scholarly journals Experimental Assessment of Fiber Reinforced Ceramics for Combustor Walls

1997 ◽  
Author(s):  
D. Filsinger ◽  
S. Münz ◽  
A. Schulz ◽  
S. Wittig ◽  
G. Andrees
Keyword(s):  
High Temperature ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Gas Flow ◽  
Ceramic Materials ◽  
Inlet Temperature ◽  
Test Duration ◽  
Fiber Reinforced ◽  
Hot Gas ◽  
Sic Composites

Experimental and theoretical work concerning the application of ceramic components in small high temperature gas turbines has been performed for several years. The significance of some non-oxide ceramic materials for gas turbines in particular is based on their excellent high temperature properties. The application of ceramic materials allows an increase of the turbine inlet temperature resulting in higher efficiencies and a reduction of pollution emissions. The inherent brittleness of monolithic ceramic materials can be virtually reduced by reinforcement with ceramic fibers leading to a quasi-ductile behavior. Unfortunately, some problems arise due to oxidation of these composite materials in the presence of hot gas flow containing oxygen. At the Motoren- und Turbinen Union, München GmbH, comprehensive investigations including strength, oxidation, and thermal shock tests of several materials that seemed to be appropriate for combustor liner applications were undertaken. As a result, C/C, SiC/SiC, and two C/SiC-composites coated with SiC, as oxidation protection, were chosen for examination in a gas turbine combustion chamber. To prove the suitability of these materials under real engine conditions, the fiber reinforced flame tubes were installed in a small gas turbine operating under varying conditions. The loading of the flame tubes was characterized by wall temperature measurements. The materials showed different oxidation behavior when exposed to the hot gas flow. Inspection of the C/SiC-composites revealed debonding of the coatings. The C/C- and the SiC/SiC-materials withstood the tests with a maximum cumulated test duration of 90 hours without damage.

Experimental Assessment of Fiber-Reinforced Ceramics for Combustor Walls

1997 ◽  
Vol 123 (2) ◽  
pp. 271-276 ◽  
Author(s):  
D. Filsinger ◽  
S. Mu¨nz ◽  
A. Schulz ◽  
S. Wittig ◽  
G. Andrees
Keyword(s):  
High Temperature ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Gas Flow ◽  
Ceramic Materials ◽  
Inlet Temperature ◽  
Test Duration ◽  
Fiber Reinforced ◽  
Hot Gas ◽  
Sic Composites

Experimental and theoretical work concerning the application of ceramic components in small high-temperature gas turbines has been performed for several years. The significance of some nonoxide ceramic materials for gas turbines in particular is based on their excellent high-temperature properties. The application of ceramic materials allows an increase of the turbine inlet temperature resulting in higher efficiencies and a reduction of pollution emissions. The inherent brittleness of monolithic ceramic materials can be virtually reduced by reinforcement with ceramic fibers leading to a quasiductile behavior. Unfortunately, some problems arise due to oxidation of these composite materials in the presence of hot gas flow containing oxygen. At the Motoren und Turbinen Union, Mu¨nchen GmbH, comprehensive investigations including strength, oxidation, and thermal shock tests of several materials that seemed to be appropriate for combustor liner applications were undertaken. As a result, C/C, SiC/SiC, and two C/SiC composites coated with SiC, as oxidation protection, were chosen for examination in a gas turbine combustion chamber. To prove the suitability of these materials under real engine conditions, the fiber-reinforced flame tubes were installed in a small gas turbine operating under varying conditions. The loading of the flame tubes was characterized by wall temperature measurements. The materials showed different oxidation behavior when exposed to the hot gas flow. Inspection of the C/SiC composites revealed debonding of the coatings. The C/C and SiC/SiC materials withstood the tests with a maximum cumulated test duration of 90 h without damage.

