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Aristide F. Massardo - One of the best experts on this subject based on the ideXlab platform.

  • micro gas turbine Recuperator steady state and transient experimental investigation
    Journal of Engineering for Gas Turbines and Power-transactions of The Asme, 2010
    Co-Authors: Mario L. Ferrari, Loredana Magistri, Matteo Pascenti, Aristide F. Massardo
    Abstract:

    The aim of this work is the experimental analysis of a primary-surface Recuperator, operating in a 100 kW micro gas turbine, as in a standard recuperated cycle. These tests, performed in both steady-state and transient conditions, have been carried out using the micro gas turbine test rig, developed by the Thermochemical Power Group at the University of Genova, Italy. Even if this facility has mainly been designed for hybrid system emulations, it is possible to exploit the plant for component tests, such as experimental studies on Recuperators. The valves installed in the rig make it possible to operate the plant in the standard recuperated configuration, and the facility has been equipped with new probes essential for this kind of tests. A wide-ranging analysis of the Recuperator performance has been carried out with the machine, operating in stand-alone configuration, or connected to the electrical grid, to test different control strategy influences. Particular attention has been given to tests performed at different electrical load values and with different mass flow rates through the Recuperator ducts. The final section of this paper reports the transient analysis carried out on this Recuperator. The attention is mainly focused on thermal transient performance of the component, showing the effects of both temperature and flow steps. [DOI: 10.1115/1.3156822].

  • micro gas turbine Recuperator steady state and transient experimental investigation
    Volume 5: Microturbines and Small Turbomachinery; Oil and Gas Applications, 2009
    Co-Authors: Mario L. Ferrari, Loredana Magistri, Matteo Pascenti, Aristide F. Massardo
    Abstract:

    The aim of this work is the experimental analysis of a primary-surface Recuperator operating in a 100 kW micro gas turbine, as in a standard recuperated cycle. These tests, performed in both steady-state and transient conditions, have been carried out using the micro gas turbine test rig developed by TPG at the University of Genoa, Italy. Even if this facility has mainly been designed for hybrid system emulations, it is possible to exploit the plant for component tests, such as experimental studies on Recuperators. The valves installed in the rig make it possible to operate the plant in the standard recuperated configuration, and the facility has been equipped with new probes essential for this kind of tests. A wide-ranging analysis of the Recuperator performance has been carried out with the machine operating in stand-alone configuration, or connected to the electrical grid, to test different control strategy influences. Particular attention has been given to tests performed at different electrical load values and with different mass flow rates through the Recuperator ducts. The final section of this paper reports the transient analysis carried out on this Recuperator. The attention is mainly focused on thermal transient performance of the component, showing the effects of both temperature and flow steps.Copyright © 2009 by ASME

  • optimal design of compact Recuperators for microturbine application
    Applied Thermal Engineering, 2005
    Co-Authors: Alberto Traverso, Aristide F. Massardo
    Abstract:

    Abstract This paper presents a new approach for the optimization of microturbine Recuperators from the technical and economic standpoints. The procedure proposed has been implemented in the software called CHEOPE (compact heat exchanger optimization and performance evaluation), which considers two types of Recuperator concept, which have proved to be the most promising for microturbine applications: the furnace-brazed plate-fin type and the welded primary surface type. The general design rules for performance evaluation of gas–gas heat exchangers are summarized and specifically applied to these two types of Recuperator. Moreover, the cost equation, employed to estimate the capital cost of these types of heat exchanger, is discussed. With regard to the sizing procedure, a special optimization procedure of the Recuperator matrix has been developed, which takes into account several targets in a single multi-objective function: the compactness, the pressure drops and the expected cost of the device. The tests performed for the validation are presented, and three case studies are illustrated for three different microturbine sizes, for a 50 kW, 100 kW and 500 kW machine, respectively.

