Tarjei Heggset, Ole Meyer, Luis Tay Wo Chong Hilares, Andrea Ciani, Andrea Gruber
Abstract In a future energy-system prospective, predictably dominated by (often) remote and (always) unsteady, non-dispatchable renewable power generation from solar and wind resources, hydrogen (H2) and ammonia (NH3) have emerged as logistically convenient, chemically-simple and carbon-free chemicals for energy transport and storage. In this context, a convenient feature of Ansaldo's Constant Pressure Sequential Combustion (CPSC) system, resulting in a fundamental advantage compared to alternative approaches, is the possibility of controlling the amount of fuel independently fed to the two combustion stages, depending on the fuel reactivity and combustion characteristics. However, ammonia combustion is governed by widely different thermo-chemical processes compared to hydrogen, requiring a considerably different approach to mitigate crucial issues with extremely low flame reactivity (blow-out) and formation of significant amounts of undesired pollutants and greenhouse gases (NOx and N2O). In this work, we present a fuel-flexible operational concept for the CPSC system and, based on unsteady Reynolds-Averaged Navier-Stokes (uRANS) and Large Eddy Simulation (LES) performed in conjunction with detailed chemical kinetics, we explore for the first time full-load operation of the CPSC architecture in a Rich-Quench-Lean (RQL) strategy applied to combustion of partially-decomposed ammonia. Results from the numerical simulations confirm the main features of ammonia-firing in RQL operation already observed from previous work on different combustion systems and suggests that the CPSC architecture has excellent potential to operate in RQL-mode with low NOx and N2O emissions and good combustion efficiency.
{"title":"Numerical Assessment of a Rich-Quench-Lean Staging Strategy for Clean and Efficient Combustion of Partially Decomposed Ammonia in the Constant Pressure Sequential Combustion System","authors":"Tarjei Heggset, Ole Meyer, Luis Tay Wo Chong Hilares, Andrea Ciani, Andrea Gruber","doi":"10.1115/1.4063958","DOIUrl":"https://doi.org/10.1115/1.4063958","url":null,"abstract":"Abstract In a future energy-system prospective, predictably dominated by (often) remote and (always) unsteady, non-dispatchable renewable power generation from solar and wind resources, hydrogen (H2) and ammonia (NH3) have emerged as logistically convenient, chemically-simple and carbon-free chemicals for energy transport and storage. In this context, a convenient feature of Ansaldo's Constant Pressure Sequential Combustion (CPSC) system, resulting in a fundamental advantage compared to alternative approaches, is the possibility of controlling the amount of fuel independently fed to the two combustion stages, depending on the fuel reactivity and combustion characteristics. However, ammonia combustion is governed by widely different thermo-chemical processes compared to hydrogen, requiring a considerably different approach to mitigate crucial issues with extremely low flame reactivity (blow-out) and formation of significant amounts of undesired pollutants and greenhouse gases (NOx and N2O). In this work, we present a fuel-flexible operational concept for the CPSC system and, based on unsteady Reynolds-Averaged Navier-Stokes (uRANS) and Large Eddy Simulation (LES) performed in conjunction with detailed chemical kinetics, we explore for the first time full-load operation of the CPSC architecture in a Rich-Quench-Lean (RQL) strategy applied to combustion of partially-decomposed ammonia. Results from the numerical simulations confirm the main features of ammonia-firing in RQL operation already observed from previous work on different combustion systems and suggests that the CPSC architecture has excellent potential to operate in RQL-mode with low NOx and N2O emissions and good combustion efficiency.","PeriodicalId":15685,"journal":{"name":"Journal of Engineering for Gas Turbines and Power-transactions of The Asme","volume":"26 4","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135934174","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}
Carlo Cravero, Davide Marsano, Vishnu Sishtla, Chaitanya Halbe, William T. Cousins
Abstract Modern compressor design targets require high performance and a wide operating range in order to reduce the environmental impact. To understand the fluid dynamics mechanisms that trigger instability, studying the system at the stability limit is required. In this work, a two-stage back-to-back centrifugal compressor for refrigerant applications has been simulated with computational fluid dynamics (CFD) techniques using unsteady calculations in different operating points close to surge. These models have been validated by comparing numerical performance with experimental data. An in-depth fluid dynamics analysis combined with the monitoring of several pressure signals, postprocessed with FFT, identified different flow phenomena in the two stages toward the surge limit. The key role of the volute that induces a stronger upstream counterpressure in the first stage has been highlighted. This effect causes the formation of high entropy (low momentum) rotating cells in the diffuser that involve a higher channel portion with respect to the flow structure in the second diffuser. This phenomenon affects the upstream flow conditions at the impeller. In addition, the interaction between the inlet guide vane (IGV) and the inducer has been analyzed, observing that in the second stage, due to the flow nonuniformity after the intermediate compressor pipe, non-negligible separations occur. Starting from the peaks detected in the FFT analysis of the pressure signals, all the above flow mechanisms have been detected and discussed.
