CFD Prediction of Partload CO Emissions Using a Two-Timescale Combustion Model

2011 ◽  
Vol 133 (7) ◽  
Author(s):  
Bernhard Wegner ◽  
Uwe Gruschka ◽  
Werner Krebs ◽  
Y. Egorov ◽  
H. Forkel ◽  
...  
Keyword(s):  
Power Supply ◽  
Gas Turbines ◽  
Flame Stabilization ◽  
Combustion Model ◽  
Scale Analysis ◽  
Combustion System ◽  
Operational Flexibility ◽  
Ansys Cfx ◽  
Low Nox Combustion ◽  
Computational Fluid Dynamics Cfd

Today’s and future electric power generation is characterized by a large diversification using all kind of sources, including renewables resulting in noncoherent fluctuations of power supply and power usage. In this context, gas turbines offer a high operational flexibility and a good turn down ratio. In order to guide the design and down select promising solutions for improving partload emissions, a new combustion model based on the assumption of two separate timescales for the fast premixed flame stabilization and the slow post flame burnout zone is developed within the commercial computational fluid dynamics (CFD) code ANSYS CFX. This model enables the prediction of CO emissions generally limiting the turn down ratio of gas turbines equipped with modern low NOx combustion systems. The model is explained and validated at lab scale conditions. Finally, the application of the model for a full scale analysis of a gas turbine combustion system is demonstrated.

CFD Prediction of Partload CO Emissions Using a Two-Timescale Combustion Model

2010 ◽  
Author(s):  
Bernhard Wegner ◽  
Uwe Gruschka ◽  
Werner Krebs ◽  
Y. Egorov ◽  
H. Forkel ◽  
...  
Keyword(s):  
Power Supply ◽  
Gas Turbines ◽  
Flame Stabilization ◽  
Premixed Flame ◽  
Combustion Model ◽  
Scale Analysis ◽  
Combustion System ◽  
Operational Flexibility ◽  
Ansys Cfx ◽  
Low Nox Combustion

Todays and future electric power generation is characterized by a large diversification using all kind of sources including renewables resulting in non coherent fluctuations of power supply and power usage. In this context, gas turbines offer a high operational flexibility and a good turn down ratio. In order to guide design and down select promising solutions for improving part load emissions a new combustion model based on the assumption of two separate time scales for the fast premixed flame stabilization and the slow post flame burnout zone has been developed within the commercial CFD code ANSYS CFX. This model enables the prediction of CO emissions generally limiting the turn down ratio of gas turbines equipped with modern low NOx combustion systems. The model will be explained and validated at lab scale conditions. Finally application of the model for a full scale analysis of a gas turbine combustion system is demonstrated.

Comparison of Combustion Models and Reaction Mechanisms for FLOX® Combustion

2009 ◽  
Author(s):  
Tobias Panne ◽  
Axel Widenhorn ◽  
Manfred Aigner
Keyword(s):  
Reaction Mechanisms ◽  
Gas Turbines ◽  
Combustion Model ◽  
Atmospheric Conditions ◽  
Flameless Combustion ◽  
High Pressure And Temperature ◽  
Detailed Chemistry ◽  
Ansys Cfx ◽  
Typical Operating Condition ◽  
Commercial Software Package

Flameless combustion is characterized by very low NOx and CO emissions. It has successfully been used in technical furnaces under atmospheric conditions for many years. For the use in modern gas turbines the combustors have to be redesigned to meet the typical operating condition, i.e. high pressure and temperature. The flameless combustion under gas turbine relevant conditions has successfully been simulated using a detailed chemistry model [1]. However computational costs and turnaround times are very high for these simulations. In this work the influence of different reduced reaction mechanisms on the heat release and on the temperature and flow field depending on the implied combustion model are investigated. As a benchmark the simulations are compared to experimental data obtained by OH* chemiluminescence and OH LIF measurements [2]. The simulations are performed on the basis of the commercial software package ANSYS CFX 11.0.

