Boundary Conditions for Ceramic Turbine Components: Analytical Prediction and Test Validation

1999 ◽  
Author(s):  
Hamid Bagheri ◽  
Oscar Jimenez
Keyword(s):  
Finite Element ◽  
Boundary Conditions ◽  
Gas Turbines ◽  
Department Of Energy ◽  
Analytical Prediction ◽  
Finite Element Analyses ◽  
Ceramic Component ◽  
Engine Operation ◽  
Component Development ◽  
Ceramic Components

Ceramics allow gas turbine engines to run at higher temperatures to increase power and efficiency. Ceramic component development is therefore required to understand transient thermal behavior and temperature distributions. As a part of contract with US Department of Energy (DOE), a series of finite element analyses were completed and a Solar Turbine (Solar) Centaur 50S engine was tested to characterize this behavior. To better understand the interaction between the metallic and ceramic components during engine operation, a finite element model was prepared. The boundary conditions for this model were estimated analytically or using existing test data. To verify the boundary conditions in the vicinity of uncooled ceramic components, two engine tests were performed on a metallic engine simulating the ceramic engine configuration. The Solar Centaur 50S engine normally operates at 1010°C with all metallic components. A Centaur 50S eagine was retrofitted with a ceramic combustor liner and uncooled first stage turbine blades and nozzles. Two tests were conducted at firing temperatures of 1095 and 980°C. Using metallic components saved time, reduced the complexity of working with ceramic components, and eliminated some of the difficulties of attaching instrumentation to ceramic parts. Component temperatures were measured and used in the finite element analyses to help predict blade tip clearances, ceramic component temperatures, stresses and ultimately component lives. The strategy undertaken and results presented herein provided a reliable and effective approach to ceramic component development and provides critical temperature information in the qualification process for ceramic gas turbines.

scholarly journals Ceramic Stationary Gas Turbine Development Program: Design and Life Assessment of Ceramic Components

1995 ◽  
Author(s):  
Paul F. Norton ◽  
Gary A. Frey ◽  
Hamid Bagheri ◽  
Aaron Flerstein ◽  
Chris Twardochleb ◽  
...  
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Failure Modes ◽  
Development Program ◽  
The United States ◽  
Department Of Energy ◽  
Life Assessment ◽  
United States Department ◽  
Ceramic Component ◽  
Engine Operation

A program is being performed under the sponsorship of the United States Department of Energy, Office of Industrial Technology, to improve the performance of stationary gas turbines in cogeneration through the selective replacement of hot section components with ceramic parts. It is envisioned that the successful demonstration of ceramic gas turbine technology, and the systematic incorporation of ceramics in existing and future gas turbines will enable more efficient engine operation, resulting in significant fuel savings, increased output power, and reduced emissions. The engine selected for the program, the Centaur 50 (formerly named Centaur ‘H’) will be retrofitted with first stage ceramic blades, first stage ceramic nozzles, and a ceramic combustor liner. The engine hot section is being redesigned to adapt the ceramic parts to the existing metallic support structure. The program currently in Phase II focuses on detailed engine and component design, ceramic component fabrication, ceramic component testing, establishment of a long term materials property database, and the development and application of supporting technologies in the areas of life prediction and non-destructive evaluation. This paper outlines the design activities associated with the introduction of a ceramic first stage nozzle and two configurations of ceramic first stage turbine blade. In addition, probabilistic life assessment of the ceramic parts for major failure modes (fast fracture, slow crack growth and where relevant, creep and oxidation) will be discussed.

