Gas Turbine Emission Characteristics in Perfectly Premixed Combustion

Elkady, A. M.; Herbon, John T.; Kalitan, Danielle M.; Leonard, G.; Akula, Rajesh; Karim, Hasan; Hadley, M.

doi:10.1115/1.4006058

Cited by 15 publications

(5 citation statements)

References 12 publications

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“…This is due to the flame stabilization that happens farther downstream of the combustion chamber, and this stabilization increases the temperature near the exit of the combustion chamber. The results are in good agreement with the literature [10].…”

Section: Turbulent Kinetic Energysupporting

confidence: 92%

Effects of Swirl Number and Central Rod on Flow in a Lean Premixed Swirl Combustor

Yellugari,

Villalva Gomez,

Gutmark

2023

Combustion Science and Technology

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Gas turbine combustors are used to extract chemical energy from the combustion of fuel in presence of an oxidizer to power turbines. Environmental concerns provide motivation to develop more efficient and less polluting gas turbine engines. To achieve good emission performance, lean burn combustors with low pollutant emissions have been developed. These combustors operate at fuel lean conditions and they can be classified into lean premixed and pre-vaporized (LPP) combustor, where the fuel and oxidizer are premixed and pre-vaporized to form a homogeneous mixture in a dedicated region, premixer, just before the fuel-oxidizer mixture enters the combustion chamber, and lean direct injection (LDI) combustor, where the fuel is directly injected into the flame zone without any premixing with oxidizer [1]. The premixing and pre-vaporizing reduce the residence time, the amount of time the gases are in the combustion chamber. The reduction in residence time reduces the NO x emissions, as the high NO x emissions are produced with a long residence time in the combustion chamber.The flow behavior of non-reacting and reacting flow in a lean premixed swirl combustor, adapted from KAUST experimental rig, has been studied using RANS in the commercial software, Ansys -Fluent. Turbulence is modeled using the two equation realizable k − model and the turbulence -chemistry interaction is modeled by a flamelet generated manifold (FGM) technique. At first, non-reacting flow was simulated in lean premixed swirl combustor. These simulation results were compared to the experiments done by Sabatino et al. [2] and LES work of Maestro et al. [3]. This non-reacting flow solution was used as an initial condition to the reacting flow for a faster convergence of the solution, with methane-air mixture at an equivalence ratio of 0.67. GRI 3.0 mechanism was used for modeling chemistry, which had 325 i I specially thank Dr. Urmila Ghia, for supporting me all the time. I would like to thank Ohio Supercomputer Center for letting me use the resources.I would like to thank my friends and people from work, for being patient, cooperative and supportive all these years in Cincinnati. All this could not be possible without my parents and my older brother. I so grateful to my parents and my brother for always believing in me.Their unconditional love and support always made me to dream big and achieve my dreams with ease. Finally, I am so thankful to my Master and Sir for their continuous blessings and guidance throughout my life . v

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Section: Turbulent Kinetic Energysupporting

confidence: 92%

Effects of Swirl Number and Central Rod on Flow in a Lean Premixed Swirl Combustor

Yellugari,

Villalva Gomez,

Gutmark

2023

Combustion Science and Technology

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“…In the last decade, MSA has found versatile application in the aviation industry, from aircraft tyre pressure assessment [43] to assembly checks of aircraft engine exhaust nozzles [44]. However, all of the reviewed studies in aviation applied Gauge R&R [43][44][45][46][47][48] as opposed to Attribute Agreement Analysis, except for [49], which will be discussed later. Barbosa et al compared the reliability of laser technology to the manual measurement of gaps in aircraft assemblies [45].…”

Section: Literature Reviewmentioning

confidence: 99%

Assessment of Aircraft Engine Blade Inspection Performance Using Attribute Agreement Analysis

