Vipul Goyal, Mengyu Xu, Jayanta Kapat, Ladislav Veselý
Abstract This study is based on time-series data taken from the combined cycle heavy-duty utility gas turbines. For analysis, first a multistage vector autoregressive model is constructed for the nominal operation of the powerplant assuming sparsity in the association among variables and this is used as a basis for anomaly detection and prediction. This prediction is compared with the time-series data of the plant-operation containing anomalies. The comparative advantage based on prediction accuracy and applicability of the algorithms is discussed for the postprocessing. Next, the long-memory behavior of residuals is modeled, and heterogeneous variances are observed from the residuals of the generalized additive model. Autoregressive fractionally integrated moving average (ARFIMA) and generalized autoregressive conditional heteroskedasticity (GARCH) models are employed to fit the residual process, which significantly improve the prediction. Rolling one-step-ahead forecast is studied. Numerical experiments of abrupt changes and trend in the blade-path temperature are performed to evaluate the specificity and sensitivity of the prediction. The prediction is sensitive given reasonable signal-to-noise ratio and has lower false positive rate. The control chart is able to detect the simulated abrupt jump quickly.
{"title":"Prediction Enhancement of Machine Learning Using Time Series Modeling in Gas Turbines","authors":"Vipul Goyal, Mengyu Xu, Jayanta Kapat, Ladislav Veselý","doi":"10.1115/1.4063459","DOIUrl":"https://doi.org/10.1115/1.4063459","url":null,"abstract":"Abstract This study is based on time-series data taken from the combined cycle heavy-duty utility gas turbines. For analysis, first a multistage vector autoregressive model is constructed for the nominal operation of the powerplant assuming sparsity in the association among variables and this is used as a basis for anomaly detection and prediction. This prediction is compared with the time-series data of the plant-operation containing anomalies. The comparative advantage based on prediction accuracy and applicability of the algorithms is discussed for the postprocessing. Next, the long-memory behavior of residuals is modeled, and heterogeneous variances are observed from the residuals of the generalized additive model. Autoregressive fractionally integrated moving average (ARFIMA) and generalized autoregressive conditional heteroskedasticity (GARCH) models are employed to fit the residual process, which significantly improve the prediction. Rolling one-step-ahead forecast is studied. Numerical experiments of abrupt changes and trend in the blade-path temperature are performed to evaluate the specificity and sensitivity of the prediction. The prediction is sensitive given reasonable signal-to-noise ratio and has lower false positive rate. The control chart is able to detect the simulated abrupt jump quickly.","PeriodicalId":15685,"journal":{"name":"Journal of Engineering for Gas Turbines and Power-transactions of The Asme","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135944432","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}
Baha Suleiman, Hatem Selim, Alaaeldin Dawood, Jinkwan Song, Jongguen Lee, Abdurrahman Alkhalidi, Kamal M. AlAhmadi, Ibrahim A. AlGhamdi, Eid Badr, Mohammed Al-Gahatani
Abstract Employing a mixture or an emulsion of water and diesel fuel is considered a way to reduce gas emissions such as NOx and soot in a gas turbine. This study presents detailed experimental results on the spray characteristics of a water-diesel emulsion injected by a pressure swirl atomizer with a 90-degree spray angle and a flow number of 0.58 under a non-reacting environment at high pressure and temperature conditions. Acquiring this data is a key step when configuring a combustor that will employ emulsified fuels. In addition, this study seeks to confirm that the emulsion stays intact when it gets sprayed into the combustor. Furthermore, this study attempts to understand if a water-diesel emulsion prepared by a sonicator improves fuel atomization as compared to a water-diesel mixture prepared by a static mixer, i.e., not a proper emulsion. Tests are conducted in a high pressure and temperature testing facility at two ambient pressures and three ambient temperatures and water to diesel ratio (W/D) is varied from 11% to 100% by mass. Phase Doppler Particle Anemometry (PDPA) is employed to measure the spray characteristics. Through a backlit high-speed photography, overall spray patterns over different test conditions are visualized. Mie-scattering and planar laser-induced fluorescence imaging are utilized to visualize the mixture field. In general, the results indicate that emulsion stays intact as it gets sprayed into the combustor; and emulsion is a better solution to reduce emissions than a statically mixed mixture.
