Academic literature on the topic 'Gas turbine, combustor turbine interaction, scale adaptive simulation, film cooled nozzle'
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Journal articles on the topic "Gas turbine, combustor turbine interaction, scale adaptive simulation, film cooled nozzle"
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Cubeda, S., L. Mazzei, T. Bacci, and A. Andreini. "Impact of Predicted Combustor Outlet Conditions on the Aerothermal Performance of Film-Cooled High Pressure Turbine Vanes." Journal of Engineering for Gas Turbines and Power 141, no. 5 (December 12, 2018). http://dx.doi.org/10.1115/1.4041038.
Full textAbstract:
Turbine inlet conditions in lean-burn aeroengine combustors are highly swirled and present nonuniform temperature distributions. Uncertainty and lack of confidence associated with combustor-turbine interaction affect significantly engine performance and efficiency. It is well known that only Large-eddy and scale-adaptive simulations (SAS) can overcome the limitations of Reynolds-averaged Navier–Stokes (RANS) in predicting the combustor outlet conditions. However, it is worth investigating the impact of such improvements on the predicted aerothermal performance of the nozzle guide vanes (NGVs), usually studied with RANS-generated boundary conditions. Three numerical modelling strategies were used to investigate a combustor-turbine module designed within the EU Project FACTOR: (i) RANS model of the NGVs with RANS-generated inlet conditions; (ii) RANS model of the NGVs with scale-adaptive simulation (SAS)-generated inlet conditions; (iii) SAS model inclusive of both combustor and NGVs. It was shown that estimating the aerodynamics through the NGVs does not demand particularly complex approaches, in contrast to situations where turbulent mixing is key. High-fidelity predictions of the turbine entrance conditions proved very beneficial to reduce the discrepancies in the estimation of adiabatic temperature distributions. However, a further leap forward can be achieved with an integrated simulation, capable of reproducing the transport of unsteady fluctuations generated from the combustor through the turbine, which play a key role in presence of film cooling. This work, therefore, shows how separate analysis of combustor and NGVs can lead to a poor estimation of the thermal loads and ultimately to a wrong thermal design of the cooling system.
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Andreini, A., T. Bacci, M. Insinna, L. Mazzei, and S. Salvadori. "Hybrid RANS-LES Modeling of the Aerothermal Field in an Annular Hot Streak Generator for the Study of Combustor–Turbine Interaction." Journal of Engineering for Gas Turbines and Power 139, no. 2 (September 20, 2016). http://dx.doi.org/10.1115/1.4034358.
Full textAbstract:
The adoption of lean-burn technology in modern aero-engines influences the already critical aerothermal conditions at turbine entry, where the absence of dilution holes preserves the swirl component generated by burners and prevents any control on pattern factor. The associated uncertainty and lack of confidence entail the application of wide safety margins in turbine cooling design, with a detrimental effect on engine efficiency. Computational fluid dynamics (CFD) can provide a deeper understanding of the physical phenomena involved in combustor–turbine interaction, especially with hybrid Reynolds-averaged Navier–Stokes (RANS) large eddy simulation (LES) models, such as scale adaptive simulation (SAS), which are proving to overcome the well-known limitations of the RANS approach and be a viable approach to capture the complex flow physics. This paper describes the numerical investigation on a test rig representative of a lean-burn, effusion cooled, annular combustor developed in the EU Project Full Aerothermal Combustor-Turbine interactiOns Research (FACTOR) with the aim of studying combustor–turbine interaction. Results obtained with RANS and SAS were critically compared to experimental data and analyzed to better understand the flow physics, as well as to assess the improvements related to the use of hybrid RANS-LES models. Significant discrepancies are highlighted for RANS in predicting the recirculating region, which has slight influence on the velocity field at the combustor outlet, but affects dramatically mixing and the resulting temperature distribution. The accuracy of the results achieved suggests the exploitation of SAS model with a view to the future inclusion of the nozzle guide vanes in the test rig.
Dissertations / Theses on the topic "Gas turbine, combustor turbine interaction, scale adaptive simulation, film cooled nozzle"
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Cubeda, Simone. "Impacts of gas-turbine combustors outlet flow on the aero-thermal performance of film-cooled first stage nozzles." Doctoral thesis, 2020. http://hdl.handle.net/2158/1197567.
