Adam C Frey, David Bosak, Joseph Stonham, Carl Sangan, Oliver Pountney
Electric propulsors powered by Proton Exchange Membrane Fuel Cells (PEMFCs) offer a net zero solution to aircraft propulsion. Heat generated by the PEMFCs can be transferred to atmospheric air via a liquid cooling system; however, the cooling system results in parasitic power and adds mass to the propulsion system, thereby affecting system specific power. The design of the cooling system is sensitive to the choice of liquid coolant and so informed coolant selection is required if associated parasitic power and mass are to be minimized. Two approaches to selection of coolants for PEMFC-powered aircraft are presented in this paper for operating temperatures in the range 80-200°C (this covers low, intermediate, and high temperature PEMFCs). The first approach uses a Figure of Merit (FoM) alongside minimum and maximum operating temperature requirements. The FoM supports the selection of coolants that minimize pumping power and mass while maximizing heat transfer rate. The second approach uses a cooling system model to select ȜPareto efficientȝ coolants. A hybrid-electric aircraft using a PEMFC stack is used as a representative case study for the two approaches. Hydrocarbon-based coolants are shown to be favorable for the case study considered here (aromatics for PEMFCs operating at <130°C and aliphatics for PEMFCs operating at >130°C). As the PEMFC operating temperature increases, the parasitic power and mass of the TMS decreases. Operating at elevated temperatures is therefore beneficial for liquid cooled PEMFC-powered aircraft. Nevertheless, there are diminishing performance gains at higher operating temperatures.
{"title":"Liquid Cooling of Fuel Cell Powered Aircraft: The Effect of Coolants on Thermal Management","authors":"Adam C Frey, David Bosak, Joseph Stonham, Carl Sangan, Oliver Pountney","doi":"10.1115/1.4066047","DOIUrl":"https://doi.org/10.1115/1.4066047","url":null,"abstract":"\u0000 Electric propulsors powered by Proton Exchange Membrane Fuel Cells (PEMFCs) offer a net zero solution to aircraft propulsion. Heat generated by the PEMFCs can be transferred to atmospheric air via a liquid cooling system; however, the cooling system results in parasitic power and adds mass to the propulsion system, thereby affecting system specific power. The design of the cooling system is sensitive to the choice of liquid coolant and so informed coolant selection is required if associated parasitic power and mass are to be minimized. Two approaches to selection of coolants for PEMFC-powered aircraft are presented in this paper for operating temperatures in the range 80-200°C (this covers low, intermediate, and high temperature PEMFCs). The first approach uses a Figure of Merit (FoM) alongside minimum and maximum operating temperature requirements. The FoM supports the selection of coolants that minimize pumping power and mass while maximizing heat transfer rate. The second approach uses a cooling system model to select ȜPareto efficientȝ coolants. A hybrid-electric aircraft using a PEMFC stack is used as a representative case study for the two approaches. Hydrocarbon-based coolants are shown to be favorable for the case study considered here (aromatics for PEMFCs operating at <130°C and aliphatics for PEMFCs operating at >130°C). As the PEMFC operating temperature increases, the parasitic power and mass of the TMS decreases. Operating at elevated temperatures is therefore beneficial for liquid cooled PEMFC-powered aircraft. Nevertheless, there are diminishing performance gains at higher operating temperatures.","PeriodicalId":508252,"journal":{"name":"Journal of Engineering for Gas Turbines and Power","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141814606","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The growth stresses induced by the thermally grown oxide (TGO) will be amplified at the free-edge site, making the free-edge site a weak part of the thermal barrier coatings (TBCs). In this study, the TBCs failure behavior is investigated based on different TGO morphologies under free edges. The thermomechanical model is established by creating straight lines and simplified sinusoidal curves, respectively. Dynamic TGO growth is realized by the secondary development of the subroutine. The cohesive element is inserted at the TC/TGO interface to simulate the delamination. The stress evolution near different TGO morphologies under the influence of the free edge are examined. In addition, the interfacial cracking behavior near the free edge is also explored. The results show that the appearance of the free edge will deteriorate the stress condition in the nearby area, change the preferred cracking area, and induce the earlier failure behavior. The straight line morphology has the most “friendly” stress distribution. The sinusoidal curves have peaks and valleys, and different areas of the TGO shape are different under the influence of the free edge, but all of them have the effect of stress “convergence”. These results can provide significant guidance to develop the next-generation advanced TBCs.