{"title":"Characterization of Spray Field for Water-Emulsified Diesel Using a Pressure Swirl Atomizer Under a Non-Reacting Environment","authors":"Baha Suleiman, Hatem Selim, Alaaeldin Dawood, Jinkwan Song, Jongguen Lee, Abdurrahman Alkhalidi, Kamal M. AlAhmadi, Ibrahim A. AlGhamdi, Eid Badr, Mohammed Al-Gahatani","doi":"10.1115/1.4063778","DOIUrl":"https://doi.org/10.1115/1.4063778","url":null,"abstract":"Abstract Employing a mixture or an emulsion of water and diesel fuel is considered a way to reduce gas emissions such as NOx and soot in a gas turbine. This study presents detailed experimental results on the spray characteristics of a water-diesel emulsion injected by a pressure swirl atomizer with a 90-degree spray angle and a flow number of 0.58 under a non-reacting environment at high pressure and temperature conditions. Acquiring this data is a key step when configuring a combustor that will employ emulsified fuels. In addition, this study seeks to confirm that the emulsion stays intact when it gets sprayed into the combustor. Furthermore, this study attempts to understand if a water-diesel emulsion prepared by a sonicator improves fuel atomization as compared to a water-diesel mixture prepared by a static mixer, i.e., not a proper emulsion. Tests are conducted in a high pressure and temperature testing facility at two ambient pressures and three ambient temperatures and water to diesel ratio (W/D) is varied from 11% to 100% by mass. Phase Doppler Particle Anemometry (PDPA) is employed to measure the spray characteristics. Through a backlit high-speed photography, overall spray patterns over different test conditions are visualized. Mie-scattering and planar laser-induced fluorescence imaging are utilized to visualize the mixture field. In general, the results indicate that emulsion stays intact as it gets sprayed into the combustor; and emulsion is a better solution to reduce emissions than a statically mixed mixture.","PeriodicalId":15685,"journal":{"name":"Journal of Engineering for Gas Turbines and Power-transactions of The Asme","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135993984","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 With air traffic expected to grow 5% annually until the year 2030, alternative fuels such as hydrogen are being investigated in order to tackle the current environmental crisis. Due to safety concerns, future hydrogen combustion chambers will require new designs of injection systems and are expected to operate under multi-mode combustion regimes. From a Large-Eddy-Simulation (LES) perspective, a prerequisite for the shift towards new hy- drogen combustion chamber technologies is a robust turbulent combustion model capable of functioning in non-premixed condi- tions. Turbulent combustion modeling using flame front filtering is a well-developed strategy in premixed combustion (Filtered- TAbulated Chemistry for Large-Eddy-Simulation - F-TACLES). This approach has been extended to non-premixed flames how- ever, it suffers from high flame filter size sensitivity. Moreover, thin hydrogen flame fronts will result in lower resolution on the LES grid, potentially amplifying this issue. In order to address the feasibility of the non-premixed F-TACLES model applied to hydrogen fuel, simple 1-D and 2-D laminar counterflow diffusion flames are computed. The model is then tested on the 3-D Sandia hydrogen jet flame with a Reynolds number of 10000. Simulations and a-priori tests show that tabulated sub-grid-scale correction terms are stiff and can result in nonphysical results, however the model is capable of correctly reproducing non-premixed flame structures for small filter sizes.