Full textAbstract:
Modern aero-engine and industrial gas turbines typically employ lean-type combustors, which are capable of limiting pollutant emissions thanks to premixed flames, while sustaining high turbine inlet temperatures that increase the single-cycle thermal efficiency. In such technology gas-turbine first stage nozzles are characterised by a highly-swirled and temperature-distorted inlet flow field. However, due to several sources of uncertainty during the design phase, wide safety margins are commonly adopted, which can have a direct impact on the engine performance and efficiency.
Therefore, with the aim of increasing the knowledge on combustor-turbine interaction and improving standard design practices, two non-reactive test rigs were assembled at the University of Florence, Italy. The rigs, both accommodating three lean-premix swirlers within a combustion chamber and a first stage film-cooled nozzles cascade, were operated in similitude conditions to mimic an aero-engine and an industrial gas turbine arrangements. The rigs were designed to reproduce the real engine periodic flow field on the central sector, allowing also to perform measurements far enough from the lateral walls. The periodicity condition was enforced by the installation of circular ducts at the injectors outlet section as to preserve the non-reactive swirling flow down to the nozzles inlet plane.
For the aero-engine simulator rig and as part of two previous PhD works, of which the present is a continuation, an extensive test campaign was conducted. The flow field within the combustion chamber was investigated via particle-image velocimetry (PIV) and the combustor-turbine interface section was experimentally characterised in terms of velocity, pressure and turbulence fields by means of a five-hole pressure plus thermocouple probe and hot-wire anemometers, mounted on an automatic traverse system. To study the evolution of the combustor outlet flow through the nozzles and its interaction with the film-cooling flow, such measurements have been also replicated slightly downstream of the airfoils' trailing edge. Lastly, the film-cooling adiabatic effectiveness distribution over the airfoils was evaluated via coolant concentration measurements based on pressure sensitive paints (PSP) application. As far as the industrial turbine rig is concerned, the same type of measurements were carried out except for PIV.
Within such experimental scenario, the core of the present work is related to numerical analyses. In fact, since the design of industrial high-pressure turbines historically relies on 1D, circumferentially-averaged profiles of pressure, velocity and temperature at the combustor/turbine interface in conjunction with Reynolds-averaged Navier-Stokes (RANS) models, this thesis describes how measurements can be leveraged to improve numerical modelling procedures. Within such context, hybrid scale resolving techniques, such as Scale-Adaptive Simulation (SAS), can suit the purpose, whilst containing computational costs, as also shown in the literature. Furthermore, the investigation of the two components within the same integrated simulation enables the transport of unsteady fluctuations from the combustor down to the first stage nozzles, which can make the difference in the presence of film cooling.
Conference papers on the topic "Gas turbine, combustor turbine interaction, scale adaptive simulation, film cooled nozzle"
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Cubeda, Simone, Tommaso Bacci, Lorenzo Mazzei, Simone Salvadori, Bruno Facchini, Lorenzo Fiorineschi, and Yary Volpe. "Design of a Non-Reactive Warm Rig With Real Lean-Premix Combustor Swirlers and Film-Cooled First Stage Nozzles." In ASME Turbo Expo 2020: Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2020. http://dx.doi.org/10.1115/gt2020-14186.
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Abstract Modern industrial gas turbines typically employ lean-premix combustors, which can limit pollutant emissions thanks to premixed flames, while sustaining high turbine inlet temperatures that increase the single-cycle thermal efficiency. As such, gas-turbine first stage nozzles can be characterized by a highly-swirled and temperature-distorted inlet flow field. However, due to several sources of uncertainty during the design phase, wide safety margins are commonly adopted, having a direct impact on engine performance and efficiency. Therefore, aiming at increasing the knowledge on combustor-turbine interaction and improving standard design practices, a non-reactive test rig composed of real hardware was assembled at the University of Florence, Italy. The rig, accommodating three lean-premix swirlers within a combustion chamber and two first stage film-cooled nozzles of a Baker Hughes heavy-duty gas turbine, is operated in similitude conditions. The rig has been designed to reproduce the real engine periodic flow field on the central vane channel, also allowing for measurements far enough from the lateral walls. The periodicity condition on the central sector was achieved by the proper design of both the angular profile and pitch value of the tailboards with respect to the vanes, which was carried out in a preliminary phase via a Design of Experiments procedure. In addition, circular ducts needed to be installed at the injectors outlet section to preserve the non-reactive swirling flow down to the nozzles’ inlet plane. The combustor-turbine interface section has been experimentally characterized in nominal operating conditions as per the temperature, velocity and pressure fields by means of a five-hole pressure probe provided with a thermocouple, installed on an automatic traverse system. To study the evolution of the combustor outlet flow through the vanes and its interaction with the film-cooling flow, such measurements have been replicated also downstream of the vanes’ trailing edge. This work allowed for designing and providing preliminary data on a combustor simulator capable of equipping and testing real hardware film-cooled nozzles of a heavy-duty gas turbine. Ultimately, the activity sets the basis for an extensive test campaign aimed at characterizing the metal temperature, film effectiveness and heat transfer coefficient at realistic aerothermal conditions. In addition, and by leveraging experimental data, this activity paves the way for a detailed validation of current design practices as well as more advanced numerical methodologies such as Scale-Adaptive Simulations of the integrated combustor-turbine domain.
