High-Speed Imaging of Fuel/OH Distributions in a Gas Turbine Pilot Burner at Elevated Pressure

2011 ◽  
Author(s):  
Andreas Lantz ◽  
Robert Collin ◽  
Johan Sjöholm ◽  
Zhongshan Li ◽  
Per Petersson ◽  
...  
Keyword(s):  
Gas Turbine ◽  
High Speed ◽  
Elevated Pressure ◽  
High Speed Imaging ◽  
Pilot Burner

Fuel Influence on Targeted Gas Turbine Combustion Properties: Part I — Detailed Diagnostics

2014 ◽  
Author(s):  
Thomas Mosbach ◽  
Victor Burger ◽  
Barani Gunasekaran
Keyword(s):  
Gas Turbine ◽  
High Speed ◽  
Leading Edge ◽  
Operating Conditions ◽  
Optical Measurements ◽  
Test Facility ◽  
Research Centre ◽  
High Speed Imaging ◽  
Combustion Properties ◽  
First Results

The threshold combustion performance of different fuel formulations under simulated altitude relight conditions were investigated in the altitude relight test facility located at the Rolls-Royce plc. Strategic Research Centre in Derby, UK. The combustor employed was a twin-sector representation of an RQL gas turbine combustor. Eight fuels including conventional crude-derived Jet A-1 kerosene, synthetic paraffinic kerosenes (SPKs), linear paraffinic solvents, aromatic solvents and pure compounds were tested. The combustor was operated at sub-atmospheric air pressure of 41 kPa and air temperature of 265 K. The temperature of all fuels was regulated to 288 K. The combustor operating conditions corresponded to a low stratospheric flight altitude near 9 kilometres. The experimental work at the Rolls-Royce (RR) test-rig consisted of classical relight envelope ignition and extinction tests, and ancillary optical measurements: Simultaneous high-speed imaging of the OH* chemiluminescence and of the soot luminosity was used to visualize both the transient combustion phenomena and the combustion behaviour of the steady burning flames. Flame luminosity spectra were also simultaneously recorded with a spectrometer to obtain information about the different combustion intermediates and about the thermal soot radiation curve. This paper presents first results from the analysis of the weak extinction measurements. Further detailed test fuel results are the subject of a separate complementary paper [1]. It was found in general that the determined weak extinction parameters were not strongly dependent on the fuels investigated, however at the leading edge of the OH* chemiluminescence intensity development in the pre-flame region fuel-related differences were observed.

Synchronization During Multi-Mode Thermoacoustic Oscillations in a Liquid-Fueled Gas Turbine Combustor at Elevated Pressure

2019 ◽  
Author(s):  
Mitchell L. Passarelli ◽  
J. D. Maxim Cirtwill ◽  
Timothy Wabel ◽  
Adam M. Steinberg ◽  
A. J. Wickersham
Keyword(s):  
Heat Release ◽  
Gas Turbine ◽  
Heat Release Rate ◽  
Release Rate ◽  
High Speed ◽  
Elevated Pressure ◽  
Fuel Injector ◽  
Frequency Pulling ◽  
Industrial Gas Turbine ◽  
Thermoacoustic Oscillations

Abstract This paper analyzes intermittent self-excited thermoacoustic oscillations in which the pressure (P′) and heat release rate (q̇′) fluctuations are harmonically coupled. That is to say, P′ and q̇′ do not oscillate at the same frequencies, but rather at frequencies in integer ratios. Thus, this system represents a case dominated by nonlinear cross-mode coupling. The measurements were obtained in an optically-accessible combustor equipped with an industrial gas turbine fuel injector operating with liquid fuel under partially-premixed conditions at elevated pressure. High-speed chemiluminescence (CL) imaging of OH* was used as an indicator of the heat release rate. The data was processed using spectral proper orthogonal decomposition (SPOD) to isolate the dominant heat release and pressure modes. Synchronization theory was used to determine when the modes are coupled and how their interaction manifests in the measurements, particularly how it relates to the observed intermittency. The results show three distinct intervals of synchronized oscillation shared by all the mode pairs analyzed. The first interval exhibits the same characteristics as a pair of noisy, phase-locked self-oscillators, with phase-slipping and frequency-pulling. While the behaviour of the second interval differs among mode pairs, strong frequency-pulling is observed during the third interval for all pairs.