  • cheope a tool for the optimal design of compact Recuperators
    ASME Turbo Expo 2004: Power for Land Sea and Air, 2004
    Co-Authors: Alberto Traverso, Federico Zanzarsi, Aristide F. Massardo
    Abstract:

    This paper presents the organization, theoretical background and application of a new software tool for the optimization of the technical and economical design of microturbine Recuperators. The code called CHEOPE (Compact Heat Exchanger Optimization and Performance Evaluation) considered two types of Recuperator concept, which proved to be the most promising for microturbine applications: the furnace-brazed plate-fin type and the welded primary surface type. The general design rules for performance evaluation of gas-gas heat exchangers are summarized and specifically applied to these two types of Recuperator. Moreover, the cost equation, employed to estimate the capital cost of these types of heat exchanger, is discussed. CHEOPE can be used both for solving the sizing problem and the rating problem. With regard to the former, the code is capable of a special optimization of the Recuperator matrix, which takes into account the compactness, the pressure drops and the expected cost of the device. The objective function can be customized according to the designer’s priorities. The tests performed for the validation are presented, and three case studies are illustrated for three different microturbine sizes, for a 50kW, a 100kW and a 500kW machine.Copyright © 2004 by ASME

Larry R Walker - One of the best experts on this subject based on the ideXlab platform.

  • comparison of three microturbine primary surface Recuperator alloys
    Journal of Engineering for Gas Turbines and Power-transactions of The Asme, 2010
    Co-Authors: Wendy J. Matthews, Karren L More, Larry R Walker
    Abstract:

    Extensive work performed by Capstone Turbine Corporation, Oak Ridge National Laboratory, and various others has shown that the traditional primary surface Recuperator alloy, type 347 stainless steel, is unsuitable for applications above 650 C ({approx}1200 F). Numerous studies have shown that the presence of water vapor greatly accelerates the oxidation rate of type 347 stainless steel at temperatures above 650 C ({approx}1200 F). Water vapor is present as a product of combustion in the microturbine exhaust, making it necessary to find replacement alloys for type 347 stainless steel that will meet the long life requirements of microturbine primary surface Recuperators. It has been well established over the past few years that alloys with higher chromium and nickel contents than type 347 stainless steel have much greater oxidation resistance in the microturbine environment. One such alloy that has replaced type 347 stainless steel in primary surface Recuperators is Haynes Alloy HR-120 (Haynes and HR-120 are trademarks of Haynes International, Inc.), a solid-solution-strengthened alloy with nominally 33 wt % Fe, 37 wt % Ni and 25 wt % Cr. Unfortunately, while HR-120 is significantly more oxidation resistant in the microturbine environment, it is also a much more expensive alloy. In the interest more » of cost reduction, other candidate primary surface Recuperator alloys are being investigated as possible alternatives to type 347 stainless steel. An initial rainbow Recuperator test has been performed at Capstone to compare the oxidation resistance of type 347 stainless steel, HR-120, and the Allegheny Ludlum austenitic alloy AL 20-25+Nb (AL 20-25+Nb is a trademark of ATI Properties, Inc. and is licensed to Allegheny Ludlum Corporation). Evaluation of surface oxide scale formation and associated alloy depletion and other compositional changes has been carried out at Oak Ridge National Laboratory. The results of this initial rainbow test will be presented and discussed in this paper. « less

  • long term microturbine exposure of an advanced alloy for microturbine primary surface Recuperators
    Journal of Engineering for Gas Turbines and Power-transactions of The Asme, 2009
    Co-Authors: Wendy J. Matthews, Karren L More, Larry R Walker
    Abstract:

    Haynes alloy HR-120 (Haynes and HR-120 are trademarks of Haynes International, Inc.) forms a protective oxide scale when exposed to the harsh operating environment of a microturbine primary surface Recuperator. Primary surface Recuperators manufactured from HR-120 are currently in use on the Capstone C65 MicroTurbine (MicroTurbine is a registered trademark of Capstone Turbine Corporation). Long-term microturbine tests of this alloy are currently being conducted at an elevated turbine exit temperature ({approx}100 F higher than that in a normal operation) at Capstone Turbine Corporation. Alloy samples that have been tested under steady-state microturbine operating conditions are removed after predetermined exposure intervals for characterization by Capstone Turbine Corporation in collaboration with Oak Ridge National Laboratory. Such evaluations include the characterization of surface oxide scales and the associated alloy compositional changes following a steady-state operation ranging from 1800 h to 14,500 h. Results from the microstructural and compositional analyses of these long-term steady-state engine-tested HR-120 samples are used to illustrate the progression of alloy oxidation in the microturbine operating environment.