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Tomasello, Stella Grazia, Antonio Andreini, Roberto Meloni, Simone Cubeda, Luca Andrei, and Vittorio Michelassi. "Numerical Study of Combustor-Turbine Interaction by Using Hybrid RANS-LES Approach." In ASME Turbo Expo 2022: Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2022. http://dx.doi.org/10.1115/gt2022-82139.
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Abstract The complex flow field of gas turbine lean combustors is meant to reduce NOx emissions and maintain a stable flame by controlling the local temperature and promoting high turbulent mixing. Still, this may produce large flow and temperature unsteady distortions capable of disrupting the aerodynamics and heat transfer of the first high-pressure-turbine cooled nozzle. Therefore, the interaction between the combustion chamber and the turbine nozzle is analyzed first with the help of scale-resolving simulations that notably also include a realistic turbine nozzle cooling system. To determine the nature and severity of the interaction, and the risks associated to performing decoupled simulation, the results of the coupled computer simulation are analyzed and compared with those of decoupled simulations. In this case, the combustor is computed by replacing the turbine nozzle with a discharge convergent with the same throat area, and the conditions at the interface plane are used as inlet boundary conditions for a conventional RANS of the nozzle. The analyses of the coupled and decoupled simulation reveal that the combustion chamber is weakly affected by the presence of the nozzle, whereas the two thermal fields of the nozzle surface differ considerably, as well as the disruption of the film cooling by the incoming flow distortions.
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Hilgert, Jonathan, Martin Bruschewski, Holger Werschnik, and Heinz-Peter Schiffer. "Numerical Studies on Combustor-Turbine Interaction at the Large Scale Turbine Rig (LSTR)." In ASME Turbo Expo 2017: Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/gt2017-64504.
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In order to fully understand the physical behavior of lean burn combustors and its influence on high pressure turbine stages in modern jet engines, the use of Computational Fluid Dynamics (CFD) promises to be a valuable addition to experimental techniques. The numerical investigations of this paper are based on the Large Scale Turbine Rig (LSTR) at Technische Universität Darmstadt, Germany which has been set up to explore the aerothermal combustor turbine interaction. The underlying numerical grids of the simulations take account of the complex cooling design to the fullest extent, considering coolant cavities, cooling holes and vane trailing edge slots within the meshing process. In addition to the k-ω-SST turbulence model, Scale-Adaptive Simulation (SAS) is applied for a computational domain comprising swirl generator and nozzle guide vanes in order to overcome the shortcomings of eddy viscosity turbulence models with regard to streamline curvature. The numerical results are compared with Five Hole Probe measurements at different streamwise locations showing good agreement and allowing for a more detailed examination of the complex flow physics caused by the interaction of turbine flow with lean-burn combustion and advanced film-cooling concepts. Moreover, numerically predicted Nu-contours on the hub end wall of the nozzle guide vane are validated by means of Infrared Thermography measurements.
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Krichbaum, Alexander, Holger Werschnik, Manuel Wilhelm, Heinz-Peter Schiffer, and Knut Lehmann. "A Large Scale Turbine Test Rig for the Investigation of High Pressure Turbine Aerodynamics and Heat Transfer With Variable Inflow Conditions." In ASME Turbo Expo 2015: Turbine Technical Conference and Exposition. American Society of Mechanical Engineers, 2015. http://dx.doi.org/10.1115/gt2015-43261.