Development and Fabrication of Silicon Nitride Components for Ceramic Gas Turbine

1997 ◽  
Author(s):  
Keisuke Makino ◽  
Ken-Ichi Mizuno ◽  
Toru Shimamori
Keyword(s):  
High Temperature ◽  
Silicon Nitride ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Turbine Blades ◽  
High Strength ◽  
Inlet Temperature ◽  
Turbine Inlet Temperature ◽  
Spark Plug ◽  
Power Turbine

NGK Spark Plug Co., Ltd. has been developing various silicon nitride materials, and the technology for fabricating components for ceramic gas turbines (CGT) using theses materials. We are supplying silicon nitride material components for the project to develop 300 kW class CGT for co-generation in Japan. EC-152 was developed for components that require high strength at high temperature, such as turbine blades and turbine nozzles. In order to adapt the increasing of the turbine inlet temperature (TIT) up to 1,350 °C in accordance with the project goals, we developed two silicon nitride materials with further unproved properties: ST-1 and ST-2. ST-1 has a higher strength than EC-152 and is suitable for first stage turbine blades and power turbine blades. ST-2 has higher oxidation resistance than EC-152 and is suitable for power turbine nozzles. In this paper, we report on the properties of these materials, and present the results of evaluations of these materials when they are actually used for CGT components such as first stage turbine blades and power turbine nozzles.

Model Combustor to Assess the Oxidation Behavior of Ceramic Materials Under Real Engine Conditions

1999 ◽  
Author(s):  
D. Filsinger ◽  
A. Schulz ◽  
S. Wittig ◽  
C. Taut ◽  
H. Klemm ◽  
...  
Keyword(s):  
High Temperature ◽  
International Development ◽  
Gas Turbines ◽  
Gas Flow ◽  
Oxidation Behavior ◽  
Elevated Temperatures ◽  
Ceramic Materials ◽  
Test Rig ◽  
Combustion Gas ◽  
Wide Range

A further increase of thermal efficiency and a reduction of the exhaust emissions of ground based gas turbines can be achieved by introducing new high temperature resistant materials. Therfore, ceramics are under international development. They offer excellent strengths at room and elevated temperatures. For gas turbine combustor applications, however, these materials have to maintain their advantageous properties under hostile environment. For the assessment and comparison of the oxidation behavior of different nonoxide ceramic materials a test rig was developed at the Institute for Thermal Turbomachinery (ITS), University of Karlsruhe, Germany. The test rig was integrated into the high temperature/ high pressure laboratory. A ceramic model combustion chamber was designed which allowed the exposure of standard four-point flexure specimens to the hot combustion gas flow. Gas temperatures and pressures could be varied in a wide range. Additionally, the partial steam pressure could be adjusted to real combustor conditions. The present paper gives a detailed description of the test rig and presents results of 100 hours endurance tests of ceramic materials at 1400°C. The initial strengths and the strengths after oxidation tests are compared. In addition to this, photographs illustrating the changes of the material’s microstructure are presented.

scholarly journals Development of Ceramic Rotor Blade for Power Generating Gas Turbine

1994 ◽  
Author(s):  
Tetsuo Teramae ◽  
Yutaka Furuse ◽  
Katsuo Wada ◽  
Takashi Machida
Keyword(s):  
High Temperature ◽  
Electric Power ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Rotor Blade ◽  
Evaluation System ◽  
Research Work ◽  
Inlet Temperature ◽  
Cooperative Research ◽  
Metal Disc

To cope with the increasing demand of electric power, many research and development programs have been performed in the field of electric power industry. Among them, the application of highly thermal resistive ceramics to hot parts of the gas turbines is one of the most promising ways to raise the thermal efficiency of the gas turbine, and several projects have been executed in the U.S.A., Europe and Japan. Tokyo Electric Power Co., Inc. (TEPCO) also has been conducting a research project to apply ceramic components to hot parts of a 20MW class gas turbine with a turbine inlet temperature of 1300C. In this project. TEPCO and Hitachi have been conducting the cooperative research work to develop a first stage ceramic rotor blade. After several design modifications, it was decided to select ceramic blades attached directly to a metal rotor disc, and to insert metal pads between the dovetail of the ceramic blade and metal disc to convey the centrifugal force produced by the blade smoothly to the metal disc. The strength of this ceramic blade has been verified by a series of experiments such as tensile tests, room temperature spin tests, thermal loading tests, and high temperature spin tests using a high temperature gas turbine development unit (HTDU). In addition, the reliability of the ceramic blade under design and test conditions has been analyzed by a computer program GFICES (Gas turbine - Fine Ceramics Evaluation System) which was developed on the basis of statistical strength theory using two parameter Weibull probability distribution. These experiments and analyses demonstrate the integrity of the developed ceramic rotor blade.