{"title":"Comprehensive Understanding of TGO Morphology Effect on the Thermal Barrier Coatings Failure Under Free Edges","authors":"Da Qiao, Wu Zeng","doi":"10.1115/1.4066027","DOIUrl":"https://doi.org/10.1115/1.4066027","url":null,"abstract":"\u0000 The growth stresses induced by the thermally grown oxide (TGO) will be amplified at the free-edge site, making the free-edge site a weak part of the thermal barrier coatings (TBCs). In this study, the TBCs failure behavior is investigated based on different TGO morphologies under free edges. The thermomechanical model is established by creating straight lines and simplified sinusoidal curves, respectively. Dynamic TGO growth is realized by the secondary development of the subroutine. The cohesive element is inserted at the TC/TGO interface to simulate the delamination. The stress evolution near different TGO morphologies under the influence of the free edge are examined. In addition, the interfacial cracking behavior near the free edge is also explored. The results show that the appearance of the free edge will deteriorate the stress condition in the nearby area, change the preferred cracking area, and induce the earlier failure behavior. The straight line morphology has the most “friendly” stress distribution. The sinusoidal curves have peaks and valleys, and different areas of the TGO shape are different under the influence of the free edge, but all of them have the effect of stress “convergence”. These results can provide significant guidance to develop the next-generation advanced TBCs.","PeriodicalId":508252,"journal":{"name":"Journal of Engineering for Gas Turbines and Power","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141816120","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Aircraft electrification introduces challenges in power and thermal management. In a hybrid-electric aircraft (HEA), the additional heat loads generated by the high-power electrical components in the propulsion system can negate the benefits of the HEA. Consequently, an integrated energy management system is required for the HEA to reject the additional heat loads while minimizing energy consumption. This paper presents the integrated modelling method for an integrated power and thermal management system (IPTMS) for HEA. With this method, a platform can be developed to assess the varying efficiencies of the components in the electrical propulsion system (EPS), and the performance of the thermal management system (TMS), such as passive cooling, during a flight mission. This makes it applicable to modular designs and optimizations of the IPTMS. A small/medium range (SMR) aircraft similar to ATR72 is studied. In this study, the EPS operates only during take-off and climb. Therefore, the platform assesses the heat and power loads of the IPTMS for a typical flight mission (take-off and climb) in this study. The performance of passive cooling is also analysed across this typical flight mission and under normal, hot-day, and cold-day conditions. It was found that passive cooling is sufficient under these three conditions, and the active temperature control is requried to ensure the components' temperatures are above the minimum temperatures. These findings imply the potential to minimize TMS weight and energy consumption, providing an insight for further research on IPTMS.
