Journal articles on the topic 'Gas-turbine flame analysis'
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1
Mohammad Nurizat Rahman, Norshakina Shahril, and Suzana Yusup. "Hydrogen-Enriched Natural Gas Swirling Flame Characteristics: A Numerical Analysis." CFD Letters 14, no. 7 (July 17, 2022): 100–112. http://dx.doi.org/10.37934/cfdl.14.7.100112.
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Increasing the amount of hydrogen (H2) in natural gas mixtures contributes to gas turbine (GT) decarbonisation initiatives. Hence, the swirling flame characteristics of natural gas mixtures with H2 are investigated in the current work using a numerical assessment of a single swirl burner, which is extensively employed in GT combustors. The baseline numerical and experimental cases pertained to natural gas compositions largely consisting of methane (CH4). The results show that the numerical model adequately describes the swirling component of the flame observed in the experiment. Altogether, the findings show that hydroxyl (OH) radical levels increase in H2-enriched CH4 flames, implying that greater OH pools are responsible for the change in flame structure caused by considerable H2 addition. The addition of 10 % H2 is predicted to raise the peak flame temperature by 4 % compared to the baseline CH4 flame. Therefore, adding 10 % H2 into a GT combustor without any flowrate tuning raises the risk of turbine material deterioration and increased thermal NOx emission. Due to the lower volumetric Lower Heating Value (LHV) of H2, which needs a higher volumetric fuel flow rate than burning natural gas/CH4 at the same thermal output, the addition of 2 % H2 is predicted to reduce the peak flame temperature by 4 % compared to the baseline CH4 flame. Hence, if 2 % H2 is fed into a GT combustor without any flowrate tuning, the required load may not be obtained. When compared to the baseline CH4 case, the addition of 5 % H2 is predicted to provide almost identical peak flame temperature, which can be postulated that the addition of 5 % H2 can produce roughly the same peak flame temperature as the pure CH4 flame because the Wobbe Index is comparable. Therefore, it reveals that incorporating 5 % H2 in the natural gas-fired GT combustor with nearly no modification is viable. More research, however, is required to fully capture the flame structure and strain for assessing transient-related phenomena such as flashback and blow off by raising the H2 proportion and utilising a higher precision turbulence model.
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Fadhil, Siti Sarah Ain, Hasril Hasini, Mohd Nasharuddin Mohd Jaafar, and Nor Fadzilah Othman. "Temperature Distribution Analysis on Syngas Combustion in Microgas Turbine." Applied Mechanics and Materials 819 (January 2016): 282–86. http://dx.doi.org/10.4028/www.scientific.net/amm.819.282.
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Gas turbines are capable to utlize variety of fuel including natural gas, fuel oils and synthetic gas. It has environmental advantages and thus gas turbines are favourable in the power generating industries. The use of synthetic gas or syngas may reduce the CO2 and NOx emissions. The efficiency of syngas is comparable with natural gas. With the current constrain on the environmental issues, the use of syngas in gas turbines has been increasing. Despite its many advantages, the study on the combustion characteristics still remains a challenge, due to its variety fuel components. This paper aims to discuss the CFD analysis on the flame and flue gas temperature distribution in a full scale microgas turbine operating on syngas. Three cases were simulated with variety of natural gas concentration. A base case firing natural gas (100% methane) was first established using actual operation. Validation on the combustion model is made by comparing the flame temperature distribution of methane with reasonable accuracy. Simulation results with syngas show similar flame temperature distribution as natural gas combustion. The average temperature is much dependent on the composition of methane in syngas. The highest temperature given by syngas is made from the highest methane composiotion.
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Wang, Cheng Jun, Xin Xin, Ping Jiang, and Wen Zeng. "Analysis of Fuel Properties Effects on Flame Radiation in a Gas Turbine Combustor." Applied Mechanics and Materials 385-386 (August 2013): 196–99. http://dx.doi.org/10.4028/www.scientific.net/amm.385-386.196.
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The influence of fuel properties on flame radiation transfer was investigated with numerical method under certain combustor fuel-air ratio and inlet air temperature in a gas turbine combustor. The numerical results show that the fuel properties affected the fuel pulverization quality, evaporation efficiency and combustion efficiency, which caused the flame temperature and its distribution change. Meanwhile, it has an effect on the formation and concentration distribution of soot, resulting in the changes of inner flame radiation heat flux and temperature caused by flame emitting radiation. Furthermore, the gas temperature change caused by the fuel properties more but the hydrogen content effect is relatively small, has an influence on the generation of NO which caused the change of the combustion efficiency.
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Bellucci, Valter, Bruno Schuermans, Dariusz Nowak, Peter Flohr, and Christian Oliver Paschereit. "Thermoacoustic Modeling of a Gas Turbine Combustor Equipped With Acoustic Dampers." Journal of Turbomachinery 127, no. 2 (April 1, 2005): 372–79. http://dx.doi.org/10.1115/1.1791284.
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In this work, the TA3 thermoacoustic network is presented and used to simulate acoustic pulsations occurring in a heavy-duty ALSTOM gas turbine. In our approach, the combustion system is represented as a network of acoustic elements corresponding to hood, burners, flames and combustor. The multi-burner arrangement is modeled by describing the hood and combustor as Multiple Input Multiple Output (MIMO) acoustic elements. The MIMO transfer function (linking acoustic pressures and acoustic velocities at burner locations) is obtained by a three-dimensional modal analysis performed with a Finite Element Method. Burner and flame analytical models are fitted to transfer function measurements. In particular, the flame transfer function model is based on the time-lag concept, where the phase shift between heat release and acoustic pressure depends on the time necessary for the mixture fraction (formed at the injector location) to be convected to the flame. By using a state-space approach, the time domain solution of the acoustic field is obtained. The nonlinearity limiting the pulsation amplitude growth is provided by a fuel saturation term. Furthermore, Helmholtz dampers applied to the gas turbine combustor are acoustically modeled and included in the TA3 model. Finally, the predicted noise reduction is compared to that achieved in the engine.
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Kim, Daesik, Sa Ryang Kim, and Kyu Tae Kim. "Thermoacoustic Analysis Considering Flame Location in a Gas Turbine Combustor." Journal of the Korean Society of Combustion 18, no. 1 (March 31, 2013): 1–6. http://dx.doi.org/10.15231/jksc.2013.18.1.001.
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Winkler, Dieter, Weiqun Geng, Geoffrey Engelbrecht, Peter Stuber, Klaus Knapp, and Timothy Griffin. "Staged combustion concept for gas turbines." Journal of the Global Power and Propulsion Society 1 (September 27, 2017): CVLCX0. http://dx.doi.org/10.22261/cvlcx0.
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AbstractGas turbine power plants with high load flexibility are particularly suitable to compensate power fluctuations of wind and solar plants. Conventional gas turbines suffer from higher emissions at low load operation. With the objective of improving this situation a staged combustion system has been investigated. At low gas turbine load an upstream stage (first stage) provides stable combustion at low emissions while at higher loads the downstream stage (second stage) is started to supplement the power. Three injection geometries have been studied by means of computational fluid dynamics (CFD) simulations and atmospheric tests. The investigated geometries were a simple annular gap, a jet-in-cross-flow configuration and a lobe mixer. With CFD simulations the quality of mixing of second stage fresh gas with first stage exhaust gas was assessed. The lobe mixer showed the best mixing quality and hence was expected to also be the best variant in terms of combustion. However atmospheric combustion tests showed lower emissions for the jet-in-cross-flow configuration. Comparing flame photos in the visible and ultraviolet (UV) range suggest that the flame might be lifted off for the lobe mixer, leading to insufficient time for carbon monoxide (CO) burnout. CFD analysis of turbulent flame speed, turbulence and strain rates support the hypotheses of lifted off flame. Overall the staged concept was found to show very promising results not only with natural gas but also with natural gas enriched with propane or hydrogen. The investigations showed that apart from having an efficient and compact mixing of the two stages it is also very important to design the flow field such that the second flame can be anchored properly in order to achieve compact flames with sufficient time for CO burnout.
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Hasini, Hasril, Norshah Hafeez Shuaib, and Wan Ahmad Fahmi Wan Abdullah. "CFD Analysis of Temperature Distribution in Can-Type Combustor Firing Synthetic Gas." Applied Mechanics and Materials 393 (September 2013): 741–46. http://dx.doi.org/10.4028/www.scientific.net/amm.393.741.