{"title":"Large-Eddy-Simulation of Turbulent Non-Premixed Hydrogen Combustion Using the Filtered Tabulated Chemistry Approach","authors":"Samuel Dillon, Renaud Mercier, Benoît Fiorina","doi":"10.1115/1.4063790","DOIUrl":"https://doi.org/10.1115/1.4063790","url":null,"abstract":"Abstract With air traffic expected to grow 5% annually until the year 2030, alternative fuels such as hydrogen are being investigated in order to tackle the current environmental crisis. Due to safety concerns, future hydrogen combustion chambers will require new designs of injection systems and are expected to operate under multi-mode combustion regimes. From a Large-Eddy-Simulation (LES) perspective, a prerequisite for the shift towards new hy- drogen combustion chamber technologies is a robust turbulent combustion model capable of functioning in non-premixed condi- tions. Turbulent combustion modeling using flame front filtering is a well-developed strategy in premixed combustion (Filtered- TAbulated Chemistry for Large-Eddy-Simulation - F-TACLES). This approach has been extended to non-premixed flames how- ever, it suffers from high flame filter size sensitivity. Moreover, thin hydrogen flame fronts will result in lower resolution on the LES grid, potentially amplifying this issue. In order to address the feasibility of the non-premixed F-TACLES model applied to hydrogen fuel, simple 1-D and 2-D laminar counterflow diffusion flames are computed. The model is then tested on the 3-D Sandia hydrogen jet flame with a Reynolds number of 10000. Simulations and a-priori tests show that tabulated sub-grid-scale correction terms are stiff and can result in nonphysical results, however the model is capable of correctly reproducing non-premixed flame structures for small filter sizes.","PeriodicalId":15685,"journal":{"name":"Journal of Engineering for Gas Turbines and Power-transactions of The Asme","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135994115","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}
Daniel Pugh, Philip Bowen, Rukshan Navaratne, Burak Goktepe, Anthony Giles, Agustin Valera Medina, Steven Morris, Robin Vivoli
Abstract As alternative fuels are designated for future energy applications, flexible combustor designs require considerable development to ensure stable operation with reduced NOx emissions. A non-premixed variable swirl burner was used to experimentally appraise changes in NO production pathways, with CH4 NH3, and H2 flames, alongside intermediate fuel blends. Maintaining an equivalent thermal power and flame temperature between fuels, preheated reactants (500 K) were supplied to the burner, with parametric changes made to pressure (1 - 6 bara) and swirl number (0.8 - 2.0). NO production was characterized, alongside variations in flame structure and topology, with a correlation demonstrated for exhaust emissions. NO production was shown to be sensitive to combustor pressure, providing an expected increase for CH4 and H2 flames. Emission profiles from both NH3 and H2 flames are shown to be significantly augmented by a change in swirl number. As NH3 fractions were increased in the H2 blend, a decaying trend in NO emissions was observed with an increase in pressure, and as a function of mixture ratio. However, this behaviour was markedly augmented by a change in swirl number and suggests that further reductions may be possible at increased pressure. At the low swirl/high pressure condition the NH3/H2 blend outperformed pure H2, providing lower NO concentrations. Emissions data were normalised using the traditional dry/O2 correction, alongside mass scaled by thermal power, with a comparison provided. The corresponding differences in emission formation pathways were investigated, alongside high-speed OH* chemiluminescence to further elucidate findings.
