-Induced-Fluorescence (LIF). The flashback limit was determined under atmospheric pressure for three air mass flows and 673 K preheat temperature for H2-air-mixtures. Flashback mechanism and trajectory of the flame tip during flashback were identified with two stereoscopically oriented intensified high-speed cameras observing the OH* radiation. We notice flashback in the core flow due to Combustion Induced Vortex Breakdown (CIVB) and Turbulent upstream Flame Propagation (TFP) near the wall dependent on the injector type. The Flashback Resistance (FBR) defined as the ratio between a characteristic flow speed and a characteristic flame speed measures the direction of propagation of a turbulent flame in the flow field. Although CIVB cannot be predicted solely based on the FBR, its distribution gives evidence for CIVB-prone states. The fuel should be injected preferably isokinetic to the air flow along the entire trailing edge in oder to reduce the RMS fluctuation of velocity and fuel concentration. The characteristic velocity in the entire cross section of the combustion chamber inlet should be at least twice the characteristic flame speed. The position of the stagnation point should be tuned to be located in the combustion chamber by adjusting the axial momentum. Those measures lead to safe operation with highly reactive fuels at high equivalence ratios.

Predicting Flashback Limits of a Gas Turbine Model Combustor Based on Velocity and Fuel Concentration for H2–Air Mixtures

2016 ◽  
Vol 139 (4) ◽  
Author(s):  
Matthias Utschick ◽  
Daniel Eiringhaus ◽  
Christian Köhler ◽  
Thomas Sattelmayer
Keyword(s):  
Combustion Chamber ◽  
Gas Turbine ◽  
High Speed ◽  
Air Flow ◽  
Turbulent Flame ◽  
Flame Speed ◽  
Fuel Injector ◽  
Trailing Edge ◽  
Fuel Concentration ◽  
Turbine Model

This study investigates the influence of the fuel injection strategy on safety against flashback in a gas turbine model combustor with premixing of H2–air mixtures. The flashback propensity is quantified and the flashback mechanism is identified experimentally. The A2EV swirler concept exhibits a hollow, thick-walled conical structure with four tangential slots. Four fuel injector geometries were tested. One of them injects the fuel orthogonal to the air flow in the slots (jet-in-crossflow injector (JICI)). Three injector types introduce the fuel almost isokinetic to the air flow at the trailing edge of the swirler slots (trailing edge injector (TEI)). Velocity and mixing fields in mixing zone and combustion chamber in isothermal water flow were measured with high-speed particle image velocimetry (PIV) and high-speed laser-induced fluorescence (LIF). The flashback limit was determined under atmospheric pressure for three air mass flows and 673 K preheat temperature for H2–air mixtures. Flashback mechanism and trajectory of the flame tip during flashback were identified with two stereoscopically oriented intensified high-speed cameras observing the OH* radiation. We notice flashback in the core flow due to combustion-induced vortex breakdown (CIVB) and turbulent flame propagation (TFP) near the wall dependent on the injector type. The flashback resistance (FBR) defined as the ratio between a characteristic flow speed and a characteristic flame speed measures the direction of propagation of a turbulent flame in the flow field. Although CIVB cannot be predicted solely based on the FBR, its distribution gives evidence for CIVB-prone states. The fuel should be injected preferably isokinetic to the air flow along the entire trailing edge in order to reduce the RMS fluctuation of velocity and fuel concentration. The characteristic velocity in the entire cross section of the combustion chamber inlet should be at least twice the characteristic flame speed. The position of the stagnation point should be tuned to be located in the combustion chamber by adjusting the axial momentum. Those measures lead to safe operation with highly reactive fuels at high equivalence ratios.

An Investigation of the Effects of Fuel Staging on Flame Structure in a Gas Turbine Model Combustor

2013 ◽  
Author(s):  
J. D. Gounder ◽  
I. Boxx ◽  
P. Kutne ◽  
F. Biagioli ◽  
H. Luebcke
Keyword(s):  
Gas Turbine ◽  
High Speed ◽  
Equivalence Ratio ◽  
Fuel Injection ◽  
Laser Diagnostics ◽  
Thermal Power ◽  
Flame Structure ◽  
Operating Conditions ◽  
Fuel Staging ◽  
Turbine Model

