Abstract Rotating detonation combustors (RDC) have gained increased interest for integration with power-generating gas turbines due to the potential to increase thermal efficiency. The unsteady flow field exiting the RDC is fundamentally different compared to traditional swirl-stabilized combustors. Successful integration of RDC with gas turbines will depend on the ability to properly condition the unsteady flow to achieve performance levels comparable to swirl-stabilized combustors. RDC simulations require significant computational resources due to the small spatial and temporal time scales required to resolve the detonation phenomenon. Furthermore, traditional steady-state computational fluid dynamics (CFD) analyses are not possible for RDC simulations. The present study develops and validates a computationally efficient approach for predicting unsteady flow fields exiting the combustor using 2D, transient reacting CFD with periodic boundary conditions in the combustor and a downstream plenum. Validation is performed by comparing the CFD results to various experimental measurements: i) wave speed obtained from high-speed ion probe and dynamic pressure data, ii) average wall static pressure measurements, and iii) time-resolved particle image velocimetry (PIV) at 100 kHz at the RDC exit. Results indicate good agreement between CFD and experiments with respect to velocity field exiting the RDC, detonation wave speed, and static pressure distribution.
{"title":"Validation of Rotating Detonation Combustor CFD for Predicting Unsteady Supersonic-Subsonic Flow Field At the Exit","authors":"Piyush Raj, Shaon Talukdar, Dalton Langner, Apurav Gupta, Joseph Meadows, Ajay Agrawal","doi":"10.1115/1.4063706","DOIUrl":"https://doi.org/10.1115/1.4063706","url":null,"abstract":"Abstract Rotating detonation combustors (RDC) have gained increased interest for integration with power-generating gas turbines due to the potential to increase thermal efficiency. The unsteady flow field exiting the RDC is fundamentally different compared to traditional swirl-stabilized combustors. Successful integration of RDC with gas turbines will depend on the ability to properly condition the unsteady flow to achieve performance levels comparable to swirl-stabilized combustors. RDC simulations require significant computational resources due to the small spatial and temporal time scales required to resolve the detonation phenomenon. Furthermore, traditional steady-state computational fluid dynamics (CFD) analyses are not possible for RDC simulations. The present study develops and validates a computationally efficient approach for predicting unsteady flow fields exiting the combustor using 2D, transient reacting CFD with periodic boundary conditions in the combustor and a downstream plenum. Validation is performed by comparing the CFD results to various experimental measurements: i) wave speed obtained from high-speed ion probe and dynamic pressure data, ii) average wall static pressure measurements, and iii) time-resolved particle image velocimetry (PIV) at 100 kHz at the RDC exit. Results indicate good agreement between CFD and experiments with respect to velocity field exiting the RDC, detonation wave speed, and static pressure distribution.","PeriodicalId":15685,"journal":{"name":"Journal of Engineering for Gas Turbines and Power-transactions of The Asme","volume":"53 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136210565","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}
Soichiro Tabata, Kiyoshi Segawa, Tadashi Takahashi, Jin Aoyagi
Abstract This study focused on the expansion rate of steam; the effect on efficiency was investigated experimentally and numerically by varying the expansion rate of steam in the stage where condensation occurs by varying the flow rate and inlet temperature using a five-stage model steam turbine. The steam expansion rate of the stator blades in each stage was evaluated from the measured wall pressure and total pressure. In addition, the turbine efficiency was evaluated from the measured torque and mass flow rate, and the effect of flow rate and condensing stage can be taken into account for losses caused by condensation. In addition, numerical calculations to account for the effects of non-equilibrium condensation were performed using ANSYS CFX. The numerical calculations were able to show the details of the nucleation situation and the resulting changes in flow patterns. Numerical evaluation of the subcooling loss showed that there was no difference in subcooling loss between different mass flow rates. The steam expansion rate was evaluated from the measurement results, and it was found that there was no difference in the steam expansion rate due to differences in mass flow rate. This corresponds to the numerical result that the subcooling loss does not vary with flow rate.
