Javier Rodriguez Camacho, Michel Akiki, James Blust, Jacqueline O'Connor
Abstract Carbon sequestration and utilization has been proposed as a method for decarbonizing high-efficiency gas turbines operating on natural gas fuels. To increase the efficiency of the carbon removal process, exhaust gas recirculation (EGR) can be used. EGR recycles a portion of the engine exhaust into the inlet, increasing the concentration of inert species in the exhaust stream to improve the performance and cost effectiveness of CO2 separation systems. This strategy can reduce the oxygen concentration in the air, leading to changes in flame stabilization. In this study, we investigate the effect of air diluted with inert gases and the impact that these mixtures have on static and dynamic stability. A swirl-stabilized flame in a single-nozzle, variable-length combustor is used to measure the flame behavior for oxygen concentrations of 15% to 21% by volume. A constant flame temperature test matrix is conducted to mimic operation in an industrial gas turbine. High-speed chemiluminescence imaging is used to determine the change in flame shape and dynamics for each gas composition. As the oxygen concentration decreases, the flame lifts, resulting in an aerodynamically-stabilized flame at the lowest O2 concentrations. Different compositions of gases result in different flame shapes, where higher levels of N2 in the diluents result in more flame stabilization in the outer recirculation zone as compared to those with higher levels of CO2. The flame oscillation mechanisms also change with oxygen concentration, where the lifted flames at low O2 levels exhibit an ignition/extinction oscillation mode.
{"title":"Effect of Inert Species On the Static and Dynamic Stability of a Piloted, Swirl-Stabilized Flame","authors":"Javier Rodriguez Camacho, Michel Akiki, James Blust, Jacqueline O'Connor","doi":"10.1115/1.4064048","DOIUrl":"https://doi.org/10.1115/1.4064048","url":null,"abstract":"Abstract Carbon sequestration and utilization has been proposed as a method for decarbonizing high-efficiency gas turbines operating on natural gas fuels. To increase the efficiency of the carbon removal process, exhaust gas recirculation (EGR) can be used. EGR recycles a portion of the engine exhaust into the inlet, increasing the concentration of inert species in the exhaust stream to improve the performance and cost effectiveness of CO2 separation systems. This strategy can reduce the oxygen concentration in the air, leading to changes in flame stabilization. In this study, we investigate the effect of air diluted with inert gases and the impact that these mixtures have on static and dynamic stability. A swirl-stabilized flame in a single-nozzle, variable-length combustor is used to measure the flame behavior for oxygen concentrations of 15% to 21% by volume. A constant flame temperature test matrix is conducted to mimic operation in an industrial gas turbine. High-speed chemiluminescence imaging is used to determine the change in flame shape and dynamics for each gas composition. As the oxygen concentration decreases, the flame lifts, resulting in an aerodynamically-stabilized flame at the lowest O2 concentrations. Different compositions of gases result in different flame shapes, where higher levels of N2 in the diluents result in more flame stabilization in the outer recirculation zone as compared to those with higher levels of CO2. The flame oscillation mechanisms also change with oxygen concentration, where the lifted flames at low O2 levels exhibit an ignition/extinction oscillation mode.","PeriodicalId":15685,"journal":{"name":"Journal of Engineering for Gas Turbines and Power-transactions of The Asme","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-11-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135136307","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Ruonan Wang, Feng Gao, John W. Chew, Olaf Marxen, Zixiang Sun
Abstract Code_Saturne, an open-source computational fluid dynamics (CFD) code, has been applied to a range of problems related to turbomachinery internal air systems. These include a closed rotor-stator disc cavity, a co-rotating disc cavity with radial outflow and a co-rotating disc cavity with axial throughflow. Unsteady Reynolds-averaged Navier-Stokes (RANS) simulations and large eddy simulations (LES) are compared with experimental data and previous direct numerical simulation (DNS) and LES results. The results demonstrate Code_Saturne's capabilities for flow and heat transfer in rotating disc cavity flows. The Boussinesq approximation was implemented into the code for modelling centrifugally buoyant flow and heat transfer in the rotating cavity with axial throughflow. This development is validated using recent experimental data and CFD results. Good agreement is found between LES and RANS modelling in some cases, but for the axial throughflow cases, advantages of LES compared to URANS are significant for a high Reynolds number condition. The wall-modelled large eddy simulation (WMLES) method is recommended for balancing computational accuracy and cost in engineering applications.
