Observations of Flame Behavior in a Laboratory-Scale Pre-Mixed Natural Gas/Air Gas Turbine Combustor From LDA Velocity Measurements

2002 ◽  
Author(s):  
Paul O. Hedman ◽  
Robert L. Murray ◽  
Thomas H. Fletcher
Keyword(s):  
Natural Gas ◽  
Gas Turbine ◽  
Tangential Velocity ◽  
Operating Conditions ◽  
Laboratory Scale ◽  
Flame Velocity ◽  
Velocity Measurements ◽  
Gas Turbine Combustor ◽  
Stable Case ◽  
Gas Flame

The objective of this study was to obtain simultaneous axial/radial and axial/tangential velocity measurements in a laboratory-scale, gas-turbine combustor (LSGTC) with a pre-mixed, swirl-stabilized, natural gas flame. Velocity measurements were obtained at each of four operating conditions (high swirl and medium swirl at fuel equivalence ratios of 0.80 and 0.65). Example results of mean and standard deviation axial, radial, and tangential velocities are included in this paper for the high swirl (HS), φ = 0.80 case (most stable flame) and the medium swirl (MS), φ = 0.65 case (least stable case). Additionally, example probably density distributions (PDF) for the axial velocity at the 80 mm axial location are presented for the same two cases.

Observations of Flame Behavior in a Laboratory-Scale Pre-Mixed Natural Gas/Air Gas Turbine Combustor From CARS Temperature Measurements

2002 ◽  
Author(s):  
Paul O. Hedman ◽  
Daniel V. Flores ◽  
Thomas H. Fletcher
Keyword(s):  
Natural Gas ◽  
Gas Turbine ◽  
Operating Conditions ◽  
Laboratory Scale ◽  
Temperature Measurements ◽  
Gas Temperature ◽  
Gas Turbine Combustor ◽  
Stable Flame ◽  
Gas Flame ◽  
Anti Stokes

This objective of this study was to obtain instantaneous gas temperature measurements using a coherent anti-Stokes Raman spectrometer (CARS) in a laboratory-scale, gas-turbine combustor (LSGTC) with a pre-mixed, swirl-stabilized, natural gas flame. These measurements complement PLIF measurements of OH radical, and LDA measurements of velocity which are presented in companion papers [1,2]. Gas temperature measurements were obtained at each of four operating conditions (high swirl and medium swirl at fuel equivalence ratios of 0.80 and 0.65). Results of mean and standard deviation measurements are included in this paper for all four test cases. Additionally, example probably density functions (PDF) for the gas temperature at the 40 mm, 60 mm, and 80 mm axial locations are presented for the for the high swirl (HS) φ = 0.80 case (most stable flame) and the medium swirl (MS) φ = 0.65 case (least stable flame).

scholarly journals Observations of Flame Behavior in a Laboratory-Scale Pre-Mixed Natural Gas/Air Gas Turbine Combustor From PLIF Measurements of OH

2002 ◽  
Author(s):  
Paul O. Hedman ◽  
Thomas H. Fletcher ◽  
Stewart G. Graham ◽  
G. Wayne Timothy ◽  
Daniel V. Flores ◽  
...  
Keyword(s):  
Natural Gas ◽  
Gas Turbine ◽  
Flame Structure ◽  
Operating Conditions ◽  
Laboratory Scale ◽  
Airflow Rate ◽  
Gas Turbine Combustor ◽  
Planar Laser ◽  
Swirl Injector ◽  
Order Of Magnitude

The objective of this study was to obtain instantaneous planar laser induced fluorescence (PLIF) images of OH in a laboratory-scale, gas-turbine combustor (LSGTC) with a pre-mixed, swirl-stabilized, natural gas flame. Instantaneous PLIF images of OH were obtained at each of four operating conditions (high swirl and medium swirl at fuel equivalence ratios of 0.80 and 0.65). Comparison of the instantaneous images illustrates the stochastic nature of the flame structure. Pixel by pixel statistical analysis of each collection of images allowed both mean and standard deviation images to be generated, and analysis at selected locations has allowed probability density functions to be obtained in various regions of the flame structure. PLIF images of OH, along with visual photographs and video recordings, showed a wide variation in flame structure for the different operating conditions. The variations in flame shapes are primarily a result of the effect of the swirl intensity and fuel equivalence ratio. Changes in the airflow rate over an order of magnitude do not seem to affect the visual flame structure in this experiment. Operation at φ = 0.80 produced the most stable flames with both injectors. The flame with the high swirl injector was more coalesced and closer to the injector than with the medium swirl injector. At φ = 0.65, the flame was quite unstable for both swirl injectors. With the medium swirl injector, the flame would oscillate between two different flame structures, one that was more or less attached to the vortex funnel, and one that was lifted well above the vortex funnel. The MS case at φ = 0.65 was at the very edge of the lean flammability limit, and would on occasion extinguish.