Development and Implementation of the AEV Burner for the Alstom GT13E2

2012 ◽  
Author(s):  
Martin Zajadatz ◽  
Douglas Pennell ◽  
Stefano Bernero ◽  
Bettina Paikert ◽  
Raffaele Zoli ◽  
...  
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Public Awareness ◽  
Gas Composition ◽  
Combustion System ◽  
Transient Operation ◽  
Operational Flexibility ◽  
Ambient Conditions ◽  
Additional Advantage ◽  
Energy Demands

Increasing public awareness and more stringent legislation on pollutants drive gas turbine manufacturers to develop combustion systems with low NOx emissions. In combination to this demand the gas turbines have to provide a broad range of operational flexibility to cover variations in gas composition and ambient conditions as well as varying daily and seasonal energy demands and load profiles. This paper describes the development and implementation of the Alstom AEV (Advanced EnVironmental) burner, an evolution of the EV. Continuous fuel supply to two fuel stages at any engine load simplifies the operation and provides a fast and reliable response of the combustion system during transient operation of the gas turbine. Increased turndown with low emissions is an additional advantage of the combustion system upgrade.

Conjugate Heat Transfer Analysis of a Cooled Turbine Blade Using Frozen Rotor Approach

2015 ◽  
Author(s):  
Kuo-San Ho ◽  
Jong Liu ◽  
Christopher Urwiller ◽  
S. Murthy Konan ◽  
Bruno Aguilar
Keyword(s):  
Heat Transfer ◽  
Gas Turbines ◽  
High Performance ◽  
Conjugate Heat Transfer ◽  
Cfd Simulation ◽  
Heat Transfer Analysis ◽  
Research Papers ◽  
Ansys Cfx ◽  
Computational Fluid Dynamics Cfd ◽  
Maximum Temperatures

In recent years, conjugate heat transfer (CHT) computational fluid dynamics (CFD) simulation in turbomachinery played an important role in predicting metal temperature. Most of research papers of CHT CFD simulation were emphasized on the mixing plane method. In this paper the ANSYS CFX 14.0 CHT simulation using the frozen rotor approach is employed to predict the blade temperatures. The frozen rotor included five time instances in which the stator-rotor wake influence could be captured. In this study, the temperature predictions using the frozen rotor approach were compared to the mixing plane predictions and Silicon Carbide (SiC) chip measurements on three different radial spans. The frozen rotor results predicted the minimum and maximum temperatures that bounded the SiC chip data. Compared to the mixing plane predictions, the frozen rotor approach results were similar within 8 K at the mid-span. However, the frozen rotor approach provided more insight information and detailed guidance for model calibration. Finally several future works were suggested to continue striving for high performance gas turbines.

Staged Combustion System for Improved Emissions Operability and Flexibility for 7HA Class Heavy Duty Gas Turbine Engine

2017 ◽  
Author(s):  
Hasan Karim ◽  
Jayaprakash Natarajan ◽  
Venkat Narra ◽  
Jun Cai ◽  
Shreekrishna Rao ◽  
...  
Keyword(s):  
Gas Turbine ◽  
Firing Temperature ◽  
Gas Turbines ◽  
Test Facility ◽  
Engine Test ◽  
Combustion System ◽  
Operational Flexibility ◽  
Staged Combustion ◽  
Combustion Dynamics ◽  
Gas Turbine Combustion

Driven by global warming, a relentless march towards increased fuel efficiency has resulted in increased firing temperature for HA-class engines without an increase in baseload emissions. Moreover, emissions compliance for CO, NOx, and unburned hydrocarbons are desired over increased range in gas turbine load. In addition, exceptional gas turbine operational flexibility is desired to address potential intermittency due to the penetration of renewables in the electrical grid. Staged/sequential combustion is a state of the technology to provide operational flexibility and reduced emissions in power generation gas turbines. GE Power’s 7HA-class gas turbine combustion system combines GE’s proven DLN-2.6+ combustion technology, that has run reliably for over 1.3 million fired hours across more than eighty 9FA.03, 9F.05 & 7FA gas turbine engines, with an axially fuel staged system (AFS). Axially staging combustion to two zones allows for increased firing temperature at baseload (while maintaining the same NOx level) by operating the later/second stage hotter than the first/primary stage. During low load operation as the gas turbine firing temperature is reduced, percentage fuel split in the staged fuel system can either be reduced significantly or turned off and thereby keeping the overall combustion system into emissions compliance over a wider range of firing temperatures. This paper presents both the development testing of the staged combustion in the FA and HA class gas turbine combustion system rigs at GE Power’s Gas Turbine Technology Laboratory and the validation testing of staged combustion system for the 7HA.01 engine completed during Spring 2016 at GE Power’s engine test facility in Greenville, SC. The paper also discusses the significant simplification of operational principle and flexibility of startup, loading and baseload operation of the 7HA combustion system. Discussion of engine test results will show how axial fuel staging was utilized to demonstrate emissions compliance ( NOx (15% O2) < 25 ppm; CO < 9 ppm), operation from 14% load to 100% load with low combustion dynamics and also to enable wide wobbe capability, which is a normalized measure of fuel flexibility.