{"title":"Numerical Investigations of Near Surge Operating Conditions in a Two-Stage Radial Compressor with Refrigerant Gas","authors":"Carlo Cravero, Davide Marsano, Vishnu Sishtla, Chaitanya Halbe, William T. Cousins","doi":"10.1115/1.4063577","DOIUrl":"https://doi.org/10.1115/1.4063577","url":null,"abstract":"Abstract Modern compressor design targets require high performance and a wide operating range in order to reduce the environmental impact. To understand the fluid dynamics mechanisms that trigger instability, studying the system at the stability limit is required. In this work, a two-stage back-to-back centrifugal compressor for refrigerant applications has been simulated with computational fluid dynamics (CFD) techniques using unsteady calculations in different operating points close to surge. These models have been validated by comparing numerical performance with experimental data. An in-depth fluid dynamics analysis combined with the monitoring of several pressure signals, postprocessed with FFT, identified different flow phenomena in the two stages toward the surge limit. The key role of the volute that induces a stronger upstream counterpressure in the first stage has been highlighted. This effect causes the formation of high entropy (low momentum) rotating cells in the diffuser that involve a higher channel portion with respect to the flow structure in the second diffuser. This phenomenon affects the upstream flow conditions at the impeller. In addition, the interaction between the inlet guide vane (IGV) and the inducer has been analyzed, observing that in the second stage, due to the flow nonuniformity after the intermediate compressor pipe, non-negligible separations occur. Starting from the peaks detected in the FFT analysis of the pressure signals, all the above flow mechanisms have been detected and discussed.","PeriodicalId":15685,"journal":{"name":"Journal of Engineering for Gas Turbines and Power-transactions of The Asme","volume":"63 8","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135874241","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 A three-stream combined Joule-Humphrey cycle that employs a heat recovery stream to function as a recuperator is presented. Based on an in-house developed thermodynamic performance tool, the operation of a modified dual-shaft turbofan engine is proposed. The engine core is modified by adding an intercooler and a reheating chamber to approach isothermal compression and expansion processes. A fraction of the primary flow is introduced into a reheat chamber that uses rotating detonation combustion (RDC) technology. The outflow of the RDC is then merged with the rest of the nucleus current before being discharged to the next turbine stage. The overall system behavior is captured by means of a nonlinear mathematical model featuring eight decision variables, including mass flow rates and compression ratios. A parametric analysis identifies the operational and performance envelope of the proposed engine concept. Ultimately, the model is endowed with an objective function, which includes global efficiency and thrust looking for an operation regime that boosts the thermodynamic performance. A generalized reduced gradient based algorithm is used to solve the nonlinear model, where each iteration solves a linearly constrained subproblem to generate a search direction. The performance and operational envelope presented here could be used as guidance for others considering the implementation of any of the discussed Joule cycle modifications or assessing the cost-effective balance of their use.
