2010
Marconcini, Michele; Rubechini, Filippo; Pacciani, Roberto; Arnone, Andrea; Bertini, Francesco
Redesign of High-Lift LP-Turbine Airfoils for Low Speed Testing Proceedings
ASME, Glasgow, UK, June 14–18, 2010, vol. 7: Turbomachinery, Parts A, B, and C, 2010, ISBN: 978-0-7918-4402-1, (Paper GT2010-23284).
@proceedings{949,
title = {Redesign of High-Lift LP-Turbine Airfoils for Low Speed Testing},
author = {Michele Marconcini and Filippo Rubechini and Roberto Pacciani and Andrea Arnone and Francesco Bertini},
url = {http://proceedings.asmedigitalcollection.asme.org/proceeding.aspx?articleid=1609849&resultClick=3},
doi = {dx.doi.org/10.1115/GT2010-23284},
isbn = {978-0-7918-4402-1},
year = {2010},
date = {2010-06-01},
journal = {ASME Turbo Expo 2010: Power for Land, Sea, and Air},
volume = {7: Turbomachinery, Parts A, B, and C},
pages = {909-918},
publisher = {ASME},
address = {Glasgow, UK, June 14–18, 2010},
abstract = {Low pressure turbine airfoils of the present generation usually operate at subsonic conditions, with exit Mach numbers of about 0.6. To reduce the costs of experimental programs it can be convenient to carry out measurements in low speed tunnels in order to determine the cascades performance. Generally speaking, low speed tests are usually carried out on airfoils with modified shape, in order to compensate for the effects of compressibility. A scaling procedure for high-lift, low pressure turbine airfoils to be studied in low speed conditions is presented and discussed. The proposed procedure is based on the matching of a prescribed blade load distribution between the low speed airfoil and the actual one. Such a requirement is fulfilled via an Artificial Neural Network (ANN) methodology and a detailed parameterization of the airfoil. A RANS solver is used to guide the redesign process. The comparison between high and low speed profiles is carried out, over a wide range of Reynolds numbers, by using a novel three-equation, transition-sensitive, turbulence model. Such a model is based on the coupling of an additional transport equation for the so-called laminar kinetic energy (LKE) with the Wilcox k–ω model and it has proven to be effective for transitional, separated-flow configurations of high-lift cascade flows.},
note = {Paper GT2010-23284},
keywords = {},
pubstate = {published},
tppubtype = {proceedings}
}
Low pressure turbine airfoils of the present generation usually operate at subsonic conditions, with exit Mach numbers of about 0.6. To reduce the costs of experimental programs it can be convenient to carry out measurements in low speed tunnels in order to determine the cascades performance. Generally speaking, low speed tests are usually carried out on airfoils with modified shape, in order to compensate for the effects of compressibility. A scaling procedure for high-lift, low pressure turbine airfoils to be studied in low speed conditions is presented and discussed. The proposed procedure is based on the matching of a prescribed blade load distribution between the low speed airfoil and the actual one. Such a requirement is fulfilled via an Artificial Neural Network (ANN) methodology and a detailed parameterization of the airfoil. A RANS solver is used to guide the redesign process. The comparison between high and low speed profiles is carried out, over a wide range of Reynolds numbers, by using a novel three-equation, transition-sensitive, turbulence model. Such a model is based on the coupling of an additional transport equation for the so-called laminar kinetic energy (LKE) with the Wilcox k–ω model and it has proven to be effective for transitional, separated-flow configurations of high-lift cascade flows.
Marconcini, Michele; Rubechini, Filippo; Arnone, Andrea; Ibaraki, Seiichi
Numerical Analysis of the Vaned Diffuser of a Transonic Centrifugal Compressor Journal Article
In: ASME Journal of Turbomachinery, vol. 132, no. 4, pp. 041012, 2010, ISSN: 0889-504X.
