Flow Field and Combustion Characterization of Premixed Gas Turbine Flames by Planar Laser Techniques

2008 ◽  
Vol 131 (2) ◽  
Author(s):  
Ulrich Stopper ◽  
Manfred Aigner ◽  
Wolfgang Meier ◽  
Rajesh Sadanandan ◽  
Michael Stöhr ◽  
...  
Keyword(s):  
Flow Field ◽  
Gas Turbine ◽  
Shear Layers ◽  
Diagnostic Methods ◽  
Single Shot ◽  
Mean Flow ◽  
Planar Laser ◽  
Primary Reactions ◽  
Reaction Zones ◽  
Industrial Gas Turbine

Lean premixed natural gas/air flames produced by an industrial gas turbine burner were analyzed using laser diagnostic methods. For this purpose, the burner was equipped with an optical combustion chamber and operated with preheated air at various thermal powers P, equivalence ratios Φ, and pressures up to p=6 bars. For the visualization of the flame emissions OH∗ chemiluminescence imaging was applied. Absolute flow velocities were measured using particle image velocimetry (PIV), and the reaction zones as well as regions of burnt gas were characterized by planar laser-induced fluorescence (PLIF) of OH. Using these techniques, the combustion behavior was characterized in detail. The mean flow field could be divided into different regimes: the inflow, a central and an outer recirculation zone, and the outgoing exhaust flow. Single-shot PIV images demonstrated that the instantaneous flow field was composed of small and medium sized vortices, mainly located along the shear layers. The chemiluminescence images reflected the regions of heat release. From the PLIF images it was seen that the primary reactions are located in the shear layers between the inflow and the recirculation zones and that the appearance of the reaction zones changed with flame parameters.

Flow Field and Combustion Characterization of Premixed Gas Turbine Flames by Planar Laser Techniques

2008 ◽  
Author(s):  
Ulrich Stopper ◽  
Manfred Aigner ◽  
Wolfgang Meier ◽  
Rajesh Sadanandan ◽  
Michael Sto¨hr ◽  
...  
Keyword(s):  
Flow Field ◽  
Gas Turbine ◽  
Shear Layers ◽  
Diagnostic Methods ◽  
Single Shot ◽  
Mean Flow ◽  
Planar Laser ◽  
Primary Reactions ◽  
Reaction Zones ◽  
Industrial Gas Turbine

Lean premixed natural gas/air flames produced by an industrial gas turbine burner were analyzed using laser diagnostic methods. For this purpose, the burner was equipped with an optical combustion chamber and operated with preheated air at various thermal powers P, equivalence ratios Φ, and pressures up to p = 6 bar. For the visualization of the flame emissions OH* chemiluminescence imaging was applied. Absolute flow velocities were measured using particle image velocimetry (PIV), and the reaction zones as well as regions of burnt gas were characterized by planar laser induced fluorescence (PLIF) of OH. Using these techniques, the combustion behavior was characterized in detail. The mean flow field could be divided into different regimes: the inflow, a central and an outer recirculation zone, and the outgoing exhaust flow. Single-shot PIV images demonstrated that the instantaneous flow field was composed of small and medium sized vortices, mainly located along the shear layers. The chemiluminescence images reflected the regions of heat release. From the PLIF images it was seen that the primary reactions are located in the shear layers between the inflow and the recirculation zones and that the appearance of the reaction zones changed with flame parameters.

Experimental Analysis of the Combustion Behavior of a Gas Turbine Burner by Laser Measurement Techniques

2010 ◽  
Vol 132 (5) ◽  
Author(s):  
Holger Ax ◽  
Ulrich Stopper ◽  
Wolfgang Meier ◽  
Manfred Aigner ◽  
Felix Güthe
Keyword(s):  
Gas Turbine ◽  
Mixture Fraction ◽  
Measurement Techniques ◽  
Elevated Pressure ◽  
Flame Stabilization ◽  
Single Shot ◽  
Laser Raman ◽  
Planar Laser ◽  
Industrial Gas Turbine ◽  
Gas Turbine Burner