Ceramic Stationary Gas Turbine Development Program: Second Annual Summary

1995 ◽  
Author(s):  
Mark van Roode ◽  
William D. Brentnall ◽  
Paul F. Norton ◽  
Bryan D. Edwards
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Fatigue Testing ◽  
The United States ◽  
United States Department ◽  
Ceramic Component ◽  
Support Structure ◽  
Engine Operation ◽  
Ceramic Components ◽  
Combustor Liner

A program is being performed under the sponsorship of the United States Department of Energy, Office of Industrial Technologies, to improve the performance of stationary gas turbines in cogeneration through the selective replacement of hot section components with ceramic parts. Solar Turbines Incorporated leads a team that includes major U.S. and offshore suppliers of ceramic components, recognized test laboratories and a cogeneration enduser to develop and demonstrate ceramic insertion in a stationary gas turbine with the objectives of more efficient engine operation, resulting in significant fuel savings, increased output power, and reduced emissions. The engine selected for the program, the Centaur 50 is being retrofitted with first stage ceramic blades, first stage ceramic nozzles, and a ceramic combustor liner. The engine hot section is being redesigned to accommodate the ceramic parts to the existing metallic support structure. Detailed design of the ceramic components and of the interfacing metallic support structure has been completed. Two blade designs with different attachments and a nozzle design with a modified airfoil geometry have been developed. Three combustor liner designs are being evaluated based on monolithic tiles or rings, or integral cylinders of continuous fiber-reinforced ceramic matrix composites (CFCC). Fabrication of first generation prototype blades and nozzles is in progress. Fabrication of subscale combustor hardware has been completed. Materials property data are being gathered in support of the ceramic component design and life prediction. Fast fracture and dynamic fatigue testing were performed for the candidate blade and nozzle materials. Creep and oxidation testing is in progress. Nondestructive methodologies are being applied to test specimens, simulated components, subscale hardware and prototype components. A Centaur 50 engine was procured and has been modified for ceramic component testing in a full-size engine configuration.

scholarly journals Analysis of Monolithic and Sandwich Panels Subjected To Non-Uniform Thickness-Wise Boundary Conditions

2016 ◽  
Vol 5 (1) ◽  
pp. 232-249
Author(s):  
Riccardo Vescovini ◽  
Lorenzo Dozio
Keyword(s):  
Finite Element ◽  
Boundary Conditions ◽  
Sandwich Plate ◽  
Sandwich Plates ◽  
Vibration Frequencies ◽  
Thickness Direction ◽  
Finite Element Analyses ◽  
Uniform Thickness ◽  
Bending Problems ◽  
High Degree

Abstract The analysis of monolithic and sandwich plates is illustrated for those cases where the boundary conditions are not uniform along the thickness direction, and run at a given position along the thickness direction. For instance, a sandwich plate constrained at the bottom or top face can be considered. The approach relies upon a sublaminate formulation,which is applied here in the context of a Ritz-based approach. Due to the possibility of dividing the structure into smaller portions, viz. the sublaminates, the constraints can be applied at any given location, providing a high degree of flexibility in modeling the boundary conditions. Penalty functions and Lagrange multipliers are introduced for this scope. Results are presented for free-vibration and bending problems. The close matching with highly refined finite element analyses reveals the accuracy of the proposed formulation in determining the vibration frequencies, as well as the internal stress distribution. Reference results are provided for future benchmarking purposes.

Progress on the Advanced Turbine Technology Applications Project (ATTAP)

1994 ◽  
Author(s):  
S. G. Berenyi
Keyword(s):  
Life Cycle Cost ◽  
High Speed ◽  
Design Procedure ◽  
Department Of Energy ◽  
Laboratory Evaluation ◽  
Ceramic Component ◽  
Turbine Engine ◽  
Oak Ridge ◽  
Turbine Inlet ◽  
Ceramic Components