Experimental Assessment of the Emissions Benefits of a Ceramic Gas Turbine Combustor

1996 ◽  
Author(s):  
K. O. Smith ◽  
A. Fahme
Keyword(s):  
Natural Gas ◽  
Gas Turbine ◽  
Flow Distribution ◽  
Operating Conditions ◽  
Nox Emissions ◽  
Fuel Injector ◽  
Gas Turbine Combustor ◽  
Experimental Assessment ◽  
Industrial Gas Turbine ◽  
Combustor Liner

Three subscale, cylindrical combustors were rig tested on natural gas at typical industrial gas turbine operating conditions. The intent of the testing was to determine the effect of combustor liner cooling on NOx and CO emissions. In order of decreasing liner cooling, a metal louvre-cooled combustor, a metal effusion-cooled combustor, and a backside-cooled ceramic (CFCC) combustor were evaluated. The three combustors were tested using the same lean-premixed fuel injector. Testing showed that reduced liner cooling produced lower CO emissions as reaction quenching near the liner wall was reduced. A reduction in CO emissions allows a reoptimization of the combustor air flow distribution to yield lower NOx emissions.

Micro Gas Turbine Combustor Emissions Evaluation Using the Chemical Reactor Modelling Approach

2007 ◽  
Author(s):  
Carmine Russo ◽  
Giulio Mori ◽  
Vyacheslav V. Anisimov ◽  
Joa˜o Parente
Keyword(s):  
Natural Gas ◽  
Gas Turbine ◽  
Atmospheric Pressure ◽  
Chemical Reactor ◽  
Exhaust Emissions ◽  
Operating Conditions ◽  
Gas Turbine Combustor ◽  
Micro Gas Turbine ◽  
Simulation Results ◽  
Modelling Approach

Chemical Reactor Modelling approach has been applied to evaluate exhaust emissions of the newly designed ARI100 (Patent Pending) recuperated micro gas turbine combustor developed by Ansaldo Ricerche SpA. The development of the chemical reactor network has been performed based on CFD reacting flow analysis, obtained with a global 2-step reaction mechanism, applying boundary conditions concerning the combustion chamber at atmospheric pressure, with 100% of thermal load and fuelled with natural gas. The network consists of 11 ideal reactors: 6 perfectly stirred reactors, and 5 plug flow reactors, including also 13 mixers and 12 splitters. Simulations have been conducted using two detailed reaction mechanisms: GRI Mech 3.0 and Miller & Bowman reaction mechanisms. Exhaust emissions have been evaluated at several operating conditions, obtained at different pressure, and considering different fuel gases, as natural gas and a high H2 content SYNGAS fuel. Furthermore, emissions at different thermal loads have been investigated when natural gas at atmospheric pressure is fuelled. Simulation results have been compared with those obtained from combustion experimental campaign. CO and NOx emissions predicted with CRM approach closely match experimental results at representative operating conditions. Ongoing efforts to improve the proposed reactors network should allow extending the range of applicability to those operating conditions whose simulation results are not completely satisfying. Given the small computational effort required, and the accuracy in predicting combustor experimental exhaust emissions, both CO and NOx, the CRM approach turnout to be an efficient way to reasonably evaluate exhaust emissions of a micro gas turbine combustor.

Gas Turbine Combined Cycle With CO2-Capture Using Auto-Thermal Reforming of Natural Gas

2000 ◽  
Author(s):  
Thormod Andersen ◽  
Hanne M. Kvamsdal ◽  
Olav Bolland
Keyword(s):  
Natural Gas ◽  
Gas Turbine ◽  
Process Integration ◽  
Combined Cycle ◽  
Co2 Removal ◽  
Gas Turbine Combustor ◽  
Chemical Absorption ◽  
Fuel Gas ◽  
The Impact ◽  
Water Gas

A concept for capturing and sequestering CO2 from a natural gas fired combined cycle power plant is presented. The present approach is to decarbonise the fuel prior to combustion by reforming natural gas, producing a hydrogen-rich fuel. The reforming process consists of an air-blown pressurised auto-thermal reformer that produces a gas containing H2, CO and a small fraction of CH4 as combustible components. The gas is then led through a water gas shift reactor, where the equilibrium of CO and H2O is shifted towards CO2 and H2. The CO2 is then captured from the resulting gas by chemical absorption. The gas turbine of this system is then fed with a fuel gas containing approximately 50% H2. In order to achieve acceptable level of fuel-to-electricity conversion efficiency, this kind of process is attractive because of the possibility of process integration between the combined cycle and the reforming process. A comparison is made between a “standard” combined cycle and the current process with CO2-removal. This study also comprise an investigation of using a lower pressure level in the reforming section than in the gas turbine combustor and the impact of reduced steam/carbon ratio in the main reformer. The impact on gas turbine operation because of massive air bleed and the use of a hydrogen rich fuel is discussed.