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Focusing on the experimental analysis of the effect of variable inlet flows on aerodynamics, efficiency and heat transfer of a modern high pressure turbine, the Large Scale Turbine Rig (LSTR) at Technische Universität Darmstadt has been extensively redesigned. The LSTR is a full annular, rotating low speed turbine test rig carrying a scaled 1.5-stage (NGV1 - Rotor - NGV2) axial high-pressure turbine geometry designed by Rolls-Royce Deutschland to match engine-realistic Reynolds numbers. To simulate real turbine inflow conditions, the LSTR is equipped with a combustor simulator module including exchangeable swirlers. Other inflow conditions include axial or turbulent inflow as well as altered relative positions of swirl cores and NGVs by traversing. To investigate combustor-turbine interaction, the LSTR offers a large variety of optical and physical access ports as well as high flexibility to the application of measurement techniques. An elaborate secondary air system enables the simulation of various cooling air flows. The turbine section is equipped with film-cooled NGVs, a hub side seal air injection between NGVs and rotor, as well as a hub side RIDN cooling air injection module designed to provide realistic turbine flow conditions. Exchangeable hub side RIDN-plates allow for investigation of different coolant injection geometries. Measurement capabilities include 5-hole-probes, Pitot and total temperature rakes, as well as static pressure taps distributed along NGV radial sections and at the hub side passage endwall. The NGV passage flow can be visualized by means of Particle Image Velocimetry (PIV). Hot Wire Anemometry (HWA) will be used for time-resolved measurements of the turbulence level at several positions. The distributions of heat transfer and film cooling effectiveness are acquired using infrared thermography and CO2-gas tracing.
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Xiong, Yan, Lucheng Ji, Zhedian Zhang, Yue Wang, and Yunhan Xiao. "Three-Dimensional CFD Analysis of a Gas Turbine Combustor for Medium/Low Heating Value Syngas Fuel." In ASME Turbo Expo 2008: Power for Land, Sea, and Air. ASMEDC, 2008. http://dx.doi.org/10.1115/gt2008-50662.
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Gas turbine is one of the key components for integrated gasification combined cycle (IGCC) system. Combustor of the gas turbine needs to burn medium/low heating value syngas produced by coal gasification. In order to save time and cost during the design and development of a gas turbine combustor for medium/low heating value syngas, computational fluid dynamics (CFD) offers a good mean. In this paper, 3D numerical simulations were carried out on a full scale multi-nozzle gas turbine combustor using commercial CFD software FLUENT. A 72 degrees sector was modeled to minimize the number of cells of the grid. For the fluid flow part, viscous Navier-Stokes equations were solved. The realizable k-ε turbulence model was adopted. Steady laminar flamelet model was used for the reacting system. The interaction between fluid turbulence and combustion chemistry was taken into account by the PDF (probability density function) model. The simulation was performed with two design schemes which are head cooling using film-cooling and impingement cooling. The details of the flow field and temperature distribution inside the two gas turbine combustors obtained could be cited as references for design and retrofit. Similarities were found between the predicted and experimental data of the transition duct exit temperature profile. There is much work yet to be done on modeling validation in the future.
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Andreini, A., T. Bacci, M. Insinna, L. Mazzei, and S. Salvadori. "Hybrid RANS-LES Modeling of the Aero-Thermal Field in an Annular Hot Streak Generator for the Study of Combustor-Turbine Interaction." In ASME Turbo Expo 2016: Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/gt2016-56583.
Full textAbstract:
Turbine entry conditions are characterized by unsteady and strongly non-uniform velocity, temperature and pressure fields. The uncertainty and the lack of confidence associated with these conditions require the application of wide safety margins during the design of the turbine cooling systems, with a detrimental effect on engine efficiency. The adoption of lean-burn technology in modern aero-engines to reduce NOx emissions exacerbates the situation, as the absence of dilution holes keeps the strong swirl component generated by the burners up to the combustor outlet and prevents to control the pattern factor. Complexity and costs associated with the experimental investigation of combustor-turbine interaction, makes Computational Fluid Dynamics (CFD) paramount to understand the physical phenomena involved. Moreover, due to the well-known limitations of the Reynolds-Averaged Navier-Stokes (RANS) approach and the increase in computational resources, hybrid RANS-LES models, such as Scale Adaptive Simulation (SAS), are proving to be a viable approach to capture the main structures of the flow field. This paper reports the main findings of the numerical investigation on a test rig representative of a lean-burn, effusion cooled, annular combustor, developed in the context of the EU Project FACTOR (Full Aerothermal Combustor-Turbine interactiOns Research) with the aim of studying combustor-turbine interaction. Results obtained with RANS and unsteady SAS were critically compared to experimental data and analysed in order to better understand the flow physics within such a device, as well as to assess the improvements related to the use of hybrid models. The main discrepancies between RANS and SAS are highlighted in predicting the recirculating region, which has slight influence on the velocity field at the combustor outlet, but affects dramatically mixing and the resulting temperature distribution. Accuracy of the results achieved suggest a possible exploitation of SAS model with a view to the future inclusion of the nozzle guide vanes within the test rig.