This technology project, sponsored by the U.S. Department of Energy, is intended to advance the technological readiness of the ceramic automotive gas turbine engine. Of the several technologies requiring development before such an engine becomes a commercial reality, structural ceramic components represent the greatest technical challenge, and are the prime project focus. The ATTAP aims at developing and demonstrating such ceramic components that have a potential for: (1) competitive automotive engine life cycle cost and (2) operating for 3500 hr in a turbine engine environment at turbine inlet temperatures up to 1371°C (2500°F). Allison is addressing the ATTAP goal using internal technical resources, an extensive technology and data base from General Motors (GM), technical resources from several subcontracted domestic ceramic suppliers, and supporting technology developments from Oak Ridge and other federal programs. The development activities have resulted in the fabrication and delivery of numerous ceramic engine components, which have been characterized through laboratory evaluation, cold spin testing, hot rig testing, and finally through engine testing as appropriate. These component deliveries are the result of the ATTAP design/process development/fabrication/characterization/test cycles. Ceramic components and materials have been characterized in an on-going program using nondestructive and destructive techniques. So far in ATTAP, significant advancements include: • evolution of a correlated design procedure for monolithic ceramic components • evolution of materials and processes to meet the demanding design and operational requirements of high temperature turbines • demonstration of ceramic component viability through thousands of hours of both steady-slate and transient testing while operating at up to full design speed, and at turbine inlet temperatures up to 1371°C (2500°F) • completion of hundreds of hours of durability cyclic testing utilizing several “all ceramic” gasifier turbine assemblies • demonstration of ceramic rotor survivability under conditions of extreme foreign object ingestion, high speed turbine tip rub, severe start-up transients, and a very demanding durability cycle In addition to the ceramic component technology, progress has been made in the areas of low emission combustion technology and regenerator design and development.

Advanced Turbine Technology Applications Project (ATTAP): Overview, and Ceramic Component Technology Status

1991 ◽  
Author(s):  
Philip J. Haley
Keyword(s):  
High Speed ◽  
High Volume ◽  
Department Of Energy ◽  
High Yield ◽  
Design System ◽  
Ceramic Component ◽  
Forming Process ◽  
Technology Applications ◽  
Ceramic Components ◽  
Monolithic Ceramics

The automotive gas turbine’s (AGT) significant potential payoffs in fuel economy, emissions, and alternate fuels usage continue to motivate development activities worldwide. The U.S. Department of Energy-sponsored, NASA-managed Advanced Turbine Technology Applications Project (ATTAP) focuses on developing critical AGT structural ceramic component technologies. The area of greatest challenge is that of cost-effective, near-net-shape, high-volume, high-yield manufacturing processes. Process physics modeling and Taguchi analyses are affording substantial progress, and new processes are being explored. Laboratory characterization is building a shared materials data base among Allison, Garrett, Government labs, and ceramic manufacturers. General Motors (GM) has logged over 700 test hours with ceramic components in hot gasifier rigs during ATTAP. A key ATTAP milestone was addressed by successfully demonstrating full goal temperature and speed (2500°F rotor inlet at 100% shaft speed) with ceramic components. Fast-fracture ceramic component design tools are well correlated. Although time-dependent data and mechanistic models exist, a validated design system for such phenomena does not, and is a pressing need. Damage tolerance and impact resistance have been substantially addressed through tailored component designs, tougher monolithic ceramics, and increased ceramic strengths. Ceramic turbine rotors are now continuing to run after various substantial impacts, and after chipping damage. Ceramic-ceramic and ceramic-metal interfacing is being addressed by minimizing components’ joints, and by other DOE-sponsored work on joining models, processes, and materials. The extruded regenerator disk is a continuing goal which requires both forming process and materials technology development. Controlling turbine tip clearances and tolerating tip rubs are key technologies. GM has demonstrated clearance control schemes, as well as rotor survivability to high speed/temperature tip rubs. Several noteworthy ceramic materials reflect the rapid progress over the past decade of monolithic ceramics, especially the Si3N4 family. GM forecasts achieving ATTAP engine cyclic durability goals.

scholarly journals Ceramic Stationary Gas Turbine Development Program — Fifth Annual Summary

1998 ◽  
Author(s):  
Jeffrey R. Price ◽  
Oscar Jimenez ◽  
Les Faulder ◽  
Bryan Edwards ◽  
Vijay Parthasarathy
Keyword(s):  
Gas Turbines ◽  
Development Program ◽  
Field Testing ◽  
The United States ◽  
Turbine Rotor ◽  
Department Of Energy ◽  
Inlet Temperature ◽  
United States Department ◽  
Performance Improvements ◽  
Ceramic Components