{"title":"Advanced Modelling of Flow and Heat Transfer in Rotating Disc Cavities Using Open-Source CFD","authors":"Ruonan Wang, Feng Gao, John W. Chew, Olaf Marxen, Zixiang Sun","doi":"10.1115/1.4063989","DOIUrl":"https://doi.org/10.1115/1.4063989","url":null,"abstract":"Abstract Code_Saturne, an open-source computational fluid dynamics (CFD) code, has been applied to a range of problems related to turbomachinery internal air systems. These include a closed rotor-stator disc cavity, a co-rotating disc cavity with radial outflow and a co-rotating disc cavity with axial throughflow. Unsteady Reynolds-averaged Navier-Stokes (RANS) simulations and large eddy simulations (LES) are compared with experimental data and previous direct numerical simulation (DNS) and LES results. The results demonstrate Code_Saturne's capabilities for flow and heat transfer in rotating disc cavity flows. The Boussinesq approximation was implemented into the code for modelling centrifugally buoyant flow and heat transfer in the rotating cavity with axial throughflow. This development is validated using recent experimental data and CFD results. Good agreement is found between LES and RANS modelling in some cases, but for the axial throughflow cases, advantages of LES compared to URANS are significant for a high Reynolds number condition. The wall-modelled large eddy simulation (WMLES) method is recommended for balancing computational accuracy and cost in engineering applications.","PeriodicalId":15685,"journal":{"name":"Journal of Engineering for Gas Turbines and Power-transactions of The Asme","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135476363","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract By tilting the burners of an annular aeronautical combustor in circumferential direction, the potential of increased combustion stability is opened up due to an enhanced exhaust gas recirculation between adjacent flames. The innovative gas turbine combustor concept, called the Short Helical Combustor (SHC), allows the main reaction zone to be operated at low equivalence ratios. A lean lifted flame is implemented in the staggered SHC burner arrangement. The objective is to reach ultra-low NOx emissions by extensive premixing of fuel and air upstream of the lean reaction zone. In the present work, a modeling approach is developed to investigate the characteristics of the lifted flame, using the gaseous fuel methane. It is demonstrated that by using the Large Eddy Simulation method, the shape and lift-off height of the flame is adequately reproduced by means of the finite-rate chemistry approach. For the numerical prediction of the lean lifted flame in the SHC arrangement, the focus is on the interaction of adjacent burners. It is shown that the swirling jet flow is deflected towards the sidewall of the staggered combustor dome, which is attributed to the asymmetrical confinement. Since the stabilization mechanism of the low-swirl flame relies on outer recirculation zones, the upstream transport of hot combustion products back to the flame base is studied by the variation of the combustor confinement ratio. It turns out that increasing the combustor size amplifies the exhaust gas recirculation along the sidewall, and increases the temperature of recirculating burned gases.
{"title":"Reacting Flow Prediction of the Low-Swirl Lifted Flame in an Aeronautical Combustor with Angular Air Supply","authors":"Sven Hoffmann, Rainer Koch, Hans-Jörg Bauer","doi":"10.1115/1.4063988","DOIUrl":"https://doi.org/10.1115/1.4063988","url":null,"abstract":"Abstract By tilting the burners of an annular aeronautical combustor in circumferential direction, the potential of increased combustion stability is opened up due to an enhanced exhaust gas recirculation between adjacent flames. The innovative gas turbine combustor concept, called the Short Helical Combustor (SHC), allows the main reaction zone to be operated at low equivalence ratios. A lean lifted flame is implemented in the staggered SHC burner arrangement. The objective is to reach ultra-low NOx emissions by extensive premixing of fuel and air upstream of the lean reaction zone. In the present work, a modeling approach is developed to investigate the characteristics of the lifted flame, using the gaseous fuel methane. It is demonstrated that by using the Large Eddy Simulation method, the shape and lift-off height of the flame is adequately reproduced by means of the finite-rate chemistry approach. For the numerical prediction of the lean lifted flame in the SHC arrangement, the focus is on the interaction of adjacent burners. It is shown that the swirling jet flow is deflected towards the sidewall of the staggered combustor dome, which is attributed to the asymmetrical confinement. Since the stabilization mechanism of the low-swirl flame relies on outer recirculation zones, the upstream transport of hot combustion products back to the flame base is studied by the variation of the combustor confinement ratio. It turns out that increasing the combustor size amplifies the exhaust gas recirculation along the sidewall, and increases the temperature of recirculating burned gases.","PeriodicalId":15685,"journal":{"name":"Journal of Engineering for Gas Turbines and Power-transactions of The Asme","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135476370","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Luca Boscagli, david G. MacManus, Robert Christie, Christopher T. J. Sheaf