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This paper presents CFD analysis of the effect of syngas combustion in a full scale gas turbine combustor with specific emphasis given to the flame and flue gas temperature distribution. A base case solution was first established using conventional natural gas combustion. Actual operating boundary conditions such as swirl, diffusion and fuel mass flow were imposed on the model. The simulation result is validated with the flame temperature of typical natural gas combustion. Result from flow and combustion calculation shows reasonable trend of the swirl mixing effect. The maximum flame temperature was found to be the highest for syngas with the highest H2/CO ratio. However, the flue gas temperature was found to be approximately identical for all cases. The prediction of temperature distribution in the combustor would enable further estimation of pollutant species such as CO2and NOxin complex regions within the combustor.
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Dulin, Vladimir, Leonid Chikishev, Dmitriy Sharaborin, Aleksei Lobasov, Roman Tolstoguzov, Zundi Liu, Xiaoxiang Shi, Yuyang Li, and Dmitriy Markovich. "On the Flow Structure and Dynamics of Methane and Syngas Lean Flames in a Model Gas-Turbine Combustor." Energies 14, no. 24 (December 8, 2021): 8267. http://dx.doi.org/10.3390/en14248267.
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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.
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Kuznetsov, Borys, Andrii Diadechko, Viktor Hudyma, Ihor Ovcharenko, Oleksandr Yaroshenko, Oleksandr Sampir, Yana Horbachova, and Mariia Tsurkan. "Numerical research of flame propagation conditions in narrow channels using the technology of thermal impulse treatment of turbine blades." Strength of Materials and Theory of Structures, no. 107 (October 29, 2021): 236–46. http://dx.doi.org/10.32347/2410-2547.2021.107.236-246.
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The analysis of the main modern trends in the development of views on the issue of cleaning of the cooling channels of turbine blades in gas turbine engines in the process of manufacture and repair at military repair enterprises has been carried out; the usage of the method of thermo impulse treatment with detonating gas mixtures for cleaning of the cooling channels of turbine blades in gas turbine engines is proposed.
Cleaning the cooling channels of turbine blades of modern gas turbine engines is one of the most complex processes in their manufacture and repair. At the manufacturing stage, the cleaning process is necessary to remove microparticles of ceramics and cutting chip that are produced during the formation of the output edges of the cooling.
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Rahman, Mohammad Nurizat, Norshakina Shahril, Suzana Yusup, and Ismail Shariff. "Hydrogen Co-Firing Characteristics in a Single Swirl Burner: A Numerical Analysis." IOP Conference Series: Materials Science and Engineering 1257, no. 1 (October 1, 2022): 012020. http://dx.doi.org/10.1088/1757-899x/1257/1/012020.
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Abstract Hydrogen is gaining traction as an energy carrier in the decarbonisation and net-zero-emissions agenda. Because hydrogen is a clean energy carrier, increasing the percentage of hydrogen in natural gas mixtures aids in the decarbonisation initiatives. Hence, the flame characteristics of the natural gas mixtures, together with hydrogen are explored in the current study through a numerical assessment of a single swirl burner (swirl number, SN 0.78) since the said burner is widely used in gas turbine (GT) combustors. The baseline CFD and experimental cases referred to natural gas compositions primarily composed of methane (CH4). The results reveal that the CFD model can effectively represent the swirling component of the flame as seen in the experiment. A 5% hydrogen addition had virtually no effect on the swirling flame structure, as shown by qualitative evaluation of hydroxyl (OH) behaviour and flame temperature in comparison to the baseline methane flame. Despite this, the addition of hydrogen has increased the OH radical pool during combustion, causing a small change in flame temperature. Overall, the novelty of the current research is the opportunity to fire 5% hydrogen in a CH4-dominated GT combustor without any major retrofitting operations, as the study discovered that 5% hydrogen in a pure CH4 stream has a minor affect. However, more research is needed to properly capture the flame structure and strain for assessing transient-related phenomena like flashback and blow off by increasing the hydrogen proportion and using a higher accuracy turbulence model.
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Stuttaford, P. J., and P. A. Rubini. "Preliminary Gas Turbine Combustor Design Using a Network Approach." Journal of Engineering for Gas Turbines and Power 119, no. 3 (July 1, 1997): 546–52. http://dx.doi.org/10.1115/1.2817019.
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The preliminary design process of a gas turbine combustor often involves the use of cumbersome, geometry restrictive semi-empirical models. The objective of this analysis is the development of a versatile design tool for gas turbine combustors, able to model all conceivable combustor types. A network approach is developed that divides the flow into a number of independent semi-empirical subflows. A pressure-correction methodology solves the continuity equation and a pressure-drop/flow rate relationship. The development of a full conjugate heat transfer model allows the calculation of flame tube heat loss in the presence of cooling films, annulus heat addition, and flame tube feature heat pick-up. A constrained equilibrium calculation, incorporating mixing and recirculation models, simulates combustion processes. Comparison of airflow results to a well-validated combustor design code showed close agreement. The versatility of the network solver is illustrated with comparisons to experimental data from a reverse flow combustor.
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Gruhlke, Pascal, Christian Beck, Bertram Janus, and Andreas M. Kempf. "LES Analysis of CO Emissions from a High Pressure Siemens Gas Turbine Prototype Combustor at Part Load." Energies 13, no. 21 (November 3, 2020): 5751. http://dx.doi.org/10.3390/en13215751.
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This work contributes to the understanding of mechanisms that lead to increased carbon monoxide (CO) concentrations in gas turbine combustion systems. Large-eddy simulations (LES) of a full scale high pressure prototype Siemens gas turbine combustor at three staged part load operating conditions are presented, demonstrating the ability to predict carbon monoxide pollutants from a complex technical system by investigating sources of incomplete CO oxidation. Analytically reduced chemistry is applied for the accurate pollutant prediction together with the dynamic thickened flame model. LES results show that carbon monoxide emissions at the probe location are predicted in good agreement with the available test data, indicating two operating points with moderate pollutant levels and one operating point with CO concentrations below 10 ppm. Large mixture inhomogeneities are identified in the combustion chamber for all operating points. The investigation of mixture formation indicates that fuel-rich mixtures mainly emerge from the pilot stage resulting in high equivalence ratio streaks that lead to large CO levels at the combustor outlet. Flame quenching due to flame-wall-interaction are found to be of no relevance for CO in the investigated combustion chamber. Post-processing with Lagrangian tracer particles shows that cold air—from effusion cooling or stages that are not being supplied with fuel—lead to significant flame quenching, as mixtures are shifted to leaner equivalence ratios and the oxidation of CO is inhibited.
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Stu¨rmer, G., A. Schulz, and S. Wittig. "Lifetime Prediction for Ceramic Gas Turbine Components." Journal of Engineering for Gas Turbines and Power 115, no. 1 (January 1, 1993): 70–75. http://dx.doi.org/10.1115/1.2906688.
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At the Institute for Thermal Turbomachinery, University of Karlsruhe (ITS), theoretical and experimental investigations of ceramic gas turbine components are performed. For the reliability analysis by finite element calculations the computer code CERITS has been developed. This code is used to determine the fast fracture reliability of ceramic components subjected to polyaxial stress states with reference to volumetric flaws and was presented at the 1990 IGTI Gas Turbine Conference. CERITS-L now includes subcritical crack growth. With the new code CERITS-L, failure probabilities of ceramic components can be calculated under given load situations versus time. In comparing these time-dependent failure probabilities with a given permissible failure probability, the maximum operation time of a component can be determined. The considerable influence of the subcritical crack growth upon the lifetime of ceramic components is demonstrated at the flame tube segments of the ITS ceramic combustor.
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Yang, Li, Wubin Weng, Yanqun Zhu, Yong He, Zhihua Wang, and Zhongshan Li. "Investigation of Hydrogen Content and Dilution Effect on Syngas/Air Premixed Turbulent Flame Using OH Planar Laser-Induced Fluorescence." Processes 9, no. 11 (October 23, 2021): 1894. http://dx.doi.org/10.3390/pr9111894.
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Syngas produced by gasification, which contains a high hydrogen content, has significant potential. The variation in the hydrogen content and dilution combustion are effective means to improve the steady combustion of syngas and reduce NOx emissions. OH planar laser-induced fluorescence technology (OH-PLIF) was applied in the present investigation of the turbulence of a premixed flame of syngas with varied compositions of H2/CO. The flame front structure and turbulent flame velocities of syngas with varied compositions and turbulent intensities were analyzed and calculated. Results showed that the trend in the turbulent flame speed with different hydrogen proportions and dilutions was similar to that of the laminar flame speed of the corresponding syngas. A higher hydrogen proportion induced a higher turbulent flame speed, higher OH concentration, and a smaller flame. Dilution had the opposite effect. Increasing the Reynolds number also increased the turbulent flame speed and OH concentration. In addition, the effect of the turbulence on the combustion of syngas was independent of the composition of syngas after the analysis of the ratio between the turbulent flame speed and the corresponding laminar flame speed, for the turbulent flames under low turbulent intensity. These research results provide a theoretical basis for the practical application of syngas with a complex composition in gas turbine power generation.