A Combustion Study of Gas Turbines Using Multi-Species/Reacting Computational Fluid Dynamic

2002 ◽  
Author(s):  
Sasan Armand ◽  
Mei Chen
Keyword(s):  
Carbon Monoxide ◽  
Gas Turbine ◽  
Environmental Contamination ◽  
Gas Turbines ◽  
Gas Flow ◽  
Fluid Dynamic ◽  
Combustion Products ◽  
Contamination Level ◽  
Short Term ◽  
Hot Gas

A multi-species/reacting combustion study was performed. The focus of the study was to quantify the effects of variation in air extraction and power rates on flame/outlet temperatures of a General Electric (GE), Frame 5 gas turbine. The environmental contamination level due to generation of carbon monoxide was also reported. GE, Frame 5 gas turbine has been widely used around the world for power generation, and as mechanical drives. The combustion products were examined throughout a range of air extraction rates, upon which it was determined that the combustion liners were susceptible to damage at air extraction rates above 10%, and the environmental contamination level due to carbon monoxide was increased. Furthermore, the gas flow exiting the combustion liner became non-homogeneous (i.e. a pocket of relatively hot gas formed in the middle of the flow path), which would cause damage to the downstream components. In conclusion, the short-term monetary gains from using compressed air from a gas turbine do not justify the costs of down time for repairs and the replacement of expensive hot-gas-path components.

A Rotary Heat Exchanger for Automotive and Other Ground Based Gas Turbines

1994 ◽  
Author(s):  
J. Paul Day
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Ceramic Materials ◽  
Department Of Energy ◽  
Inlet Temperature ◽  
Peak Acceleration ◽  
Turbine Engine ◽  
Temperature Capability ◽  
The Status ◽  
Ongoing Development

This paper discusses the ongoing development of a ceramic regenerator for a high temperature automotive gas turbine engine sponsored by the U.S. Department of Energy. The ceramic gas turbine has a steady state gas inlet temperature of 774°C and a 982°C peak acceleration temperature which precludes the use of metallic discs. Ceramic materials have successfully operated to 982°C, with a peak acceleration temperature exceeding 1093°C. Ceramic regenerator temperature capability is currently limited by seal tribomaterial properties. The requirements of the ceramic regenerator, ceramic disc materials being evaluated, and the processing of these materials to obtain the required strength, chemical resistance, cost, including quality control are discussed. The status of the extruded regenerator program to date will also be described.

scholarly journals Current Status of Industrial and Automotive Ceramic Gas Turbine R&D in Japan

1991 ◽  
Author(s):  
Soichi Nagamatsu ◽  
Kazuyuki Mizuhara ◽  
Yukio Matsuda ◽  
Akio Iwanaga ◽  
Shoji Ishiwata
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Technology Development ◽  
Ceramic Materials ◽  
Current Status ◽  
Inlet Temperature ◽  
Development Organization ◽  
Design Concepts ◽  
Ceramic Components ◽  
Engine Components