飞机电气化给电源和热管理带来了挑战。在混合动力电动飞机（HEA）中，推进系统中大功率电气组件产生的额外热负荷可能会抵消 HEA 的优势。因此，混合动力飞机需要一个综合能源管理系统，以抵消额外的热负荷，同时最大限度地降低能耗。本文介绍了用于 HEA 的集成功率和热管理系统 (IPTMS) 的集成建模方法。利用这种方法，可以开发一个平台来评估电力推进系统（EPS）中各组件的不同效率，以及热管理系统（TMS）的性能，如飞行任务期间的被动冷却。因此，它适用于模块化设计和 IPTMS 的优化。研究对象是一架类似于 ATR72 的小型/中程（SMR）飞机。在这项研究中，EPS 仅在起飞和爬升期间运行。因此，在这项研究中，平台评估了典型飞行任务（起飞和爬升）中 IPTMS 的热负荷和功率负荷。此外，还分析了在正常、炎热日和寒冷日条件下执行这一典型飞行任务时的被动冷却性能。研究发现，在这三种条件下，被动冷却是足够的，而主动温度控制是确保组件温度高于最低温度的必要条件。这些发现意味着最大限度地减少 TMS 重量和能耗的潜力，为进一步研究 IPTMS 提供了启示。
{"title":"Integrated Power and Thermal Management System for a Hybrid-Electric Aircraft: Integrated Modelling and Passive Cooling Analysis","authors":"Zeyu Ouyang, T. Nikolaidis, S. Jafari","doi":"10.1115/1.4066050","DOIUrl":"https://doi.org/10.1115/1.4066050","url":null,"abstract":"\u0000 Aircraft electrification introduces challenges in power and thermal management. In a hybrid-electric aircraft (HEA), the additional heat loads generated by the high-power electrical components in the propulsion system can negate the benefits of the HEA. Consequently, an integrated energy management system is required for the HEA to reject the additional heat loads while minimizing energy consumption. This paper presents the integrated modelling method for an integrated power and thermal management system (IPTMS) for HEA. With this method, a platform can be developed to assess the varying efficiencies of the components in the electrical propulsion system (EPS), and the performance of the thermal management system (TMS), such as passive cooling, during a flight mission. This makes it applicable to modular designs and optimizations of the IPTMS. A small/medium range (SMR) aircraft similar to ATR72 is studied. In this study, the EPS operates only during take-off and climb. Therefore, the platform assesses the heat and power loads of the IPTMS for a typical flight mission (take-off and climb) in this study. The performance of passive cooling is also analysed across this typical flight mission and under normal, hot-day, and cold-day conditions. It was found that passive cooling is sufficient under these three conditions, and the active temperature control is requried to ensure the components' temperatures are above the minimum temperatures. These findings imply the potential to minimize TMS weight and energy consumption, providing an insight for further research on IPTMS.","PeriodicalId":508252,"journal":{"name":"Journal of Engineering for Gas Turbines and Power","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141817194","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Hongyi Wei, Tim Kayser, E. Bach, C. O. Paschereit, Myles D. Bohon
Current total pressure measurement techniques in RDCs are based on different assumptions and therefore show different applicability for specific RDC operating conditions, and few studies have directly compared these techniques. Therefore, this study comprehensively tested three total pressure measurement techniques: the direct Kiel probe method, the Mach-corrected CTAP method, and the equivalent available pressure (EAP) method under different RDC geometries and mass flow rates, and compared them with their corresponding uncertainties considered. The results show that for all tests in this study, the EAP method shows the largest uncertainty range up to 24%, which is mainly contributed by the load cell calibration process, while the direct Kiel probe method has the lowest uncertainty range, which is consistently below 7%. These uncertainties were incorporated into the comparison between the three techniques via Gaussian process regression, showing that the direct Kiel probe method and the Mach-corrected CTAP method can present EAP-like total pressure. In particular, the total pressure of the SWCC and L modes measured by the three techniques is very comparable. This work shows that the comparability of total pressure techniques depends on the specific RDC environment, and provides the possibility to evaluate the RDC performance with the simplest implementation.