Combustion Characteristics of Small Size Gas Turbine Combustor Fueled by Biomass Gas Employing Flameless Combustion

2007 ◽  
Author(s):  
Masato Hiramatsu ◽  
Yoshifumi Nakashima ◽  
Sadamasa Adachi ◽  
Yudai Yamasaki ◽  
Shigehiko Kaneko
Keyword(s):  
Gas Turbine ◽  
Combustion Efficiency ◽  
Combustion Characteristics ◽  
Operating Conditions ◽  
Nox Emissions ◽  
Gas Turbine Combustor ◽  
Flameless Combustion ◽  
Engine Exhaust ◽  
Micro Gas Turbine

One approach to achieving 99% combustion efficiency (C.E.) and 10 ppmV or lower NOx (at 15%O2) in a micro gas turbine (MGT) combustor fueled by biomass gas at a variety of operating conditions is with the use of flameless combustion (FLC). This paper compares experimentally obtained results and CHEMKIN analysis conducted for the developed combustor. As a result, increase the number of stage of FLC combustion enlarges the MGT operation range with low-NOx emissions and high-C.E. The composition of fuel has a small effect on the characteristics of ignition in FLC. In addition, NOx in the engine exhaust is reduced by higher levels of CO2 in the fuel.

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.

Experimental and numerical study of flame structure and emissions in a micro gas turbine combustor

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Vedant Dwivedi ◽  
Srikanth Hari ◽  
S. M. Kumaran ◽  
B. V. S. S. S. Prasad ◽  
Vasudevan Raghavan
Keyword(s):  
Gas Turbine ◽  
Rural Areas ◽  
Gas Turbines ◽  
Alternative Fuels ◽  
Numerical Study ◽  
Operating Conditions ◽  
Emission Characteristics ◽  
Nitric Oxides ◽  
Gas Turbine Combustor ◽  
Micro Gas Turbine

Abstract Experimental and numerical study of flame and emission characteristics in a tubular micro gas turbine combustor is reported. Micro gas turbines are used for distributed power (DP) generation using alternative fuels in rural areas. The combustion and emission characteristics from the combustor have to be studied for proper design using different fuel types. In this study methane, representing fossil natural gas, and biogas, a renewable fuel that is a mixture of methane and carbon-dioxide, are used. Primary air flow (with swirl component) and secondary aeration have been varied. Experiments have been conducted to measure the exit temperatures. Turbulent reactive flow model is used to simulate the methane and biogas flames. Numerical results are validated against the experimental data. Parametric studies to reveal the effects of primary flow, secondary flow and swirl have been conducted and results are systematically presented. An analysis of nitric-oxides emission for different fuels and operating conditions has been presented subsequently.

Evaluation of GT Outboard Bleed Air on Overall Engine Efficiency and CO2e Emission in Natural Gas Compressor Stations

2013 ◽  
Author(s):  
K. K. Botros ◽  
H. Golshan ◽  
D. Rogers ◽  
B. Sloof
Keyword(s):  
Natural Gas ◽  
Gas Turbine ◽  
Heat Rate ◽  
Operating Conditions ◽  
Process Conditions ◽  
Inlet Temperature ◽  
Predictive Tool ◽  
Valve Opening ◽  
Overall Efficiency ◽  
Engine Emission

Gas turbine (GT) engines employed in natural gas compressor stations operate in different modes depending on the power, turbine inlet temperature and shaft speeds. These modes apply different sequencing of bleed valve opening on the air compressor side of the engine. Improper selection of the GT and the driven centrifugal gas compressor operating conditions can lead to larger bleed losses due to wider bleed valve openings. The bleed loss inevitably manifests itself in the form of higher overall heat rate of the GT and greater engine emission. It is therefore imperative to determine and understand the engine and process conditions that drive the GT to operate in these different modes. The ultimate objective is to operate the engine away from the inefficient modes by adjusting the driven gas compressor parameters as well as the overall station operating conditions (i.e. load sharing, control set points, etc.). This paper describes a methodology to couple the operating conditions of the gas compressor to the modes of GT bleed valve opening (and the subsequent air bleed rates) leading to identification of the operating parameters for optimal performance (i.e., best overall efficiency and minimum CO2e emission). A predictive tool is developed to quantify the overall efficiency loss as a result of the different bleed opening modes, and map out the condition on the gas compressor characteristics. One year’s worth of operating data taken from two different compressor stations on TransCanada Pipelines’ Alberta system were used to demonstrate the methodology. The first station employs GE-LM1600 gas turbine driving a Cooper Rolls-RFBB-30 centrifugal compressor. The second station employs GE-LM-2500+ gas turbine driving NP PCL-800/N compressor. The analysis conclusively indicates that there are operating regions on the gas compressor maps where losses due to bleed valves are reduced and hence CO2 emissions are lowered, which presents an opportunity for operation optimization.

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