Abstract The next generation of ultrahigh bypass ratio civil aero-engines promises notable engine cycle benefits. However, these benefits can be significantly eroded by a possible increase in nacelle weight and drag due to the typical larger fan diameters. More compact nacelles, with shorter intakes, may be required to enable a net reduction in aero-engine fuel burn. The aim of this paper is to assess the influence of the design style of short intakes on the unsteady interaction under crosswind conditions between fan and intake, with a focus on the separation onset and characteristics of the boundary layer within the intake. Three intake designs were assessed, and a hierarchical computational fluid dynamics (CFD) approach was used to determine and quantify primary aerodynamic interactions between the fan and the intake design. Similar to previous findings for a specific intake configuration, both intake flow unsteadiness and the unsteady upstream perturbations from the fan have a detrimental effect on the separation onset for the range of intake designs. The separation of the boundary layer within the intake was shock driven for the three different design styles. The simulations also quantified the unsteady intake flows with an emphasis on the spectral characteristics and engine-order signatures of the flow distortion. Overall, this work showed that is beneficial for the intake boundary layer to delay the diffusion closer to the fan and reduce the preshock Mach number to mitigate the adverse unsteady interaction between the fan and the shock.
{"title":"Effect of Unsteady Fan-Intake Interaction On Short Intake Design","authors":"Luca Boscagli, david G. MacManus, Robert Christie, Christopher T. J. Sheaf","doi":"10.1115/1.4063768","DOIUrl":"https://doi.org/10.1115/1.4063768","url":null,"abstract":"Abstract The next generation of ultrahigh bypass ratio civil aero-engines promises notable engine cycle benefits. However, these benefits can be significantly eroded by a possible increase in nacelle weight and drag due to the typical larger fan diameters. More compact nacelles, with shorter intakes, may be required to enable a net reduction in aero-engine fuel burn. The aim of this paper is to assess the influence of the design style of short intakes on the unsteady interaction under crosswind conditions between fan and intake, with a focus on the separation onset and characteristics of the boundary layer within the intake. Three intake designs were assessed, and a hierarchical computational fluid dynamics (CFD) approach was used to determine and quantify primary aerodynamic interactions between the fan and the intake design. Similar to previous findings for a specific intake configuration, both intake flow unsteadiness and the unsteady upstream perturbations from the fan have a detrimental effect on the separation onset for the range of intake designs. The separation of the boundary layer within the intake was shock driven for the three different design styles. The simulations also quantified the unsteady intake flows with an emphasis on the spectral characteristics and engine-order signatures of the flow distortion. Overall, this work showed that is beneficial for the intake boundary layer to delay the diffusion closer to the fan and reduce the preshock Mach number to mitigate the adverse unsteady interaction between the fan and the shock.","PeriodicalId":15685,"journal":{"name":"Journal of Engineering for Gas Turbines and Power-transactions of The Asme","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135585232","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Marie Truffot, Antoine Renaud, Laurent Zimmer, Franck Richecoeur, Alain Cayre, Yoann Méry
Abstract This study investigates the impact of the staging factor, the ratio between the fuel injected through the pilot stage and the multipoint injection, on the flame dynamic. The BIMER combustor is an atmospheric pressure rig equipped with two corotating swirling air injections (a fixed amount of around 87% of the air goes inside the multipoint stage) and two fuel injection paths for staged combustion. Liquid dodecane is injected with air preheated at 437 K with a global equivalence ratio of 0.6 and a thermal power of around 72 kW. The change of the staging factor from 100% (pilot-only injection) toward 0% (multipoint-only injection) generates changes in the flame-shape which bifurcates from an anchored V-flame into a lifted flame. This flame shape bifurcation appears at a staging of factor around 25%. Around this staging factor, one can witness multistable flames where the flame structure transits randomly between five different states. Processing microphone signals recorded in the chamber provides an understanding of the flame dynamics. The attached flame presents limited pressure fluctuations level at 270 Hz, while the lifted flame features high-pressure fluctuations at 323 Hz. The intermittency between the five states (including the two stable states) is investigated.