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Торба, Юрий Иванович, Дмитрий Викторович Павленко, and Ярослав Викторович Двирник. "ОПТИМІЗАЦІЯ КОНСТРУКЦІЇ ФАКЕЛЬНОГО ЗАПАЛЬНИКА ГТД ЧИСЕЛЬНИМ МЕТОДОМ." Aerospace technic and technology, no. 5 (August 29, 2020): 83–95. http://dx.doi.org/10.32620/aktt.2020.5.11.
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Solved the problem of gas-turbine engine combustion chamber flame igniter efficiency increasing by increasing the flame temperature via optimizing the body design. To determine the influence of the igniter body various geometric parameters, affecting the formation and combustion of the fuel-air mixture, a parametric model was developed. This model together with the developed project in the ANSYS Workbench software package made it possible to automate the modeling process. The influence of the geometric parameters of the igniter body and external factors on the average flame temperature has been studied via a numerical model of the stationary combustion process of the air-fuel mixture formed inside the igniter of the combustion chamber of a gas turbine engine by evaporation and spraying particles of aviation kerosene in the air stream. The adequacy of the numerical simulation results was confirmed by the implementation of a series of full-scale experiments using the Fisher criterion.The uniformity of temperature and adequacy of the average temperature estimation algorithm was established using the correlation analysis of the results of measured temperature at various points of the flame. To determine the degree and nature of their influence, sequentially screening (fractional), as well as full-factor experiments with varying factors at two and three levels were implemented. Based on the results of the analysis of variance, the most statistically significant factors were selected. A regression dependence was established that relates the diameter of the air inlet orifice and the air pressure drop to the flame temperature. A qualitative and quantitative assessment of the influence of the considered factors on the process of formation of a hot air mixture and its combustion has been performed. The optimal values of the geometric parameters of the igniter body and its operating conditions are determined under which the maximum flame temperature at the stationary combustion stage is ensured. Relationships between design features, igniter operation mode, and the temperature of the flame are established. This allows expanding the range of stable ignition of gas turbine engine combustion chambers in accordance with the design of the igniter, the starting fuel supply mode, and the air pressure drop.
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Serbin, Serhiy, Badri Diasamidze, and Marek Dzida. "Investigations of the Working Process in a Dual-Fuel Low-Emission Combustion Chamber for an FPSO Gas Turbine Engine." Polish Maritime Research 27, no. 3 (September 1, 2020): 89–99. http://dx.doi.org/10.2478/pomr-2020-0050.
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AbstractThis investigation is devoted to an analysis of the working process in a dual-fuel low-emission combustion chamber for a floating vessel’s gas turbine. The low-emission gas turbine combustion chamber with partial pre-mixing of fuel and air inside the outer and inner radial-axial swirlers was chosen as the object of research. When modelling processes in a dual-flow low-emission gas turbine combustion chamber, a generalized method is used, based on the numerical solution of the system of conservation and transport equations for a multi-component chemically reactive turbulent system, taking into consideration nitrogen oxides formation. The Eddy-Dissipation-Concept model, which incorporates Arrhenius chemical kinetics in a turbulent flame, and the Discrete Phase Model describing the interfacial interaction are used in the investigation. The obtained results confirmed the possibility of organizing efficient combustion of distillate liquid fuel in a low-emission gas turbine combustion chamber operating on the principle of partial preliminary formation of a fuel-air mixture. Comparison of four methods of liquid fuel supply to the channels of radial-axial swirlers (centrifugal, axial, combined, and radial) revealed the advantages of the radial supply method, which are manifested in a decrease in the overall temperature field non-uniformity at the outlet and a decrease in nitrogen oxides emissions. The calculated concentrations of nitrogen oxides and carbon monoxide at the flame tube outlet for the radial method of fuel supply are 32 and 9.1 ppm, respectively. The results can be useful for further modification and improvement of the characteristics of dual-fuel gas turbine combustion chambers operating with both gaseous and liquid fuels.
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Mangra, A. C. "Design and Numerical Analysis of a Micro Gas Turbine Combustion Chamber." Engineering, Technology & Applied Science Research 10, no. 6 (December 20, 2020): 6422–26. http://dx.doi.org/10.48084/etasr.3835.
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The interest in micro gas turbines has been steadily increasing. As a result, attention has been focused on obtaining optimal configurations for micro gas turbines depending on the applications in which they are used. This paper presents the CFD modeling results regarding an annular type combustion chamber, part of an 800N micro gas turbine, predestined to equip a small scale multifunctional airplane. Two configurations have been taken into consideration and 3D RANS numerical simulations have been conducted with the use of the commercial software ANSYS CFX. The liquid fuel droplets were modeled by the particle transport model, which tracks the particles in a Lagrangian way. An initial fuel droplet diameter of 500µm has been imposed. The numerical results obtained are encouraging. The flame was developed in the central area of the fire tube, its walls thus not being subjected to high temperatures. Also, the maximum temperatures were obtained in the primary zone of the fire tube. The temperature then decreased in the fire tube's secondary zone and dilution zone. The numerical results will be validated by conducting combustion tests on a testing rig which will be developed inside the institute's Combustion Chamber Laboratory.
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Matyunin, O. O., S. K. Arkhipov, A. A. Shilova, N. L. Bachev, and R. V. Bulbovich. "Analysis of the combustion characteristics of hydrogen and hydrocarbon fuels based on the results of numerical simulation." Problems of the Regional Energetics, no. 3(55) (August 2022): 54–67. http://dx.doi.org/10.52254/1857-0070.2022.3-55.05.
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At present, an upward trend in the field of studying the processes of hydrogen combustion in the combustion chambers of the ground-based gas turbine power plants is obvious. The use of pure hydrogen as a fuel gas would solve the problem of environmental decarbonization. One of the emerging problems is to ensure the stable combustion of such fuels in combustion chambers of various applications. The information-analytical review of studies showed that there is a large number of theoretical and experimental results on the diffusion and homogeneous combustion of hydrogen and hydrogen-containing fuels in various burners and combustion chambers, which are not part of the existing gas turbine power plants. The purpose of this work is a comparative analysis of the gas-dynamic and emission characteristics of the combustion of the hydrogen-air and methane-air components based on the results of numerical simulation of a convertible combustion chamber of a 75 kW microgas turbine power plant. This goal is achieved by numerical simulation of the diffusion combustion of hydrogen and methane with air in a convertible combustion chamber. The most significant result of the work is obtaining the isosurface of the flame, which made it possible to obtain the conditions for stable combustion in the form of the Damköhler criterion and the ratio of the midsection velocity to the velocity of turbulent combustion. The significance of the results obtained lies in the further development of the methodology for the conversion of megawatt-class gas turbine plants to hydrogen and hydrogencontaining fuels.
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Benim, Ali Cemal, Sohail Iqbal, Franz Joos, and Alexander Wiedermann. "Numerical Analysis of Turbulent Combustion in a Model Swirl Gas Turbine Combustor." Journal of Combustion 2016 (2016): 1–12. http://dx.doi.org/10.1155/2016/2572035.
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Turbulent reacting flows in a generic swirl gas turbine combustor are investigated numerically. Turbulence is modelled by a URANS formulation in combination with the SST turbulence model, as the basic modelling approach. For comparison, URANS is applied also in combination with the RSM turbulence model to one of the investigated cases. For this case, LES is also used for turbulence modelling. For modelling turbulence-chemistry interaction, a laminar flamelet model is used, which is based on the mixture fraction and the reaction progress variable. This model is implemented in the open source CFD code OpenFOAM, which has been used as the basis for the present investigation. For validation purposes, predictions are compared with the measurements for a natural gas flame with external flue gas recirculation. A good agreement with the experimental data is observed. Subsequently, the numerical study is extended to syngas, for comparing its combustion behavior with that of natural gas. Here, the analysis is carried out for cases without external flue gas recirculation. The computational model is observed to provide a fair prediction of the experimental data and predict the increased flashback propensity of syngas.
