Engine Test Experience and Characterization of Self Sealing Ceramic Matrix Composites for Nozzle Applications in Gas Turbine Engines

Author(s):  
Eric P. Bouillon ◽  
Patrick C. Spriet ◽  
Georges Habarou ◽  
Thibault Arnold ◽  
Greg C. Ojard ◽  
...  

Advanced materials are targeting durability improvement in gas turbine engines. One general area of concern for durability is in the hot section components of the engine. Ceramic matrix composites offer improvements in durability at elevated temperatures with a corresponding reduction in weight for nozzles of gas turbine engines. Building on past material efforts, ceramic matrix composites using a carbon and a SiC fiber with a self-sealing matrix have been developed for gas turbine applications. Prior to ground engine testing, a reduced test matrix was undertaken to aggressively test the material in a long-term hold cycle at elevated temperatures and environments. This tensile low cycle fatigue testing was done in air and a 90% steam environment. After completion of the aggressive testing effort, six nozzle seals were fabricated and installed in an F100-PW-229 engine for accelerated mission testing. The C fiber CMC and the SiC Fiber CMC were respectively tested to 600 and 1000 hours in accelerated conditions without damage. Engine testing is continuing to gain additional time and insight with the objective of pursuing the next phase of field service evaluation. Mechanical testing and post-test characterization results of this testing will be presented. The results of the engine testing will be shown and overall conclusions drawn.

Author(s):  
Eric P. Bouillon ◽  
Patrick C. Spriet ◽  
Georges Habarou ◽  
Caroline Louchet ◽  
Thibault Arnold ◽  
...  

The advancement of self-sealing ceramic matrix composites offers durability improvements in hot section components of gas turbine engines. These durability improvements come with no need for internal cooling and with reduced weight. Building on past material efforts, ceramic matrix composites based on either a carbon fiber or a SiC fiber with a sequenced self-sealing matrix have been developed for gas turbine applications. The specific application being pursued on this effort is an F100-PW-229 nozzle seal. Full design life ground engine testing has been accomplished with both material systems. The ground testing has demonstrated a significant durability improvement from the baseline metal design. Residual properties are being determined for both systems by extracting tensile and microstructural coupons from the ceramic matrix composite seal. Nondestructive interrogation showed no material degradation and was used as a guide in setting cutting diagrams. The results from this effort will be presented along with documentation from flight test efforts.


Author(s):  
Michael J. L. Percival ◽  
Colin P. Beesley

Currently available Ceramic Matrix Composites (CMCs) have very low stress carrying capability if they are to achieve the service life required for application in gas turbine engines. As such, they are most likely to find their first applications in non-structural components with low mechanical loads, where the majority of the stress is thermally induced. The thermal cycling experienced in gas turbine engines, coupled with the necessary interfaces with surrounding metal components and other geometric features, means that these thermal stresses are often localised, but in order to produce a valid component design they may significantly exceed the maximum design stress. The aim of this paper is to discuss the implications for the life of the component of these excess stresses. This will cover the mechanisms for the propagation of localised damage in a strain controlled environment, and the effect of this damage on the thermal conductivity and hence on the induced thermal gradients and thermal strains. Strains corresponding to stresses considerably above the normally accepted design stress can be sustained for a considerable number of cycles, but the influence of extended time periods with damage at elevated temperatures remains unexplored.


Author(s):  
Eric P. Bouillon ◽  
Greg C. Ojard ◽  
G. Habarou ◽  
Patrick C. Spriet ◽  
Jean L. Lecordix ◽  
...  

Advanced materials have the potential to improve gas turbine engine durability. One general area of concern for durability is in the hot section components of the engine. Ceramic matrix composites offer improvements in durability at elevated temperatures with a corresponding reduction in weight for nozzles of gas turbine engines. Building on past material efforts, a next generation SiC/SiC composite with a self-sealing matrix has been developed for gas turbine applications. An extensive baseline test characterization has been done that shows the overall material suitability. Prior to ground engine testing, a reduced test matrix was undertaken to aggressively test the material in a long-term hold cycle at elevated temperatures and environments. This tensile low cycle fatigue testing was done in air and a 90% steam environment. While the steam environment aggressively attacked the material, no appreciable debit in material life was noted. Nondestructive testing and post test characterization of this testing were performed. After completion of the aggressive testing effort, two nozzle seals of constant thickness were fabricated and installed in an F100-PW-229 engine for accelerated mission testing. The self sealing CMC seals were tested for over 250 hours in accelerated conditions without damage. The results of the engine testing will be shown and overall conclusions drawn.