The current status of Japan’s national Ceramic Gas Turbines (CGTs) projects is overviewed. The Japanese Ministry of International Trade and Industry (MITI) is conducting two national R&D projects on CGT. These include a project on 300kW industrial CGTs for co-generation and mobile power generation use and a project on 100kW CGT for automotive use. The 300kW project was started in 1988, and is scheduled to develop three kinds of CGTs over nine years. The New Energy and Industrial Technology Development Organization (NEDO) is the main contractor, and three groups of private industries are sub contractors. Three national research institutes are involved in the project to conduct supportive research of ceramic materials and engine components. The 100kW project has started in 1990, and is scheduled to develop a single shaft automotive CGT over seven years. Petroleum Energy Center (PEC) and JARI are the main contractors with the cooperation of several petroleum and automotive companies. The goals for the two projects are 42% and higher for thermal efficiency at a turbine inlet temperature of 1350C. Such targets could not be achieved without applying high temperature ceramics to the engine components. Therefore many R&D objectives are directed towards developing the ceramic components which have a higher flexure strength and fracture toughness. Currently, 300kW base metal gas turbine engines are being developed to prove the design concepts. Blade shapes suitable to ceramics are being studied by the FEM method. Forming and manufacturing large components are also being studied, and some ceramics components have been successfully made.

Emergence of Kelvin-Helmholtz Instabilities in Gas Turbine Rim Cavities: A Parameter Study

2012 ◽  
Author(s):  
M. Rabs ◽  
F.-K. Benra ◽  
O. Schneider
Keyword(s):  
Gas Turbine ◽  
Linear Theory ◽  
Gas Turbines ◽  
Gas Flow ◽  
Splitter Plate ◽  
Parameter Study ◽  
Plate Model ◽  
Cavity Model ◽  
Hot Gas ◽  
Vortex Velocity

In an earlier paper of the authors, the occurrence of the so called Kelvin-Helmholtz instabilities (KHI) near the rim cavity of a 1.5 stage gas turbine has been examined by the use of CFD methods. It is shown that the KHI’s occur, when the swirl component of the hot gas flow is very strong. Due to the fact, that a high swirl is produced by the guide vanes of the first stage, this matter concerns most common gas turbines. A further paper validated the CFD methods used and derived KHI parameters (vortex appearance, vortex periodicity and vortex velocity) of a splitter plate model. In the current study, essential parameters revealed by the analysis of a gas turbine rim cavity model are compared to the parameters extracted from the investigation of the splitter plate model and the potential linear theory of Turner. The rim cavity model is derived from a test rig of a 1.5 stage gas turbine. The blades and vanes have been removed from the computations. As main flow boundary conditions, surface averaged parameters are used. It is shown that a description of KHI developing in a rim cavity model is partly possible using splitter plate KHI characteristics and the potential linear theory of Turner as well. A mathematical approach is formulated, which can predict the vortex velocity of KHI’s in turbine rim cavities.

Gas Turbine Fouling: A Comparison Among One Hundred Heavy-Duty Frames

2018 ◽  
Author(s):  
Nicola Aldi ◽  
Nicola Casari ◽  
Mirko Morini ◽  
Michele Pinelli ◽  
Pier Ruggero Spina ◽  
...  
Keyword(s):  
High Temperature ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Particle Deposition ◽  
Inlet Temperature ◽  
Low Grade ◽  
Outlet Temperature ◽  
Heavy Duty ◽  
Turbine Inlet Temperature ◽  
Turbine Inlet