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Chiariello, Fabio, Fabrizio Reale, Raffaela Calabria, and Patrizio Massoli. "Off Design Behavior of a 100kW Turbec T100P Micro Gas Turbine." Applied Mechanics and Materials 390 (August 2013): 275–80. http://dx.doi.org/10.4028/www.scientific.net/amm.390.275.
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The off design behavior of a 100kW Turbec T100P micro gas turbine fuelled with methane is analyzed in the paper. The work is focused on the analysis of combustion efficiency, overall performance and gaseous emissions at different loads. A critical comparison between experimental data and results of a 3D CFD analysis of the combustor is discussed. The RANS RSM turbulence model is used in the numerical computations. The Zeldovich mechanism for NO formation evaluation is coupled to a methane-oxygen multistep chemical kinetic mechanism for predicting the concentration of O2, CO2, CO and NO at the exhaust. The experimental campaign showed no sensible variations in NOxemissions by varying MGT load; otherwise a great CO increasing is highlighted by load decreasing. The results of numerical analysis are in good agreement with experimental data as concerns CO emissions, while overestimate NO production in the diffusive flame region at 50% load.
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Bhargava, Anuj, Med Colket, William Sowa, Kent Casleton, and Dan Maloney. "An Experimental and Modeling Study of Humid Air Premixed Flames." Journal of Engineering for Gas Turbines and Power 122, no. 3 (May 15, 2000): 405–11. http://dx.doi.org/10.1115/1.1286921.
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An experimental and modeling study has been performed jointly by UTRC and DOE-FETC to determine the effect of humidity in the combustion air on emissions and stability limits of gas turbine premixed flames. This study focuses on developing gas turbine combustor design criteria for the Humid Air Turbine (HAT) cycle. The experiments were conducted at different moisture levels (0 percent, 5 percent, 10 percent, and 15 percent by mass in the air), at a total pressure of 200 psi, pilot levels (0 percent, 1 percent, 3 percent, and 5 percent total fuel), and equivalence ratio (0.4 to 0.8 depending on the moisture levels). The moisture levels were achieved by injecting steam into dry air well upstream of the fuel-air premixing nozzle. Computations were made for comparison to the experiments using GRI Mech 2.11 kinetics and thermodynamic database for modeling the flame chemistry. A Perfectly Stirred Reactor (PSR) network code was used to create a network of PSRs to simulate the flame. Excellent agreement between the measured and modeled NOx (5–10 percent) was obtained. Trends of added moisture reducing NOx and the effects of equivalence ratio and piloting level were well predicted. The CO predictions were higher by about 30–50 percent. The CO discrepancies are attributed to in-probe oxidation. The agreement between the data and model predictions over a wide range of conditions indicate the consistency and reliability of the measured data and usefulness of the modeling approach. An analysis of NOx formation revealed that at constant equilibrium temperature, Teq, the presence of steam leads to lower O-atom concentration which reduces “Zeldovich and N2O” NOx while higher OH-atom concentration reduces “Fenimore” NOx.[S0742-4795(00)00703-1]
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Gounder, J. D., I. Boxx, P. Kutne, S. Wysocki, and F. Biagioli. "Phase Resolved Analysis of Flame Structure in Lean Premixed Swirl Flames of a Fuel Staged Gas Turbine Model Combustor." Combustion Science and Technology 186, no. 4-5 (April 23, 2014): 421–34. http://dx.doi.org/10.1080/00102202.2014.883204.
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Hossain, Mohammad A., Ahsan Choudhuri, and Norman Love. "Design of an optically accessible turbulent combustion system." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 233, no. 1 (February 8, 2018): 336–49. http://dx.doi.org/10.1177/0954406218757565.
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In order to design the next generation of gas turbine combustors and rocket engines, understanding the flame structure at high-intensity turbulent flows is necessary. Many experimental studies have focused on flame structures at relatively low Reynolds and Damköhler numbers, which are useful but do not help to provide a deep understanding of flame behavior at gas turbine and rocket engine operating conditions. The current work is focused on the presentation of the design and development of a high-intensity (Tu = 15–30%) turbulent combustion system, which is operated at compressible flow regime from Mach numbers of 0.3 to 0.5, preheated temperatures up to 500 K, and premixed conditions in order to investigate the flame structure at high Reynolds and Damköhler numbers in the so-called thickened flame regime. The design of an optically accessible backward-facing step stabilized combustor was designed for a maximum operating pressure of 0.6 MPa. Turbulence generator grid was introduced with different blockage ratios from 54 to 67% to generate turbulence inside the combustor. Optical access was provided via quartz windows on three sides of the combustion chamber. Extensive finite element analysis was performed to verify the structural integrity of the combustor at rated conditions. In order to increase the inlet temperature of the air, a heating section is designed and presented in this paper. Separate cooling subsystem designs are also presented. A 10 kHz time-resolved particle image velocimetry system and a 3 kHz planer laser-induced fluorescence system are integrated with the system to diagnose the flow field and the flame, respectively. The combustor utilizes a UNS 316 stainless steel with a minimum wall thickness of 12.5 mm. Quartz windows were designed with a maximum thickness of 25.4 mm resulting in an overall factor of safety of 3.5.
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Sturgess, G. J., and D. Shouse. "Lean Blowout Research in a Generic Gas Turbine Combustor With High Optical Access." Journal of Engineering for Gas Turbines and Power 119, no. 1 (January 1, 1997): 108–18. http://dx.doi.org/10.1115/1.2815533.
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The U. S. Air Force is conducting a comprehensive research program aimed at improving the design and analysis capabilities for flame stability and lean blowout in the combustors of aircraft gas turbine engines. As part of this program, a simplified version of a generic gas turbine combustor is used. The intent is to provide an experimental data base against which lean blowout modeling might be evaluated and calibrated. The design features of the combustor and its instrumentation are highlighted, and the test facility is described. Lean blowout results for gaseous propane fuel are presented over a range of operating conditions at three different dome flow splits. Comparison of results with those of a simplified research combustor is also made. Lean blowout behavior is complex, so that simple phenomenological correlations of experimental data will not be general enough for use as design tools.
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Giuliani, Fabrice, Lukas Andracher, Vanessa Moosbrugger, Nina Paulitsch, and Andrea Hofer. "Combined Optic-Acoustic Monitoring of Combustion in a Gas Turbine." International Journal of Turbomachinery, Propulsion and Power 5, no. 3 (July 6, 2020): 15. http://dx.doi.org/10.3390/ijtpp5030015.
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The need for better combustion monitoring in gas turbines has become more acute with the latest technical requirements, standards, and policies in terms of safety, environment, efficiency, operation flexibility, and operation costs. Combustion Bay One e.U. and FH JOANNEUM GmbH initiated in 2015 an experimental research program about the feasibility and first assessments of placing optical systems near the combustor. The project’s acronym “emootion” stands for “Engine health MOnitOring and refined combusTION control based on optical diagnostic techniques embedded in the combustor”. The motivation of the project is twofold. On one side, one wants to exploit the radiative feature of the flame and to transform it into a piece of reliable information about the combustion status. On the other side, this information can be useful in terms of data interpretation or data reconciliation with other information coming from other sensors such as temperature probes, fast pressure probes, or accelerometers. The focus is put on several aspects of combustor operations: on detection of the flame, on monitoring of the ignition process, on a quality assessment of combustion based on its spectral contents (including soot formation), and on the detection of possible combustion instabilities. Promising results were obtained using photodiodes that offer an adequate trade-off between narrow-band sensitivity and signal time response. It is shown that it is convenient to combine a fast-pressure sensor with an optical sensor in a compact form; this combination has led to the so-called Rayleigh Criterion Probe (RCP). The split in red, green, and blue (RGB) light components and their further analysis allows for mapping the different types of operation. Regarding the probe packaging aspect, it is discussed that the level of light collection needed to keep an acceptable signal-to-noise ratio has been so far a restraint for the use of optical fibres. Solutions are proposed to bring the optical sensor as close as possible to the optical interface and to make it operational and reliable in prevailing heat. This contribution closes with a description of the pressure tests in a new combustion facility built for this purpose. A compact and portable combustion monitoring system including at least 3 RCPs can become an instrumentation standard within the next decade.
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Ammar, Nader R., and Ahmed I. Farag. "CFD Modeling of Syngas Combustion and Emissions for Marine Gas Turbine Applications." Polish Maritime Research 23, no. 3 (September 1, 2016): 39–49. http://dx.doi.org/10.1515/pomr-2016-0030.