{"title":"Combined Joule-Humphrey-recuperator Cycle: Performance and Parametric Analysis Evaluation Towards More Efficient Air Transportation","authors":"Jorge Saavedra, Luis Cadarso","doi":"10.1115/1.4063536","DOIUrl":"https://doi.org/10.1115/1.4063536","url":null,"abstract":"Abstract A three-stream combined Joule-Humphrey cycle that employs a heat recovery stream to function as a recuperator is presented. Based on an in-house developed thermodynamic performance tool, the operation of a modified dual-shaft turbofan engine is proposed. The engine core is modified by adding an intercooler and a reheating chamber to approach isothermal compression and expansion processes. A fraction of the primary flow is introduced into a reheat chamber that uses rotating detonation combustion (RDC) technology. The outflow of the RDC is then merged with the rest of the nucleus current before being discharged to the next turbine stage. The overall system behavior is captured by means of a nonlinear mathematical model featuring eight decision variables, including mass flow rates and compression ratios. A parametric analysis identifies the operational and performance envelope of the proposed engine concept. Ultimately, the model is endowed with an objective function, which includes global efficiency and thrust looking for an operation regime that boosts the thermodynamic performance. A generalized reduced gradient based algorithm is used to solve the nonlinear model, where each iteration solves a linearly constrained subproblem to generate a search direction. The performance and operational envelope presented here could be used as guidance for others considering the implementation of any of the discussed Joule cycle modifications or assessing the cost-effective balance of their use.","PeriodicalId":15685,"journal":{"name":"Journal of Engineering for Gas Turbines and Power-transactions of The Asme","volume":"63 14","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135874445","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}
Ioannis Goulos, david G. MacManus, Josep Hueso Rebassa, Fernando Tejero, Andy Au, Christopher T. J. Sheaf
Abstract This paper presents a numerical investigation of the effect of wing integration on the aerodynamic behaviour of a typical large civil aero-engine exhaust system at wind-milling flow conditions. The work is based on the Dual Stream Jet Propulsion (DSJP) test rig, as will be tested within the Transonic Wind Tunnel (TWT) located at the Aircraft Research Association (ARA) in the UK. The DSJP rig was designed to measure the impact of the installed pressure field due to the effect of the wing on the aerodynamic performance of separate-jet exhausts. The rig is equipped with the Dual Separate Flow Reference Nozzle (DSFRN), installed under a swept wing. Computational fluid dynamic simulations were carried out for representative ranges of fan and core nozzle pressure ratios for “engine-out” wind-milling scenarios at End of Runway (EOR) take-off, diversion, and cruise conditions. Analyses were done for both isolated and installed configurations to quantify the impact of the installed pressure field on the fan and core nozzle discharge coefficients. The impact of fan and core nozzle pressure ratios, as well as free-stream Mach number and high-lift surfaces on the installed suppression effect were also evaluated. It is shown that the installed pressure field can reduce the fan nozzle discharge coefficient by up to 16%, relative to the isolated configuration for EOR wind-milling conditions. The results were used to inform the design and set-up of the experimental activity which is planned for 2023.
{"title":"Impact of Installation on The Performance of An Aero-Engine Exhaust At Wind-Milling Flow Conditions","authors":"Ioannis Goulos, david G. MacManus, Josep Hueso Rebassa, Fernando Tejero, Andy Au, Christopher T. J. Sheaf","doi":"10.1115/1.4063939","DOIUrl":"https://doi.org/10.1115/1.4063939","url":null,"abstract":"Abstract This paper presents a numerical investigation of the effect of wing integration on the aerodynamic behaviour of a typical large civil aero-engine exhaust system at wind-milling flow conditions. The work is based on the Dual Stream Jet Propulsion (DSJP) test rig, as will be tested within the Transonic Wind Tunnel (TWT) located at the Aircraft Research Association (ARA) in the UK. The DSJP rig was designed to measure the impact of the installed pressure field due to the effect of the wing on the aerodynamic performance of separate-jet exhausts. The rig is equipped with the Dual Separate Flow Reference Nozzle (DSFRN), installed under a swept wing. Computational fluid dynamic simulations were carried out for representative ranges of fan and core nozzle pressure ratios for “engine-out” wind-milling scenarios at End of Runway (EOR) take-off, diversion, and cruise conditions. Analyses were done for both isolated and installed configurations to quantify the impact of the installed pressure field on the fan and core nozzle discharge coefficients. The impact of fan and core nozzle pressure ratios, as well as free-stream Mach number and high-lift surfaces on the installed suppression effect were also evaluated. It is shown that the installed pressure field can reduce the fan nozzle discharge coefficient by up to 16%, relative to the isolated configuration for EOR wind-milling conditions. The results were used to inform the design and set-up of the experimental activity which is planned for 2023.","PeriodicalId":15685,"journal":{"name":"Journal of Engineering for Gas Turbines and Power-transactions of The Asme","volume":"38 8","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136104684","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}