Experimental results from optical and laser spectroscopic measurements on a scaled industrial gas turbine burner at elevated pressure are presented. Planar laser induced fluorescence on the OH radical and OH∗ chemiluminescence imaging were applied to natural gas/air flames for a qualitative analysis of the position and shape of the flame brush, the flame front and the stabilization mechanism. The results exhibit two different ways of flame stabilization, a conical more stable flame and a pulsating opened flame. For quantitative results, one-dimensional laser Raman scattering was applied to these flames and evaluated on an average and single-shot basis in order to simultaneously determine the major species concentrations, the mixture fraction, and the temperature. The mixing of fuel and air, as well as the reaction progress, could thus be spatially and temporally resolved, showing differently strong variations depending on the flame stabilization mode and the location in the flame.

Experimental Investigation of Airflow and Spray Stability in an Air-Blast Injector of an Industrial Gas Turbine

2004 ◽  
Author(s):  
Andrei Secareanu ◽  
Dragan Stankovic ◽  
Laszlo Fuchs ◽  
Vladimir Milosavljevic ◽  
Jonas Holmborn
Keyword(s):  
Flow Field ◽  
Gas Turbine ◽  
Swirling Flow ◽  
Laser Sheet ◽  
Front Panel ◽  
Mean Flow ◽  
Air Blast ◽  
Full Cross Section ◽  
Airflow Field ◽  
Industrial Gas Turbine

The airflow field and spray characteristics from an air blast type of injector in an industrial gas turbine (GT) combustor geometry have been investigated experimentally and numerically. The flame in the current combustor is stabilized by a highly swirling flow. The stabilization of the flame is strongly dependent on the stability of the flow field out from the injector and into the combustor. Liquid fuel spray formation in the current type of injector is highly dependent on the airflow from the internal swirler, which supplies the shear to break the liquid film, and form the spray. Experiments were performed in a Perspex model of a 12° sector of the combustor with airflow scaled to atmospheric conditions. The geometry was comprised of the air section including the full primary zone, injector, combustor swirler, front panel and primary air jets. The flow field was visualized using particles that were illuminated by a laser sheet. Quantitative characterization was done using LDA. The airflow field was characterized by the mean flow pattern covering the full cross-section of the flow field and additional long time measurements at a number of locations in order to capture frequency content of the flow. Isothermal spray measurements were performed in an unconfined geometry including the injector, swirl generator and front panel. The spray uniformity was qualitatively investigated using video camera and quantitatively characterized by PDA. The studies of the flow field and fuel atomization (droplet size and density) under different conditions are summarized below.

Experimental Analysis of the Combustion Behavior of a Gas Turbine Burner by Laser Measurement Techniques

2009 ◽  
Author(s):  
Holger Ax ◽  
Ulrich Stopper ◽  
Wolfgang Meier ◽  
Manfred Aigner ◽  
Felix Gu¨the
Keyword(s):  
Gas Turbine ◽  
Mixture Fraction ◽  
Measurement Techniques ◽  
Elevated Pressure ◽  
Flame Stabilization ◽  
Single Shot ◽  
Laser Raman ◽  
Planar Laser ◽  
Stable Flame ◽  
Industrial Gas Turbine

Experimental results from optical and laser spectroscopic measurements on a scaled industrial gas turbine (GT) burner at elevated pressure are presented. Planar laser induced fluorescence on the OH radical and OH* chemiluminescence imaging were applied to natural gas/air flames for a qualitative analysis of the position and shape of the flame brush, the flame front and the stabilization mechanism. The results exhibit two different ways of flame stabilization, a conical more stable flame and a pulsating opened flame. For quantitative results, 1D-laser Raman scattering was applied to these flames and evaluated on an average and single shot basis in order to simultaneously determine the major species concentrations, the mixture fraction and the temperature. The mixing of fuel and air as well as the reaction progress could thus be spatially and temporally resolved, showing differently strong variations depending on the flame stabilization mode and the location in the flame.