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Abstract Strong restrictions on emissions from marine power plants will probably be adopted in the near future. One of the measures which can be considered to reduce exhaust gases emissions is the use of alternative fuels. Synthesis gases are considered competitive renewable gaseous fuels which can be used in marine gas turbines for both propulsion and electric power generation on ships. The paper analyses combustion and emission characteristics of syngas fuel in marine gas turbines. Syngas fuel is burned in a gas turbine can combustor. The gas turbine can combustor with swirl is designed to burn the fuel efficiently and reduce the emissions. The analysis is performed numerically using the computational fluid dynamics code ANSYS FLUENT. Different operating conditions are considered within the numerical runs. The obtained numerical results are compared with experimental data and satisfactory agreement is obtained. The effect of syngas fuel composition and the swirl number values on temperature contours, and exhaust gas species concentrations are presented in this paper. The results show an increase of peak flame temperature for the syngas compared to natural gas fuel combustion at the same operating conditions while the NO emission becomes lower. In addition, lower CO2 emissions and increased CO emissions at the combustor exit are obtained for the syngas, compared to the natural gas fuel.
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Swain, Daniel, and S. O. Bade Shrestha. "CFD Performance Analysis of a Spark Ignition Engine Fueled by Landfill Gas." Open Fuels & Energy Science Journal 7, no. 1 (April 18, 2014): 26–33. http://dx.doi.org/10.2174/1876973x01407010026.
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Landfill gas (LFG) that is generated in an anaerobic environment in landfills and consists primarily of methane and carbondioxide with small amount of nitrogen and other non-methane gases, could be collected and used to produce energy either by extracting methane or using the landfill gas directly in an internal combustion engine or a gas turbine. It amounts to be a net-negative greenhouse gas emission process. Carbondioxide component of LFG dilutes the fuel and absorbs some of the heat of combustion, causing reduced flame temperature that decreases NOx emissions and also suppresses knock. A model was developed and validated with the experimental data available in literature, using the computation fluid dynamic (CFD) code, KIVA-4. Various engine performance parameters at various operating conditions were evaluated and the benefits of methane purification and or direct use of LFG as a fuel in the engine scenarios were compared. It was found that landfill gas used directly at higher compression ratios can be used for pure methane fuel with higher fuel efficiency than can be achieved using pure methane fuel only.
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Yoon, Jisu, Min-Chul Lee, Seongpil Joo, Jeongjin Kim, and Youngbin Yoon. "Instability mode and flame structure analysis of various fuel compositions in a model gas turbine combustor." Journal of Mechanical Science and Technology 29, no. 3 (March 2015): 899–907. http://dx.doi.org/10.1007/s12206-015-0203-1.
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Liu, Yize, Theoklis Nikolaidis, Seyed Hossein Madani, Mohammad Sarkandi, Abdelaziz Gamil, Muhamad Firdaus Sainal, and Seyed Vahid Hosseini. "Multi-Fidelity Combustor Design and Experimental Test for a Micro Gas Turbine System." Energies 15, no. 7 (March 23, 2022): 2342. http://dx.doi.org/10.3390/en15072342.
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A multi-fidelity micro combustor design approach is developed for a small-scale combined heat and power CHP system. The approach is characterised by the coupling of the developed preliminary design model using the combined method of 3D high-fidelity modelling and experimental testing. The integrated multi-physics schemes and their underlying interactions are initially provided. During the preliminary design phase, the rapid design exploration is achieved by the coupled reduced-order models, where the details of the combustion chamber layout, flow distributions, and burner geometry are defined as well as basic combustor performance. The high-fidelity modelling approach is then followed to provide insights into detailed flow and emission physics, which explores the effect of design parameters and optimises the design. The combustor is then fabricated and assembled in the MGT test bench. The experimental test is performed and indicates that the designed combustor is successfully implemented in the MGT system. The multi-physics models are then verified and validated against the test data. The details of refinement on lower-order models are given based on the insights acquired by high-fidelity methods. The shortage of conventional fossil fuels and the continued demand for energy supplies have led to the development of a micro-turbine system running renewable fuels. Numerical analysis is then carried out to assess the potential operation of biogas in terms of emission and performance. It produces less NOx emission but presents a flame stabilisation design challenge at lower methane content. The details of the strategy to address the flame stabilisation are also provided.
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Brandauer, M., A. Schulz, and S. Wittig. "Mechanisms of Coke Formation in Gas Turbine Combustion Chambers." Journal of Engineering for Gas Turbines and Power 118, no. 2 (April 1, 1996): 265–70. http://dx.doi.org/10.1115/1.2816587.
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New gas turbine combustor designs are developed to reduce pollutant and NOx emissions. In these new combustors, the formation of carbonaceous deposits, especially in prevaporizers, affects the reliability and effectiveness of operation. To avoid deposits, a detailed knowledge of the origins and mechanisms of formation is required. To obtain a deeper insight, the phenomena were studied systematically. The deposits under consideration show differing characteristics suggesting more than one formation mechanism in the combustor. Consequently, the primary goal was to identify the formation mechanisms and, subsequently, to simulate the mechanisms under well-defined conditions in bench tests for determining the relevant parameters of deposit build-up. The mechanisms of formation were identified based on the properties of the deposits in the combustion chamber. In order to characterize the deposits, physical and chemical analysis techniques were utilized. In summary, tests and numerical predictions identified two major paths of formation: a deposit build-up resulting from flame products such as soot or coked droplets and a deposit build-up resulting from liquid fuel impinging the wall accompanied with chemical reactions at the wall. The deposits caused by fuel droplet impingement were intensively studied in bench tests. In analyzing the processes, the influence of wall temperature, fuel composition, and the oxygen content in the environment is shown in detail. In addition, the importance of thermal instabilities of the fuel, previously studied under fuel supply system conditions, is demonstrated for a deposit formation inside a combustion chamber.
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Li, Xu, and Kai Liu. "Study of an Experiment System and Flow Measurement of Group Nozzles in a Heavy-Duty Gas Turbine." Applied Mechanics and Materials 66-68 (July 2011): 311–14. http://dx.doi.org/10.4028/www.scientific.net/amm.66-68.311.
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Study of experiment system and experimental investigation results of the group nozzles in a heavy-duty gas turbine are expatiated. In order to measure gas flows of every flow branch in the group nozzles, flow meter of type SH-1 is specifically developed, The measure system, control system, data display system, data acquisition analysis system subtly combine, the SH-1 gas flow test equipment and these measured flows data are precise, stable, good reproducibility, the errors of the measuring are less 0.5%. Using SH-1 flow meter, gas flows of Ⅲ,Ⅳ,Ⅴbranches are precisely measured, the combustion testing of the group nozzles in the flame tube is made, its performance is satisfied with the design requirements, these demonstrate: the testing results by using SH-1 flowmeter are reliable, stable.
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Behrendt, T., and Ch Hassa. "A test rig for investigations of gas turbine combustor cooling concepts under realistic operating conditions." Proceedings of the Institution of Mechanical Engineers, Part G: Journal of Aerospace Engineering 222, no. 2 (February 1, 2008): 169–77. http://dx.doi.org/10.1243/09544100jaero288.
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In the current paper, a new test rig for the characterization of advanced combustor cooling concepts for gas turbine combustors is presented. The test rig is designed to allow investigations at elevated pressures and temperatures representing realistic operating conditions of future lean low emission combustors. The features and capabilities of the test rig in comparison to existing rigs are described. The properties of the hot gas flow are measured in order to provide the necessary data for a detailed analysis of the measured cooling effectivity of combustor wall test samples. Results of the characterization of the velocity and temperature distribution in the hot gas flow at the leading edge of the test sample at pressures up to p = 10 bar and global flame temperatures up to TF = 2000 K are presented.
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Yurievich Orlov, Michael, Oleg Vladimirovich Kolomzarov, Vladislav Mikhailovich Anisimov, Nikita Igorevich Gurakov, and Nikolai Sergeevich Mironov. "The advisability of using combustion chambers with a toroidal recirculation-mixing zone in small-sized gas turbine engines." MATEC Web of Conferences 209 (2018): 00019. http://dx.doi.org/10.1051/matecconf/201820900019.
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The interrelations between the size of the gas turbine engine (GTE) and the size and workflow of the combustion chamber (CC) were considered. On the base of analysis of workflow organization the design of CC with toroidal recirculation mixing zone was proposed. The theoretical justification of chosen design was carried out on the base of comparison of combustion volumes, which formed in traditional CC with swirlers and in proposed CC. The comparison of combustion volumes, schematic display of combustion zones with a discrete flame and a combined combustion zone were given.