Gas turbine (GT) flames at lean operating conditions are susceptible to instabilities that can lead to unsteady operation, flame extinction, and thermoacoustic oscillations. High speed (10 kHz) laser and optical diagnostic techniques have been used to investigate the effect of fuel staging on the mechanisms involved in such instabilities and the overall performance of a gas turbine model combustor. The GT burner used in this study consists of coaxial swirlers which allow for fuel staging capability, where the fuel is varied from 100% to 20% fuel injection in the inner swirler. The burner is equipped with a combustion chamber with large quartz windows, allowing for the application of optical and laser diagnostics. Simultaneous high speed OH Planar Laser Induced Fluorescence (PLIF) and OH* chemiluminescence (CL) imaging, exhaust gas sampling and acoustic measurements were applied to characterize the flames and determine the operability limits of the combustor. Methane air flames at atmospheric pressure have been investigated at a constant thermal power of 58 kW. The global equivalence ratio was kept constant, while the fuel staging was varied. The bulk flow velocity at the exit plane was kept constant at 20 m/s. Simultaneous high speed particle image velocity (PIV) and OH PLIF measurements were performed at a repetition rate of 10 kHz on specifically chosen flames with a fixed staging and equivalence ratio. This paper will present the flame and the flow field structure resolved using the kHz measurement technique. The interaction between the velocity field and the flame front marked by the OH LIF will be presented. The mean PIV image provides the location of the inner and outer recirculation zones. The flame structure presented in this paper will also show the effectiveness of fuel mixing as the staging is varied. The changes in flame shape with variation in fuel staging is determined using the OH* chemiluminescence images. As the fuel flow in the inner swirler is reduced, the NOx and CO emissions also reduce and reach a minimum at a staging of 45% fuel being injected in the inner swirler. As fuel injection in the outer swirler increases beyond 60% the NOx and CO emissions start also increasing.

scholarly journals Wall Temperature Measurements in Gas Turbine Combustors With Thermographic Phosphors

2018 ◽  
Vol 141 (4) ◽  
Author(s):  
Patrick Nau ◽  
Zhiyao Yin ◽  
Oliver Lammel ◽  
Wolfgang Meier
Keyword(s):  
Gas Turbine ◽  
Wall Temperature ◽  
Gas Turbines ◽  
High Speed ◽  
Bluff Body ◽  
Temperature Measurements ◽  
Transient Temperature ◽  
High Time Resolution ◽  
Ceramic Surface ◽  
Precessing Vortex Core

Phosphor thermometry has been developed for wall temperature measurements in gas turbines and gas turbine model combustors. An array of phosphors has been examined in detail for spatially and temporally resolved surface temperature measurements. Two examples are provided, one at high pressure (8 bar) and high temperature and one at atmospheric pressure with high time resolution. To study the feasibility of this technique for full-scale gas turbine applications, a high momentum confined jet combustor at 8 bar was used. Successful measurements up to 1700 K on a ceramic surface are shown with good accuracy. In the same combustor, temperatures on the combustor quartz walls were measured, which can be used as boundary conditions for numerical simulations. An atmospheric swirl-stabilized flame was used to study transient temperature changes on the bluff body. For this purpose, a high-speed setup (1 kHz) was used to measure the wall temperatures at an operating condition where the flame switches between being attached (M-flame) and being lifted (V-flame) (bistable). The influence of a precessing vortex core (PVC) present during M-flame periods is identified on the bluff body tip, but not at positions further inside the nozzle.

scholarly journals Influence of Single-Component Fuels on Gas-Turbine Model Combustor Lean Blowout

2018 ◽  
Vol 34 (1) ◽  
pp. 97-107 ◽  
Author(s):  
J. Grohmann ◽  
B. Rauch ◽  
T. Kathrotia ◽  
W. Meier ◽  
M. Aigner
Keyword(s):  
Gas Turbine ◽  
Single Component ◽  
Lean Blowout ◽  
Turbine Model

scholarly journals Dynamics of lean blowout of a swirl-stabilized flame in a gas turbine model combustor

2011 ◽  
Vol 33 (2) ◽  
pp. 2953-2960 ◽  
Author(s):  
M. Stöhr ◽  
I. Boxx ◽  
C. Carter ◽  
W. Meier
Keyword(s):  
Gas Turbine ◽  
Lean Blowout ◽  
Turbine Model
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