Auto-Ignition of In-Line Injected Hydrogen/Nitrogen Fuel Mixtures at Reheat Combustor Operating Conditions

2015 ◽  
Author(s):  
Christoph Schmalhofer ◽  
Peter Griebel ◽  
Michael Stöhr ◽  
Manfred Aigner ◽  
Torsten Wind
Keyword(s):  
Gas Turbine ◽  
High Speed ◽  
Design Guidelines ◽  
Operating Conditions ◽  
Fuel Injector ◽  
High Speed Imaging ◽  
Capture Process ◽  
Carrier Medium ◽  
Auto Ignition ◽  
Ignition Limits

De-carbonization of the power generation sector becomes increasingly important in order to achieve the European climate targets. Coal or biomass gasification together with a pre-combustion carbon capture process might be a solution resulting in hydrogen-rich gas turbine (GT) fuels. However, the high reactivity of these fuels poses challenges to the operability of lean premixed gas turbine combustion systems because of a higher auto-ignition and flashback risk. Investigation of these phenomena at GT relevant operating conditions is needed to gain knowledge and to derive design guidelines for a safe and reliable operation. The present investigation focusses on the influence of the fuel injector configuration on auto-ignition and kernel development at reheat combustor relevant operating conditions. Auto-ignition of H2-rich fuels was investigated in the optically accessible mixing section of a generic reheat combustor. Two different geometrical in-line configurations were investigated. In the premixed configuration, the fuel mixture (H2 / N2) and the carrier medium nitrogen (N2) were homogeneously premixed before injection, whereas in the co-flow configuration the fuel (H2 / N2) jet was embedded in a carrier medium (N2 or air) co-flow. High-speed imaging was used to detect auto-ignition and to record the temporal and spatial development of auto-ignition kernels in the mixing section. A high temperature sensitivity of the auto-ignition limits were observed for all configurations investigated. The lowest auto-ignition limits are measured for the premixed in-line injection. Significantly higher auto-ignition limits were determined in the co-flow in-line configuration. The analysis of auto-ignition kernels clearly showed the inhibiting influence of fuel dilution for all configurations.

scholarly journals On the Flow Structure and Dynamics of Methane and Syngas Lean Flames in a Model Gas-Turbine Combustor

Energies ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 8267
Author(s):  
Vladimir Dulin ◽  
Leonid Chikishev ◽  
Dmitriy Sharaborin ◽  
Aleksei Lobasov ◽  
Roman Tolstoguzov ◽  
...  
Keyword(s):  
Flame Front ◽  
Gas Turbine ◽  
Flow Structure ◽  
High Speed ◽  
Longitudinal Mode ◽  
Elevated Pressure ◽  
Transverse Instability ◽  
Flame Dynamics ◽  
Instability Modes ◽  
Lift Off

The present paper compares the flow structure and flame dynamics during combustion of methane and syngas in a model gas-turbine swirl burner. The burner is based on a design by Turbomeca. The fuel is supplied through injection holes between the swirler blades to provide well-premixed combustion, or fed as a central jet from the swirler’s centerbody to increase flame stability via a pilot flame. The measurements of flow structure and flame front are performed by using the stereo particle image velocimetry and OH planar laser-induced fluorescence methods. The measurements are performed for the atmospheric pressure without preheating and for 2 atm with the air preheated up to 500 K. The flow Reynolds numbers for the non-reacting flows at these two conditions are 1.5 × 103 and 1.0 × 103, respectively. The flame dynamics are analyzed based on a high-speed OH* chemiluminescence imaging. It is found that the flame dynamics at elevated conditions are related with frequent events of flame lift-off and global extinction, followed by re-ignition. The analysis of flow structure via the proper orthogonal decomposition reveals the presence of two different types of coherent flow fluctuations, namely, longitudinal and transverse instability modes. The same procedure is applied to the chemiluminescence images for visualization of bulk movement of the flame front and similar spatial structures are observed. Thus, the longitudinal and transverse instability modes are found in all cases, but for the syngas at the elevated pressure and temperature the longitudinal mode is related to strong thermoacoustic fluctuations. Therefore, the present study demonstrates that a lean syngas flame can become unstable at elevated pressure and temperature conditions due to a greater flame propagation speed, which results in periodic events of flame flash-back, extinction and re-ignition. The reported data is also useful for the validation of numerical simulation codes for syngas flames.

Detection of Precursor Event Before Blowout in a Gas Turbine Type Combustor at Atmospheric Pressure

2012 ◽  
Author(s):  
K. P. Aditya ◽  
T. M. Muruganandam
Keyword(s):  
Gas Turbine ◽  
High Speed ◽  
Gas Turbine Combustor ◽  
High Speed Imaging ◽  
Safety Hazard ◽  
Lean Blowout ◽  
Imaging Camera ◽  
Swirl Flame ◽  
Vane Angle ◽  
Lean Conditions

The need for stringent emission requirements compel modern gas turbine (GT) combustors to work under lean conditions and lower temperatures, thereby reducing NOx emissions. The operation of a combustor close to lean blowout limit increases the risk of a complete flame blowout posing a safety hazard in aircraft engines. A study was carried out on a divergent gas turbine combustor, in order to sense and detect a similar blowout phenomenon in a non/partially premixed swirl flame. Inside combustor, 45° vane angle swirler created weak recirculation zone. New swirler with 5° and 60° at entry and exit respectively was used as replacement. 5 bar and 6 bar of stagnation pressure of air were used as loading parameters during the experimentation. Photodiode sensors and high speed imaging camera were used to record data of flame. It was observed that, bursts (or unsteady events) characterized by an almost complete loss of flame i. e. abrupt extinctions were followed by re-occurrence of flame. ‘Precursor events’ before flame blowout were detected. These events occurred and reoccurred in an interval of several milliseconds. In both scenarios, high speed visualization was recorded at 1000 Hz for 16–20 seconds. Detection of precursor events for the liquid fuelled combustor will assist in carrying out further research using sensing methods to estimate the proximity of the combustor to LBO.