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Barwey, Shivam, Malik Hassanaly, Qiang An, Venkat Raman, and Adam Steinberg. "Experimental data-based reduced-order model for analysis and prediction of flame transition in gas turbine combustors." Combustion Theory and Modelling 23, no. 6 (April 9, 2019): 994–1020. http://dx.doi.org/10.1080/13647830.2019.1602286.
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Bohn, D., G. Deutsch, and U. Kru¨ger. "Numerical Predication of the Dynamic Behavior of Turbulent Diffusion Flames." Journal of Engineering for Gas Turbines and Power 120, no. 4 (October 1, 1998): 713–20. http://dx.doi.org/10.1115/1.2818458.
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Environmental compatibility requires low-emission burners for gas turbine power plants as well as for jet engines. In the Past, significant progress has been made developing low NOx and CO burners. Unfortunately, these burners often have a more pronounced tendency than conventional burner designs to produce combustion driven oscillations. The oscillations may be excited to such an extent that pronounced pulsation may possibly occur; this is associated with a risk of engine failure. The stability of a burner system can be investigated by means of a stability analysis under the assumption of acoustical behavior. The problem with all these algorithms is the transfer function of the flame. A new method is presented here to predict the dynamic flame behavior by means of a full Navier-Stokes simulation of the complex combustion process. The first step is to get a steady-state solution of a flame configuration. After that a transient simulation follows with a sudden change in the mass flow rate at the flame inlet. The time-dependent answer of the flame to this disturbance is then transformed into the frequency space by a Laplace Transformation. This leads, in turn, to the frequency response representing the dynamic behavior of the flame. In principle, this method can be adapted for both diffusion as well as premixed flame systems. However, due to the fact that diffusion flames are more controlled by the mixing process than by the chemical kinetic, the method has first been used for the prediction of the dynamic behavior of turbulent diffusion flames. The combustion has been modelled by a mixed-is-burnt model. The influence of the turbulence has been taken into account by a modified k-ε model and the turbulence influences the combustion rate by presumed probability density functions (pdf). The steady state as well as the transient results have been compared with experimental data for two different diffusion flame configurations. Although the burner configuration is relatively complex, the steady-state results collaborate very well with the experiments for velocity, temperature, and species distribution. The most important result is that the heat release that drives the oscillations can be modeled sufficiently accurately. The effect of using different pdf models has been discussed and the best model has been used for the transient calculations of the dynamic flame behavior. The results for the frequency response of the flame are very encouraging. The principal behavior of the flame—higher order time element with a delay time—can be predicted with sufficient precision. In addition, the qualitative results collaborate fairly well with the experiments.
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Serbin, Serhiy, Badri Diasamidze, Viktor Gorbov, and Jerzy Kowalski. "Investigations of the Emission Characteristics of a Dual-Fuel Gas Turbine Combustion Chamber Operating Simultaneously on Liquid and Gaseous Fuels." Polish Maritime Research 28, no. 2 (June 1, 2021): 85–95. http://dx.doi.org/10.2478/pomr-2021-0025.
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Abstract This study is dedicated to investigations of the working process in a dual-fuel low-emission combustion chamber for a floating vessel’s gas turbine. As the object of the research, a low-emission gas turbine combustion chamber with partial premixing of fuel and air inside the outer and inner radial-axial swirls was chosen. The method of the research is based on the numerical solution of the system of differential equations which represent the physical process of mass and energy conservation and transformations and species transport for a multi-component chemically reactive turbulent system, considering nitrogen oxides formation and a discrete ordinates model of radiation. The chemistry kinetics is presented by the 6-step mechanism of combustion. Seven fuel supply operating modes, varying from 100% gaseous fuel to 100% liquid fuel, have been analysed. This analysis has revealed the possibility of the application of computational fluid dynamics for problems of dual-fuel combustion chambers for the design of a floating vessel’s gas turbine. Moreover, the study has shown the possibility of working in different transitional gaseous and liquid fuel supply modes, as they satisfy modern ecological requirements. The dependencies of the averaged temperature, NO, and CO concentrations along the length of the low-emission gas turbine combustion chamber for different cases of fuel supply are presented. Depending on the different operating modes, the calculated emission of nitrogen oxides NO and carbon monoxide CO at the outlet cross-section of a flame tube are different, but, they lie in the ranges of 31‒50 and 23‒24 mg/nm3 on the peak of 100% liquid fuel supply mode. At operating modes where a gaseous fuel supply prevails, nitrogen oxide NO and carbon monoxide CO emissions lie in the ranges of 1.2‒4.0 and 0.04‒18 mg/nm3 respectively.
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Surya Narayanan, Subramanian, and Parammasivam K.M. "A review of computational studies on trapped vortex combustors for gas turbine applications." Aircraft Engineering and Aerospace Technology 95, no. 4 (October 20, 2022): 658–67. http://dx.doi.org/10.1108/aeat-12-2021-0366.
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Purpose The purpose of this paper is to comprehensively evaluate the progress in the development of trapped vortex combustors (TVCs) in the past three decades. The review aims to identify the needs, predict the scope and discuss the challenges of numerical simulations in TVCs applied to gas turbines. Design/methodology/approach TVC is an emerging combustion technology for achieving low emissions in gas turbine combustors. The overall operation of such TVCs can be on very lean mixture ratio and hence it helps in achieving high combustion efficiency and low overall emission levels. This review introduces the TVC concept and the evolution of this technology in the past three decades. Various geometries that were explored in TVC research are listed and their operating principles are explained. The review then categorically arranges the progress in computational studies applied to TVCs. Findings Analyzing extensive literature on TVCs the review discusses results of numerical simulations of various TVC geometries. Numerical simulations that were used to optimize TVC geometry and to enhance mixing are discussed. Reactive flow studies to comprehend flame stability and emission characteristics are then listed for different TVC geometries. Originality/value To the best of the authors’ knowledge, this review is the first of its kind to discuss extensively the computational progress in TVC development specific to gas turbine engines. Earlier review on TVC covers a wide variety of applications including land-based gas turbines, supersonic Ramjets, incinerators and hence compromise on the depth of analysis given to gas turbine engine applications. This review also comprehensively group the numerical studies based on geometry, flow and operating conditions.
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Asaad, Abdullah Abdalrazaq, and Munther A. Mussa. "An experimental and numerical investigation of heat transfer effect on cyclic fatigue of gas turbine blade." Journal of Engineering 25, no. 7 (June 30, 2019): 61–82. http://dx.doi.org/10.31026/j.eng.2019.07.04.
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Blades of gas turbine are usually suffered from high thermal cyclic load which leads to crack initiated and then crack growth and finally failure. The high thermal cyclic load is usually coming from high temperature, high pressure, start-up, shut-down and load change. An experimental and numerical analysis was carried out on the real blade and model of blade to simulate the real condition in gas turbine. The pressure, temperature distribution, stress intensity factor and the thermal stress in model of blade have been investigated numerically using ANSYS V.17 software. The experimental works were carried out using a particular designed and manufactured rig to simulate the real condition that blade suffers from. A new controlled method in this rig was suggested to heating the specimen depending on Oxygen-gas flame. The numerical result shows that the temperature distribution over the blade varying with the load change, which leads to increase the stress intensity factor along the crack. The experimental result indicates that the rate of crack propagation varying with the position of crack and with the angle of inclined. Based on this result, more effective cracks on the blade were satisfied which are highly effect the blade lifetime.
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Giuliani, Fabrice, Markus Stütz, Nina Paulitsch, and Lukas Andracher. "Forcing Pulsations by Means of a Siren for Gas Turbine Applications." International Journal of Turbomachinery, Propulsion and Power 5, no. 2 (May 13, 2020): 9. http://dx.doi.org/10.3390/ijtpp5020009.
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A siren is a robust fast-valve that generates effective flow pulsations and powerful noise levels under well-controlled conditions. It operates under the inlet flow conditions of a gas turbine combustor. Its principle is based on a sonic air jet periodically sheared by a cogged wheel rotating at a given speed. It is used as an alternative to loudspeakers in combustion laboratories when the use of these is made difficult by aggressive flow conditions, such as hot air under pressure, possibly containing impurities. It is also a serious candidate as an effective flow actuator to be deployed on power gas turbine fleets. The authors have gathered more than twenty years of knowledge on siren technology. This pulsator was originally developed for research on thermoacoustics. By scanning through a given frequency range, one detects the acoustic resonance of specific parts of the combustor assembly, or possibly triggers a combustion instability during a sensitivity analysis of a flame to small perturbations. In 2010, Giuliani et al. developed a novel siren model with the capacity to vary the amplitude of pulsation independently from the frequency. In this contribution, the physics, the metrics, and the resulting parameters of the pulsator are discussed. Technical solutions are unveiled about visiting large frequency ranges (currently 6 kHz) and achieving elevated pressure fluctuations (150 dB SPL proven, possibly up to 155 dB SPL) with a compact device. A multimodal excitation is available with this technology, one idea being to dissipate the acoustic energy on nearby peaks. The contribution ends with a summary of the applications performed so far and the perspective of an industrial application.