@article{MRAI10,
title = {Numerical Analysis of the Vaned Diffuser of a Transonic Centrifugal Compressor},
author = {Michele Marconcini and Filippo Rubechini and Andrea Arnone and Seiichi Ibaraki},
url = {http://turbomachinery.asmedigitalcollection.asme.org/article.aspx?articleid=1468248},
doi = {10.1115/1.2988481},
issn = {0889-504X},
year = {2010},
date = {2010-01-01},
journal = {ASME Journal of Turbomachinery},
volume = {132},
number = {4},
pages = {041012},
abstract = {A three-dimensional Navier-Stokes solver is used to investigate the flow field of a high pressure ratio centrifugal compressor for turbocharger applications. Such a compressor consists of a double-splitter impeller followed by a vaned diffuser. Particular attention is focused on the analysis of the vaned diffuser, designed for high subsonic inlet conditions. The diffuser is characterized by a complex three-dimensional flow field, and influenced by the unsteady interaction with the impeller. Detailed Particle Image Velocimetry (PIV) flow measurements within the diffuser are available for comparison.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
A three-dimensional Navier-Stokes solver is used to investigate the flow field of a high pressure ratio centrifugal compressor for turbocharger applications. Such a compressor consists of a double-splitter impeller followed by a vaned diffuser. Particular attention is focused on the analysis of the vaned diffuser, designed for high subsonic inlet conditions. The diffuser is characterized by a complex three-dimensional flow field, and influenced by the unsteady interaction with the impeller. Detailed Particle Image Velocimetry (PIV) flow measurements within the diffuser are available for comparison.
2009
Rubechini, Filippo; Schneider, Andrea; Arnone, Andrea; Cecchi, Stefano; Malavasi, F
A Redesign Strategy to Improve the Efficiency of a 17-Stage Steam Turbine Proceedings
ASME, Orlando, FL, USA, June 8–12, 2009, vol. 7: Turbomachinery, Parts A and B, 2009, ISBN: 978-0-7918-4888-3, (Paper GT2009-60083).
@proceedings{950,
title = {A Redesign Strategy to Improve the Efficiency of a 17-Stage Steam Turbine},
author = {Filippo Rubechini and Andrea Schneider and Andrea Arnone and Stefano Cecchi and F Malavasi},
url = {http://proceedings.asmedigitalcollection.asme.org/proceeding.aspx?articleid=1647664&resultClick=3},
doi = {10.1115/GT2009-60083},
isbn = {978-0-7918-4888-3},
year = {2009},
date = {2009-06-01},
journal = {ASME Turbo Expo 2009: Power for Land, Sea, and Air},
volume = {7: Turbomachinery, Parts A and B},
pages = {1463-1470},
publisher = {ASME},
address = {Orlando, FL, USA, June 8–12, 2009},
abstract = {A three-dimensional RANS solver was applied to the aerodynamic redesigning of a 17-stage steam turbine. The redesign procedure was divided into three steps. In the first one, a single embedded stage was considered, and an optimization of stator lean and rotor twist was carried out by applying suitable repeating inlet/outlet boundary conditions. In the second step, a proper geometrical transformation between the original reference stage and the optimized one was identified and then applied to all other turbine stages, thus leading to a first approximation of the redesigned turbine. Finally, a neural-network-based refinement of the stator and rotor twist of each stage was performed to account for its actual position and operating conditions within the meridional channel. In this work, a detailed description of the redesign procedure is provided, and the aerodynamic characteristics of the optimized geometry are discussed and compared to the original ones.},
note = {Paper GT2009-60083},
keywords = {},
pubstate = {published},
tppubtype = {proceedings}
}
A three-dimensional RANS solver was applied to the aerodynamic redesigning of a 17-stage steam turbine. The redesign procedure was divided into three steps. In the first one, a single embedded stage was considered, and an optimization of stator lean and rotor twist was carried out by applying suitable repeating inlet/outlet boundary conditions. In the second step, a proper geometrical transformation between the original reference stage and the optimized one was identified and then applied to all other turbine stages, thus leading to a first approximation of the redesigned turbine. Finally, a neural-network-based refinement of the stator and rotor twist of each stage was performed to account for its actual position and operating conditions within the meridional channel. In this work, a detailed description of the redesign procedure is provided, and the aerodynamic characteristics of the optimized geometry are discussed and compared to the original ones.
Arnone, Andrea; Marconcini, Michele; Rubechini, Filippo; Schneider, Andrea; Alba, G
Kaplan Turbine Performance Prediction Using CFD: an Artificial Neural Network Approach Conference
HYDRO 2009 Conference Proceedings, 2009, (Lyon, France, 26-28 October 2009, paper n.263).