Dimtrios Vitlaris, David John Rajendran, Richard J. Tunstall, John Whurr, Vassilios Pachidis
Abstract The flow field during the transition of a VPF from nominal operation to reverse thrust mode at typical ‘Approach Idle’ engine power setting is described in this work. An integrated airframe-engine-VPF research model is used to explore the flow field in a fully transient URANS simulation with imposed wall motion. A novel methodology that implements an adaptation of a mesh displacement equation to mimic the fan blade aerofoil rotation is developed. The implementation of this method with gradual, small step deformation along with an automated mesh update routine enables a high quality, near ‘real-time’ simulation of the complete transition. The flow field during transition is characterised by the evolution from typical forward flow to the development of massive recirculation regions at the feather pitch setting and finally to development of a reverse flow. The transient development of the flow features, ingested mass flow, airframe decelerating force and core engine distorted flow, apropos the fan aerofoil rotation to reverse thrust mode are discussed. A hitherto unresolved fan power peaking during the middle of the transition and higher power requirement at reverse thrust mode is captured. The effect of fan rotational speed and touch down velocity on the transition flow physics is explored. A comparison of the transient approach with discrete steady state runs for different stagger angle settings is presented. The new capability to study the transition in a fully transient simulation can be used as a design development aid for engineering the reverse thrust VPF.
{"title":"On The Flow Physics During The Transition of a Variable Pitch Fan From Nominal Operation To Reverse Thrust Mode","authors":"Dimtrios Vitlaris, David John Rajendran, Richard J. Tunstall, John Whurr, Vassilios Pachidis","doi":"10.1115/1.4063900","DOIUrl":"https://doi.org/10.1115/1.4063900","url":null,"abstract":"Abstract The flow field during the transition of a VPF from nominal operation to reverse thrust mode at typical ‘Approach Idle’ engine power setting is described in this work. An integrated airframe-engine-VPF research model is used to explore the flow field in a fully transient URANS simulation with imposed wall motion. A novel methodology that implements an adaptation of a mesh displacement equation to mimic the fan blade aerofoil rotation is developed. The implementation of this method with gradual, small step deformation along with an automated mesh update routine enables a high quality, near ‘real-time’ simulation of the complete transition. The flow field during transition is characterised by the evolution from typical forward flow to the development of massive recirculation regions at the feather pitch setting and finally to development of a reverse flow. The transient development of the flow features, ingested mass flow, airframe decelerating force and core engine distorted flow, apropos the fan aerofoil rotation to reverse thrust mode are discussed. A hitherto unresolved fan power peaking during the middle of the transition and higher power requirement at reverse thrust mode is captured. The effect of fan rotational speed and touch down velocity on the transition flow physics is explored. A comparison of the transient approach with discrete steady state runs for different stagger angle settings is presented. The new capability to study the transition in a fully transient simulation can be used as a design development aid for engineering the reverse thrust VPF.","PeriodicalId":15685,"journal":{"name":"Journal of Engineering for Gas Turbines and Power-transactions of The Asme","volume":"27 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136105700","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 We present a quantifiable, reproducible, and repeatable definition of the three-dimensional spray width and depth for a canonical jet in an open-source supersonic crossflow. An expanding Mach 2 dry-air crossflow is generated through a converging-diverging nozzle with a 25.4 mm by 230 mm wide throat area. A one-millimeter injector with ethanol seeding provides the liquid injection. Injector characteristics and losses are quantified through a calibrated cavitating venturi. Momentum flux ratios ranged from 0.1 to 20, and Reynolds number scaled by the injector diameter ranged from 5,000 to 40,000. A shadowgraph setup with a telecentric lens provides uniform magnification for precise and repeatable measurements from injection to 150 mm downstream of the jet. A Phantom v2012 camera with a frame rate of 20 kHz and shutter time of 285 ns was employed. Light transmittance is defined and calculated for each image pixel with a ratio method paired with no-spray images collected immediately before injection. These values are then related to an attenuation coefficient by incorporating spray width profiles collected with cross-sectional Mie-scatter imaging at multiple axial locations with a burst mode laser.