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Ax, Holger, Ulrich Stopper, Wolfgang Meier, Manfred Aigner, and Felix Güthe. "Experimental Analysis of the Combustion Behavior of a Gas Turbine Burner by Laser Measurement Techniques." Journal of Engineering for Gas Turbines and Power 132, no. 5 (March 5, 2010). http://dx.doi.org/10.1115/1.3205033.
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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.
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De Rosa, Alexander J., Janith Samarasinghe, Stephen J. Peluso, Bryan D. Quay, and Domenic A. Santavicca. "Flame Area Fluctuation Measurements in Velocity-Forced Premixed Gas Turbine Flames." Journal of Engineering for Gas Turbines and Power 138, no. 4 (October 28, 2015). http://dx.doi.org/10.1115/1.4031708.
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Fluctuations in the heat release rate that occur during unstable combustion in lean-premixed gas turbine combustors can be attributed to velocity and equivalence ratio fluctuations. For a fully premixed flame, velocity fluctuations affect the heat release rate primarily by inducing changes in the flame area. In this paper, a technique to analyze changes in the flame area using chemiluminescence-based flame images is presented. The technique decomposes the flame area into separate components which characterize the relative contributions of area fluctuations in the large-scale structure and the small-scale wrinkling of the flame. The fluctuation in the wrinkled area of the flame which forms the flame brush is seen to dominate its response in the majority of cases tested. Analysis of the flame area associated with the large-scale structure of the flame resolves convective perturbations that move along the mean flame position. Results are presented that demonstrate the application of this technique to both single-nozzle and multi-nozzle flames.
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Rashwan, Sherif S., Bassel Abdelkader, Ahmed Abdalmonem, Tharwat W. Abou-Arab, Medhat A. Nemitallah, Mohamed A. Habib, and Abdelmaged H. Ibrahim. "Experimental and Statistical ANOVA Analysis on Combustion Stability of CH4/O2/CO2 in a Partially Premixed Gas Turbine Combustor." Journal of Energy Resources Technology 144, no. 6 (August 4, 2021). http://dx.doi.org/10.1115/1.4051755.
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Abstract The application of the oxy-fuel combustion technique could tackle the combustion process's environmental issues. Experiments were conducted on partially premixed air- and oxy-methane combustion flames stabilized over a novel perforated burner in the present work. The burner has a premixing ratio of 7.0. In oxy-fuel combustion, the experiments were performed at oxygen fractions (OF%: volumetric percentage of O2 in the oxidizer mixture) of 29%, 32%, and 36% and over a range of operating conditions necessary for a stable flame. The results of oxy-combustion flames were compared with the corresponding air-combustion flames at the same operating conditions. Two sets of statistical analyses were performed for further confirmation of the experimental results. The first set investigated the operating parameters’ effect, including OF and oxidizer Reynolds number (Re), on the upper flammability limits (UFL). Simultaneously, the second set studied the impact of OF and equivalence ratio on flame length. The experimental results revealed that the flammability limits get wider as the OF increases due to the resulting flame speed rise with O2-enrichment. The statistical analysis is conducted by analysis of variance (ANOVA) technique, which carries innovation and confirms that OF and Re significantly impacted the UFL. The visual flame length of oxy-flames was longer than its correspondents of air-flames due to the reduction of flame speed associated with the negative influence of CO2 dilution in oxy-flames. The statistical analysis showed a significant effect of OF and equivalence ratio on the visible flame appearance.
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Lellek, Stephan, and Thomas Sattelmayer. "NOx-Formation and CO-Burnout in Water-Injected, Premixed Natural Gas Flames at Typical Gas Turbine Combustor Residence Times." Journal of Engineering for Gas Turbines and Power 140, no. 5 (December 19, 2017). http://dx.doi.org/10.1115/1.4038239.
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With the transition of the power production markets toward renewable energy sources, an increased demand for flexible, fossil-based power production systems arises. Steep load gradients and a high range of flexibility make gas turbines a core technology in this ongoing change. In order to further increase this flexibility research on power augmentation of premixed gas turbine combustors is conducted at the Lehrstuhl für Thermodynamik, TU München. Water injection in gas turbine combustors allows for the simultaneous control of NOx emissions as well as the increase of the power output of the engine and has therefore been transferred to a premixed combustor at lab scale. So far stable operation of the system has been obtained for water-to-fuel ratios up to 2.25 at constant adiabatic flame temperatures. This paper focuses on the effects of water injection on pollutant formation in premixed gas turbine flames. In order to guarantee for high practical relevance, experimental measurements are conducted at typical preheating temperatures and common gas turbine combustor residence times of about 20 ms. Spatially resolved and global species measurements are performed in an atmospheric single burner test rig for typical adiabatic flame temperatures between 1740 and 2086 K. Global measurements of NOx and CO emissions are shown for a wide range of equivalence ratios and variable water-to-fuel ratios. Cantera calculations are used to identify nonequilibrium processes in the measured data. To get a close insight into the emission formation processes in water-injected flames, local concentration measurements are used to calculate distributions of the reaction progress variable. Finally, to clarify the influence of spray quality on the composition of the exhaust gas, a variation of the water droplet diameters is done. For rising water content at constant adiabatic flame temperature, the NOx emissions can be held constant, whereas CO concentrations increase. On the contrary, both values decrease for measurements at constant equivalence ratio and reduced flame temperatures. Further analysis of the data shows the close dependency of CO concentration on the equivalence ratio; however, due to the water addition, a shift of the CO curves can be detected. In the local measurements, changes in the distribution of the reaction progress variable and an increase of the flame length were detected for water-injected flames along with changes of the maximum as well as the averaged CO values. Finally, a strong influence of water droplet size on NOx and CO formation is shown for constant operating conditions.
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Geigle, Klaus Peter, Jochen Zerbs, Markus Köhler, Michael Stöhr, and Wolfgang Meier. "Experimental Analysis of Soot Formation and Oxidation in a Gas Turbine Model Combustor Using Laser Diagnostics." Journal of Engineering for Gas Turbines and Power 133, no. 12 (September 12, 2011). http://dx.doi.org/10.1115/1.4004154.
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Sooting ethylene/air flames were investigated experimentally in a dual swirl gas turbine model combustor with good optical access at atmospheric pressure. The goals of the investigations were a detailed characterization of the soot formation and oxidation processes under gas turbine relevant conditions and the establishment of a data base for the validation of numerical combustion simulations. The flow field was measured by stereoscopic particle image velocimetry, the soot volume fractions by laser-induced incandescence, the heat release by OH chemiluminescence imaging and the temperatures by coherent anti-Stokes Raman scattering. Two flames are compared: a fuel-rich partially premixed flame with moderate soot concentrations and a second one with the same parameters but additional injection of secondary air. Instantaneous as well as average distributions of the measured quantities are presented and discussed. The measured soot distributions exhibit a high temporal and spatial dynamic. This behavior correlates with broad temperature probability density functions. With injection of secondary air downstream of the flame zone the distributions change drastically. The data set, including PDFs of soot concentration, temperature and flow velocity, is unique in combining different laser diagnostics with a combustor exhibiting a more challenging geometry than existing validation experiments.
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Wang, Ping, Qian Yu, Prashant Shrotriya, and Mingmin Chen. "Numerical Analysis of Equivalence Ratio Fluctuations in a Partially Premixed Gas Turbine Combustor Using Large Eddy Simulations." Journal of Engineering for Gas Turbines and Power 141, no. 4 (November 16, 2018). http://dx.doi.org/10.1115/1.4041656.