Numerical Simulation of Blade Fault Signatures From Unsteady Wall Pressure Signals

1997 ◽  
Vol 119 (2) ◽  
pp. 362-369 ◽  
Author(s):  
V. Dedoussis ◽  
K. Mathioudakis ◽  
K. D. Papailiou
Keyword(s):  
Numerical Simulation ◽  
Flow Field ◽  
Gas Turbine ◽  
Wall Pressure ◽  
Operating Point ◽  
Calculation Time ◽  
Rotating Blades ◽  
Time Signals ◽  
Gas Turbine Compressor ◽  
Industrial Gas Turbine

A method for establishing signatures of faults in the rotating blades of a gas turbine compressor is presented. The method employs a panel technique for the calculation of the flow field around blade cascades, with disrupted periodicity, a situation encountered when a blade fault has occurred. From this calculation, time signals of the pressure at a location on the casing wall, facing the rotating blades, are constituted. Processing these signals, in combination with “healthy” pressure signals, allows the constitution of fault signatures. The proposed method employs geometric data, as well as data about the operating point of the engine. It gives the possibility of establishing the fault signatures without the need of performing experiments with implanted faults. The successful application of the method is demonstrated by comparison of signatures obtained by simulation to signatures derived from experiments with implanted blade faults, in an industrial gas turbine.

Spray Flame Study Using a Model Gas Turbine Swirl Burner

2013 ◽  
Vol 316-317 ◽  
pp. 17-22 ◽  
Author(s):  
Cheng Tung Chong ◽  
Simone Hochgreb
Keyword(s):  
Flow Field ◽  
Gas Turbine ◽  
Flame Structure ◽  
Fuel Droplets ◽  
Spray Flame ◽  
Spray Flames ◽  
Reaction Zones ◽  
Fixed Power ◽  
Particle Imaging ◽  
Gas Turbine Burner

A model gas turbine burner was employed to investigate spray flames established under globally lean, continuous, swirling conditions. Two types of fuel were used to generate liquid spray flames: palm biodiesel and Jet-A1. The main swirling air flow was preheated to 350 °C prior to mixing with airblast-atomized fuel droplets at atmospheric pressure. The global flame structure of flame and flow field were investigated at the fixed power output of 6 kW. Flame chemiluminescence imaging technique was employed to investigate the flame reaction zones, while particle imaging velocimetry (PIV) was utilized to measure the flow field within the combustor. The flow fields of both flames are almost identical despite some differences in the flame reaction zones.

Amplitude-Dependent Damping and Driving Rates of High-Frequency Thermoacoustic Oscillations in a Lab-Scale Lean-Premixed Gas Turbine Combustor

2021 ◽  
Author(s):  
Thomas Hofmeister ◽  
Thomas Sattelmayer
Keyword(s):  
Flow Field ◽  
Gas Turbine ◽  
Limit Cycle ◽  
High Frequency ◽  
Mean Flow ◽  
Gas Turbine Combustor ◽  
Cfd Simulations ◽  
The Mean ◽  
Amplitude Dependency ◽  
Thermoacoustic Oscillations

Abstract This paper presents numerical investigations of the amplitude-dependent stability behavior of thermoacoustic oscillations at screech level frequencies in a lean-premixed, swirl-stabilized, lab-scale gas turbine combustor. A hybrid Computational Fluid Dynamics / Computational AeroAcoustics (CFD / CAA) approach is applied to individually compute thermoacoustic damping and driving rates for various acoustic amplitude levels at the combustors' first transversal (T1) eigenfrequency. Forced CFD simulations with the Unsteady Reynolds-Averaged Navier-Stokes (URANS) equations mimic the real combustor's rotating T1 eigenmode. An increase of the forcing amplitude over time allows observation of the amplitude-dependent flow field and flame evolution. In accordance with measured OH*-chemiluminescence images, a pulsation amplitude-dependent flame contraction is reproduced in the CFD simulations. At several amplitude levels, period-averaged flow fields are then denoted as reference states, which serve as inputs for the CAA part. There, eigenfrequency simulations with linearized flow equations are performed with the Finite Element Method (FEM). The outcomes are damping and driving rates as a response to the amplitude-dependency of the mean flow field. It is found that driving due to flame-acoustics interactions governs a weak amplitude-dependency, which agrees with experimentally based studies at the authors' institute. This disqualifies the perception of heat release saturation as the root-cause for limit-cycle oscillations in this high-frequency thermoacoustic system. Instead, significantly increased dissipation due to the interaction of acoustically induced vorticity perturbations with the mean flow is identified, which may explain the formation of a limit-cycle.