{"title":"Influence of Variable Swirl On Emissions in a Non-Premixed Fuel-Flexible Burner At Elevated Ambient Conditions","authors":"Daniel Pugh, Philip Bowen, Rukshan Navaratne, Burak Goktepe, Anthony Giles, Agustin Valera Medina, Steven Morris, Robin Vivoli","doi":"10.1115/1.4063786","DOIUrl":"https://doi.org/10.1115/1.4063786","url":null,"abstract":"Abstract As alternative fuels are designated for future energy applications, flexible combustor designs require considerable development to ensure stable operation with reduced NOx emissions. A non-premixed variable swirl burner was used to experimentally appraise changes in NO production pathways, with CH4 NH3, and H2 flames, alongside intermediate fuel blends. Maintaining an equivalent thermal power and flame temperature between fuels, preheated reactants (500 K) were supplied to the burner, with parametric changes made to pressure (1 - 6 bara) and swirl number (0.8 - 2.0). NO production was characterized, alongside variations in flame structure and topology, with a correlation demonstrated for exhaust emissions. NO production was shown to be sensitive to combustor pressure, providing an expected increase for CH4 and H2 flames. Emission profiles from both NH3 and H2 flames are shown to be significantly augmented by a change in swirl number. As NH3 fractions were increased in the H2 blend, a decaying trend in NO emissions was observed with an increase in pressure, and as a function of mixture ratio. However, this behaviour was markedly augmented by a change in swirl number and suggests that further reductions may be possible at increased pressure. At the low swirl/high pressure condition the NH3/H2 blend outperformed pure H2, providing lower NO concentrations. Emissions data were normalised using the traditional dry/O2 correction, alongside mass scaled by thermal power, with a comparison provided. The corresponding differences in emission formation pathways were investigated, alongside high-speed OH* chemiluminescence to further elucidate findings.","PeriodicalId":15685,"journal":{"name":"Journal of Engineering for Gas Turbines and Power-transactions of The Asme","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136033325","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}
Alexander Murray, Peter Ireland, Nick Green, Michael Wickins, Richard Hood, Janendra Telisinghe
Abstract With the hot stage of a modern aeroengine operating with combustor firing temperatures well beyond the melting point of the nickel superalloys from which the turbine blades are manufactured, developments to the methods of cooling of these components are required to advance performance. Double-wall, effusion systems exhibit a quasi-transpiration like cooling effect with recent work demonstrating their exceptional cooling performance. Such systems are characterized by two walls, one with impingement holes and the other with film cooling holes, that are mechanically and thermally connected via pedestals. However, manufacturing such geometries from single-crystal nickel superalloys remains a significant barrier to entry into service. This paper presents a method of manufacturing double-wall effusion specimens from a nickel superalloy commonly used in modern commercial high-pressure turbine components. The method maintains the mechanical integrity associated with nickel superalloys. Details of the method are presented alongside X-ray and GOM laser scan data of a flat-plate test article that demonstrates the success of the manufacturing process. Aerothermal testing of the specimen in a bespoke recirculating wind-tunnel facility was undertaken in which the overall cooling effectiveness of the system is obtained. The results reaffirm the excellent cooling performance of double-wall, effusion systems and further validate the manufacturing methodology as a method by which to realize enhanced cooling effectiveness in service.
{"title":"The Manufacturing and Experimental Validation of a Nickel Superalloy Double-Wall, Effusion Test Specimen","authors":"Alexander Murray, Peter Ireland, Nick Green, Michael Wickins, Richard Hood, Janendra Telisinghe","doi":"10.1115/1.4063448","DOIUrl":"https://doi.org/10.1115/1.4063448","url":null,"abstract":"Abstract With the hot stage of a modern aeroengine operating with combustor firing temperatures well beyond the melting point of the nickel superalloys from which the turbine blades are manufactured, developments to the methods of cooling of these components are required to advance performance. Double-wall, effusion systems exhibit a quasi-transpiration like cooling effect with recent work demonstrating their exceptional cooling performance. Such systems are characterized by two walls, one with impingement holes and the other with film cooling holes, that are mechanically and thermally connected via pedestals. However, manufacturing such geometries from single-crystal nickel superalloys remains a significant barrier to entry into service. This paper presents a method of manufacturing double-wall effusion specimens from a nickel superalloy commonly used in modern commercial high-pressure turbine components. The method maintains the mechanical integrity associated with nickel superalloys. Details of the method are presented alongside X-ray and GOM laser scan data of a flat-plate test article that demonstrates the success of the manufacturing process. Aerothermal testing of the specimen in a bespoke recirculating wind-tunnel facility was undertaken in which the overall cooling effectiveness of the system is obtained. The results reaffirm the excellent cooling performance of double-wall, effusion systems and further validate the manufacturing methodology as a method by which to realize enhanced cooling effectiveness in service.","PeriodicalId":15685,"journal":{"name":"Journal of Engineering for Gas Turbines and Power-transactions of The Asme","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135944433","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}