{"title":"Quantitative Definition of Spray Edge with Extinction Diagnostics and Evaluation of Attenuation Coefficient for Liquid Jets in Supersonic Crossflow","authors":"Aubrey McKelvy, James Braun, Guillermo Paniagua, Thierry Andre, Etienne Choquet, Francois Falempin","doi":"10.1115/1.4063887","DOIUrl":"https://doi.org/10.1115/1.4063887","url":null,"abstract":"Abstract We present a quantifiable, reproducible, and repeatable definition of the three-dimensional spray width and depth for a canonical jet in an open-source supersonic crossflow. An expanding Mach 2 dry-air crossflow is generated through a converging-diverging nozzle with a 25.4 mm by 230 mm wide throat area. A one-millimeter injector with ethanol seeding provides the liquid injection. Injector characteristics and losses are quantified through a calibrated cavitating venturi. Momentum flux ratios ranged from 0.1 to 20, and Reynolds number scaled by the injector diameter ranged from 5,000 to 40,000. A shadowgraph setup with a telecentric lens provides uniform magnification for precise and repeatable measurements from injection to 150 mm downstream of the jet. A Phantom v2012 camera with a frame rate of 20 kHz and shutter time of 285 ns was employed. Light transmittance is defined and calculated for each image pixel with a ratio method paired with no-spray images collected immediately before injection. These values are then related to an attenuation coefficient by incorporating spray width profiles collected with cross-sectional Mie-scatter imaging at multiple axial locations with a burst mode laser.","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":"2023-10-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136235068","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 Tip clearance monitoring is essential for the active health monitoring of turbomachinery and their development towards more efficient systems. Proper sensor calibration is paramount to this purpose, frequently being a time-consuming process. This paper introduces a novel in-situ dynamic calibration routine for high-frequency capacitance sensor measurements for tip clearance. The method predicts the calibration curve based on a single clearance measurement, the evolution of the acquired signal through various operational conditions, and the dimensional features of the multi-rim squealer-tip passing blades. The experimental data was obtained at 2MHz in a state-of-the-art two-stage high-speed turbine operated by the Purdue Experimental Turbine aerothermal Lab. A description of the empirical setup is provided, emphasizing the capacitance probes, the conditioning and acquisition systems, the metrology instruments used, and other ancillary instrumentation relevant to the calibration procedure. The prior filtering and data identification from the raw signal is detailed. The step-by-step development of the algorithm is presented, including justification of the curves imposed by the method. The resulting calibrations are provided, achieving accuracies of a few microns. The results are compared against previously used calibration techniques, emphasizing the potential advantages of the presented routine. Finally, the time-resolved tip clearance is analyzed against high frequency aerothermal data within the gap region, identifying relationships between the tip gap, unsteady pressure, and heat flux on the shroud.
{"title":"Robust Tip Gap Measurements: A Universal In-Situ Dynamic Calibration & Demonstration In A Two-Stage High-Speed Turbine","authors":"Antonio Castillo Sauca, Guillermo Paniagua","doi":"10.1115/1.4063886","DOIUrl":"https://doi.org/10.1115/1.4063886","url":null,"abstract":"Abstract Tip clearance monitoring is essential for the active health monitoring of turbomachinery and their development towards more efficient systems. Proper sensor calibration is paramount to this purpose, frequently being a time-consuming process. This paper introduces a novel in-situ dynamic calibration routine for high-frequency capacitance sensor measurements for tip clearance. The method predicts the calibration curve based on a single clearance measurement, the evolution of the acquired signal through various operational conditions, and the dimensional features of the multi-rim squealer-tip passing blades. The experimental data was obtained at 2MHz in a state-of-the-art two-stage high-speed turbine operated by the Purdue Experimental Turbine aerothermal Lab. A description of the empirical setup is provided, emphasizing the capacitance probes, the conditioning and acquisition systems, the metrology instruments used, and other ancillary instrumentation relevant to the calibration procedure. The prior filtering and data identification from the raw signal is detailed. The step-by-step development of the algorithm is presented, including justification of the curves imposed by the method. The resulting calibrations are provided, achieving accuracies of a few microns. The results are compared against previously used calibration techniques, emphasizing the potential advantages of the presented routine. Finally, the time-resolved tip clearance is analyzed against high frequency aerothermal data within the gap region, identifying relationships between the tip gap, unsteady pressure, and heat flux on the shroud.","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":"2023-10-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136317721","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 