Development and Implementation of the Advanced Environmental Burner for the Alstom GT13E2

2013 ◽  
Vol 135 (6) ◽  
Author(s):  
Martin Zajadatz ◽  
Douglas Pennell ◽  
Stefano Bernero ◽  
Bettina Paikert ◽  
Raffaele Zoli ◽  
...  
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Public Awareness ◽  
Gas Composition ◽  
Combustion System ◽  
Operational Flexibility ◽  
Ambient Conditions ◽  
Additional Advantage ◽  
Energy Demands ◽  
Ev Burner

Increasing public awareness and more stringent legislation on pollutants drive gas turbine manufacturers to develop combustion systems with low NOx emissions. In combination with this demand, the gas turbines have to provide a broad range of operational flexibility to cover variations in gas composition and ambient conditions along with varying daily and seasonal energy demands and load profiles. This paper describes the development and implementation of the Alstom AEV (advanced environmental) burner, an evolution of the envorinmental (EV) burner. A continuous fuel supply to two fuel stages at any engine load simplifies the operation and provides a fast and reliable response of the combustion system during transient operation of the gas turbine. Increased turndown with low emissions is an additional advantage of the combustion system upgrade.

Low NOx SEV Lean Premix Reheat Combustion in Alstom GT24 Gas Turbines

2015 ◽  
Author(s):  
Daniel Guyot ◽  
Gabrielle Tea ◽  
Christoph Appel
Keyword(s):  
High Pressure ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Fuel Injection ◽  
Test Facility ◽  
Inlet Temperature ◽  
Combustion System ◽  
Operational Flexibility ◽  
Term Operation ◽  
Fuel Flexibility

Reducing gas turbine emissions and increasing their operational flexibility are key targets in today’s gas turbine market. In order to further reduce emissions and increase the operational flexibility of its GT24 (60Hz) and GT26 (50Hz), Alstom has introduced an improved SEV burner and fuel lance into its GT24 upgrade 2011 and GT26 upgrade 2011 sequential reheat combustion system. Sequential combustion is a key differentiator of Alstom GT24 engines in the F-class gas turbine market. The inlet temperature for the GT24 SEV combustor is around 1000 degC and reaction of the fuel/oxidant mixture is initiated through auto-ignition. The recent development of the Alstom sequential combustion system is a perfect example of evolutionary design optimizations and technology transfer between Alstom GT24 and GT26 engines. Better overall performance is achieved through improved SEV burner aerodynamics and fuel injection, while keeping the main features of the sequential burner technology. The improved SEV burner/lance concept has been optimized towards rapid fuel/oxidant mixing for low emissions, improved fuel flexibility with regards to highly reactive fuels (higher C2+ and hydrogen content), and to sustain a wide operation window. In addition, the burner front panel features an improved cooling concept based on near-wall cooling as well as integrated acoustics damping devices designed to reduce combustion pulsations thus extending the SEV combustor’s operation window even further. After having been validated extensively in the Alstom high pressure sector rig test facility, the improved GT24 SEV burner has been retrofitted into a commercial GT24 field engine for full engine validation during long-term operation. This paper presents the obtained high pressure sector rig and engine validation results for the GT24 (2011) SEV burner/lance hardware with a focus on reduced NOX and CO emissions and improved operational behavior of the SEV combustor. The high pressure tests demonstrated robust SEV burner/lance operation with up to 50% lower NOX formation and a more than 70K higher SEV burner inlet temperature compared to the GT24 (2006) hardware. For the GT24 engine with retrofitted upgrade 2011 SEV burner/lance all validation targets were achieved including an extremely robust operation behavior, up to 40% lower GT NOX emissions, significantly lower CO emissions at partload and baseload, a very broad operation window (up to 100K width in SEV combustor inlet temperature) and all measured SEV burner/lance temperatures in the expected range. Sector rig and engine validation results have confirmed the expected SEV burner fuel flexibility (up to 18%-vol. C2+ and up to 5%-vol. hydrogen as standard).