Stefano Piola, Francesco Bavassano, Marcello Benvenuto, Roberto Canepa, Tiziano Garbarino, Elena Pestelli
Abstract At an ever-faster pace, market's requirements for operational flexibility and turn-down capabilities are fundamental for heavy-duty gas turbines. Gas turbine energy plants require the lowest Minimum Environmental Load (MEL) for times when the power request is mainly covered by renewable sources and, however, need to promptly respond to green energy shortages. Ansaldo Energia has addressed such requirements overall its gas turbine portfolio, recently including GT26, as discussed in GT2021-59457. The present paper addresses the MEL reduction for AE94.3A via a modular upgrade package intended for the 110+ units Service fleet. To accomplish that, several features were designed and tested including VIGV extra-closure, air bypass through compressor blow-off lines and extended use of anti-ice air recirculation. None of these require major hardware changes but only upgrades within a normal service outage, together with minor control system adaptations. The wide-ranging technical challenges attached to the MEL reduction features are discussed. Validation on field via special instrumentation focused on compressor, secondary air system and turbine for several engines is also presented. The achieved Minimum Environmental Load reduction is shown and its potential discussed together with some features already in place, such as the use of CO catalyzer or the regulation of control valves put on external cooling lines. The readiness and performance level of this MEL upgrade package, already in operation on several power plants, is here demonstrated. This makes the AE94.3A gas turbine more flexible towards current and future market requirements.
{"title":"Turn-Down Capability of Ansaldo Energia's AE94.3A","authors":"Stefano Piola, Francesco Bavassano, Marcello Benvenuto, Roberto Canepa, Tiziano Garbarino, Elena Pestelli","doi":"10.1115/1.4063777","DOIUrl":"https://doi.org/10.1115/1.4063777","url":null,"abstract":"Abstract At an ever-faster pace, market's requirements for operational flexibility and turn-down capabilities are fundamental for heavy-duty gas turbines. Gas turbine energy plants require the lowest Minimum Environmental Load (MEL) for times when the power request is mainly covered by renewable sources and, however, need to promptly respond to green energy shortages. Ansaldo Energia has addressed such requirements overall its gas turbine portfolio, recently including GT26, as discussed in GT2021-59457. The present paper addresses the MEL reduction for AE94.3A via a modular upgrade package intended for the 110+ units Service fleet. To accomplish that, several features were designed and tested including VIGV extra-closure, air bypass through compressor blow-off lines and extended use of anti-ice air recirculation. None of these require major hardware changes but only upgrades within a normal service outage, together with minor control system adaptations. The wide-ranging technical challenges attached to the MEL reduction features are discussed. Validation on field via special instrumentation focused on compressor, secondary air system and turbine for several engines is also presented. The achieved Minimum Environmental Load reduction is shown and its potential discussed together with some features already in place, such as the use of CO catalyzer or the regulation of control valves put on external cooling lines. The readiness and performance level of this MEL upgrade package, already in operation on several power plants, is here demonstrated. This makes the AE94.3A gas turbine more flexible towards current and future market requirements.","PeriodicalId":15685,"journal":{"name":"Journal of Engineering for Gas Turbines and Power-transactions of The Asme","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135993982","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}
Simon Gövert, Pascal Gruhlke, Thomas Behrendt, Bertram Janus
Abstract A numerical procedure is presented for the scaling of lean aeronautical gas turbine combustors to different thrust classes. The procedure considers multiple operating points and aims for a self-similar flow field with respect to a reference configuration. The developed scaling approach relies on an optimization-based workflow which involves automated geometry and grid generation, unsteady Reynolds-averaged Navier-Stokes (URANS) simulations and post-processing. Kriging is applied as a meta model to identify new sets of geometrical parameters. A scaling function based on pressure loss, axial location of heat release, pilot air split and the temperature profile at the combustor exit is proposed. A generic internally-staged lean-burn high pressure aeronautical combustor has been designed to serve as a first verification test case with reactive flow characteristics comparable to real combustion chambers. The burner geometry is parameterized by 23 free parameters which are altered within the scaling process. The developed procedure is applied to scale the combustor to a lower thrust class considering multiple operating points simultaneously: take-off, approach and idle. In total, 65 different combustor variants have been evaluated within the scaling procedure. The final combustor configuration, scaled to a lower thrust class, shows good agreement to the reference configuration in terms of the scaling targets and reasonably resembles the emission indices. Integrating the scaling procedure into the design process of future combustion systems could reduce the required design iterations and thereby contribute to significantly reduced development times and costs.