{"title":"Experimental and Numerical Investigations of Steam Expansion Rate in Low Pressure Steam Turbine","authors":"Soichiro Tabata, Kiyoshi Segawa, Tadashi Takahashi, Jin Aoyagi","doi":"10.1115/1.4063711","DOIUrl":"https://doi.org/10.1115/1.4063711","url":null,"abstract":"Abstract This study focused on the expansion rate of steam; the effect on efficiency was investigated experimentally and numerically by varying the expansion rate of steam in the stage where condensation occurs by varying the flow rate and inlet temperature using a five-stage model steam turbine. The steam expansion rate of the stator blades in each stage was evaluated from the measured wall pressure and total pressure. In addition, the turbine efficiency was evaluated from the measured torque and mass flow rate, and the effect of flow rate and condensing stage can be taken into account for losses caused by condensation. In addition, numerical calculations to account for the effects of non-equilibrium condensation were performed using ANSYS CFX. The numerical calculations were able to show the details of the nucleation situation and the resulting changes in flow patterns. Numerical evaluation of the subcooling loss showed that there was no difference in subcooling loss between different mass flow rates. The steam expansion rate was evaluated from the measurement results, and it was found that there was no difference in the steam expansion rate due to differences in mass flow rate. This corresponds to the numerical result that the subcooling loss does not vary with flow rate.","PeriodicalId":15685,"journal":{"name":"Journal of Engineering for Gas Turbines and Power-transactions of The Asme","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136211405","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 In high-speed gear systems for aeroengines, reducing the fluid dynamic loss, which accounts for the majority of power loss, can significantly improve fuel economy. However, few practical numerical examples are available regarding high-speed gas-liquid two-phase flows involving gear meshing and gear shrouds (gear enclosures, which are effective for loss reduction). Therefore, in this study, the porosity method for object boundaries including the gear meshing, the volume of fluid method, and the surface compression method for the gas-liquid interface were used as fast and numerically stable calculation methods. In addition, a gap was provided at the contact surface of the gear tooth surface to improve the calculation stability, and the oil properties were set considering the difference between the flow resistance in a two-phase flow and that in a single-phase flow (due to the separation of oil particles) to improve the calculation accuracy. To validate the numerical simulation method, a two-axis helical gearbox with a maximum peripheral speed of 100 m/s with specifications equivalent to aeroengine gears was used, and the air flow, oil flow, and fluid dynamic losses were validated. Once the practical accuracy was confirmed, the numerical simulation was used to understand the relationship among air and oil flows, torque, and the effect of the shroud. Consequently, the fluid dynamic loss could be classified phenomenologically.
{"title":"Applicability of Numerical Simulation to the Classification of Fluid Dynamic Loss in Aeroengine Transmission Gears","authors":"Hidenori Arisawa, Mitsuaki TANAKA, Hironori HASHIMOTO, Tatsuhiko Goi, Takahiko Banno, Hideyuki Imai","doi":"10.1115/1.4063713","DOIUrl":"https://doi.org/10.1115/1.4063713","url":null,"abstract":"Abstract In high-speed gear systems for aeroengines, reducing the fluid dynamic loss, which accounts for the majority of power loss, can significantly improve fuel economy. However, few practical numerical examples are available regarding high-speed gas-liquid two-phase flows involving gear meshing and gear shrouds (gear enclosures, which are effective for loss reduction). Therefore, in this study, the porosity method for object boundaries including the gear meshing, the volume of fluid method, and the surface compression method for the gas-liquid interface were used as fast and numerically stable calculation methods. In addition, a gap was provided at the contact surface of the gear tooth surface to improve the calculation stability, and the oil properties were set considering the difference between the flow resistance in a two-phase flow and that in a single-phase flow (due to the separation of oil particles) to improve the calculation accuracy. To validate the numerical simulation method, a two-axis helical gearbox with a maximum peripheral speed of 100 m/s with specifications equivalent to aeroengine gears was used, and the air flow, oil flow, and fluid dynamic losses were validated. Once the practical accuracy was confirmed, the numerical simulation was used to understand the relationship among air and oil flows, torque, and the effect of the shroud. Consequently, the fluid dynamic loss could be classified phenomenologically.","PeriodicalId":15685,"journal":{"name":"Journal of Engineering for Gas Turbines and Power-transactions of The Asme","volume":"239 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136097984","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}
Anne Lise Fiquet, Alexandra Schneider, Benoit Paoletti, Xavier Ottavy, Christoph Brandstetter
Abstract Research of the past decades has shown that the operating range of modern fans and compressors is often limited by aeroelastic phenomena before the onset of pure aerodynamic instability. Prediction of these mechanisms is challenging for state-of-the-art numerical methods, particularly for configurations with flexible wide-chord blades. To provide a benchmark configuration for the community, the composite-material fan stage ECL5, representative of near future Ultra-High-Bypass Ratio architectures, has been designed at Ecole Centrale de Lyon and recently shared as an open-test-case. In research program CATANA, different configurations with variable tuning and intake geometries are investigated experimentally, and here we present a comprehensive aeroelastic study of the tuned reference configuration. The study encompasses the investigation of the whole subsonic and transonic operating range using multi-physical instrumentation. A characterization of structural properties under running conditions is analyzed in comparison to individual blade measurements and FEM-predictions. The stability limit is investigated at different speedlines. At transonic conditions, rotating stall occurred without aeroelastic precursors. Severe non-synchronous-vibrations were observed at subsonic speeds and limited the operating range before the onset of rotating stall. Through a detailed analysis of the aeroelastic coupling mechanism, a full characterization of interacting modes is presented. The challenging prediction of this coupled phenomenon and the discrepancy to aeroelastic simulations are discussed. The results are a promising benchmark for future method development, particularly involving high-fidelity methods.