Low NOx Lean Premix Reheat Combustion in Alstom GT24 Gas Turbines

2015 ◽  
Vol 138 (5) ◽  
Author(s):  
Daniel Guyot ◽  
Gabrielle Tea ◽  
Christoph Appel
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Fuel Injection ◽  
Test Facility ◽  
Inlet Temperature ◽  
Combustion System ◽  
Operational Flexibility ◽  
Nox Formation ◽  
Term Operation ◽  
Fuel Flexibility

Reducing gas turbine emissions and increasing their operational flexibility are key targets in today's gas turbine market. In order to further reduce emissions and increase the operational flexibility of its GT24 (60 Hz) and GT26 (50 Hz), Alstom has introduced an improved sequential environmental (SEV) burner and fuel lance into its GT24 and GT26 upgrades 2011 sequential reheat combustion system. Sequential combustion is a key differentiator of Alstom GT24/GT26 engines in the F-class gas turbine market. The inlet temperature for the SEV combustor is around 1000 °C and reaction of the fuel/oxidant mixture is initiated through auto-ignition. The recent development of the Alstom sequential combustion system is a perfect example of evolutionary design optimizations and technology transfer between Alstom GT24 and GT26 engines. Better overall performance is achieved through improved SEV burner aerodynamics and fuel injection, while keeping the main features of the sequential burner technology. The improved SEV burner/lance concept has been optimized toward rapid fuel/oxidant mixing for low emissions, improved fuel flexibility with regard to highly reactive fuels (higher C2+ and hydrogen content), and to sustain a wide operation window. The burner front panel features an improved cooling concept based on near-wall cooling as well as integrated acoustics damping devices designed to reduce combustion pulsations, thus extending the SEV combustor's operation window even further. After having been validated extensively in Alstom's high pressure (HP) sector rig test facility, the improved GT24 SEV burner has been retrofitted into a commercial GT24 field engine for full engine validation during long-term operation. This paper presents the obtained HP sector rig and engine validation results for the GT24 (2011) SEV burner/lance hardware with a focus on reduced NOx and CO emissions and improved operational behavior of the SEV combustor. The HP tests demonstrated robust SEV burner/lance operation with up to 50% lower NOx formation and a more than 70 K higher SEV burner inlet temperature compared to the GT24 (2006) hardware. For the GT24 engine with retrofitted upgrade 2011 SEV burner/lance, all validation targets were achieved including an extremely robust operation behavior, up to 40% lower GT NOx emissions, significantly lower CO emissions at partload and baseload, a very broad operation window (up to 100 K width in SEV combustor inlet temperature), and all measured SEV burner/lance temperatures in the expected range. Sector rig and engine validation results have confirmed the expected SEV burner fuel flexibility (up to 18 vol. % C2+ and up to 5 vol. % hydrogen as standard).

scholarly journals Development and Integration of the Dual Fuel Combustion System for the MGT Gas Turbine Family

2021 ◽  
Author(s):  
Bernhard Ćosić ◽  
Frank Reiß ◽  
Marc Blümer ◽  
Christian Frekers ◽  
Franklin Genin ◽  
...  
Keyword(s):  
High Pressure ◽  
Natural Gas ◽  
Gas Turbine ◽  
Distribution System ◽  
Gas Turbines ◽  
Liquid Fuel ◽  
Flame Stabilization ◽  
Experimental Investigations ◽  
Dual Fuel ◽  
Combustion System