{"title":"Scaling of Lean Aeronautical Gas Turbine Combustors","authors":"Simon Gövert, Pascal Gruhlke, Thomas Behrendt, Bertram Janus","doi":"10.1115/1.4063776","DOIUrl":"https://doi.org/10.1115/1.4063776","url":null,"abstract":"Abstract A numerical procedure is presented for the scaling of lean aeronautical gas turbine combustors to different thrust classes. The procedure considers multiple operating points and aims for a self-similar flow field with respect to a reference configuration. The developed scaling approach relies on an optimization-based workflow which involves automated geometry and grid generation, unsteady Reynolds-averaged Navier-Stokes (URANS) simulations and post-processing. Kriging is applied as a meta model to identify new sets of geometrical parameters. A scaling function based on pressure loss, axial location of heat release, pilot air split and the temperature profile at the combustor exit is proposed. A generic internally-staged lean-burn high pressure aeronautical combustor has been designed to serve as a first verification test case with reactive flow characteristics comparable to real combustion chambers. The burner geometry is parameterized by 23 free parameters which are altered within the scaling process. The developed procedure is applied to scale the combustor to a lower thrust class considering multiple operating points simultaneously: take-off, approach and idle. In total, 65 different combustor variants have been evaluated within the scaling procedure. The final combustor configuration, scaled to a lower thrust class, shows good agreement to the reference configuration in terms of the scaling targets and reasonably resembles the emission indices. Integrating the scaling procedure into the design process of future combustion systems could reduce the required design iterations and thereby contribute to significantly reduced development times and costs.","PeriodicalId":15685,"journal":{"name":"Journal of Engineering for Gas Turbines and Power-transactions of The Asme","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135994114","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}
Ahlem Ghabi, Toufik Boushaki, Pablo Escot Bocanegra, Eric Robert
Abstract This paper evaluates the effect of a microsecond pulsed plasma (MPP) on the stabilization and emission characteristics of non-premixed biogas/air flames with various CO2 contents. The MPP is generated by a unique DC-pulsed power generator providing high voltage (HV) pulses over a wide range of pulse repetition frequencies. The burner configuration is made up of two concentric tubes in which a swirler is placed inside the annular part, ensuring the oxidizer's rotation. The central tube delivers the fuel through an injector placed close to the burner exit. Electrical diagnostics, including voltage, were performed. OH* chemiluminescence measurements were done to describe the structure and stability of the flame. Results showed that plasma generated by microsecond HV pulses can improve flame stability. In this regard, the distribution of key active species in the burner was studied via optical emission spectroscopy (OES). The results revealed that the pulsed plasma generates chemically active species such as excited N2*, CH*, OH* molecules, and H* and O* atoms, thereby improving flame stability. The dependence of the emitted species intensities on plasma parameters was investigated in detail. It is demonstrated that MPP can drastically enhance the dynamic flame stability of swirling non-premixed biogas flames, especially at lean operating conditions. In addition, NOx and CO emissions were studied over a wide range of pulse repetition frequencies. It is seen that the pulsed plasma increases NOx emission slightly and significantly reduces CO concentration in the flue gases.