A lumped-parameter dynamic performance model for a single-spool turbojet engine is presented in this paper. This model can handle pre and poststall transients under forward and reverse-flow conditions. The inter-component volume technique is employed instead of the standard matching technique to be able to handle high-frequency transients and reverse-flow conditions. Inspired by Greitzer's lumped-parameter surge model, momentum (duct) and volume elements are placed within the flow path to handle surge dynamics. Compressor and turbine maps are extended to low-flow and reverse-flow regions using a combination of the guidelines presented by Kurzke, the cubic axisymmetric characteristics of Moore and Greitzer, and a quadratic function guess for in-stall characteristics. Combustor efficiency, stability limits, and delay are taken from the literature. Poststall behavior of the model is validated using the data available in the literature for a Rolls-Royce Viper engine. A good match is observed with a correct prediction of poststall behaviors, which transition from surge after locked stall to multiple surge cycles around 80% speed and multiple surge cycles to surge after flameout around 95% speed. The effects of different modeling choices and modeling parameters on the obtained results are discussed. The produced model can be calibrated for a specific engine with surge tests, and it can be used for hard-to-test scenarios like surge after shaft breakage. Different surge/stall-causing events, such as fuel spiking, in-bleeding, and shaft breakage, are simulated to see the capabilities of the model.
{"title":"A Surge/Stall-Capable Dynamic Performance Simulation Methodology for a Turbojet Engine","authors":"Emrah Güllü, Gökhan Aran","doi":"10.1115/1.4063422","DOIUrl":"https://doi.org/10.1115/1.4063422","url":null,"abstract":"Abstract A lumped-parameter dynamic performance model for a single-spool turbojet engine is presented in this paper. This model can handle pre and poststall transients under forward and reverse-flow conditions. The inter-component volume technique is employed instead of the standard matching technique to be able to handle high-frequency transients and reverse-flow conditions. Inspired by Greitzer's lumped-parameter surge model, momentum (duct) and volume elements are placed within the flow path to handle surge dynamics. Compressor and turbine maps are extended to low-flow and reverse-flow regions using a combination of the guidelines presented by Kurzke, the cubic axisymmetric characteristics of Moore and Greitzer, and a quadratic function guess for in-stall characteristics. Combustor efficiency, stability limits, and delay are taken from the literature. Poststall behavior of the model is validated using the data available in the literature for a Rolls-Royce Viper engine. A good match is observed with a correct prediction of poststall behaviors, which transition from surge after locked stall to multiple surge cycles around 80% speed and multiple surge cycles to surge after flameout around 95% speed. The effects of different modeling choices and modeling parameters on the obtained results are discussed. The produced model can be calibrated for a specific engine with surge tests, and it can be used for hard-to-test scenarios like surge after shaft breakage. Different surge/stall-causing events, such as fuel spiking, in-bleeding, and shaft breakage, are simulated to see the capabilities of the model.","PeriodicalId":15685,"journal":{"name":"Journal of Engineering for Gas Turbines and Power-transactions of The Asme","volume":"151 7","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134972112","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 A distorted air stream entering an aeroengine fan or compressor leads to harmonic forces on the rotating blades. These aerodynamically induced forces are well known causes for blade vibration and associated fatigue problems. Significant levels of distortion can arise from different sources that occur at specific operating conditions as well as from upstream obstructions in the flow. Unsteady response to a specific distortion can be modeled using CFD methods to a high degree of fidelity. With a focus on understanding the aeroacoustic interaction the analyses used here considers generic harmonics of the distortion. Harmonic responses are calculated from low to transonic speeds for a range of cases. Major phenomena and driving parameters affecting the forcing strength and pressure amplitudes in the blade passage are identified from the analyses. It is demonstrated that the forcing strength is strongly affected by the cut-on/cut-off conditions upstream and downstream of the blades. Also, depending on design parameters of the blade, the aeroacoustics of the blade passage is important for the resulting forcing. The analyses used are made in 2D over a wide range of flow conditions as well as geometric variations. The results of the study provides an increased understanding of the harmonic forcing of blades. A simple model is proposed that can identify condition where increased pressure amplitudes in the blade passage may be expected. The sensitivities to parameters may also give some guidance in how design and operation can be adapted to reduce the aerodynamic forcing.