{"title":"Experiments On Tuned UHBR Open-Test-Case Fan ECL5/CATANA: Stability Limit","authors":"Anne Lise Fiquet, Alexandra Schneider, Benoit Paoletti, Xavier Ottavy, Christoph Brandstetter","doi":"10.1115/1.4063717","DOIUrl":"https://doi.org/10.1115/1.4063717","url":null,"abstract":"Abstract Research of the past decades has shown that the operating range of modern fans and compressors is often limited by aeroelastic phenomena before the onset of pure aerodynamic instability. Prediction of these mechanisms is challenging for state-of-the-art numerical methods, particularly for configurations with flexible wide-chord blades. To provide a benchmark configuration for the community, the composite-material fan stage ECL5, representative of near future Ultra-High-Bypass Ratio architectures, has been designed at Ecole Centrale de Lyon and recently shared as an open-test-case. In research program CATANA, different configurations with variable tuning and intake geometries are investigated experimentally, and here we present a comprehensive aeroelastic study of the tuned reference configuration. The study encompasses the investigation of the whole subsonic and transonic operating range using multi-physical instrumentation. A characterization of structural properties under running conditions is analyzed in comparison to individual blade measurements and FEM-predictions. The stability limit is investigated at different speedlines. At transonic conditions, rotating stall occurred without aeroelastic precursors. Severe non-synchronous-vibrations were observed at subsonic speeds and limited the operating range before the onset of rotating stall. Through a detailed analysis of the aeroelastic coupling mechanism, a full characterization of interacting modes is presented. The challenging prediction of this coupled phenomenon and the discrepancy to aeroelastic simulations are discussed. The results are a promising benchmark for future method development, particularly involving high-fidelity methods.","PeriodicalId":15685,"journal":{"name":"Journal of Engineering for Gas Turbines and Power-transactions of The Asme","volume":"28 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136097999","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}
Hervé Magnes, Sylvain Marragou, Andrea Aniello, Laurent Selle, Thierry Poinsot, Thierry Schuller
Abstract Flame stabilization, flame structure, and pollutant emissions are explored experimentally in a swirled injection system using lean air/hydrogen mixtures at atmospheric conditions and moderate Reynolds numbers. The system comprises two coaxial ducts: hydrogen flows through a central channel while air flows through an annular one, both streams being swirled. Two flame stabilization modes, M-shape and V-shape, are identified. Regions of existence for each mode are mapped based on operating conditions. At low air flow rates, the flame is either anchored or lifted depending on the path to the operating condition; at high air flow rates, the flame is always lifted. The influence of air inlet temperature (T = 300 K to 770 K) on stabilization is analyzed. Flame re-attachment is found to be governed by edge flame propagation and well-modeled by preheating effects. Unburnt hydrogen is detected only for global equivalence ratios below 0.4 and at ambient temperatures. NOx emissions decrease with reduced global equivalence ratios and show a decreasing trend as thermal power increases, irrespective of air preheating and flame stabilization regime. At high power, NOx emissions plateau at an asymptotic value. Factors like flame shape, air preheating, and chamber wall heat losses impact on NOx emissions are evaluated. NOx emissions correlate with the adiabatic flame temperature (Tad) and residence time within the combustor.