{"title":"Comparative Analysis of Total Pressure Measurement Techniques in Rotating Detonation Combustors","authors":"Hongyi Wei, Tim Kayser, E. Bach, C. O. Paschereit, Myles D. Bohon","doi":"10.1115/1.4066049","DOIUrl":"https://doi.org/10.1115/1.4066049","url":null,"abstract":"\u0000 Current total pressure measurement techniques in RDCs are based on different assumptions and therefore show different applicability for specific RDC operating conditions, and few studies have directly compared these techniques. Therefore, this study comprehensively tested three total pressure measurement techniques: the direct Kiel probe method, the Mach-corrected CTAP method, and the equivalent available pressure (EAP) method under different RDC geometries and mass flow rates, and compared them with their corresponding uncertainties considered. The results show that for all tests in this study, the EAP method shows the largest uncertainty range up to 24%, which is mainly contributed by the load cell calibration process, while the direct Kiel probe method has the lowest uncertainty range, which is consistently below 7%. These uncertainties were incorporated into the comparison between the three techniques via Gaussian process regression, showing that the direct Kiel probe method and the Mach-corrected CTAP method can present EAP-like total pressure. In particular, the total pressure of the SWCC and L modes measured by the three techniques is very comparable. This work shows that the comparability of total pressure techniques depends on the specific RDC environment, and provides the possibility to evaluate the RDC performance with the simplest implementation.","PeriodicalId":508252,"journal":{"name":"Journal of Engineering for Gas Turbines and Power","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141815700","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Etienne Lameloise, B. Cuenot, E. Riber, Aurélien Perrier, Gilles Cabot, Frédéric Grisch
The present work proposes a methodology to include accurate kinetics for soot modeling taking into account real fuel complexity in Large Eddy Simulation of aeronautical engines at a reasonable computational cost. The methodology is based on the construction of an analytically reduced kinetic mechanism describing both combustion and gaseous soot precursors growth with sufficient accuracy on selected target properties. This is achieved in several steps, starting from the selection of the detailed kinetic model for combustion and soot precursors growth, followed by the determination of a fuel surrogate model describing the complex real fuel blend. Finally the selected kinetic model is analytically reduced with the code ARCANE while controlling the error on flame properties and soot prediction for the considered fuel surrogate. To perform all evaluation and reduction tests on canonical sooting flames, a Discrete Sectional Model for soot has been implemented in Cantera. The resulting code (Cantera-soot) is now available for the fast calculation of soot production in laminar flames for any fuel. The obtained reduced kinetic scheme is finally validated in a Rich-Quench-Lean burner of the literature in terms of soot prediction capabilities by comparison of LES coupled to the Lagrangian Soot Tracking model with measurements. Results show a significant improvement of the soot level prediction when using the reduced more realistic kinetics, which also allows a more detailed analysis of the soot emission mechanisms. This demonstrates the gain in accuracy obtained with improved reduced kinetics, and validates the methodology to build such schemes.
本研究提出了一种方法，在航空发动机大涡模拟中考虑到实际燃料的复杂性，以合理的计算成本将精确的动力学纳入烟尘建模。该方法的基础是构建一个分析减少的动力学机制，描述燃烧和气态烟尘前体的生长，并对选定的目标特性有足够的准确性。这一过程分为几个步骤，首先是选择详细的燃烧和烟尘前体生长动力学模型，然后是确定描述复杂实际混合燃料的燃料替代模型。最后，使用 ARCANE 代码对选定的动力学模型进行分析还原，同时控制所考虑的燃料代用物的火焰特性和烟尘预测误差。为了对典型烟尘火焰进行所有评估和还原测试，在 Cantera 中实施了烟尘离散截面模型。由此产生的代码（Cantera-soot）现在可用于快速计算任何燃料在层流火焰中的烟尘生成。通过将 LES 与拉格朗日烟尘跟踪模型和测量结果进行比较，最终在文献中的 Rich-Quench-Lean 燃烧器中验证了所获得的简化动力学方案的烟尘预测能力。结果表明，在使用更符合实际情况的简化动力学方案时，烟尘水平预测有了明显改善，同时还能对烟尘排放机制进行更详细的分析。这表明使用改进的还原动力学可以提高精度，并验证了建立此类方案的方法。
{"title":"Prediction of Soot in an RQL Burner Using a Semi-Detailed Jeta-1 Chemistry","authors":"Etienne Lameloise, B. Cuenot, E. Riber, Aurélien Perrier, Gilles Cabot, Frédéric Grisch","doi":"10.1115/1.4066029","DOIUrl":"https://doi.org/10.1115/1.4066029","url":null,"abstract":"\u0000 The present work proposes a methodology to include accurate kinetics for soot modeling taking into account real fuel complexity in Large Eddy Simulation of aeronautical engines at a reasonable computational cost. The methodology is based on the construction of an analytically reduced kinetic mechanism describing both combustion and gaseous soot precursors growth with sufficient accuracy on selected target properties. This is achieved in several steps, starting from the selection of the detailed kinetic model for combustion and soot precursors growth, followed by the determination of a fuel surrogate model describing the complex real fuel blend. Finally the selected kinetic model is analytically reduced with the code ARCANE while controlling the error on flame properties and soot prediction for the considered fuel surrogate. To perform all evaluation and reduction tests on canonical sooting flames, a Discrete Sectional Model for soot has been implemented in Cantera. The resulting code (Cantera-soot) is now available for the fast calculation of soot production in laminar flames for any fuel. The obtained reduced kinetic scheme is finally validated in a Rich-Quench-Lean burner of the literature in terms of soot prediction capabilities by comparison of LES coupled to the Lagrangian Soot Tracking model with measurements. Results show a significant improvement of the soot level prediction when using the reduced more realistic kinetics, which also allows a more detailed analysis of the soot emission mechanisms. This demonstrates the gain in accuracy obtained with improved reduced kinetics, and validates the methodology to build such schemes.","PeriodicalId":508252,"journal":{"name":"Journal of Engineering for Gas Turbines and Power","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141815983","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Alexander Jaeschke, Bernhard Ćosić, Dominik Wassmer, C. O. Paschereit