{"title":"Intermittency of Flame Structure and Thermo-acoustic Behavior in a Staged Multipoint Injector Using Liquid Fuel","authors":"Marie Truffot, Antoine Renaud, Laurent Zimmer, Franck Richecoeur, Alain Cayre, Yoann Méry","doi":"10.1115/1.4063638","DOIUrl":"https://doi.org/10.1115/1.4063638","url":null,"abstract":"Abstract This study investigates the impact of the staging factor, the ratio between the fuel injected through the pilot stage and the multipoint injection, on the flame dynamic. The BIMER combustor is an atmospheric pressure rig equipped with two corotating swirling air injections (a fixed amount of around 87% of the air goes inside the multipoint stage) and two fuel injection paths for staged combustion. Liquid dodecane is injected with air preheated at 437 K with a global equivalence ratio of 0.6 and a thermal power of around 72 kW. The change of the staging factor from 100% (pilot-only injection) toward 0% (multipoint-only injection) generates changes in the flame-shape which bifurcates from an anchored V-flame into a lifted flame. This flame shape bifurcation appears at a staging of factor around 25%. Around this staging factor, one can witness multistable flames where the flame structure transits randomly between five different states. Processing microphone signals recorded in the chamber provides an understanding of the flame dynamics. The attached flame presents limited pressure fluctuations level at 270 Hz, while the lifted flame features high-pressure fluctuations at 323 Hz. The intermittency between the five states (including the two stable states) is investigated.","PeriodicalId":15685,"journal":{"name":"Journal of Engineering for Gas Turbines and Power-transactions of The Asme","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135585435","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract Operating under harsh conditions and exposed to fluctuating loads for extended periods, wind turbines experience a heightened vulnerability in their key components. Early fault detection is crucial to enhance the reliability of wind turbines, minimize downtime, and optimize power generation efficiency. Although deep learning techniques have been widely applied to fault diagnosis tasks, yielding remarkable performance, practical implementations frequently confront the obstacle of acquiring a substantial quantity of labeled data to train an effective deep learning model. Consequently, this paper introduces an unsupervised global and local domain adaptation network (GLDAN) for fault diagnosis across wind turbines, enabling the model to efficiently transfer acquired knowledge to the target domain in the absence of labeled data. This feature renders it an appropriate solution for situations with limited labeled data availability. Employing adversarial training, GLDAN aligns global domain distributions, diminishing the overall discrepancy between source and target domains, and local domain distributions within a single fault category for both domains, capturing more intricate and specific fault features. The proposed approach is corroborated using actual wind farm data, and comprehensive experimental results demonstrate that GLDAN surpasses deep global domain adaptation methods in cross-wind turbine fault diagnosis, underlining its practical value in the field.
{"title":"Gldan: Global and Local Domain Adaptation Network for Cross-Wind Turbine Fault Diagnosis","authors":"Dandan Peng, Wim Desmet, Konstantinos Gryllias","doi":"10.1115/1.4063578","DOIUrl":"https://doi.org/10.1115/1.4063578","url":null,"abstract":"Abstract Operating under harsh conditions and exposed to fluctuating loads for extended periods, wind turbines experience a heightened vulnerability in their key components. Early fault detection is crucial to enhance the reliability of wind turbines, minimize downtime, and optimize power generation efficiency. Although deep learning techniques have been widely applied to fault diagnosis tasks, yielding remarkable performance, practical implementations frequently confront the obstacle of acquiring a substantial quantity of labeled data to train an effective deep learning model. Consequently, this paper introduces an unsupervised global and local domain adaptation network (GLDAN) for fault diagnosis across wind turbines, enabling the model to efficiently transfer acquired knowledge to the target domain in the absence of labeled data. This feature renders it an appropriate solution for situations with limited labeled data availability. Employing adversarial training, GLDAN aligns global domain distributions, diminishing the overall discrepancy between source and target domains, and local domain distributions within a single fault category for both domains, capturing more intricate and specific fault features. The proposed approach is corroborated using actual wind farm data, and comprehensive experimental results demonstrate that GLDAN surpasses deep global domain adaptation methods in cross-wind turbine fault diagnosis, underlining its practical value in the field.","PeriodicalId":15685,"journal":{"name":"Journal of Engineering for Gas Turbines and Power-transactions of The Asme","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135585640","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Brittney Antous, Gwibo Byun, K. Todd Lowe, C. Frederic Smith
Abstract Propulsion systems are exposed to environmental ingestion hazards that can cause significant damage and decrease performance. Particles are ingested in a wide range of flight environments that can cause immediate engine failure or long-term damage. An accurate measurement technique has been developed to quantify particle ingestion and aid engine health monitoring. This sensor utilizes scattering and extinction techniques along with machine learning models to measure particle characteristics based on a robust and versatile library. The capabilities of this sensor have been demonstrated using solid quartz particles on the Rolls-Royce M250-C20B particle ingestion turboshaft test engine. To the authors' knowledge, this work presents the first demonstration and validation of optical solid particle sensing in a turbine engine. CSPEC sand (Mil-E-5007C) was ingested for the validation test at two different feed rates using a sand feeder. The sand concentrations were 45 mg/m3 and 22 mg/m3. The sensor outputs the particle characteristics of aspect ratio (AR), size distribution (σ), Sauter mean diameter (D32), and the particle mass flowrate. The Sauter mean diameter and mass flowrate of ingested sand were calculated using the machine learning model outputs and validated by independent measurements. The sensor produced a 0.1 g/min RMS error compared to the validation measurement.