{"title":"Impact of Preheating On Flame Stabilization and NOx Emissions From a Dual Swirl Hydrogen Injector","authors":"Hervé Magnes, Sylvain Marragou, Andrea Aniello, Laurent Selle, Thierry Poinsot, Thierry Schuller","doi":"10.1115/1.4063719","DOIUrl":"https://doi.org/10.1115/1.4063719","url":null,"abstract":"Abstract Flame stabilization, flame structure, and pollutant emissions are explored experimentally in a swirled injection system using lean air/hydrogen mixtures at atmospheric conditions and moderate Reynolds numbers. The system comprises two coaxial ducts: hydrogen flows through a central channel while air flows through an annular one, both streams being swirled. Two flame stabilization modes, M-shape and V-shape, are identified. Regions of existence for each mode are mapped based on operating conditions. At low air flow rates, the flame is either anchored or lifted depending on the path to the operating condition; at high air flow rates, the flame is always lifted. The influence of air inlet temperature (T = 300 K to 770 K) on stabilization is analyzed. Flame re-attachment is found to be governed by edge flame propagation and well-modeled by preheating effects. Unburnt hydrogen is detected only for global equivalence ratios below 0.4 and at ambient temperatures. NOx emissions decrease with reduced global equivalence ratios and show a decreasing trend as thermal power increases, irrespective of air preheating and flame stabilization regime. At high power, NOx emissions plateau at an asymptotic value. Factors like flame shape, air preheating, and chamber wall heat losses impact on NOx emissions are evaluated. NOx emissions correlate with the adiabatic flame temperature (Tad) and residence time within the combustor.","PeriodicalId":15685,"journal":{"name":"Journal of Engineering for Gas Turbines and Power-transactions of The Asme","volume":"35 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136098168","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 This article introduces a numerical procedure dedicated to the identification of isolated branches of solutions for nonlinear mechanical systems. It is here applied to a fan blade subject to rubbing interactions and harmonic forcing. Both contact, which is initiated by means of the harmonic forcing, and dry friction are accounted for. The presented procedure relies on the computation of the system's nonlinear normal modes and their analysis through the application of an energy principle derived from the Melnikov function. The dynamic Lagrangian frequency-time strategy associated with the harmonic balance method (DLFT-HBM) is used to predict the blade's dynamics response as well as to compute the autonomous nonlinear normal modes. The open industrial fan blade NASA rotor 67 is employed in order to avoid confidentiality issues and to promote the reproducibility of the presented results. Previous publications have underlined the complexity of NASA rotor 67's dynamics response as it undergoes structural contacts, thus making it an ideal benchmark blade when searching for isolated solutions. The application of the presented procedure considering a varying amplitude of the harmonic forcing allows to predict isolated branches of solutions featuring nonlinear resonances. With the use of the Melnikov energy principle, nonlinear modal interactions are shown to be responsible for the separation of branches of solutions from the main response curve. In the end, the application of the presented procedure on an industrial blade model with contact interactions demonstrates it is both industry-ready and applicable to highly nonlinear mechanical systems.