{"title":"Aeroacoustic Effects on The Forcing Of Fan and Compressor Blades Due to Distortion","authors":"Hans Mårtensson, Mattias Billson","doi":"10.1115/1.4063867","DOIUrl":"https://doi.org/10.1115/1.4063867","url":null,"abstract":"Abstract A distorted air stream entering an aeroengine fan or compressor leads to harmonic forces on the rotating blades. These aerodynamically induced forces are well known causes for blade vibration and associated fatigue problems. Significant levels of distortion can arise from different sources that occur at specific operating conditions as well as from upstream obstructions in the flow. Unsteady response to a specific distortion can be modeled using CFD methods to a high degree of fidelity. With a focus on understanding the aeroacoustic interaction the analyses used here considers generic harmonics of the distortion. Harmonic responses are calculated from low to transonic speeds for a range of cases. Major phenomena and driving parameters affecting the forcing strength and pressure amplitudes in the blade passage are identified from the analyses. It is demonstrated that the forcing strength is strongly affected by the cut-on/cut-off conditions upstream and downstream of the blades. Also, depending on design parameters of the blade, the aeroacoustics of the blade passage is important for the resulting forcing. The analyses used are made in 2D over a wide range of flow conditions as well as geometric variations. The results of the study provides an increased understanding of the harmonic forcing of blades. A simple model is proposed that can identify condition where increased pressure amplitudes in the blade passage may be expected. The sensitivities to parameters may also give some guidance in how design and operation can be adapted to reduce the aerodynamic forcing.","PeriodicalId":15685,"journal":{"name":"Journal of Engineering for Gas Turbines and Power-transactions of The Asme","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135513154","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}
Lee Weller, Priyav Shah, Anthony Giles, Francesca De Domenico, Steven Morris, Benjamin A.O. Williams, Simone Hochgreb
Abstract Laser-Induced Grating Spectroscopy (LIGS) was applied in a high-pressure combustion facility. Instantaneous (sub-μs), spatially resolved (within 5 mm) measurements of temperature and molar fractions of water were obtained using thermal and electrostrictive LIGS signals. Temperatures up to 1800~K and water molar fractions between 0.01 and 0.12 were measured. A new analytic approach was developed to extract temperature from the frequencies of the measured signal within the flame brush region, where mixtures contain both burnt and unburnt gases. Mean product temperatures are shown to be 8% lower than the adiabatic temperatures for the nominal equivalence ratio, and 14% higher than measurements made with a thermocouple, uncorrected for radiation losses. This work represents the first application of LIGS to a high-pressure, turbulent swirling flame, opening up the potential for future uses in other real world applications. Challenges associated with the deployment of the technique are described, as are potential measures to overcome these difficulties.
{"title":"Spatial Temperature and Water Molar Concentration Measurements Using Thermal and Electrostrictive Ligs During Operation of a Swirl Burner at Pressure","authors":"Lee Weller, Priyav Shah, Anthony Giles, Francesca De Domenico, Steven Morris, Benjamin A.O. Williams, Simone Hochgreb","doi":"10.1115/1.4063865","DOIUrl":"https://doi.org/10.1115/1.4063865","url":null,"abstract":"Abstract Laser-Induced Grating Spectroscopy (LIGS) was applied in a high-pressure combustion facility. Instantaneous (sub-μs), spatially resolved (within 5 mm) measurements of temperature and molar fractions of water were obtained using thermal and electrostrictive LIGS signals. Temperatures up to 1800~K and water molar fractions between 0.01 and 0.12 were measured. A new analytic approach was developed to extract temperature from the frequencies of the measured signal within the flame brush region, where mixtures contain both burnt and unburnt gases. Mean product temperatures are shown to be 8% lower than the adiabatic temperatures for the nominal equivalence ratio, and 14% higher than measurements made with a thermocouple, uncorrected for radiation losses. This work represents the first application of LIGS to a high-pressure, turbulent swirling flame, opening up the potential for future uses in other real world applications. Challenges associated with the deployment of the technique are described, as are potential measures to overcome these difficulties.","PeriodicalId":15685,"journal":{"name":"Journal of Engineering for Gas Turbines and Power-transactions of The Asme","volume":"4 1-2","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135513158","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}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：