A program is being performed under the sponsorship of the United States Department of Energy, Office of Industrial Technologies, to improve the performance of stationary gas turbines in cogeneration through the selective replacement of metallic hot section components with ceramic parts. The program focuses on design, fabrication, and testing of ceramic components, generating a materials properties data base, and applying life prediction and nondestructive evaluation (NDE). The development program is being performed by a team led by Solar Turbines Incorporated, and which includes suppliers of ceramic components, U.S. research laboratories and an industrial cogeneration end user. The Solar Centaur 50S engine was selected for the development program. The program goals included an increase in the turbine rotor inlet temperature (TRIT) from 1010°C (1850°F) to 1121°C (2050°F), accompanied by increases in thermal efficiency and output power. The performance improvements are attributable to the increase in TRIT and the reduction in cooling air requirements for the ceramic parts. The ceramic liners are also expected to lower the emissions of NOx and CO. Under the program uncooled ceramic blades and nozzles have been inserted for currently cooled metal components in the first stage of the gas producer turbine. The louvre-cooled metal combustor liners have been replaced with uncooled continuous-fiber reinforced ceramic composite (CFCC) liners. Modifications have been made to the engine hot section to accommodate the ceramic parts. To-date all first generation designs have been completed. Ceramic components have been fabricated, and are being tested in rigs and in the Centaur 50S engine. Field testing at an industrial co-generation site was started in May, 1997. This paper will provide an update of the development work and details of engine testing of ceramic components under the program.

Investigation on Ceramic–Metal Joints for Shaft–Hub Connections in Gas Turbines

1996 ◽  
Vol 118 (3) ◽  
pp. 626-631 ◽  
Author(s):  
G. v. Esebeck ◽  
M. Kising ◽  
U. Neuhof
Keyword(s):  
Finite Element ◽  
Tensile Stress ◽  
Carrying Capacity ◽  
Gas Turbines ◽  
Adhesive Bonding ◽  
Experimental Investigations ◽  
Finite Element Analyses ◽  
Dynamic Torsion ◽  
Static Shear ◽  
Shear Bending

This paper shows possibilities for joining ceramic rotors to metal shafts. The investigations presented include exemplary joining methods for shaft–hub connections for ceramic rotors in gas turbines, as positive, permanent locking, or a combination of both. Active brazing as well as the combination of brazing or adhesive bonding and positive locking are discussed. Different shaft–hub connections were tested. The results of experimental investigations as static shear, bending, and torsion tests as well as dynamic torsion tests will be presented. In addition to the experimental investigations, finite-element analyses were made. Elastic calculations on simple geometries have shown the influence of different parameters like the thermal coefficients and the geometry at the joint face. Calculations were done to reduce the induced tensile stress in the joint and to increase carrying capacity. The calculations were also transferred to the shaft–hub connections to optimize the geometry of the joint faces.

Probabilistic Finite-Element Analyses on Turbine Blades

2009 ◽  
Author(s):  
Thomas Weiss ◽  
Matthias Voigt ◽  
Hartmut Schlums ◽  
Roland Mu¨cke ◽  
Karl-Helmut Becker ◽  
...  
Keyword(s):  
Finite Element ◽  
Turbine Blade ◽  
Gas Turbines ◽  
Numerical Models ◽  
System Level ◽  
Structural Behavior ◽  
Design Parameters ◽  
Innovative Technology ◽  
Finite Element Analyses ◽  
Operation Conditions