Decarbonization of gas turbine combustion creates a pressing demand for new technical solutions for the combustion process. While switching to hydrogen fuels may solve the problem of carbon emissions and associated pollutants it can also lead to stability issues for swirl-stabilized combustors due to its increased reactivity. However, with jet flame burner systems, the required flashback safety can be achieved with high axial flow velocities even for premixed combustion of 100% hydrogen fuel. The development of such an engineering solution, however, requires significant effort to reach the maturity of today's swirl burners. This study examines the capacity of a premixed multi-tube jet burner to manage the chemical reactivity change over a range of volumetric blends from pure natural gas to pure hydrogen fuel. NOx emissions are measured and analyzed for atmospheric tests. The changes in emissions originate not only from altered combustion chemistry but also from changes in flame shape and turbulence intensity. To get a deeper understanding of the NOx formation process, a low-order model is designed and compared to the experimental data of technically and perfectly premixed combustion tests. Parameter variations of the low-order model are conducted to assess the influences on the NOx emission production of the multi jet burner. The information on the combustion process required for the model is obtained computationally and experimentally. Therefore, flame images are recorded and analyzed.
{"title":"Nox Emissions Assessment of a Multi Jet Burner Operated with Premixed High Hydrogen Natural Gas Blends","authors":"Alexander Jaeschke, Bernhard Ćosić, Dominik Wassmer, C. O. Paschereit","doi":"10.1115/1.4066030","DOIUrl":"https://doi.org/10.1115/1.4066030","url":null,"abstract":"\u0000 Decarbonization of gas turbine combustion creates a pressing demand for new technical solutions for the combustion process. While switching to hydrogen fuels may solve the problem of carbon emissions and associated pollutants it can also lead to stability issues for swirl-stabilized combustors due to its increased reactivity. However, with jet flame burner systems, the required flashback safety can be achieved with high axial flow velocities even for premixed combustion of 100% hydrogen fuel. The development of such an engineering solution, however, requires significant effort to reach the maturity of today's swirl burners. This study examines the capacity of a premixed multi-tube jet burner to manage the chemical reactivity change over a range of volumetric blends from pure natural gas to pure hydrogen fuel. NOx emissions are measured and analyzed for atmospheric tests. The changes in emissions originate not only from altered combustion chemistry but also from changes in flame shape and turbulence intensity. To get a deeper understanding of the NOx formation process, a low-order model is designed and compared to the experimental data of technically and perfectly premixed combustion tests. Parameter variations of the low-order model are conducted to assess the influences on the NOx emission production of the multi jet burner. The information on the combustion process required for the model is obtained computationally and experimentally. Therefore, flame images are recorded and analyzed.","PeriodicalId":508252,"journal":{"name":"Journal of Engineering for Gas Turbines and Power","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141816047","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The Authors developed 1400°C(2552°F) class CMC material system which consist of SiC fibers and SiC matrix and ytterbium silicate base matrix, aiming for higher temperature capability. Then they designed and manufactured high pressure turbine shrouds for aircraft engines using that 1400°C class material system, and they conducted strength tests and thermal cycle tests for turbine shroud components. After that they conducted engine tests for the CMC turbine shrouds demonstration in the actual engine environment jointly with the Japan Aerospace Exploration Agency (JAXA) in 2021. The engine test was conducted for over 75 hours including over 35 hour hot time. After the test teardown inspection was conducted. No spallation of EBC, no recession and no wear on CMC turbine shrouds were found. As the result of the microstructure observation for cut faces of CMC turbine shrouds, no oxidation in SiC fibers, no chemical reaction in matrix, and no microcrack in matrix were found, but, some oxidation in fiber interface coating and microcrack in EBC were found. Bending strength tests with specimens cut out from CMC turbine shrouds were conducted in order to survey the degradation of material. As the result of bending test, the strength of the specimens cut out from engine tested shrouds were equivalent to the strength of the specimens cut out from unused shrouds. The CMC turbine shrouds after engine test were determined to be serviceable, therefore the developed 1400°C class CMC shrouds was proven to be sound in an actual engine environment.