{"title":"Experimental Investigation On Microsecond Pulsed Plasma Supported Biogas Combustion","authors":"Ahlem Ghabi, Toufik Boushaki, Pablo Escot Bocanegra, Eric Robert","doi":"10.1115/1.4063771","DOIUrl":"https://doi.org/10.1115/1.4063771","url":null,"abstract":"Abstract This paper evaluates the effect of a microsecond pulsed plasma (MPP) on the stabilization and emission characteristics of non-premixed biogas/air flames with various CO2 contents. The MPP is generated by a unique DC-pulsed power generator providing high voltage (HV) pulses over a wide range of pulse repetition frequencies. The burner configuration is made up of two concentric tubes in which a swirler is placed inside the annular part, ensuring the oxidizer's rotation. The central tube delivers the fuel through an injector placed close to the burner exit. Electrical diagnostics, including voltage, were performed. OH* chemiluminescence measurements were done to describe the structure and stability of the flame. Results showed that plasma generated by microsecond HV pulses can improve flame stability. In this regard, the distribution of key active species in the burner was studied via optical emission spectroscopy (OES). The results revealed that the pulsed plasma generates chemically active species such as excited N2*, CH*, OH* molecules, and H* and O* atoms, thereby improving flame stability. The dependence of the emitted species intensities on plasma parameters was investigated in detail. It is demonstrated that MPP can drastically enhance the dynamic flame stability of swirling non-premixed biogas flames, especially at lean operating conditions. In addition, NOx and CO emissions were studied over a wide range of pulse repetition frequencies. It is seen that the pulsed plasma increases NOx emission slightly and significantly reduces CO concentration in the flue gases.","PeriodicalId":15685,"journal":{"name":"Journal of Engineering for Gas Turbines and Power-transactions of The Asme","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136033320","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}
Sean P. Cooper, Damien Nativel, Olivier E. Mathieu, Mustapha Fikri, Eric Petersen, Christof Schulz
Abstract Syngas is a desirable fuel for combustion in the Allam-Fetvedt cycle, which involves combustion under supercritical-CO2 conditions. While some work has been conducted in collecting ignition delay times (IDT) at the extreme pressures required by these systems, significant model deficiencies remain. Additionally, considerable barriers in terms of nonideal gas dynamic effects have been shown for these experiments in shock tubes. Further investigation into the fundamental combustion kinetics of H2/CO/CO2 mixtures is required. Time-resolved speciation measurements for target species have been shown to better aid in improving the understanding of underlying chemical kinetics than global ignition delay time measurements. Therefore, laser absorption measurements of CO were measured behind reflected shock waves during combustion of syngas at 5 and 10 bar and temperatures between 1080 and 2100 K. The mixtures investigated utilized H2-to-CO ratios of 1:1 and 1:4, respectively, each at stoichiometric conditions, allowing for discussions of the effect of initial fuel composition. A ratio of fuel to CO2 of 1:2 was also utilized to represent commercially available syngas. The mixtures were diluted in helium and argon (20% He, 76.5% Ar) to minimize thermal effects and to expedite CO thermal relaxation during the experiment. The resulting CO time histories were then compared to modern chemical kinetics mechanisms, and disagreement is seen for this system, which is assumed to be fairly well known. This study elucidates particular chemistry that needs improvement in moving toward a better understanding of syngas combustion at elevated pressures.