  • comparison of three microturbine primary surface Recuperator alloys
    Volume 5: Microturbines and Small Turbomachinery; Oil and Gas Applications, 2009
    Co-Authors: Wendy J. Matthews, Karren L More, Larry R Walker
    Abstract:

    Extensive work performed by Capstone Turbine Corporation, Oak Ridge National laboratory, and various others has shown that the traditional primary surface Recuperator alloy, type 347 stainless steel, is unsuitable for applications above 650°C (∼1200°F). Numerous studies have shown that the presence of water vapor greatly accelerates the oxidation rate of type 347 stainless steel at temperatures above 650°C (∼1200°F). Water vapor is present as a product of combustion in the microturbine exhaust, making it necessary to find replacement alloys for type 347 stainless steel that will meet the long life requirements of microturbine primary surface Recuperators. It has been well established over the past few years that alloys with higher Chromium and Nickel contents than type 347 stainless steel have much greater oxidation resistance in the microturbine environment. One such alloy that has replaced type 347 stainless steel in primary surface Recuperators is Haynes Alloy HR-120, a solid-solution-strengthened alloy with nominally 33 wt.% Fe, 37 wt.% Ni and 25 wt.% Cr. Unfortunately, while HR-120 is significantly more oxidation resistant in the microturbine environment, it is also a much more expensive alloy. In the interest of cost reduction, other candidate primary surface Recuperator alloys are being investigated as possible alternatives to type 347 stainless steel. An initial rainbow Recuperator test has been performed at Capstone to compare the oxidation resistance of type 347 stainless steel, HR-120 and the Allegheny Ludlum austenitic alloy AL 20-25+Nb. Evaluation of surface oxide scale formation and associated alloy depletion and other compositional changes has been carried out at Oak Ridge National Laboratory. The results of this initial rainbow test will be presented and discussed in this paper.Copyright © 2009 by ASME

  • long term microturbine exposure of an advanced alloy for microturbine primary surface Recuperators
    Volume 1: Aircraft Engine; Ceramics; Coal Biomass and Alternative Fuels; Manufacturing Materials and Metallurgy; Microturbines and Small Turbomachiner, 2008
    Co-Authors: Wendy J. Matthews, Karren L More, Larry R Walker
    Abstract:

    Haynes Alloy HR-120 forms a protective oxide scale when exposed to the harsh operating environment of a microturbine primary surface Recuperator. Primary surface Recuperators manufactured from HR-120 are currently in use on the Capstone C65 MicroTurbine. Long-term microturbine tests of this alloy are currently being conducted at an elevated turbine exit temperature (∼100F° higher than normal operation) at Capstone Turbine Corporation. Alloy samples that have been tested under steady-state microturbine operating conditions are removed after pre-determined exposure intervals for characterization by Capstone Turbine Corporation in collaboration with Oak Ridge National Laboratory. Such evaluations include characterization of surface oxide scales and the associated alloy compositional changes following steady-state operation ranging from 1,800 – 14,500 hours. Results from the microstructural and compositional analyses of these long-term, steady-state engine-tested HR-120 samples are used to illustrate the progression of alloy oxidation in the microturbine operating environment.Copyright © 2008 by ASME

  • accelerated oxidation of type 347 stainless steel primary surface Recuperators operating above 600 c
    ASME Turbo Expo 2007: Power for Land Sea and Air, 2007
    Co-Authors: Wendy J. Matthews, Karren L More, Larry R Walker
    Abstract:

    Type 347 stainless steel has traditionally been used in the manufacture of microturbine primary surface Recuperators. It has been established during the past few years that the water vapor present in the microturbine exhaust gas causes accelerated oxidation of austenitic stainless steels at operating temperatures above ∼600°C (∼1110°F), which has resulted in the replacement of austenitic stainless steels with more highly alloyed Fe-based alloys and Ni-based alloys in microturbine Recuperators. The effect of water vapor on type 347 stainless steel primary surface Recuperators has been studied extensively by Capstone Turbine Corporation in collaboration with Oak Ridge National Laboratory. Several Recuperators exposed in a Capstone C60 MicroTurbine™ under different steady-state and cyclic operating conditions, have been microstructurally characterized. Evaluation of surface oxide scale formation and associated compositional changes has been carried out on representative sections from Recuperators with operating lives ranging from ∼2,000–15,000 hours. Results from the microstructural and compositional analyses of the engine-tested Recuperators illustrate the progression of accelerated oxidation of type 347 stainless steel at Recuperator operating temperatures above 600°C.Copyright © 2007 by ASME

Shengming Liao - One of the best experts on this subject based on the ideXlab platform.

  • multi objective optimization of supercritical carbon dioxide recompression brayton cycle considering printed circuit Recuperator design
    Energy Conversion and Management, 2019
    Co-Authors: Kaixin Huang, Shengming Liao
    Abstract:

    Abstract Supercritical carbon dioxide recompression Brayton cycle is well suited to a broad range of applications including nuclear and concentrated solar energy. As printed circuit Recuperators are employed to optimize the thermal performance of the cycle, the Recuperator optimal design is required with the objective of maximizing the cycle thermal efficiency and minimizing the total cycle cost. In this paper, a thermo-economic model of recompression Brayton cycle with the S-shaped fin printed circuit Recuperator is developed to perform multi-objective optimization considering the Recuperator design parameters (i.e. mass fluxes and enthalpy efficiencies of Recuperators and recompression fraction). Nondominated sorting genetic algorithm is used to obtain Pareto frontier. The results show that compared to the mass fluxes, the enthalpy efficiencies of Recuperators and recompression fraction play more important roles in the optimization. From the Pareto frontier, the optimum range of the cycle thermal efficiency is 0.4303–0.5380 and that of the total cycle cost is 7.468 M$–12.31 M$. As high cycle thermal efficiency is preferred, the high recompression fraction, high mass flux and high enthalpy efficiency of low temperature Recuperator, low mass flux and high enthalpy efficiency of high temperature Recuperator are required. In contrast, as low cycle cost is preferred, the opposite selections of design parameters are required.

Anestis I Kalfas - One of the best experts on this subject based on the ideXlab platform.

  • Recuperators investigation for high temperature supercritical carbon dioxide power generation cycles
    Applied Thermal Engineering, 2017
    Co-Authors: Apostolos A Gkountas, Anastassios Stamatelos, Anestis I Kalfas
    Abstract:

    Abstract Supercritical carbon dioxide (s-CO2) Brayton cycles are a promising technology for the next generation power conversion cycles, attaining equivalent or higher cycle efficiency compared to conventional power cycles at similar temperatures (550–750 °C). The recompression cycle attracts the main research interest among the s-CO2 layouts. Recompressing a fraction of the flow without heat rejection, results to an increase in thermal efficiency, while the majority of heat transfer occurs in Recuperators. In this study, a thermodynamic analysis of a 600 MWth power cycle has been carried out using two different simulation tools to model the recompression system. The analysis focuses on the parameters that have the most significant impact on the components and cycle efficiency. A segmental analysis of the Recuperators took place to assess the effect of flow characteristics on the heat transfer. Finally, a comparative analysis of the results of the two simulation tools versus the results of a reference cycle from literature is carried out, showing that the prediction of the overall heat transfer coefficient and Recuperator effectiveness between the developed code and reference model has a maximum deviation of 4%, whereas the prediction deviation between the commercial software and reference model is about 2.8%.