{"title":"Computation of Isolated Periodic Solutions for Forced Response Blade-Tip/Casing Contact Problems","authors":"Thibaut Vadcard, Fabrice Thouverez, Alain Batailly","doi":"10.1115/1.4063704","DOIUrl":"https://doi.org/10.1115/1.4063704","url":null,"abstract":"Abstract This article introduces a numerical procedure dedicated to the identification of isolated branches of solutions for nonlinear mechanical systems. It is here applied to a fan blade subject to rubbing interactions and harmonic forcing. Both contact, which is initiated by means of the harmonic forcing, and dry friction are accounted for. The presented procedure relies on the computation of the system's nonlinear normal modes and their analysis through the application of an energy principle derived from the Melnikov function. The dynamic Lagrangian frequency-time strategy associated with the harmonic balance method (DLFT-HBM) is used to predict the blade's dynamics response as well as to compute the autonomous nonlinear normal modes. The open industrial fan blade NASA rotor 67 is employed in order to avoid confidentiality issues and to promote the reproducibility of the presented results. Previous publications have underlined the complexity of NASA rotor 67's dynamics response as it undergoes structural contacts, thus making it an ideal benchmark blade when searching for isolated solutions. The application of the presented procedure considering a varying amplitude of the harmonic forcing allows to predict isolated branches of solutions featuring nonlinear resonances. With the use of the Melnikov energy principle, nonlinear modal interactions are shown to be responsible for the separation of branches of solutions from the main response curve. In the end, the application of the presented procedure on an industrial blade model with contact interactions demonstrates it is both industry-ready and applicable to highly nonlinear mechanical systems.","PeriodicalId":15685,"journal":{"name":"Journal of Engineering for Gas Turbines and Power-transactions of The Asme","volume":"48 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136098346","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}
Aksel Ånestad, Ramgopal Sampath, Jonas Moeck, Andrea Gruber, Nicholas Worth
Abstract An experimental investigation of flame structure, stability, and emissions performance was conducted in a two-stage combustor design operated with CH4, H2, and NH3/H2 fuel blends. The main flame zone features a premixed bluff body stabilized flame, with a secondary premixed opposing jet flame. The total power and air flow rate are kept constant between the different fuelling cases, while the air split between stages and equivalence ratios are varied to explore conditions relevant to gas turbine operation. Special emphasis is given to analysing the structure of the opposing jet flames in the secondary stage. In contrast to previous literature on reacting jets in cross flow, these interact significantly due to their proximity, leading to a merged flame zone(MFZ) at the impingement layer in the centre of the combustion chamber. As the jet-to-crossflow momentum ratio increases, the MFZ changes shape, reaching close to the walls for the methane cases, but remaining very compact when operating with almost pure hydrogen. For the hydrogen flames, diverting more air to the second stage allows higher total thermal power conditions to be reached, while avoiding flashback and instability. For ammonia-hydrogen flames, the fuel is kept in the primary zone, resulting in some locally rich conditions when air is diverted to the secondary. A local NOx minima occurs when the primary flame is operated at an equivalence ratio of 1.15. Analysis of the flame structure links decreasing NOx to NH3 pyrolysis, followed by a secondary H2 inverse diffusion flame.
{"title":"The Structure And Stability of Premixed CH4, H2, and NH3/H2 Flames in an Axially Staged Can Combustor","authors":"Aksel Ånestad, Ramgopal Sampath, Jonas Moeck, Andrea Gruber, Nicholas Worth","doi":"10.1115/1.4063718","DOIUrl":"https://doi.org/10.1115/1.4063718","url":null,"abstract":"Abstract An experimental investigation of flame structure, stability, and emissions performance was conducted in a two-stage combustor design operated with CH4, H2, and NH3/H2 fuel blends. The main flame zone features a premixed bluff body stabilized flame, with a secondary premixed opposing jet flame. The total power and air flow rate are kept constant between the different fuelling cases, while the air split between stages and equivalence ratios are varied to explore conditions relevant to gas turbine operation. Special emphasis is given to analysing the structure of the opposing jet flames in the secondary stage. In contrast to previous literature on reacting jets in cross flow, these interact significantly due to their proximity, leading to a merged flame zone(MFZ) at the impingement layer in the centre of the combustion chamber. As the jet-to-crossflow momentum ratio increases, the MFZ changes shape, reaching close to the walls for the methane cases, but remaining very compact when operating with almost pure hydrogen. For the hydrogen flames, diverting more air to the second stage allows higher total thermal power conditions to be reached, while avoiding flashback and instability. For ammonia-hydrogen flames, the fuel is kept in the primary zone, resulting in some locally rich conditions when air is diverted to the secondary. A local NOx minima occurs when the primary flame is operated at an equivalence ratio of 1.15. Analysis of the flame structure links decreasing NOx to NH3 pyrolysis, followed by a secondary H2 inverse diffusion flame.","PeriodicalId":15685,"journal":{"name":"Journal of Engineering for Gas Turbines and Power-transactions of The Asme","volume":"84 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136098493","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}
Tom Tanneberger, Johannes Mundstock, Christoph Rex, Sebastian Rösch, Christian Oliver Paschereit
Abstract In the H2mGT project, funded by the German BMWK, a micro gas turbine (mGT) burner with 100% hydrogen firing is developed and validated. The project is a collaboration between TUB and the manufacturer Euro-K GmbH. It consists of three phases: 1. Atmospheric pressure tests with optical access; 2. Atmospheric pressure tests with secondary air injection; 3. Validation of the burner in the mGT. This paper will present the results of Phase 1. The hydrogen burner is based on a swirl-stabilized burner of TUB. The burner design features multiple geometrical parameters to enable the optimization towards low NOx emissions. Therefore, a variable swirl intensity, additional axial momentum of air in the mixing tube, a movable center-body and different fuel injection locations are implemented. Phase 1 investigates the parameter space in terms of flame stability, operational range and parameter impact on flame shape and emissions. It is found that the flame can be operated over a large range of equivalence ratios and preheating temperatures up to 500°C for many parameter settings. However, at some geometries flashback into the mixing tube is triggered. As expected, the NOx emissions are mainly influenced by the equivalence ratio, the fuel distribution, and the swirl intensity. Single digit emissions are reached up to an equivalence ratio of 0.4 at atmospheric pressure conditions. Furthermore, the burner can be operated at 100% natural gas or 100% hydrogen without any geometry changes without a significant change in NOx emissions.