Abstract Industrial gas turbines like the MGT6000 are often operated as power supply or as mechanical drives for pumps and compressors at remote locations on islands and in deserts. Moreover, small gas turbines are used in CHP applications with a high need for availability. In these applications, liquid fuels like ‘Diesel Fuel No. 2’ can be used either as main fuel or as backup fuel if natural gas is not reliably available. The MAN Gas Turbines (MGT) operate with the Advanced Can Combustion (ACC) system, which is already capable of ultra-low NOx emissions for a variety of gaseous fuels. This system has been further developed to provide dry dual fuel capability to the MGT family. In the present paper, we describe the design and detailed experimental validation process of the liquid fuel injection, and its integration into the gas turbine package. A central lance with an integrated two-stage nozzle is employed as a liquid pilot stage, enabling ignition and start-up of the engine on liquid fuel only, without the need for any additional atomizing air. The pilot stage is continuously operated to support further the flame stabilization across the load range, whereas the bulk of the liquid fuel is injected through the premixed combustor stage. The premixed stage comprises a set of four decentralized nozzles placed at the exit of the main air swirler. These premixed nozzles are based on fluidic oscillator atomizers, wherein a rapid and effective atomization of the liquid fuel is achieved through self-induced oscillations of the liquid fuel stream. We present results of numerical and experimental investigations performed in the course of the development process illustrating the spray, hydrodynamic, and thermal performance of the pilot injectors. Extensive testing of the burner at atmospheric and full load high-pressure conditions has been performed, before verification of the whole combustion system within full engine tests. The burner shows excellent emission performance (NOx, CO, UHC, soot) without additional water injection, while maintaining the overall natural gas performance. Soot and particle emissions, quantified via several methods, are well below legal restrictions. Furthermore, when not in liquid fuel operation, a continuous purge of the injectors based on compressor outlet (p2) air has been laid out. Generic atmospheric coking tests were conducted before verifying the purge system in full engine tests. Thereby we completely avoid the need for an additional high-pressure auxiliary compressor or demineralized water. We show the design of the fuel supply and distribution system. We designed it to allow for rapid fuel switchovers from gaseous fuel to liquid fuel, and for sharp load jumps. Finally, we discuss the integration of the dual fuel system into the standard gas turbine package of the MGT6000 in detail.

Development and Atmospheric Testing of a High Hydrogen FlameSheet™ Combustor for the OP16 Gas Turbine

2021 ◽  
Author(s):  
Thijs Bouten ◽  
Jan Withag ◽  
Lars-Uno Axelsson ◽  
Joris Koomen ◽  
Diethard Jansen ◽  
...  
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Alternative Fuels ◽  
Cost Effective ◽  
Flame Stabilization ◽  
Combustion System ◽  
Low Carbon ◽  
Load Range ◽  
High Hydrogen ◽  
Trapped Vortex

Abstract Gas turbines with a combustion system for hydrogen operation offer a low carbon solution to support the stability of the energy grid. This provides a solution capturing the needs for energy storage, in the form of hydrogen, and flexible power generation. Fuel flexibility is a key requirement to reduce the operational risks in case hydrogen is not available, whereby hydrogen can be combined with other conventional or alternative fuels. A key issue to achieve 100% hydrogen combustion with low emissions is to prevent flashback. To address the challenges, a project consortium was set-up consisting of gas turbine equipment manufacturers, academia and end-users. The major objective is to develop a cost-effective, ultra-low emissions (sub 9 ppm NOx and CO) combustion system for gas turbines in the 1–300 MW output range, including the 1.85 MWe OPRA OP16 gas turbine. At the center of this innovative high-technology project is the patented and novel aerodynamic trapped vortex FlameSheet™ combustion technology platform. Burner concepts based on an aerodynamically trapped vortex flame stabilization have a higher resistance towards flame blowout than conventional swirl stabilized burners. This paper will present the results of the first phase of the project, whereby atmospheric testing of the upgraded FlameSheet™ combustor has been performed operating on natural gas, hydrogen and mixtures thereof. The optimized combustor configurations demonstrated a wide load range on 100% hydrogen, and these results will be presented.

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