{"title":"CO Laser Absorption Measurements During Syngas Combustion at High Pressure","authors":"Sean P. Cooper, Damien Nativel, Olivier E. Mathieu, Mustapha Fikri, Eric Petersen, Christof Schulz","doi":"10.1115/1.4063414","DOIUrl":"https://doi.org/10.1115/1.4063414","url":null,"abstract":"Abstract Syngas is a desirable fuel for combustion in the Allam-Fetvedt cycle, which involves combustion under supercritical-CO2 conditions. While some work has been conducted in collecting ignition delay times (IDT) at the extreme pressures required by these systems, significant model deficiencies remain. Additionally, considerable barriers in terms of nonideal gas dynamic effects have been shown for these experiments in shock tubes. Further investigation into the fundamental combustion kinetics of H2/CO/CO2 mixtures is required. Time-resolved speciation measurements for target species have been shown to better aid in improving the understanding of underlying chemical kinetics than global ignition delay time measurements. Therefore, laser absorption measurements of CO were measured behind reflected shock waves during combustion of syngas at 5 and 10 bar and temperatures between 1080 and 2100 K. The mixtures investigated utilized H2-to-CO ratios of 1:1 and 1:4, respectively, each at stoichiometric conditions, allowing for discussions of the effect of initial fuel composition. A ratio of fuel to CO2 of 1:2 was also utilized to represent commercially available syngas. The mixtures were diluted in helium and argon (20% He, 76.5% Ar) to minimize thermal effects and to expedite CO thermal relaxation during the experiment. The resulting CO time histories were then compared to modern chemical kinetics mechanisms, and disagreement is seen for this system, which is assumed to be fairly well known. This study elucidates particular chemistry that needs improvement in moving toward a better understanding of syngas combustion at elevated pressures.","PeriodicalId":15685,"journal":{"name":"Journal of Engineering for Gas Turbines and Power-transactions of The Asme","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135944595","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}
Mertol Tufekci, Fadi El-Haddad, Loic Salles, Richard Setchfield, Ludovic Renson
Abstract Complicated systems made of multiple components are known to be difficult to model, considering their solutions can change dramatically even with the slightest variations in conditions. Aircraft engines contain such complicated systems, and some components in aircraft engines' turbines can cause significant changes in the system's overall response. Hence, this study is focused on investigating the behavior of a turbine blade of an aircraft engine and the effects of the contact between the blade and the seal wire on the dynamics of the blade-disk system. The investigation is performed via various numerical simulations in time and frequency domains. One sector of the bladed disk is modeled using the finite element method with the lock plate and the seal wire imposing cyclic symmetry boundary conditions in the static, modal, and frequency domain forced response analyses. In time domain analyses, the cyclic symmetry is replaced with simplified displacement restricting boundary conditions. The time domain analysis contains steady-state forced responses of the system. The results show that contact with the seal wire is not a major source of nonlinearity and damping. The contacts with the lock plate contribute more to the vibration damping than the seal wire. However, compared to the contacts at the root of the blade, both components remain less significant with regard to frictional damping and nonlinearity.
{"title":"Effects of the Seal Wire On the Nonlinear Dynamics of the Aircraft Engine Turbine Blades","authors":"Mertol Tufekci, Fadi El-Haddad, Loic Salles, Richard Setchfield, Ludovic Renson","doi":"10.1115/1.4063413","DOIUrl":"https://doi.org/10.1115/1.4063413","url":null,"abstract":"Abstract Complicated systems made of multiple components are known to be difficult to model, considering their solutions can change dramatically even with the slightest variations in conditions. Aircraft engines contain such complicated systems, and some components in aircraft engines' turbines can cause significant changes in the system's overall response. Hence, this study is focused on investigating the behavior of a turbine blade of an aircraft engine and the effects of the contact between the blade and the seal wire on the dynamics of the blade-disk system. The investigation is performed via various numerical simulations in time and frequency domains. One sector of the bladed disk is modeled using the finite element method with the lock plate and the seal wire imposing cyclic symmetry boundary conditions in the static, modal, and frequency domain forced response analyses. In time domain analyses, the cyclic symmetry is replaced with simplified displacement restricting boundary conditions. The time domain analysis contains steady-state forced responses of the system. The results show that contact with the seal wire is not a major source of nonlinearity and damping. The contacts with the lock plate contribute more to the vibration damping than the seal wire. However, compared to the contacts at the root of the blade, both components remain less significant with regard to frictional damping and nonlinearity.","PeriodicalId":15685,"journal":{"name":"Journal of Engineering for Gas Turbines and Power-transactions of The Asme","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135944779","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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