@conference{AMRSA09,
title = {Kaplan Turbine Performance Prediction Using CFD: an Artificial Neural Network Approach},
author = {Andrea Arnone and Michele Marconcini and Filippo Rubechini and Andrea Schneider and G Alba},
year = {2009},
date = {2009-01-01},
booktitle = {HYDRO 2009 Conference Proceedings},
abstract = {In this work a response surface approach was used for the prediction of the hill chart of a small horizontal shaft Kaplan turbine. To this aim artificial neural networks (ANN) were chosen as a fast, reliable, and computationally inexpensive tool. The training of the ANN was based on computational fluid dynamics (CFD).
The optimization of the runner-guide vane stagger correlation is a time consuming and expensive task when obtained either on experimental models or directly on the power plant. The use of CFD coupled with ANN may represent an attractive alternative.In order to obtain a more general prediction tool it was decided to characterize the turbine performance coupled with a generic draft tube.
The draft tube is a key component for the performance of small head power plants. As a matter of fact, the kinetic energy recovery may represent a considerable fraction of the total head, thus strongly affecting the efficiency. It presents a very complex flow environment characterized by unsteady, large scale vortices, and the prediction of its performance is a challenging task for the CFD. Moreover, in the refurbishment and repowering of hydro power plants, the turbine may often be coupled with a pre-existing draft tube.
For these reasons the draft tube was not included in the computational domain, and a simple 1D model was used to account for its influence on the turbine.
The three-dimensional version of the TRAF code developed at the University of Florence, coupled with a two equation turbulence closure has been used to predict the turbine flow features and the operating characteristics. The code exploits the artificial compressibility concept to work with incompressible flows. Steady multirow viscous single-phase analysis has been applied to compute the flow field from the inlet struts to the runner exit.
The CFD results were used for the training of a feed-forward artificial neural network with two hidden layers. As far as the training is concerned, a gradient based back propagation method was employed. In order to improve the generalization ability, a hybrid network made by multiple trained neural networks was used.
The considered input parameters were the stagger angles of both the runner and the guide vane, the mass flow rate and the draft tube recovery coefficient. The output of the neural network were the computed total head and the hydro power plant efficiency. The proposed procedure was applied to an existing power plant in order to optimize the runner-guide vane stagger correlation for all runner positions. Comparisons with the measurements obtained on the hydro power plant are presented and discussed. The predicted coupled positions of the guide vane and runner blades were successfully verified all over the range of the operating mass flows.},
note = {Lyon, France, 26-28 October 2009, paper n.263},
keywords = {},
pubstate = {published},
tppubtype = {conference}
}
In this work a response surface approach was used for the prediction of the hill chart of a small horizontal shaft Kaplan turbine. To this aim artificial neural networks (ANN) were chosen as a fast, reliable, and computationally inexpensive tool. The training of the ANN was based on computational fluid dynamics (CFD).
The optimization of the runner-guide vane stagger correlation is a time consuming and expensive task when obtained either on experimental models or directly on the power plant. The use of CFD coupled with ANN may represent an attractive alternative.In order to obtain a more general prediction tool it was decided to characterize the turbine performance coupled with a generic draft tube.
The draft tube is a key component for the performance of small head power plants. As a matter of fact, the kinetic energy recovery may represent a considerable fraction of the total head, thus strongly affecting the efficiency. It presents a very complex flow environment characterized by unsteady, large scale vortices, and the prediction of its performance is a challenging task for the CFD. Moreover, in the refurbishment and repowering of hydro power plants, the turbine may often be coupled with a pre-existing draft tube.
For these reasons the draft tube was not included in the computational domain, and a simple 1D model was used to account for its influence on the turbine.
The three-dimensional version of the TRAF code developed at the University of Florence, coupled with a two equation turbulence closure has been used to predict the turbine flow features and the operating characteristics. The code exploits the artificial compressibility concept to work with incompressible flows. Steady multirow viscous single-phase analysis has been applied to compute the flow field from the inlet struts to the runner exit.
The CFD results were used for the training of a feed-forward artificial neural network with two hidden layers. As far as the training is concerned, a gradient based back propagation method was employed. In order to improve the generalization ability, a hybrid network made by multiple trained neural networks was used.