Wendy J. Matthews - One of the best experts on this subject based on the ideXlab platform.

  • evaluation of alumina forming austenitic foil for advanced Recuperators
    Volume 5: Industrial and Cogeneration; Microturbines and Small Turbomachinery; Oil and Gas Applications; Wind Turbine Technology, 2010
    Co-Authors: Bruce A Pint, Yukinori Yamamoto, Michael L Santella, Philip J. Maziasz, Wendy J. Matthews
    Abstract:

    A corrosion- and creep-resistant austenitic stainless steel has been developed for advanced Recuperator applications. By optimizing the Al and Cr contents, the alloy is fully austenitic for creep strength while allowing the formation of a chemically-stable external alumina scale at temperatures up to 900°C. An alumina scale eliminates long-term problems with the formation of volatile Cr oxy-hydroxides in the presence of water vapor in exhaust gas. As a first step in producing foil for primary surface Recuperators, three commercially cast heats have been rolled to ∼100μm thick foil in the laboratory to evaluate performance in creep and oxidation testing. Results from initial creep testing are presented at 675° and 750°C showing excellent creep strength compared to other candidate foil materials. Laboratory exposures in humid air at 650°-800°C have shown acceptable oxidation resistance. Similar oxidation behavior was observed for sheet specimens of these alloys exposed in a modified 65kW microturbine for 2,871h. One composition that showed superior creep and oxidation resistance has been selected for preparation of a commercial batch of foil.Copyright © 2010 by ASME

  • comparison of three microturbine primary surface Recuperator alloys
    Journal of Engineering for Gas Turbines and Power-transactions of The Asme, 2010
    Co-Authors: Wendy J. Matthews, Karren L More, Larry R Walker
    Abstract:

    Extensive work performed by Capstone Turbine Corporation, Oak Ridge National Laboratory, and various others has shown that the traditional primary surface Recuperator alloy, type 347 stainless steel, is unsuitable for applications above 650 C ({approx}1200 F). Numerous studies have shown that the presence of water vapor greatly accelerates the oxidation rate of type 347 stainless steel at temperatures above 650 C ({approx}1200 F). Water vapor is present as a product of combustion in the microturbine exhaust, making it necessary to find replacement alloys for type 347 stainless steel that will meet the long life requirements of microturbine primary surface Recuperators. It has been well established over the past few years that alloys with higher chromium and nickel contents than type 347 stainless steel have much greater oxidation resistance in the microturbine environment. One such alloy that has replaced type 347 stainless steel in primary surface Recuperators is Haynes Alloy HR-120 (Haynes and HR-120 are trademarks of Haynes International, Inc.), a solid-solution-strengthened alloy with nominally 33 wt % Fe, 37 wt % Ni and 25 wt % Cr. Unfortunately, while HR-120 is significantly more oxidation resistant in the microturbine environment, it is also a much more expensive alloy. In the interest more » of cost reduction, other candidate primary surface Recuperator alloys are being investigated as possible alternatives to type 347 stainless steel. An initial rainbow Recuperator test has been performed at Capstone to compare the oxidation resistance of type 347 stainless steel, HR-120, and the Allegheny Ludlum austenitic alloy AL 20-25+Nb (AL 20-25+Nb is a trademark of ATI Properties, Inc. and is licensed to Allegheny Ludlum Corporation). Evaluation of surface oxide scale formation and associated alloy depletion and other compositional changes has been carried out at Oak Ridge National Laboratory. The results of this initial rainbow test will be presented and discussed in this paper. « less

  • long term microturbine exposure of an advanced alloy for microturbine primary surface Recuperators
    Journal of Engineering for Gas Turbines and Power-transactions of The Asme, 2009
    Co-Authors: Wendy J. Matthews, Karren L More, Larry R Walker
    Abstract:

    Haynes alloy HR-120 (Haynes and HR-120 are trademarks of Haynes International, Inc.) forms a protective oxide scale when exposed to the harsh operating environment of a microturbine primary surface Recuperator. Primary surface Recuperators manufactured from HR-120 are currently in use on the Capstone C65 MicroTurbine (MicroTurbine is a registered trademark of Capstone Turbine Corporation). Long-term microturbine tests of this alloy are currently being conducted at an elevated turbine exit temperature ({approx}100 F higher than that in a normal operation) at Capstone Turbine Corporation. Alloy samples that have been tested under steady-state microturbine operating conditions are removed after predetermined exposure intervals for characterization by Capstone Turbine Corporation in collaboration with Oak Ridge National Laboratory. Such evaluations include the characterization of surface oxide scales and the associated alloy compositional changes following a steady-state operation ranging from 1800 h to 14,500 h. Results from the microstructural and compositional analyses of these long-term steady-state engine-tested HR-120 samples are used to illustrate the progression of alloy oxidation in the microturbine operating environment.

  • comparison of three microturbine primary surface Recuperator alloys
    Volume 5: Microturbines and Small Turbomachinery; Oil and Gas Applications, 2009
    Co-Authors: Wendy J. Matthews, Karren L More, Larry R Walker
    Abstract:

    Extensive work performed by Capstone Turbine Corporation, Oak Ridge National laboratory, and various others has shown that the traditional primary surface Recuperator alloy, type 347 stainless steel, is unsuitable for applications above 650°C (∼1200°F). Numerous studies have shown that the presence of water vapor greatly accelerates the oxidation rate of type 347 stainless steel at temperatures above 650°C (∼1200°F). Water vapor is present as a product of combustion in the microturbine exhaust, making it necessary to find replacement alloys for type 347 stainless steel that will meet the long life requirements of microturbine primary surface Recuperators. It has been well established over the past few years that alloys with higher Chromium and Nickel contents than type 347 stainless steel have much greater oxidation resistance in the microturbine environment. One such alloy that has replaced type 347 stainless steel in primary surface Recuperators is Haynes Alloy HR-120, a solid-solution-strengthened alloy with nominally 33 wt.% Fe, 37 wt.% Ni and 25 wt.% Cr. Unfortunately, while HR-120 is significantly more oxidation resistant in the microturbine environment, it is also a much more expensive alloy. In the interest of cost reduction, other candidate primary surface Recuperator alloys are being investigated as possible alternatives to type 347 stainless steel. An initial rainbow Recuperator test has been performed at Capstone to compare the oxidation resistance of type 347 stainless steel, HR-120 and the Allegheny Ludlum austenitic alloy AL 20-25+Nb. Evaluation of surface oxide scale formation and associated alloy depletion and other compositional changes has been carried out at Oak Ridge National Laboratory. The results of this initial rainbow test will be presented and discussed in this paper.Copyright © 2009 by ASME

  • long term microturbine exposure of an advanced alloy for microturbine primary surface Recuperators
    Volume 1: Aircraft Engine; Ceramics; Coal Biomass and Alternative Fuels; Manufacturing Materials and Metallurgy; Microturbines and Small Turbomachiner, 2008
    Co-Authors: Wendy J. Matthews, Karren L More, Larry R Walker
    Abstract:

    Haynes Alloy HR-120 forms a protective oxide scale when exposed to the harsh operating environment of a microturbine primary surface Recuperator. Primary surface Recuperators manufactured from HR-120 are currently in use on the Capstone C65 MicroTurbine. Long-term microturbine tests of this alloy are currently being conducted at an elevated turbine exit temperature (∼100F° higher than normal operation) at Capstone Turbine Corporation. Alloy samples that have been tested under steady-state microturbine operating conditions are removed after pre-determined exposure intervals for characterization by Capstone Turbine Corporation in collaboration with Oak Ridge National Laboratory. Such evaluations include characterization of surface oxide scales and the associated alloy compositional changes following steady-state operation ranging from 1,800 – 14,500 hours. Results from the microstructural and compositional analyses of these long-term, steady-state engine-tested HR-120 samples are used to illustrate the progression of alloy oxidation in the microturbine operating environment.Copyright © 2008 by ASME