Author(s):  
Subhash K. Naik ◽  
Andrew Massar ◽  
Jean F. Lecostaouec ◽  
Bruce Thomson

The key technology requirement for advanced gas turbine engines is the availability of lightweight, higher temperature materials which will allow the components to operate with little or no cooling air. Ceramic Matrix Composites represent one such category. An interturbine duct has been selected as the first component for introducing silicon carbide fiber reinforced silicon nitride composites in advanced engines. An ongoing program is focused on process development, fabrication of components and measurement of mechanical properties. A significant property base continues to be developed for both uni-directional and multi-directional reinforced ceramic composites. The results of the program are presented.


Author(s):  
E. Bouillon ◽  
G. Ojard ◽  
Z. Ouyang ◽  
L. Zawada ◽  
G. Habarou ◽  
...  

The advancement of self-sealing ceramic matrix composites offers durability improvements in hot section components of gas turbine engines. These durability improvements come with no need for internal cooling and with reduced weight. Building on past material efforts, ceramic matrix composites based upon a silicon carbide or carbon fiber with a novel self-sealing matrix have been developed for gas turbine applications. The specific application being pursued on this effort is an F100-PW-229 nozzle seal. Ground engine testing has been completed that exceeds the full design life. The ground testing has demonstrated a significant durability improvement from the baseline metal design. Residual properties have been determined by extracting tensile and microstructural coupons from the ceramic matrix composite seal. This was done as a function of design life. Nondestructive interrogation was used as a guide in setting cutting diagrams. The results from this effort will be presented.


Author(s):  
Andy Szweda ◽  
Steve Butner ◽  
John Ruffoni ◽  
Carlos Bacalski ◽  
Jay Lane ◽  
...  

Oxide/Oxide Ceramic Matrix Composites (CMCs) are an attractive class of materials for gas turbine hot section applications. The oxide fiber reinforcement and inherent matrix porosity contributes to favorable fracture toughness and thereby enhanced resistance against impact by foreign objects. Also, the oxide composition ensures superior environmental resistance against accelerated attack by corrosive species in the gas turbine hot section and resulting surface recession typically observed in silicon-based ceramic monolithic and composite materials. Under a program sponsored by the US National Institute of Standards and Technology (NIST) a hybrid oxide/oxide CMC system has been developed with potential application for stationary gas turbine hot section components. COI Ceramics, Inc. has fabricated subscale and full scale combustor liners which have been evaluated in rig and engine testing at Solar, and in field testing in a Solar Centaur® 50S engine at a commercial end user site. Following the conclusion of the NIST program in June 2003 the engine field testing is being continued under a Solar-led program sponsored by the US Dept. of Energy (DOE). As of November 2004, a hybrid oxide/oxide CMC outer combustor liner has accumulated 12,582 field test hours with 63 starts and an extensive material experience base has been developed. The paper will summarize the progress to-date for this hybrid CMC combustor liner development and demonstration, including selected fabrication approach, NDE, and rig/engine test experience.


Author(s):  
Jay E. Lane ◽  
Jay A. Morrison ◽  
Bonnie Marini ◽  
Christian X. Campbell

Ceramic matrix composites (CMCs), in particular oxide-based systems, are of interest for use in combustion turbines. While uncoated oxide CMCs have significant hurdles to implementation in gas turbines, the Siemens hybrid oxide CMC system is able to overcome these challenges. These hybrid oxide CMCs provide distinct advantages over the current non-oxide based systems. The benefits of hybrid oxide-based systems for advanced gas turbines will be discussed. Material system developments will be discussed including those completed by a Siemens Power Generation led team in a recent NIST (National Institute of Standards and Technology) sponsored program to prove the concept of advanced hybrid oxide-oxide CMCs for gas turbine engines. The program fabricated a full scale outer combustor liner that was installed in a Solar Centaur 50S engine at a commercial end user site. In November 2006, this hybrid oxide CMC outer combustor liner met the target life goal of 25,000 hrs with 25,404 hrs of field test experience. The final hurdle for design of hybrid oxide CMC components is the ability to accurately analytically predict behavior. Methods and approaches to address this challenge are discussed as well.


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