{"title":"Development of a Hydrogen Micro Gas Turbine Combustor: Atmospheric Pressure Testing","authors":"Tom Tanneberger, Johannes Mundstock, Christoph Rex, Sebastian Rösch, Christian Oliver Paschereit","doi":"10.1115/1.4063708","DOIUrl":"https://doi.org/10.1115/1.4063708","url":null,"abstract":"Abstract In the H2mGT project, funded by the German BMWK, a micro gas turbine (mGT) burner with 100% hydrogen firing is developed and validated. The project is a collaboration between TUB and the manufacturer Euro-K GmbH. It consists of three phases: 1. Atmospheric pressure tests with optical access; 2. Atmospheric pressure tests with secondary air injection; 3. Validation of the burner in the mGT. This paper will present the results of Phase 1. The hydrogen burner is based on a swirl-stabilized burner of TUB. The burner design features multiple geometrical parameters to enable the optimization towards low NOx emissions. Therefore, a variable swirl intensity, additional axial momentum of air in the mixing tube, a movable center-body and different fuel injection locations are implemented. Phase 1 investigates the parameter space in terms of flame stability, operational range and parameter impact on flame shape and emissions. It is found that the flame can be operated over a large range of equivalence ratios and preheating temperatures up to 500°C for many parameter settings. However, at some geometries flashback into the mixing tube is triggered. As expected, the NOx emissions are mainly influenced by the equivalence ratio, the fuel distribution, and the swirl intensity. Single digit emissions are reached up to an equivalence ratio of 0.4 at atmospheric pressure conditions. Furthermore, the burner can be operated at 100% natural gas or 100% hydrogen without any geometry changes without a significant change in NOx emissions.","PeriodicalId":15685,"journal":{"name":"Journal of Engineering for Gas Turbines and Power-transactions of The Asme","volume":"40 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136353581","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}
Konstantinos I. Papadopoulos, Christos P. Nasoulis, Vasilis Gkoutzamanis, Anestis I. Kalfas
Abstract This study aims to illustrate a sequence that optimizes the flight-path trajectory for a hybrid-electric propulsion system at mission level, in addition to identifying the respective optimum power management strategy. An in-house framework for hybrid-electric propulsion system modeling is utilized. A hybrid-electric commuter aircraft serves as a virtual test-bench. Vectorized calculations, decision variable count and optimization algorithms are considered for reducing the computational time of the framework. Performance improvements are evaluated for the aircraft's design mission profile. Total energy consumption is set as the objective function. Emphasis lies on minimizing the average value and standard deviation of the energy consumption and timeframe metrics. The best performing application decreases computational time by two orders of magnitude, while retaining equal accuracy and consistency as the original model. It is employed for creating a dataset for training an artificial neural network against random mission patterns. The trained network is integrated into a surrogate model. The latter part of the analysis evaluates optimized mission profile characteristics with respect to energy consumption, against a benchmark flight-path. The combined optimization process decreases the multi-hour-scale timeframe by two orders of magnitude to a 3-minute sequence. Using the novel framework, a 12% average energy consumption benefit is calculated for short, medium and long regional missions, against equivalent benchmark profiles.