{"title":"Development of 1400°C(2552°F) class Ceramic Matrix Composite Turbine Shroud and Demonstration Test with JAXA F7 Aircraft Engine","authors":"Fumiaki Watanabe, Shohei Yamanaka, Toshihito Noguchi, Hiroto Hirano, Hayao Sato, M. Makida, Masahiro Hojo","doi":"10.1115/1.4066028","DOIUrl":"https://doi.org/10.1115/1.4066028","url":null,"abstract":"\u0000 The Authors developed 1400°C(2552°F) class CMC material system which consist of SiC fibers and SiC matrix and ytterbium silicate base matrix, aiming for higher temperature capability. Then they designed and manufactured high pressure turbine shrouds for aircraft engines using that 1400°C class material system, and they conducted strength tests and thermal cycle tests for turbine shroud components. After that they conducted engine tests for the CMC turbine shrouds demonstration in the actual engine environment jointly with the Japan Aerospace Exploration Agency (JAXA) in 2021. The engine test was conducted for over 75 hours including over 35 hour hot time. After the test teardown inspection was conducted. No spallation of EBC, no recession and no wear on CMC turbine shrouds were found. As the result of the microstructure observation for cut faces of CMC turbine shrouds, no oxidation in SiC fibers, no chemical reaction in matrix, and no microcrack in matrix were found, but, some oxidation in fiber interface coating and microcrack in EBC were found. Bending strength tests with specimens cut out from CMC turbine shrouds were conducted in order to survey the degradation of material. As the result of bending test, the strength of the specimens cut out from engine tested shrouds were equivalent to the strength of the specimens cut out from unused shrouds. The CMC turbine shrouds after engine test were determined to be serviceable, therefore the developed 1400°C class CMC shrouds was proven to be sound in an actual engine environment.","PeriodicalId":508252,"journal":{"name":"Journal of Engineering for Gas Turbines and Power","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141814640","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Novel low swirl concepts provide a promising approach to ensure stable flame anchoring over an extensive operation condition range, necessary for optimising compact designs for liquid fuel combustors as used in hybrid aero-engine or micro gas turbines in terms of scalability and flexibility. The current study utilises seven different additive manufactured low swirler integrated into a dual airblast injection concept to delineate the influence of high momentum swirling air jet on spray atomization and combustion performance. The developed injector is designed for vane angles from zero to 45° for co- and counter-direction against the orientation of the liquid sheet ejected from the pre-filming pressure swirl injector. The spray atomization in swirl afflicted air jet is demonstrated by phase Doppler interferometry and shadowgraphy. The combustion process is analysed using OH* -chemiluminescence imaging and emission measurements. The results show that a circumferential gaseous flow acting on the wall-film amplifies the radial fuel penetration and atomization. The latter produces robust spray dispersion in response to variations of operational conditions. The effect of low swirl injection on combustion process of kerosene flames leads to a noticeably more compact and intensified heat release zone. In addition, non-monotonic decomposed mode energy with considerable NOx reduction is observed.