High-Speed Fuel/Hydroxyl Radical Imaging in a Gas Turbine Pilot Burner

AIAA Journal ◽  
2012 ◽  
Vol 50 (4) ◽  
pp. 971-976 ◽  
Author(s):  
A. Lantz ◽  
R. Collin ◽  
J. Sjöholm ◽  
Z. S. Li ◽  
P. Petersson ◽  
...  
Keyword(s):  
Hydroxyl Radical ◽  
Gas Turbine ◽  
High Speed ◽  
Pilot Burner

Validation of a New Turbulent Flame Speed Facility for the Study of Gas Turbine Fuel Blends at Elevated Pressure

2019 ◽  
Author(s):  
Anibal Morones ◽  
Mattias A. Turner ◽  
Victor León ◽  
Kyle Ruehle ◽  
Eric L. Petersen
Keyword(s):  
Gas Turbine ◽  
High Speed ◽  
Turbulent Flame ◽  
Elevated Pressure ◽  
Turbine Engines ◽  
Gas Turbine Engines ◽  
Turbulent Flame Speed ◽  
Fuel Blends ◽  
New Apparatus ◽  
Fundamental Insight

Abstract Turbulent combustion is a very active and challenging research topic of direct interest to the design and operation of gas turbine engines. A spherically expanding flame immersed in a turbulent field is one way to gain fundamental insight on the effect of turbulence on combustion. This kind of experiment is often conducted inside a fan-stirred flame bomb, preferably at conditions of high pressure, high temperature, and intense turbulence. A new fan-stirred flame bomb was designed and built to provide a device for conducting fundamental turbulent flame measurements at conditions of interest to gas turbine engines. A literature review on existing systems was used as guidance in the design of the turbulence-generation elements in the present rig. A few options of impellers were explored. The flow field produced by the chosen impeller was measured with Laser Doppler Velocimetry (LDV). A detailed exposition of the vessel engineering and construction are presented, including current activities that will extend the use of the facility for heated experiments up to at least 400 K. Before turbulent experiments were attempted, a validation of the rig accuracy and pressure worthiness was made. Finally, a demonstration of the new apparatus was made by testing a lean mixture of syngas. The experiment matrix using hydrogen and H2/CO mixtures included three levels of pressure (1, 5, and, 10 bar) and three levels of turbulence fluctuation rms (1.4, 2.8, and 5.5 m/s). Data based on the high-speed schlieren diagnostic are presented.

Influence of Carrier Air Preheating on Autoignition of Inline-Injected Hydrogen-Nitrogen Mixtures in Vitiated Air of High Temperature

2017 ◽  
Author(s):  
Christoph A. Schmalhofer ◽  
Peter Griebel ◽  
Manfred Aigner
Keyword(s):  
High Temperature ◽  
Gas Turbine ◽  
Gas Turbines ◽  
High Speed ◽  
Spatial Development ◽  
Design Guidelines ◽  
Operating Conditions ◽  
High Speed Imaging ◽  
Temporal And Spatial ◽  
Fuel Mixtures

Gas turbines will play a significant role in future power generation systems because they provide peak capacity due to their fast start-up capability and high operational flexibility. However, in order to meet the COP 21 goals, de-carbonization of as turbine fuels is required. Compared to natural gas operation, autoignition and flashback risks in gas turbines operated on hydrogen-rich fuels are higher which has to be taken into account for a proper gas turbine design. From investigations of these phenomena at relevant operating conditions with appropriate measurement techniques, e.g. high-speed imaging, the understanding of the non-stationary processes occurring during autoignition can be improved and design guidelines for a safe and reliable gas turbine operation can be derived. The present study investigates the influences of elevated carrier-air preheating temperatures and hydrogen fuel volume fractions on autoignition at hot gas temperatures higher than 1100 K and pressures of 15 bar. An in-line co-flow injector is used to inject the hydrogen-nitrogen fuel mixtures. The formation, temporal and spatial development of autoignition kernels at high-temperature vitiated air conditions, e.g. relevant to reheat combustor operation, are studied. The experiments were conducted in an optically accessible mixing section of a generic reheat combustor. The hydrogen-nitrogen fuel mixtures of up to 70 vol. % hydrogen are injected in-line into the mixing section along with the carrier-air which was preheated to temperatures between 303 K and 703 K. High-speed imaging was used to detect the autoignition kernels and their temporal and spatial development from luminescence signals. Particle Image Velocimetry measurements were conducted to obtain the velocity distribution in the mixing section at autoignition conditions. The influences of vitiated air temperatures and carrier preheating temperatures on autoignition and flame stabilisation limits are shown, alongside the spatial distribution of different types of autoignition kernels, developing at different stages of the autoignition process. The development of autoignition kernels could be linked to the shear layer development derived from global experimental conditions.

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