The considered input parameters were the stagger angles of both the runner and the guide vane, the mass flow rate and the draft tube recovery coefficient. The output of the neural network were the computed total head and the hydro power plant efficiency. The proposed procedure was applied to an existing power plant in order to optimize the runner-guide vane stagger correlation for all runner positions. Comparisons with the measurements obtained on the hydro power plant are presented and discussed. The predicted coupled positions of the guide vane and runner blades were successfully verified all over the range of the operating mass flows.
The optimization of the runner-guide vane stagger correlation is a time consuming and expensive task when obtained either on experimental models or directly on the power plant. The use of CFD coupled with ANN may represent an attractive alternative.In order to obtain a more general prediction tool it was decided to characterize the turbine performance coupled with a generic draft tube.
The draft tube is a key component for the performance of small head power plants. As a matter of fact, the kinetic energy recovery may represent a considerable fraction of the total head, thus strongly affecting the efficiency. It presents a very complex flow environment characterized by unsteady, large scale vortices, and the prediction of its performance is a challenging task for the CFD. Moreover, in the refurbishment and repowering of hydro power plants, the turbine may often be coupled with a pre-existing draft tube.
For these reasons the draft tube was not included in the computational domain, and a simple 1D model was used to account for its influence on the turbine.
The three-dimensional version of the TRAF code developed at the University of Florence, coupled with a two equation turbulence closure has been used to predict the turbine flow features and the operating characteristics. The code exploits the artificial compressibility concept to work with incompressible flows. Steady multirow viscous single-phase analysis has been applied to compute the flow field from the inlet struts to the runner exit.
The CFD results were used for the training of a feed-forward artificial neural network with two hidden layers. As far as the training is concerned, a gradient based back propagation method was employed. In order to improve the generalization ability, a hybrid network made by multiple trained neural networks was used.
The considered input parameters were the stagger angles of both the runner and the guide vane, the mass flow rate and the draft tube recovery coefficient. The output of the neural network were the computed total head and the hydro power plant efficiency. The proposed procedure was applied to an existing power plant in order to optimize the runner-guide vane stagger correlation for all runner positions. Comparisons with the measurements obtained on the hydro power plant are presented and discussed. The predicted coupled positions of the guide vane and runner blades were successfully verified all over the range of the operating mass flows.
2008
Rubechini, Filippo; Marconcini, Michele; Arnone, Andrea; Maritano, Massimiliano; Cecchi, Stefano
The Impact of Gas Modeling in the Numerical Analysis of a Multistage Gas Turbine Journal Article
In: ASME Journal of Turbomachinery, vol. 130, pp. 021022, 2008, ISSN: 0889-504X.
@article{RMAMC08,
title = {The Impact of Gas Modeling in the Numerical Analysis of a Multistage Gas Turbine},
author = {Filippo Rubechini and Michele Marconcini and Andrea Arnone and Massimiliano Maritano and Stefano Cecchi},
url = {http://turbomachinery.asmedigitalcollection.asme.org/article.aspx?articleid=1467704},
doi = {10.1115/1.2752187},
issn = {0889-504X},
year = {2008},
date = {2008-04-01},
journal = {ASME Journal of Turbomachinery},
volume = {130},
pages = {021022},
abstract = {In this work a numerical investigation of a four stage heavy-duty gas turbine is presented. Fully three-dimensional, multistage, Navier-Stokes analyses are carried out to predict the overall turbine performance. Coolant injections, cavity purge flows, and leakage flows are included in the turbine modeling by means of suitable wall boundary conditions. The main objective is the evaluation of the impact of gas modeling on the prediction of the stage and turbine performance parameters. To this end, four different gas models were used: three models are based on the perfect gas assumption with different values of constant cp, and the fourth is a real gas model which accounts for thermodynamic gas properties variations with temperature and mean fuel/air ratio distribution in the through-flow direction. For the real gas computations, a numerical model is used which is based on the use of gas property tables, and exploits a local fitting of gas data to compute thermodynamic properties. Experimental measurements are available for comparison purposes in terms of static pressure values at the inlet/outlet of each row and total temperature at the turbine exit.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
In this work a numerical investigation of a four stage heavy-duty gas turbine is presented. Fully three-dimensional, multistage, Navier-Stokes analyses are carried out to predict the overall turbine performance. Coolant injections, cavity purge flows, and leakage flows are included in the turbine modeling by means of suitable wall boundary conditions. The main objective is the evaluation of the impact of gas modeling on the prediction of the stage and turbine performance parameters. To this end, four different gas models were used: three models are based on the perfect gas assumption with different values of constant cp, and the fourth is a real gas model which accounts for thermodynamic gas properties variations with temperature and mean fuel/air ratio distribution in the through-flow direction. For the real gas computations, a numerical model is used which is based on the use of gas property tables, and exploits a local fitting of gas data to compute thermodynamic properties. Experimental measurements are available for comparison purposes in terms of static pressure values at the inlet/outlet of each row and total temperature at the turbine exit.