{"title":"Low Swirl Effect On Compact Spray and Combustion Systems Using Additive Manufactured Dual Airblast Injectors","authors":"Yeonse Kang, Jihwan Ahn, Fabian Hampp","doi":"10.1115/1.4066005","DOIUrl":"https://doi.org/10.1115/1.4066005","url":null,"abstract":"\u0000 Novel low swirl concepts provide a promising approach to ensure stable flame anchoring over an extensive operation condition range, necessary for optimising compact designs for liquid fuel combustors as used in hybrid aero-engine or micro gas turbines in terms of scalability and flexibility. The current study utilises seven different additive manufactured low swirler integrated into a dual airblast injection concept to delineate the influence of high momentum swirling air jet on spray atomization and combustion performance. The developed injector is designed for vane angles from zero to 45° for co- and counter-direction against the orientation of the liquid sheet ejected from the pre-filming pressure swirl injector. The spray atomization in swirl afflicted air jet is demonstrated by phase Doppler interferometry and shadowgraphy. The combustion process is analysed using OH* -chemiluminescence imaging and emission measurements. The results show that a circumferential gaseous flow acting on the wall-film amplifies the radial fuel penetration and atomization. The latter produces robust spray dispersion in response to variations of operational conditions. The effect of low swirl injection on combustion process of kerosene flames leads to a noticeably more compact and intensified heat release zone. In addition, non-monotonic decomposed mode energy with considerable NOx reduction is observed.","PeriodicalId":508252,"journal":{"name":"Journal of Engineering for Gas Turbines and Power","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141819199","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Joshua P. Johnsen, Joshua Melvin, Joshua Drake, Muwanika Jdiobe, K. Rouser
This paper presents the experimental results of a representative aircraft turboelectric powertrain. The 180-kW hybrid gas-electric ground test rig was designed, fabricated, and experimentally evaluated for safe integration. Hybrid turboelectric power systems enable future medium- to long-range electrified aircraft, offering higher energy density over current battery technologies. Previous studies have focused on analytical models of turboelectric systems. However, as industry stakeholders continue to advance toward hybrid turboelectric aircraft, there is a need for practical knowledge regarding their implementation. The objectives of this study are two-fold. First, the study aims to evaluate the real-time transient performance of turboelectric aircraft. The second objective aims to characterize the real-world challenges of safely constructing and operating a hybrid turboelectric aircraft. To satisfy these objectives, a ground test vehicle was constructed from a modified Cessna-172 aircraft, a modified 180-kW PBS-TP100 turboprop, two wing-mounted electric motors, and a purpose-built turboelectric powertrain. The engine was brought to full power and the electric motor power was varied. Experimental observations are made regarding interdependent time responses of the electro-mechanical systems. Test run results include engine performance metrics, current, voltage, and acoustic data. The generator peaked at 4-kW and was augmented by 13-kW battery power to drive distributed propulsors. Practical recommendations for safe integration are identified, such as a pre-charge circuit, crowbar circuit, and short protection circuits. This study provides insight into the design and practical implementation of turboelectric power systems for future electrified aircraft.