{"title":"Flight-Path Optimization for a Hybrid-Electric Aircraft","authors":"Konstantinos I. Papadopoulos, Christos P. Nasoulis, Vasilis Gkoutzamanis, Anestis I. Kalfas","doi":"10.1115/1.4063707","DOIUrl":"https://doi.org/10.1115/1.4063707","url":null,"abstract":"Abstract This study aims to illustrate a sequence that optimizes the flight-path trajectory for a hybrid-electric propulsion system at mission level, in addition to identifying the respective optimum power management strategy. An in-house framework for hybrid-electric propulsion system modeling is utilized. A hybrid-electric commuter aircraft serves as a virtual test-bench. Vectorized calculations, decision variable count and optimization algorithms are considered for reducing the computational time of the framework. Performance improvements are evaluated for the aircraft's design mission profile. Total energy consumption is set as the objective function. Emphasis lies on minimizing the average value and standard deviation of the energy consumption and timeframe metrics. The best performing application decreases computational time by two orders of magnitude, while retaining equal accuracy and consistency as the original model. It is employed for creating a dataset for training an artificial neural network against random mission patterns. The trained network is integrated into a surrogate model. The latter part of the analysis evaluates optimized mission profile characteristics with respect to energy consumption, against a benchmark flight-path. The combined optimization process decreases the multi-hour-scale timeframe by two orders of magnitude to a 3-minute sequence. Using the novel framework, a 12% average energy consumption benefit is calculated for short, medium and long regional missions, against equivalent benchmark profiles.","PeriodicalId":15685,"journal":{"name":"Journal of Engineering for Gas Turbines and Power-transactions of The Asme","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136353545","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 Romedenne, Rishi Pillai, Sebastien Dryepondt, Bruce A. Pint
Abstract Hydrogen-fueled microturbines are being considered as part of the future green microgrid. However, the use of hydrogen as a fuel presents new challenges for selection and development of suitable high temperature materials for hydrogen combustion. The burning of hydrogen is expected to result in higher operating temperatures and higher than typically observed water vapor contents in exhaust gases versus burning natural gas. In the present work, foil specimens of various Fe- and Ni-based alloys were oxidized in air + 10 % H2O and air + 60% H2O for up to 5,000 h at 700 °C to simulate the exhaust atmosphere of natural gas and hydrogen-fueled microturbines. The impact of alloy composition and water vapor content on the oxidation/ volatilization induced loss of wall thickness was experimentally evaluated. Enhanced external oxidation and volatilization of Cr2O3 and Ti-doped Cr2O3 scales was observed in air + 60% H2O compared to air + 10% H2O. No significant impact of the higher water vapor content was observed on Al2O3 scales formed on Fe-based alumina forming alloys. Lifetime modeling was employed to predict the combined effects of water vapor content, gas flow rates, temperature and alloy composition on the oxidation-induced lifetime of the investigated materials.
{"title":"The Impact of Oxidation-Induced Degradation On Materials Used in Hydrogen-Fired Microturbines","authors":"Marie Romedenne, Rishi Pillai, Sebastien Dryepondt, Bruce A. Pint","doi":"10.1115/1.4063705","DOIUrl":"https://doi.org/10.1115/1.4063705","url":null,"abstract":"Abstract Hydrogen-fueled microturbines are being considered as part of the future green microgrid. However, the use of hydrogen as a fuel presents new challenges for selection and development of suitable high temperature materials for hydrogen combustion. The burning of hydrogen is expected to result in higher operating temperatures and higher than typically observed water vapor contents in exhaust gases versus burning natural gas. In the present work, foil specimens of various Fe- and Ni-based alloys were oxidized in air + 10 % H2O and air + 60% H2O for up to 5,000 h at 700 °C to simulate the exhaust atmosphere of natural gas and hydrogen-fueled microturbines. The impact of alloy composition and water vapor content on the oxidation/ volatilization induced loss of wall thickness was experimentally evaluated. Enhanced external oxidation and volatilization of Cr2O3 and Ti-doped Cr2O3 scales was observed in air + 60% H2O compared to air + 10% H2O. No significant impact of the higher water vapor content was observed on Al2O3 scales formed on Fe-based alumina forming alloys. Lifetime modeling was employed to predict the combined effects of water vapor content, gas flow rates, temperature and alloy composition on the oxidation-induced lifetime of the investigated materials.","PeriodicalId":15685,"journal":{"name":"Journal of Engineering for Gas Turbines and Power-transactions of The Asme","volume":"29 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136352610","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}
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