Rubechini, Filippo; Marconcini, Michele; Arnone, Andrea
A CFD Model for Real Gas Effects in Turbomachinery Conference
8th World Congress on Computational Mechanics (WCCM8), 5th European Congress on Computational Methods in Applied Sciences and Engineering (ECCOMAS 2008), 2008, (Venezia, Italy, June 30 – July 5, 2008).
@conference{RMA08,
title = {A CFD Model for Real Gas Effects in Turbomachinery},
author = {Filippo Rubechini and Michele Marconcini and Andrea Arnone},
year = {2008},
date = {2008-01-01},
booktitle = {8th World Congress on Computational Mechanics (WCCM8), 5th European Congress on Computational Methods in Applied Sciences and Engineering (ECCOMAS 2008)},
note = {Venezia, Italy, June 30 - July 5, 2008},
keywords = {},
pubstate = {published},
tppubtype = {conference}
}
Marconcini, Michele; Rubechini, Filippo; Arnone, Andrea; Ibaraki, Seiichi
Numerical Investigation of a Transonic Centrifugal Compressor Journal Article
In: ASME Journal of Turbomachinery, vol. 130, pp. 011010, 2008, ISSN: 0889-504X.
@article{MRAI08,
title = {Numerical Investigation of a Transonic Centrifugal Compressor},
author = {Michele Marconcini and Filippo Rubechini and Andrea Arnone and Seiichi Ibaraki},
url = {http://turbomachinery.asmedigitalcollection.asme.org/article.aspx?articleid=1467613},
doi = {10.1115/1.2752186},
issn = {0889-504X},
year = {2008},
date = {2008-01-01},
journal = {ASME Journal of Turbomachinery},
volume = {130},
pages = {011010},
abstract = {A three-dimensional Navier-Stokes solver is used to investigate the flow field of a high-pressure ratio centrifugal compressor for turbocharger applications. Such a compressor consists of a double-splitter impeller followed by a vaned diffuser. The inlet flow to the open shrouded impeller is transonic, thus giving rise to interactions between shock waves and boundary layers and between shock waves and tip leakage vortices. These interactions generate complex flow structures which are convected and distorted through the impeller blades. Detailed laser Doppler velocimetry flow measurements are available at various cross sections inside the impeller blades highlighting the presence of low-velocity flow regions near the shroud. Particular attention is focused on understanding the physical mechanisms which govern the flow phenomena in the near shroud region. To this end numerical investigations are performed using different tip clearance modelizations and various turbulence models, and their impact on the computed flow field is discussed.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
A three-dimensional Navier-Stokes solver is used to investigate the flow field of a high-pressure ratio centrifugal compressor for turbocharger applications. Such a compressor consists of a double-splitter impeller followed by a vaned diffuser. The inlet flow to the open shrouded impeller is transonic, thus giving rise to interactions between shock waves and boundary layers and between shock waves and tip leakage vortices. These interactions generate complex flow structures which are convected and distorted through the impeller blades. Detailed laser Doppler velocimetry flow measurements are available at various cross sections inside the impeller blades highlighting the presence of low-velocity flow regions near the shroud. Particular attention is focused on understanding the physical mechanisms which govern the flow phenomena in the near shroud region. To this end numerical investigations are performed using different tip clearance modelizations and various turbulence models, and their impact on the computed flow field is discussed.