{"title":"Experimental Evaluation of an Electric Powertrain Designed for a 180-kw Turboelectric Aircraft Ground Test Rig","authors":"Joshua P. Johnsen, Joshua Melvin, Joshua Drake, Muwanika Jdiobe, K. Rouser","doi":"10.1115/1.4065995","DOIUrl":"https://doi.org/10.1115/1.4065995","url":null,"abstract":"\u0000 This paper presents the experimental results of a representative aircraft turboelectric powertrain. The 180-kW hybrid gas-electric ground test rig was designed, fabricated, and experimentally evaluated for safe integration. Hybrid turboelectric power systems enable future medium- to long-range electrified aircraft, offering higher energy density over current battery technologies. Previous studies have focused on analytical models of turboelectric systems. However, as industry stakeholders continue to advance toward hybrid turboelectric aircraft, there is a need for practical knowledge regarding their implementation. The objectives of this study are two-fold. First, the study aims to evaluate the real-time transient performance of turboelectric aircraft. The second objective aims to characterize the real-world challenges of safely constructing and operating a hybrid turboelectric aircraft. To satisfy these objectives, a ground test vehicle was constructed from a modified Cessna-172 aircraft, a modified 180-kW PBS-TP100 turboprop, two wing-mounted electric motors, and a purpose-built turboelectric powertrain. The engine was brought to full power and the electric motor power was varied. Experimental observations are made regarding interdependent time responses of the electro-mechanical systems. Test run results include engine performance metrics, current, voltage, and acoustic data. The generator peaked at 4-kW and was augmented by 13-kW battery power to drive distributed propulsors. Practical recommendations for safe integration are identified, such as a pre-charge circuit, crowbar circuit, and short protection circuits. This study provides insight into the design and practical implementation of turboelectric power systems for future electrified aircraft.","PeriodicalId":508252,"journal":{"name":"Journal of Engineering for Gas Turbines and Power","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141824917","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The present work proposes an accurate and efficient surrogate modeling method for predicting combustion field in a gas-turbine combustor. The method integrates proper orthogonal decomposition-based dimensional reduction, and Gaussian process regression, in conjunction with the similarity-based sample processing technique. The design parameters of concern include fuel mass flow rate and swirler vane angle. Global surrogate models (GSMs) based on proper orthogonal decomposition and kriging produce significant errors for spatial emulation of methane concentration and turbulent kinetic energy (TKE), which is found to be largely attributed to the feature disparity of sample data at different design points. The Tanimoto coefficient is introduced to identify the similarity relation of the sample design points. The similarity-based sample processing method leverages the techniques of radial partitioning, azimuthal rotation, and sample similarity clustering to enhance the similarity among samples. The radial partitioning divides the physical fields into subzones according to the peak and trough characteristics along the radial direction. Local surrogate models (LSMs) are then adaptively constructed in the subzones, through azimuthal rotation for the methane concentration field and sample similarity clustering for the TKE field. The results show that the LSMs reduced the average prediction error of the CH4 concentration field from 19.56% to 8.16% and the TKE field from 93.75% to 9.12% compared to the GSMs. The present method can effectively support the surrogate modeling of combustors with complex variations of geometric structures and flow physics.
{"title":"Local Surrogate Modeling for Spatial Emulation of Gas-Turbine Combustion via Similarity-Based Sample Processing","authors":"Junjie Geng, Haiying Qi, Jialu Li, Xingjian Wang","doi":"10.1115/1.4065994","DOIUrl":"https://doi.org/10.1115/1.4065994","url":null,"abstract":"\u0000 The present work proposes an accurate and efficient surrogate modeling method for predicting combustion field in a gas-turbine combustor. The method integrates proper orthogonal decomposition-based dimensional reduction, and Gaussian process regression, in conjunction with the similarity-based sample processing technique. The design parameters of concern include fuel mass flow rate and swirler vane angle. Global surrogate models (GSMs) based on proper orthogonal decomposition and kriging produce significant errors for spatial emulation of methane concentration and turbulent kinetic energy (TKE), which is found to be largely attributed to the feature disparity of sample data at different design points. The Tanimoto coefficient is introduced to identify the similarity relation of the sample design points. The similarity-based sample processing method leverages the techniques of radial partitioning, azimuthal rotation, and sample similarity clustering to enhance the similarity among samples. The radial partitioning divides the physical fields into subzones according to the peak and trough characteristics along the radial direction. Local surrogate models (LSMs) are then adaptively constructed in the subzones, through azimuthal rotation for the methane concentration field and sample similarity clustering for the TKE field. The results show that the LSMs reduced the average prediction error of the CH4 concentration field from 19.56% to 8.16% and the TKE field from 93.75% to 9.12% compared to the GSMs. The present method can effectively support the surrogate modeling of combustors with complex variations of geometric structures and flow physics.","PeriodicalId":508252,"journal":{"name":"Journal of Engineering for Gas Turbines and Power","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141827136","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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