Aust

Pons

2022

Safety

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Background—Visual inspection is an important element of aircraft engine maintenance to assure flight safety. Predominantly performed by human operators, those maintenance activities are prone to human error. While false negatives imply a risk to aviation safety, false positives can lead to increased maintenance cost. The aim of the present study was to evaluate the human performance in visual inspection of aero engine blades, specifically the operators’ consistency, accuracy, and reproducibility, as well as the system reliability. Methods—Photographs of 26 blades were presented to 50 industry practitioners of three skill levels to assess their performance. Each image was shown to each operator twice in random order, leading to N = 2600 observations. The data were statistically analysed using Attribute Agreement Analysis (AAA) and Kappa analysis. Results—The results show that operators were on average 82.5% consistent with their serviceability decision, while achieving an inspection accuracy of 67.7%. The operators’ reproducibility was 15.4%, as was the accuracy of all operators with the ground truth. Subsequently, the false-positive and false-negative rates were analysed separately to the overall inspection accuracy, showing that 20 operators (40%) achieved acceptable performances, thus meeting the required standard. Conclusions—In aviation maintenance the false-negative rate of <5% as per Aerospace Standard AS13100 is arguably the single most important metric since it determines the safety outcomes. The results of this study show acceptable false-negative performance in 60% of appraisers. Thus, there is the desirability to seek ways to improve the performance. Some suggestions are given in this regard.

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“…Such measurements are complicated by the long post-flame residence times needed to study Zeldovich NO. In many of these experiments, uncertain temporal temperature histories necessitate complex reactor network approaches . Relatively recent measurements of NO formation have been performed in diffusion , and premixed flames − at atmospheric pressure.…”

Section: Comparison To Experimental Measurementsmentioning

confidence: 99%

Computational Study of NO_x Formation at Conditions Relevant to Gas Turbine Operation: Part 1

et al. 2016

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Along with other nitrogen oxides, nitric oxide (NO) is a regulated air pollutant that is primarily produced as a result of combustion processes. This pollutant is produced in every combustion system that uses oxidizer mixtures containing N2 and/or fuels that contain organically bound nitrogen. To design combustors to minimize NO emissions, high-fidelity computational models for NO production and NO/NO2 interconversion are required. To improve model performance and understanding of NO production pathways, a computational parametric study is performed to investigate the effects of fuel chemistry, reaction temperature history, and inert gas dilution on NO production in methane and ethylene combustion. Predictions using popular models from the literature are compared for premixed laminar flame conditions as well as against previously reported stirred reactor measurements. Differences in the predictions and their relationships to the NO x submodel and hydrocarbon chemistry are investigated. We find that significant differences in rich flame conditions occur as a result of differences in the CH kinetic pathways and parameters within the hydrocarbon models, while NO production in lean and stoichiometric flames is sensitive to differences in the assumed Zeldovich (thermal) NO submodel parameters. As a result of uncertainties in the spectrum of time scales and the degree of mixing in stirred reactors, jet-stirred reactor data do not provide sufficient constraints on results to resolve the existing model differences. Well-defined time history evolution of NO x formation data are shown to be critical for developing improved characterization of the relative importance of the different submechanisms on NO x formation at gas turbine conditions.

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Gas Turbine Emission Characteristics in Perfectly Premixed Combustion

Cited by 15 publications

References 12 publications

Effects of Swirl Number and Central Rod on Flow in a Lean Premixed Swirl Combustor

Effects of Swirl Number and Central Rod on Flow in a Lean Premixed Swirl Combustor

Assessment of Aircraft Engine Blade Inspection Performance Using Attribute Agreement Analysis

Computational Study of NO_x Formation at Conditions Relevant to Gas Turbine Operation: Part 1

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Gas Turbine Emission Characteristics in Perfectly Premixed Combustion

Cited by 15 publications

References 12 publications

Effects of Swirl Number and Central Rod on Flow in a Lean Premixed Swirl Combustor

Effects of Swirl Number and Central Rod on Flow in a Lean Premixed Swirl Combustor

Assessment of Aircraft Engine Blade Inspection Performance Using Attribute Agreement Analysis

Computational Study of NOx Formation at Conditions Relevant to Gas Turbine Operation: Part 1

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Computational Study of NO_x Formation at Conditions Relevant to Gas Turbine Operation: Part 1