2007
Marconcini, Michele; Rubechini, Filippo; Arnone, Andrea; Ibaraki, Seiichi
Numerical Analysis of the Vaned Diffuser of a Transonic Centrifugal Compressor Proceedings
ASME, Montreal, Canada, May 14–17, 2007, vol. 6: Turbo Expo 2007, Parts A and B, 2007, ISBN: 0-7918-4795-0, (Paper No. GT2007-27200).
@proceedings{955,
title = {Numerical Analysis of the Vaned Diffuser of a Transonic Centrifugal Compressor},
author = {Michele Marconcini and Filippo Rubechini and Andrea Arnone and Seiichi Ibaraki},
url = {http://proceedings.asmedigitalcollection.asme.org/proceeding.aspx?articleid=1602887&resultClick=1},
doi = {dx.doi.org/10.1115/GT2007-27200},
isbn = {0-7918-4795-0},
year = {2007},
date = {2007-05-01},
journal = {ASME Turbo Expo 2007: Power for Land, Sea, and Air},
volume = {6: Turbo Expo 2007, Parts A and B},
pages = {987-995},
publisher = {ASME},
address = {Montreal, Canada, May 14–17, 2007},
abstract = {A three-dimensional Navier-Stokes solver is used to investigate the flow field of a high pressure ratio centrifugal compressor for turbocharger applications. Such a compressor consists of a double-splitter impeller followed by a vaned diffuser. Particular attention is focused on the analysis of the vaned diffuser, designed for high subsonic inlet conditions. The diffuser is characterized by a complex three-dimensional flow field, and influenced by the unsteady interaction with the impeller. Detailed Particle Image Velocimetry (PIV) flow measurements within the diffuser are available for comparison purposes.},
note = {Paper No. GT2007-27200},
keywords = {},
pubstate = {published},
tppubtype = {proceedings}
}
A three-dimensional Navier-Stokes solver is used to investigate the flow field of a high pressure ratio centrifugal compressor for turbocharger applications. Such a compressor consists of a double-splitter impeller followed by a vaned diffuser. Particular attention is focused on the analysis of the vaned diffuser, designed for high subsonic inlet conditions. The diffuser is characterized by a complex three-dimensional flow field, and influenced by the unsteady interaction with the impeller. Detailed Particle Image Velocimetry (PIV) flow measurements within the diffuser are available for comparison purposes.
Rubechini, Filippo; Marconcini, Michele; Arnone, Andrea; Cecchi, Stefano; `a, Federico Dacc
Some Aspects of CFD Modeling in the Analysis of a Low-Pressure Steam Turbine Proceedings
AMER SOC MECHANICAL ENGINEERS, THREE PARK AVENUE, NEW YORK, NY 10016-5990 USA, Montreal, Canada, May 14–17, vol. 6: Turbomachinery, Parts A and B, 2007, ISBN: 0-7918-4795-0, (ASME paper GT2007-27235).
@proceedings{RMACD07,
title = {Some Aspects of CFD Modeling in the Analysis of a Low-Pressure Steam Turbine},
author = {Filippo Rubechini and Michele Marconcini and Andrea Arnone and Stefano Cecchi and Federico Dacc `a},
url = {http://link.aip.org/link/abstract/ASMECP/v2007/i47950/p519/s1},
doi = {10.1115/GT2007-27235},
isbn = {0-7918-4795-0},
year = {2007},
date = {2007-01-01},
journal = {ASME Turbo Expo},
volume = {6: Turbomachinery, Parts A and B},
pages = {519–526},
publisher = {AMER SOC MECHANICAL ENGINEERS, THREE PARK AVENUE, NEW YORK, NY 10016-5990 USA},
address = {Montreal, Canada, May 14–17},
abstract = {A three-dimensional, multistage, Navier-Stokes solver is applied to the numerical investigation of a four stage low-pressure steam turbine. The thermodynamic behavior of the wet steam is reproduced by adopting a real-gas model, based on the use of gas property tables. Geometrical features and flow-path details consistent with the actual turbine geometry, such as cavity purge flows, shroud leakage flows and partspan snubbers, are accounted for, and their impact on the turbine performance is discussed. These details are included in the analysis using simple models, which prevent a considerable growth of the computational cost and make the overall procedure attractive as a design tool for industrial purposes. Shroud leakage flows are modeled by means of suitable endwall boundary conditions, based on coupled sources and sinks, while body forces are applied to simulate the presence of the damping wires on the blades. In this work a detailed description of these models is provided, and the results of computations are compared with experimental measurements.},
note = {ASME paper GT2007-27235},
keywords = {},
pubstate = {published},
tppubtype = {proceedings}
}
A three-dimensional, multistage, Navier-Stokes solver is applied to the numerical investigation of a four stage low-pressure steam turbine. The thermodynamic behavior of the wet steam is reproduced by adopting a real-gas model, based on the use of gas property tables. Geometrical features and flow-path details consistent with the actual turbine geometry, such as cavity purge flows, shroud leakage flows and partspan snubbers, are accounted for, and their impact on the turbine performance is discussed. These details are included in the analysis using simple models, which prevent a considerable growth of the computational cost and make the overall procedure attractive as a design tool for industrial purposes. Shroud leakage flows are modeled by means of suitable endwall boundary conditions, based on coupled sources and sinks, while body forces are applied to simulate the presence of the damping wires on the blades. In this work a detailed description of these models is provided, and the results of computations are compared with experimental measurements.