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In the present work, the fluctuations of equivalence ratio in the PRECCINSTA combustor are investigated via large eddy simulations (LES). Four isothermal flow cases with different combinations of global equivalence ratios (0.7 or 0.83) and grids (1.2 or 1.8 million cells) are simulated to study the mixing process of air with methane, which is injected into the inlet channel through small holes. It is shown that the fluctuations of equivalence ratio are very large, and their ranges are [0.4, 1.3] and [0.3, 1.2] for cases 0.83 and 0.7, respectively. For simulating turbulent partially premixed flames in this burner with the well-known dynamically thickened flame (DTF) combustion model, a suitable multistep reaction mechanism should be chosen aforehand. To do that, laminar premixed flames of 15 different equivalence ratios are calculated using three different methane/air reaction mechanisms: 2S_CH4_BFER, 2sCM2 reduced mechanisms and GRI-Mech 3.0 detailed reaction mechanism. The variations of flame temperature, flame speed and thickness of the laminar flames with the equivalence ratios are compared in detail. It is demonstrated that the applicative equivalence ratio range for the 2S_CH4_BFER mechanism is [0.5, 1.3], which is larger than that of the 2sCM2 mechanism [0.5, 1.2]. Therefore, it is recommended to use the 2S_CH4_BFER scheme to simulate the partially premixed flames in the PRECCINSTA combustion chamber.
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Samarasinghe, Janith, Stephen J. Peluso, Bryan D. Quay, and Domenic A. Santavicca. "The Three-Dimensional Structure of Swirl-Stabilized Flames in a Lean Premixed Multinozzle Can Combustor." Journal of Engineering for Gas Turbines and Power 138, no. 3 (September 22, 2015). http://dx.doi.org/10.1115/1.4031439.
Full textAbstract:
Flame structure can have a significant effect on a combustor's static stability (resistance to blowoff) and dynamic stability (combustion instability) and therefore is an important aspect of the combustion process that must be taken into account in the design of gas turbine combustors. While the relationship between flame structure and flame stability has been studied extensively in single-nozzle combustors, relatively few studies have been conducted in multinozzle combustor configurations typical of actual gas turbine combustion systems. In this paper, a chemiluminescence-based tomographic reconstruction technique is used to obtain three-dimensional images of the flame structure in a laboratory-scale five-nozzle can combustor. Analysis of the 3D images reveals features of the complex, three-dimensional structure of this multinozzle flame. Effects of interacting swirling flows, flame–flame interactions, and flame–wall interactions on the flame structure are also discussed.
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Jones, Brian, Jong Guen Lee, Bryan D. Quay, and Domenic A. Santavicca. "Flame Response Mechanisms Due to Velocity Perturbations in a Lean Premixed Gas Turbine Combustor." Journal of Engineering for Gas Turbines and Power 133, no. 2 (October 27, 2010). http://dx.doi.org/10.1115/1.4001996.
Full textAbstract:
The response of turbulent premixed flames to inlet velocity fluctuations is studied experimentally in a lean premixed, swirl-stabilized, gas turbine combustor. Overall chemiluminescence intensity is used as a measure of the fluctuations in the flame’s global heat release rate, and hot wire anemometry is used to measure the inlet velocity fluctuations. Tests are conducted over a range of mean inlet velocities, equivalence ratios, and velocity fluctuation frequencies, while the normalized inlet velocity fluctuation (V′/Vmean) is fixed at 5% to ensure linear flame response over the employed modulation frequency range. The measurements are used to calculate a flame transfer function relating the velocity fluctuation to the heat release fluctuation as a function of the velocity fluctuation frequency. At low frequency, the gain of the flame transfer function increases with increasing frequency to a peak value greater than 1. As the frequency is further increased, the gain decreases to a minimum value, followed by a second smaller peak. The frequencies at which the gain is minimum and achieves its second peak are found to depend on the convection time scale and the flame’s characteristic length scale. Phase-synchronized CH∗ chemiluminescence imaging is used to characterize the flame’s response to inlet velocity fluctuations. The observed flame response can be explained in terms of the interaction of two flame perturbation mechanisms, one originating at flame-anchoring point and propagating along the flame front and the other from vorticity field generated in the outer shear layer in the annular mixing section. An analysis of the phase-synchronized flame images show that when both perturbations arrive at the flame at the same time (or phase), they constructively interfere, producing the second peak observed in the gain curves. When the perturbations arrive at the flame 180 degrees out-of-phase, they destructively interfere, producing the observed minimum in the gain curve.
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Johnson, Andressa L., and Xinyu Zhao. "Analysis of the Heat Transfer Within Combustor Liners Using a Combined Monte Carlo and Two-Flux Method." Journal of Turbomachinery 143, no. 3 (March 1, 2021). http://dx.doi.org/10.1115/1.4049913.
Full textAbstract:
Abstract One consequence of increasing efficiency of gas turbine combustors is higher temperatures within the combustor. Management of larger heat load has been advanced to protect the combustor wall and turbines, and among those are thermal barrier coatings (TBCs). Historically, both the flame and TBCs have received a simplified radiation treatment using effective absorptivities and emissivities. In this study, non-gray radiation is compared with gray and black radiation by combining three-dimensional Monte Carlo Ray Tracing solution of non-gray flames in a model gas turbine combustor to one-dimensional energy balance within combustor liners. A recent large eddy simulation of a gas turbine combustor is analyzed, where both gray and non-gray models are exercised. A two-band spectral model is employed for the TBC, where a translucent band and an opaque band are identified. A line-by-line treatment for gas-phase radiation is adopted, and the incident radiative energy on the combustor wall is collected using the MCRT solver, where the fraction of radiative energy within the translucent band is collected and compared with those obtained from the blackbody assumption. The temperature along the multilayered combustor wall is computed, and parametric comparison is conducted. The effects of the nongray flame radiation are more prominent at elevated pressures than at atmospheric pressure. The gray model is found to over-predict the TBC temperature, which leads to a difference of approximately 150 K in the prediction of peak temperature on the hot side of the TBC.
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Hummel, Tobias, Frederik Berger, Michael Hertweck, Bruno Schuermans, and Thomas Sattelmayer. "High-Frequency Thermoacoustic Modulation Mechanisms in Swirl-Stabilized Gas Turbine Combustors—Part II: Modeling and Analysis." Journal of Engineering for Gas Turbines and Power 139, no. 7 (February 14, 2017). http://dx.doi.org/10.1115/1.4035592.
Full textAbstract:
This paper deals with high-frequency (HF) thermoacoustic instabilities in swirl-stabilized gas turbine combustors. Driving mechanisms associated with periodic flame displacement and flame shape deformations are theoretically discussed, and corresponding flame transfer functions (FTF) are derived from first principles. These linear feedback models are then evaluated by means of a lab-scale swirl-stabilized combustor in combination with part one of this joint publication. For this purpose, the models are used to thermoacoustically characterize a complete set of operation points of this combustor facility. Specifically, growth rates of the first transversal modes are computed, and compared against experimentally obtained pressure amplitudes as an indicator for thermoacoustic stability. The characterization is based on a hybrid analysis approach relying on a frequency domain formulation of acoustic conservation equations, in which nonuniform temperature fields and distributed thermoacoustic source terms/flame transfer functions can be straightforwardly considered. The relative contribution of flame displacement and deformation driving mechanisms–i.e., their significance with respect to the total driving–is identified. Furthermore, promoting/inhibiting conditions for the occurrence of high frequency, transversal acoustic instabilities within swirl-stabilized gas turbine combustors are revealed.
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Bothien, Mirko R., Nicolas Noiray, and Bruno Schuermans. "Analysis of Azimuthal Thermo-acoustic Modes in Annular Gas Turbine Combustion Chambers." Journal of Engineering for Gas Turbines and Power 137, no. 6 (June 1, 2015). http://dx.doi.org/10.1115/1.4028718.
Full textAbstract:
Modern gas turbine combustors operating in lean-premixed mode are prone to thermo-acoustic instabilities. In annular combustion chambers, usually azimuthal acoustic modes are the critical ones interacting with the flame. In case of constructive interference, high amplitude oscillations might result. In this paper, the azimuthal acoustic field of a full-scale engine is investigated in detail. The analyses are based on measurements in a full-scale gas turbine, analytical models to derive the system dynamics, as well as simulations performed with an in-house 3d nonlinear network model. It is shown that the network model is able to reproduce the behavior observed in the engine. Spectra, linear growth rates, as well as the statistics of the system's dynamics can be predicted. A previously introduced algorithm is used to extract linear growth rates from engine and model time domain data. The method's accuracy is confirmed by comparison of the routine's results to analytically determined growth rates from the network model. The network model is also used to derive a burner staging configuration, resulting in the decrease of linear growth rate and thus an increase of engine operation regime; model predictions are verified by full-scale engine measurements. A thorough investigation of the azimuthal modes statistics is performed. Additionally, the network model is used to show that an unfavorable flame temperature distribution with an amplitude of merely 1% of the mean flame temperature can change the azimuthal mode from dominantly rotating to dominantly standing. This is predicted by the network model that only takes into account flame fluctuations in axial direction.