{"title":"Virginia Tech Optical Inlet Sensor for Particle Detection: Rolls Royce M250 Turboshaft Demonstration","authors":"Brittney Antous, Gwibo Byun, K. Todd Lowe, C. Frederic Smith","doi":"10.1115/1.4063584","DOIUrl":"https://doi.org/10.1115/1.4063584","url":null,"abstract":"Abstract Propulsion systems are exposed to environmental ingestion hazards that can cause significant damage and decrease performance. Particles are ingested in a wide range of flight environments that can cause immediate engine failure or long-term damage. An accurate measurement technique has been developed to quantify particle ingestion and aid engine health monitoring. This sensor utilizes scattering and extinction techniques along with machine learning models to measure particle characteristics based on a robust and versatile library. The capabilities of this sensor have been demonstrated using solid quartz particles on the Rolls-Royce M250-C20B particle ingestion turboshaft test engine. To the authors' knowledge, this work presents the first demonstration and validation of optical solid particle sensing in a turbine engine. CSPEC sand (Mil-E-5007C) was ingested for the validation test at two different feed rates using a sand feeder. The sand concentrations were 45 mg/m3 and 22 mg/m3. The sensor outputs the particle characteristics of aspect ratio (AR), size distribution (σ), Sauter mean diameter (D32), and the particle mass flowrate. The Sauter mean diameter and mass flowrate of ingested sand were calculated using the machine learning model outputs and validated by independent measurements. The sensor produced a 0.1 g/min RMS error compared to the validation measurement.","PeriodicalId":15685,"journal":{"name":"Journal of Engineering for Gas Turbines and Power-transactions of The Asme","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135585642","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Maxime Leroy, Clement Mirat, Antoine Renaud, Stefano Puggelli, Stephan Zurbach, Ronan Vicquelin
Abstract In recent years, the need for low-carbon power has seen hydrogen emerge as a potential fuel to replace conventional hydrocarbons in combustion to limit CO2 emissions in several sectors, including aeronautics. The challenges posed by hydrogen combustion are similar to the issues of kerosene flames but more challenging, like nitrogen oxide (NOx) emissions and flame flashback. One potential solution to address these problems is to burn a rich mixture of hydrogen and air in globally lean conditions on a coaxial injector to obtain a stable and staged combustion and attempt to reduce emissions. In this article, the evolution of NOx production as more air is mixed into the fuel is studied, as well as the changes in flame size and structure. In particular, the appearance of a secondary flame front is observed and increasing the proportion of air in the fuel mixture both shortens the flame and reduces the NOx emission index. Additionally, the effect of the global equivalence ratio and flame thermal power is studied. Finally, existing models for NOx emission of hydrogen flames on a coaxial injector based on average flame residence time and strain rate are tested and shown to have promising results.