Further progress in the development of modern gas turbines for aircraft engines and electric power stations requires both continuous optimization on component and system level as well as the use of new and innovative technology. Thereby, the design is often pushed closer to the physical limits, which demands an outstanding understanding and predictability of the structural behavior under different design and off-design conditions. Due to the considerable costs of real component testing, the knowledge on structural behavior and failure mechanisms of gas turbine components is often gained from validated numerical models. To obtain a realistic computational image of reality, the uncertainties inherent in the design, the material properties, the loading and the operation conditions have to be considered in the modeling process. The effect of variations in key input design parameters on critical results such as the predicted component life can be evaluated on the basis of probabilistic analyses. The paper addresses first general aspects of applying probabilistic Finite-Element analyses in the turbine blade design process. Then, probabilistic design methods are applied to investigate the lifetime of a single crystal (SX) turbine blade submodel. Thereby, variations in three SX orientations as well as different load positions and variations in the creep properties are investigated by Monte-Carlo-Simulation (MCS) techniques.

Ceramic Stationary Gas Turbine Development Program — Design and Test of a Ceramic Turbine Blade

1998 ◽  
Author(s):  
Oscar Jimenez ◽  
John McClain ◽  
Bryan Edwards ◽  
Vijay Parthasarathy ◽  
Hamid Bagheri ◽  
...  
Keyword(s):  
Gas Turbine ◽  
Turbine Blade ◽  
Gas Turbines ◽  
Fuel Efficiency ◽  
Development Program ◽  
Field Testing ◽  
The United States ◽  
Department Of Energy ◽  
United States Department ◽  
Engine Operation

The goal of the Ceramic Stationary Gas Turbine (CSGT) Development Program, under the sponsorship of the United States Department of Energy (DOE), Office of Industrial Technologies (OIT), is to improve the performance (fuel efficiency, output power, and exhaust emissions) of stationary gas turbines in cogeneration through the selective replacement of hot section components with ceramic parts. This program, which is headed by Solar Turbines Incorporated and supported by various suppliers, and national research institutes, includes detailed engine and component design, procurement, and field testing. A major challenge in the successful introduction of ceramic parts into a gas turbine is the design of the interface between the ceramic parts and metallic hardware. A turbine blade, which incorporated a dovetail root, was designed with such considerations. A relatively thin compliant layer between the ceramic-metallic loading surface was considered for equalizing pressure face load distributions. Five monolithic siliocn nitride ceramic materials were considered: AS800 and GN10, AlliedSignal Ceramic Components; NT164, Norton Advanced Ceramics; SN281 and SN253, Kyocera Industrial Ceramics Corporation. The probability of survival using NASA/CARES for 30,000 hours of engine operation was calculated for each material. The blade frequencies, stresses, and temperatures were predicted. The influence of the dovetail angle was also analyzed to determine the most optimum configuration. Prior to engine installation all blades underwent extensive nondestructive evaluation and spin proof testing. This paper will review the design, life prediction, and testing of the first stage ceramic turbine blade for the Solar Turbines Centaur 5OS engine.

scholarly journals Structural Analysis of Rear Pressure Bulkhead of Typical Transport Aircraft

2020 ◽  
Vol 8 (4S) ◽  
pp. 14-16
Keyword(s):  
Finite Element ◽  
Structural Analysis ◽  
Boundary Conditions ◽  
Normal Stress ◽  
Honeycomb Structure ◽  
Finite Element Analyses ◽  
Maximum Displacement ◽  
Transport Aircraft ◽  
Maximum Normal Stress ◽  
Modeling Software

In this study, many researchers studied flat bulkhead, but Dome-shaped bulkhead is more preferable as it withstands pressure loads. We modeled a rear pressure bulkhead of a typical transport aircraft using CATIA V5 modeling software. Finite element analyses were carried out by the rear pressure bulkhead subjected to the boundary conditions (Fuselage is fixed and attached to the aircraft honeycomb structure and 0.1Mpa pressure is applied to the bulkhead). From the FEA of the rear pressure bulkhead, we obtained Von-Misses stresses and the deformations were obtained. The maximum displacement of 5.46mm was observed on the dome. The maximum normal stress at the circumferential direction was about 306Mpa.

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