2006
Rubechini, Filippo; Marconcini, Michele; Arnone, Andrea; Maritano, Massimiliano; Cecchi, Stefano
The Impact of Gas Modeling in the Numerical Analysis of a Multistage Gas Turbine Proceedings
ASME, Barcelona, Spain, May 8–11, 2006, vol. 6: Turbomachinery, Parts A and B, 2006, ISBN: 0-7918-4241-X.
@proceedings{956,
title = {The Impact of Gas Modeling in the Numerical Analysis of a Multistage Gas Turbine},
author = {Filippo Rubechini and Michele Marconcini and Andrea Arnone and Massimiliano Maritano and Stefano Cecchi},
url = {http://proceedings.asmedigitalcollection.asme.org/proceeding.aspx?articleid=1587534&resultClick=1},
doi = {dx.doi.org/10.1115/GT2006-90129},
isbn = {0-7918-4241-X},
year = {2006},
date = {2006-05-01},
journal = {ASME Turbo Expo 2006: Power for Land, Sea, and Air},
volume = {6: Turbomachinery, Parts A and B},
pages = {531-539},
publisher = {ASME},
address = {Barcelona, Spain, May 8–11, 2006},
abstract = {In this work a numerical investigation of a four stage heavy-duty gas turbine is presented. Fully three-dimensional, multistage, Navier-Stokes analyses are carried out to predict the overall turbine performance. Coolant injections, cavity purge flows and leakage flows are included in the turbine modeling by means of suitable wall boundary conditions. The main objective is the evaluation of the impact of gas modeling on the prediction of the stage and turbine performance parameters. To this end, four different gas models were used: three models are based on the perfect gas assumption with different values of constant cp , and the fourth is a real gas model which accounts for thermodynamic gas properties variations with temperature and mean fuel/air ratio distribution in the through-flow direction. For the real gas computations, a numerical model is used which is based on the use of gas property tables, and exploits a local fitting of gas data to compute thermodynamic properties. Experimental measurements are available for comparison purposes in terms of static pressure values at inlet/outlet of each row and total temperature at the turbine exit.},
keywords = {},
pubstate = {published},
tppubtype = {proceedings}
}
In this work a numerical investigation of a four stage heavy-duty gas turbine is presented. Fully three-dimensional, multistage, Navier-Stokes analyses are carried out to predict the overall turbine performance. Coolant injections, cavity purge flows and leakage flows are included in the turbine modeling by means of suitable wall boundary conditions. The main objective is the evaluation of the impact of gas modeling on the prediction of the stage and turbine performance parameters. To this end, four different gas models were used: three models are based on the perfect gas assumption with different values of constant cp , and the fourth is a real gas model which accounts for thermodynamic gas properties variations with temperature and mean fuel/air ratio distribution in the through-flow direction. For the real gas computations, a numerical model is used which is based on the use of gas property tables, and exploits a local fitting of gas data to compute thermodynamic properties. Experimental measurements are available for comparison purposes in terms of static pressure values at inlet/outlet of each row and total temperature at the turbine exit.