{"title":"Structure and Nox Emissions of Stratified Hydrogen-Air Flames Stabilized On a Coaxial Injector","authors":"Maxime Leroy, Clement Mirat, Antoine Renaud, Stefano Puggelli, Stephan Zurbach, Ronan Vicquelin","doi":"10.1115/1.4063579","DOIUrl":"https://doi.org/10.1115/1.4063579","url":null,"abstract":"Abstract In recent years, the need for low-carbon power has seen hydrogen emerge as a potential fuel to replace conventional hydrocarbons in combustion to limit CO2 emissions in several sectors, including aeronautics. The challenges posed by hydrogen combustion are similar to the issues of kerosene flames but more challenging, like nitrogen oxide (NOx) emissions and flame flashback. One potential solution to address these problems is to burn a rich mixture of hydrogen and air in globally lean conditions on a coaxial injector to obtain a stable and staged combustion and attempt to reduce emissions. In this article, the evolution of NOx production as more air is mixed into the fuel is studied, as well as the changes in flame size and structure. In particular, the appearance of a secondary flame front is observed and increasing the proportion of air in the fuel mixture both shortens the flame and reduces the NOx emission index. Additionally, the effect of the global equivalence ratio and flame thermal power is studied. Finally, existing models for NOx emission of hydrogen flames on a coaxial injector based on average flame residence time and strain rate are tested and shown to have promising results.","PeriodicalId":15685,"journal":{"name":"Journal of Engineering for Gas Turbines and Power-transactions of The Asme","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135585641","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Theo Flament, Jean-François Deü, Antoine Placzek, Mikel Balmaseda Aguirre, Duc-Minh Tran
Abstract This work concerns the numerical modeling of geometric nonlinear vibrations of slender structures in rotation using an original reduced order model based on the use of dual modes along with the implicit condensation method. This approach is an improvement of the classical ICE method in the sense that the membrane stretching effect is taken into account in the dynamic resolution. The dynamics equations are first presented and the construction of the reduced order model (ROM) is then proposed. The second part of the paper deals with numerical applications using the finite element method, first for a three-dimensional cantilever beam, then for an Ultra-High Bypass Ratio (UHBR) fan blade subject to aerodynamic loads. In the applications considered, the proposed method predicts more accurately the geometrically nonlinear behavior than the ICE method.
{"title":"Reduced Order Model of Nonlinear Structures for Turbomachinery Aeroelasticity","authors":"Theo Flament, Jean-François Deü, Antoine Placzek, Mikel Balmaseda Aguirre, Duc-Minh Tran","doi":"10.1115/1.4063544","DOIUrl":"https://doi.org/10.1115/1.4063544","url":null,"abstract":"Abstract This work concerns the numerical modeling of geometric nonlinear vibrations of slender structures in rotation using an original reduced order model based on the use of dual modes along with the implicit condensation method. This approach is an improvement of the classical ICE method in the sense that the membrane stretching effect is taken into account in the dynamic resolution. The dynamics equations are first presented and the construction of the reduced order model (ROM) is then proposed. The second part of the paper deals with numerical applications using the finite element method, first for a three-dimensional cantilever beam, then for an Ultra-High Bypass Ratio (UHBR) fan blade subject to aerodynamic loads. In the applications considered, the proposed method predicts more accurately the geometrically nonlinear behavior than the ICE method.","PeriodicalId":15685,"journal":{"name":"Journal of Engineering for Gas Turbines and Power-transactions of The Asme","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-11-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135775573","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Luis San Andres, Azael Duran-Castillo, Juan C. Jauregui, Oscar De Santiago Duran, Daniel Lubell
Abstract This paper presents a test rig for evaluation of gas thrust foil bearings (GTFBs) and details measurements of load capacity conducted with a commercial GTFB comprising a single 360 deg, 0.127 mm thick top foil divided into six continuous arc segments with a formed taper of 0.102 mm. Coated with Teflon®, the top foil rests on a stack of shims above six underspring structures, each comprising three strips of bump foils, 0.102 mm thick. Measurements include the applied static load and break-away torque, rotor speed, bearing axial displacements at three locations 120 deg apart, the flow of a cooling stream, and temperatures in and out of the bearing. Static load tests produce the underspring deformation and a dry-sliding friction coefficient f ∼ 0.12. The underspring is rather flexible though quickly hardening for specific load (P*) > 25 kN/m2 to reach an ultimate deformation of ∼0.320 mm. Measurements at 30 krpm (OD surface speed = 111 m/s) and increasing static loads produce bearing displacements that parallel the displacements without shaft rotation. Most importantly, the difference between displacements approaches ∼0.060 mm for P* > 45 kN/m2. The test bearing operated safely to P* = 90 kN/m2 and failed at P* = 120 kN/m2. When heavily loaded, the GTFB is significantly stiffer than when lightly loaded. Designed for easiness of installation and operation, the test bearing demonstrated a stable and repeatable performance with likely a uniform gap or film thickness even for the largest loads applied.
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