Study of a Gas Turbine Combustion Chamber: Influence of the Mixing on the Flame Dynamics

2004 ◽  
Author(s):  
Christophe Duwig ◽  
Laszlo Fuchs
Keyword(s):  
Flow Field ◽  
Combustion Chamber ◽  
Gas Turbine ◽  
New Technologies ◽  
Mean Flow ◽  
Flamelet Model ◽  
Demand Growth ◽  
Eddy Simulation ◽  
Flame Dynamics ◽  
Gas Turbine Combustion

The new challenge of the Gas Turbine industry is to develop new technologies for meeting electricity demand growth and reducing harmful emissions. Thus a better understanding of the combustion phenomenon and an improvement in simulation capabilities are needed. Large Eddy Simulation tools brought the hope of meeting these two conditions and enabling the design of safe and clean burners. In the present paper, the influence of the unsteady mixing on the flame in a Lean Premixed Pre-vaporized combustor have been investigated. A premixed combustion flamelet model has been extended to non-uniform fuel/air mixtures cases. Extra terms in the equations, their effects and the modeling issues are discussed. Additionally, the effects of mixing on the flow field in an industrial gas turbine combustion chamber have been investigated. The mean flow field has been found to be weakly sensitive to the mixing effects. It is deduced that the modeling of the mixing and the combustion can be decoupled in the RANS framework. Regarding the flame dynamics, all runs show similar characteristic frequencies. However, different details of models lead to differences in the temperature fluctuations. This suggests that a rigorous modeling of the thermo-acoustic sources (e.g. heat-release fluctuations) requires accurate modeling of the mixing/combustion coupling, for handling accurately the dynamics of the flame.

Part Load Behavior of the LP Part of an Industrial Gas Turbine

2017 ◽  
Author(s):  
Milan V. Petrovic ◽  
Alexander Wiedermann ◽  
Srecko M. Nedeljkovic ◽  
Milan Banjac
Keyword(s):  
Flow Field ◽  
Gas Turbine ◽  
Incidence Angle ◽  
Pressure Ratio ◽  
Solution Procedure ◽  
Turbine Efficiency ◽  
Through Flow ◽  
Wide Range ◽  
Design Speed ◽  
Industrial Gas Turbine

The operation under off-design conditions of a two-stage LP part of a 6.5 MW industrial gas turbine was analyzed in this work. Since the turbine is able to vary the rotation speed in a wide range from 40 to 140% of the design speed, a flow with extremely large positive and negative incidence angle appears. The flow field was calculated applying 2D through-flow code for the analysis of axial multistage turbines with cooling by air from compressor bleed. The code was developed by the authors and validated by calculation of a number of test cases with different configurations. The method is based on a stream function approach and a finite element solution procedure. In parallel, the flow in the turbine was calculated using a commercial CFD code. Based on the calculated flow field, the turbine efficiency and pressure ratio and also different stage parameters were determined for the design point and for a wide range of off-design conditions. Comparison of the predicted results and measured test data for a number of parameters showed good agreement.

scholarly journals Development of a Composite Inlet Housing for GTX100

1999 ◽  
Author(s):  
Roger S. Andersson ◽  
Ingemar A. G. Eriksson ◽  
Olov C. Granström
Keyword(s):  
Flow Field ◽  
Gas Turbine ◽  
Evolutionary Process ◽  
Compressor Blade ◽  
Point Of View ◽  
Manufacturing Costs ◽  
Field Distortion ◽  
Improved Performance ◽  
New Applications ◽  
Industrial Gas Turbine

The development of the new industrial gas turbine GTX100 offered possibilities to introduce new applications for materials and design. The characteristics of the inlet housing are not just important from a power output viewpoint but also from a flow field distortion and compressor blade excitation point of view. This paper describes the evolutionary process and considerations in the development of the GTX100 composite inlet housing. The goal, which has been accomplished, was to find a new design that would result in lower manufacturing costs and improved performance.

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