Over recent decades, the variability and high costs of the traditional gas turbine fuels (e.g. natural gas), have pushed operators to consider low-grade fuels for running heavy-duty frames. Synfuels, obtained from coal, petroleum or biomass gasification, could represent valid alternatives in this sense. Although these alternatives match the reduction of costs and, in the case of biomass sources, would potentially provide a CO2 emission benefit (reduction of the CO2 capture and sequestration costs), these low-grade fuels have a higher content of contaminants. Synfuels are filtered before the combustor stage, but the contaminants are not removed completely. This fact leads to a considerable amount of deposition on the nozzle vanes due to the high temperature value. In addition to this, the continuous demand for increasing gas turbine efficiency, determines a higher combustor outlet temperature. Current advanced gas turbine engines operate at a turbine inlet temperature of (1400–1500) °C which is high enough to melt a high proportion of the contaminants introduced by low-grade fuels. Particle deposition can increase surface roughness, modify the airfoil shape and clog the coolant passages. At the same time, land based power units experience compressor fouling, due to the air contaminants able to pass through the filtration barriers. Hot sections and compressor fouling work together to determine performance degradation. This paper proposes an analysis of the contaminant deposition on hot gas turbine sections based on machine nameplate data. Hot section and compressor fouling are estimated using a fouling susceptibility criterion. The combination of gas turbine net power, efficiency and turbine inlet temperature (TIT) with different types of synfuel contaminants highlights how each gas turbine is subjected to particle deposition. The simulation of particle deposition on one hundred (100) gas turbines ranging from 1.2 MW to 420 MW was conducted following the fouling susceptibility criterion. Using a simplified particle deposition calculation based on TIT and contaminant viscosity estimation, the analysis shows how the correlation between type of contaminant and gas turbine performance plays a key role. The results allow the choice of the best heavy-duty frame as a function of the fuel. Low-efficiency frames (characterized by lower values of TIT) show the best compromise in order to reduce the effects of particle deposition in the presence of high-temperature melting contaminants. A high-efficiency frame is suitable when the contaminants are characterized by a low-melting point thanks to their lower fuel consumption.

Gas Turbine Fouling: A Comparison Among 100 Heavy-Duty Frames

2018 ◽  
Vol 141 (3) ◽  
Author(s):  
Nicola Aldi ◽  
Nicola Casari ◽  
Mirko Morini ◽  
Michele Pinelli ◽  
Pier Ruggero Spina ◽  
...  
Keyword(s):  
High Temperature ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Power Efficiency ◽  
Particle Deposition ◽  
High Efficiency ◽  
Inlet Temperature ◽  
Low Grade ◽  
Outlet Temperature ◽  
Heavy Duty

Over recent decades, the variability and high costs of the traditional gas turbine fuels (e.g., natural gas) have pushed operators to consider low-grade fuels for running heavy-duty frames. Synfuels, obtained from coal, petroleum, or biomass gasification, could represent valid alternatives in this sense. Although these alternatives match the reduction of costs and, in the case of biomass sources, would potentially provide a CO2 emission benefit (reduction of the CO2 capture and sequestration costs), these low-grade fuels have a higher content of contaminants. Synfuels are filtered before the combustor stage, but the contaminants are not removed completely. This fact leads to a considerable amount of deposition on the nozzle vanes due to the high temperature value. In addition to this, the continuous demand for increasing gas turbine efficiency determines a higher combustor outlet temperature. Current advanced gas turbine engines operate at a turbine inlet temperature (TIT) of (1400–1500) °C, which is high enough to melt a high proportion of the contaminants introduced by low-grade fuels. Particle deposition can increase surface roughness, modify the airfoil shape, and clog the coolant passages. At the same time, land-based power units experience compressor fouling, due to the air contaminants able to pass through the filtration barriers. Hot sections and compressor fouling work together to determine performance degradation. This paper proposes an analysis of the contaminant deposition on hot gas turbine sections based on machine nameplate data. Hot section and compressor fouling are estimated using a fouling susceptibility criterion. The combination of gas turbine net power, efficiency, and TIT with different types of synfuel contaminants highlights how each gas turbine is subjected to particle deposition. The simulation of particle deposition on 100 gas turbines ranging from 1.2 MW to 420 MW was conducted following the fouling susceptibility criterion. Using a simplified particle deposition calculation based on TIT and contaminant viscosity estimation, the analysis shows how the correlation between type of contaminant and gas turbine performance plays a key role. The results allow the choice of the best heavy-duty frame as a function of the fuel. Low-efficiency frames (characterized by lower values of TIT) show the best compromise in order to reduce the effects of particle deposition in the presence of high-temperature melting contaminants. A high-efficiency frame is suitable when the contaminants are characterized by a low-melting point thanks to their lower fuel consumption.

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