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

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.

Download Full-text

Investigation of Dimethyl Ether Combustion Instabilities in a Partially - Premixed Gas Turbine Model Combustor Using High-Speed Laser Diagnostics

52nd Aerospace Sciences Meeting ◽

10.2514/6.2014-0660 ◽

2014 ◽

Cited By ~ 1

Author(s):

Patton Allison ◽

Yuntao Chen ◽

James F. Driscoll

Keyword(s):

Gas Turbine ◽

Dimethyl Ether ◽

High Speed ◽

Laser Diagnostics ◽

Combustion Instabilities ◽

Partially Premixed ◽

Turbine Model

Download Full-text

1119 Chemiluminescence intensity variations of a combustion instability in a lean premixed gas-turbine model combustor

The Proceedings of Conference of Kansai Branch ◽

10.1299/jsmekansai.2013.88._11-29_ ◽

2013 ◽

Vol 2013.88 (0) ◽

pp. _11-29_

Author(s):

Taku KURIYAMA ◽

Yuta SHINODA ◽

Hiroshi GOTODA ◽

Shigeru TACHIBANA

Keyword(s):

Gas Turbine ◽

Combustion Instability ◽

Chemiluminescence Intensity ◽

Lean Premixed ◽

Turbine Model

Download Full-text

Plasma assisted combustion of lean premixed flames: High-speed imaging of streamer and flame dynamics

2016 IEEE International Conference on Plasma Science (ICOPS) ◽

10.1109/plasma.2016.7534184 ◽

2016 ◽

Author(s):

M. D. G. Evans ◽

J. M. Bergthorson ◽

S. Coulombe

Keyword(s):

High Speed ◽

Premixed Flames ◽

Plasma Assisted Combustion ◽

High Speed Imaging ◽

Lean Premixed Flames ◽

Flame Dynamics ◽

Lean Premixed

Download Full-text

Characterization of complexities in combustion instability in a lean premixed gas-turbine model combustor

Chaos An Interdisciplinary Journal of Nonlinear Science ◽

10.1063/1.4766589 ◽

2012 ◽

Vol 22 (4) ◽

pp. 043128 ◽

Cited By ~ 57

Author(s):

Hiroshi Gotoda ◽

Masahito Amano ◽

Takaya Miyano ◽

Takuya Ikawa ◽

Koshiro Maki ◽

...

Keyword(s):

Gas Turbine ◽

Combustion Instability ◽

Lean Premixed ◽

Turbine Model

Download Full-text

An optically accessible secondary combustion zone for the transverse injection of reacting jets into a high-speed, vitiated crossflow within a staged, gas turbine model combustor

Measurement Science and Technology ◽

10.1088/1361-6501/abbd57 ◽

2020 ◽

Vol 32 (2) ◽

pp. 024007

Author(s):

N S Rodrigues ◽

C T McDonald ◽

O O Busari ◽

A Satija ◽

A J North ◽

...

Keyword(s):

Gas Turbine ◽

Combustion Zone ◽

High Speed ◽

Secondary Combustion ◽

Transverse Injection ◽

Turbine Model

Download Full-text

Dynamical Properties of Combustion Instability in a Laboratory-Scale Gas-Turbine Model Combustor

Journal of Engineering for Gas Turbines and Power ◽

10.1115/1.4034700 ◽

2016 ◽

Vol 139 (4) ◽

Cited By ~ 7

Author(s):

Hiroshi Gotoda ◽

Kenta Hayashi ◽

Ryosuke Tsujimoto ◽

Shohei Domen ◽

Shigeru Tachibana

Keyword(s):

Gas Turbine ◽

Combustion Instability ◽

Turbulent Flame ◽

Surrogate Data ◽

Permutation Entropy ◽

Lean Blowout ◽

Lean Premixed ◽

Free Running ◽

Nonlinear Forecasting ◽

Turbine Model

We present an experimental study on the nonlinear dynamics of combustion instability in a lean premixed gas-turbine model combustor with a swirl-stabilized turbulent flame. Intermittent combustion oscillations switching irregularly back and forth between burst and pseudo-periodic oscillations exhibit the deterministic nature of chaos. This is clearly demonstrated by considering two nonlinear forecasting methods: an extended version (Gotoda et al., 2015, “Nonlinear Forecasting of the Generalized Kuramoto-Sivashinsky Equation,” Int. J. Bifurcation Chaos, 25, p. 1530015) of the Sugihara and May algorithm (Sugihara and May, 1990, “Nonlinear Forecasting as a Way of Distinguishing Chaos From Measurement Error in Time Series,” Nature, 344, pp. 734–741) as a local predictor, and a generalized radial basis function (GRBF) network as a global predictor (Gotoda et al., 2012, “Characterization of Complexities in Combustion Instability in a Lean Premixed Gas-Turbine Model Combustor,” Chaos, 22, p. 043128; Gotoda et al., 2016 (unpublished)). The former enables us to extract the short-term predictability and long-term unpredictability of chaos, while the latter can produce surrogate data to test for determinism by a free-running approach. The permutation entropy based on a symbolic sequence approach is estimated for the surrogate data to test for determinism and is also used as an online detector to prevent lean blowout.

Download Full-text

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

Volume 4A: Combustion, Fuels and Emissions ◽

10.1115/gt2016-56245 ◽

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.

Download Full-text