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Lörstad, Daniel, Anders Ljung, and Abdallah Abou-Taouk. "Investigation of Siemens SGT-800 Industrial Gas Turbine Combustor Using Different Combustion and Turbulence Models." In ASME Turbo Expo 2016: Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/gt2016-57694.
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Siemens SGT-800 gas turbine is the largest industrial gas turbine within Siemens medium gas turbine size range. The power rating is 53MW at 39% electrical efficiency in open cycle (ISO) and, for its power range, world class combined-cycle performance of >56%. The SGT-800 convectively cooled annular combustor with 30 Dry Low Emissions (DLE) burners has proven, for 50–100% load range, NOx emissions below 15/25ppm for gas/liquids fuels and CO emissions below 5ppm for all fuels, as well as extensive gas fuel flexible DLE capability. In this work the focus is on the combustion modelling of one burner sector of the SGT-800 annular combustor, which includes several challenges since various different physical phenomena interacts in the process. One of the most important aspects of the combustion in a gas turbine combustor is the turbulence chemistry interaction, which is dependent on both the turbulence model and the combustion model. Some turbulence-combustion model combinations that have shown reasonable results for academic generic cases and/or industrial applications at low pressure, might fail when applied to complex geometries at industrial gas turbine conditions since the combustion regime may be different. Therefore is here evaluated the performance of Reynolds Averaged Navier-Stokes (RANS) and Scale Adaptive Simulation (SAS) turbulence models combined with different combustion models, which includes the Eddy Dissipation Model (EDM) combined with Finite Rate Chemistry (FRC) using an optimized reduced 4-step scheme and two flamelet based models; Zimont’s Burning Velocity model and Lindstedt & Vaos Fractal model. The results are compared to obtained engine data and field experience, which includes for example flame position in order to evaluate the advantages and drawbacks of each model. All models could predict the flame shape and position in reasonable agreement with available data; however, for the flamelet based methods adjusted calibration constants were required to avoid a flame too far upstream or non-sufficient burn out which is not in agreement with engine data. In addition both the flamelet based models suffer from spurious results when fresh air is mixed into fully reacted gases and BVM also from spurious results inside the fuel system. The combined EDM-FRC with a properly optimized reduced chemical kinetic scheme seems to minimize these issues without the need of any calibration, with only a slight increase in computational cost.
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Rosafio, Nicola, Giove De Cosmo, Simone Salvadori, Mauro Carnevale, and Daniela Anna Misul. "Identification of Fluctuation Modes for a Cylindrical Film Cooling Hole Using the Spectral Proper Orthogonal Decomposition Method." In ASME Turbo Expo 2022: Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2022. http://dx.doi.org/10.1115/gt2022-79528.
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Abstract Film cooling is the main technology adopted to guarantee safe working conditions of vanes and blades in high-pressure turbine stages. Recent experimental investigations highlighted that unsteady interaction between the coolant jet and the hot gas contributes to the lateral dispersion of cold flow over the cooled surface. Hence, considering the harsh working environment of these devices, a fair prediction of their thermal performance requires accurate modelling of the interaction between cold and hot gases. In this paper, an experimental setup originally studied at the University of Karlsruhe during the EU-funded TATEF project is numerically investigated to determine the influence of high-frequency unsteady fluctuations on the thermal performance of the cooling device. The case study consists of a film cooling hole positioned on a flat plate, working at engine-like conditions. Unsteady Reynolds-Averaged Navier-Stokes equations are solved for a compressible flow in transonic regime on a hybrid mesh. Turbulence is modelled using the Scale-Adaptive Simulation method to correctly predict the interaction between the coolant and the main flow. Three different sets of conditions are analyzed by varying the blowing ratio from 0.5 to 1.5, aiming at highlighting the unsteady mechanisms occurring for different penetrations of the coolant into the hot gas. Time-averaged unsteady results are compared with the available experimental data to determine to what extent hybrid modelling allows for correctly predicting film cooling performance at different blowing ratios. Instantaneous solutions are then analyzed to investigate the time-dependent flow field in the vicinity of the jet exit section and on the cooled surface. Spectral Proper Orthogonal Decomposition is enforced to identify the principal fluctuation modes associated with the time-dependent coolant penetration into the main flow.