Reliability of a Conceptual Ceramic Gas Turbine Component Subjected to Static and Transient Thermomechanical Loading

1997 ◽  
Author(s):  
Paul S. DiMascio ◽  
Robert M. Orenstein ◽  
Harindra Rajiyah
Keyword(s):  
Silicon Nitride ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Ceramic Materials ◽  
Combustion Products ◽  
Tensile Creep ◽  
Creep Model ◽  
Gas Combustion ◽  
Component Reliability ◽  
Reliability Models

A three year program to evaluate the feasibility of using monolithic silicon nitride ceramic components in gas turbines was conducted. The use of ceramic materials may enable design of turbine components which operate at higher gas temperatures and/or require less cooling air than their metal counterparts. The feasibility evaluation consisted of three tasks: 1) Expand the material properties database for candidate silicon nitride materials, 2) Demonstrate the ability to predict ceramic reliability and life using a conceptual component model and 3) Evaluate the effect of proof testing on conceptual component reliability. The overall feasibility goal was to determine whether established life and reliability targets could be satisfied for the conceptual ceramic component having properties of an available material. Fast and delayed fracture reliability models were developed and validated via thermal shock and tensile experiments. A creep model was developed using tensile creep data. The effect of oxidation was empirically evaluated using four-point flexure samples exposed to flowing natural gas combustion products. The reliability- and life-limiting failure mechanisms were characterized in terms of temperature, stress and probability of component failure. Conservative limits for design of silicon nitride gas turbine components were established.

Reliability of a Conceptual Ceramic Gas Turbine Component Subjected to Static and Transient Thermomechanical Loading

1998 ◽  
Vol 120 (2) ◽  
pp. 263-270 ◽  
Author(s):  
P. S. DiMascio ◽  
R. M. Orenstein ◽  
H. Rajiyah
Keyword(s):  
Silicon Nitride ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Ceramic Materials ◽  
Combustion Products ◽  
Tensile Creep ◽  
Creep Model ◽  
Gas Combustion ◽  
Component Reliability ◽  
Reliability Models

A three year program to evaluate the feasibility of using monolithic silicon nitride ceramic components in gas turbines was conducted. The use of ceramic materials may enable design of turbine components which operate at higher gas temperatures and/or require less cooling air than their metal counterparts. The feasibility evaluation consisted of the following three tasks: (1) expand the materials properties database for candidate silicon nitride materials; (2) demonstrate the ability to predict ceramic reliability and life using a conceptual component model; and (3) evaluate the effect of proof testing on conceptual component reliability. The overall feasibility goal was to determine whether established life and reliability targets could be satisfied for the conceptual ceramic component having properties of an available material. Fast and delayed fracture reliability models were developed and validated via thermal shock and tensile experiments. A creep model was developed using tensile creep data. The effect of oxidation was empirically evaluated using four-point flexure samples exposed to flowing natural gas combustion products. The reliability and life-limiting failure mechanisms were characterized in terms of temperatures, stress, and probability of component failure. Conservative limits for design of silicon nitride gas turbine components were established.

Design Overview of a Three-Kilowatt Recuperated Ceramic Turboshaft Engine

2009 ◽  
Author(s):  
Michael J. Vick ◽  
Andrew Heyes ◽  
Keith Pullen
Keyword(s):  
Silicon Nitride ◽  
Gas Turbines ◽  
Pressure Ratio ◽  
Cost Effective ◽  
Ceramic Materials ◽  
Combustion Products ◽  
Multistage Turbine ◽  
Ceramic Recuperator ◽  
Ic Engines ◽  
Turboshaft Engine

A three-kilowatt turboshaft engine with a ceramic recuperator and turbine has been designed for small unmanned air vehicle (UAV) propulsion and portable power generation. Compared with internal combustion (IC) engines, gas turbines offer superior reliability, engine life, noise and vibration characteristics, and compatibility with military fuels. However, the efficiency of miniature gas turbines must be improved substantially, without severely compromising weight and cost, if they are to compete effectively with small IC engines for long-endurance UAV propulsion. This paper presents a design overview and supporting analytical results for an engine that could meet this goal. The system architecture was chosen to accommodate the limitations of mature, cost-effective ceramic materials: silicon nitride for the turbine rotors, and toughened mullite for the heat exchanger and turbine stators. An engine with a cycle pressure ratio below 2:1, a multistage turbine, and a highly effective recuperator is shown to have numerous advantages in this context. A key benefit is a very low water-vapor-induced surface recession rate for silicon nitride, due to an extremely low partial pressure of water in the combustion products. Others include reduced sensitivity to internal flaws, creep, and foreign object damage; an output shaft speed low enough for grease-lubricated bearings; and the potential viability of a novel premixed heat-recirculating combustor.

scholarly journals Improved Silicon Nitride Materials and Component Fabrication Processes for Aerospace and Industrial Gas Turbine Applications

1995 ◽  
Author(s):  
John P. Pollinger
Keyword(s):  
Silicon Nitride ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Hybrid Electric Vehicle ◽  
Ceramic Materials ◽  
Production Volume ◽  
Cycle Times ◽  
Fine Grained ◽  
Auxiliary Power Units ◽  
Industrial Gas Turbines

New and improved silicon nitride structural ceramic materials and component fabrication processes are being developed and refined for implementation and insertion into aerospace, industrial, and automotive gas turbine applications. These improved materials and forming processes offer the potential of meeting turbomachinery manufacturers’ performance, quality, cost, and production volume goals. AlliedSignal has developed a new generation of silicon nitride materials with isotropic acicular microstructures that result in a number of property improvements compared to current HIP’ed fine-grained silicon nitride materials. Concurrently, new silicon nitride component forming processes such as gelcasting and refinements of current forming processes such as presintered component machining are being developed and refined to achieve production volume fabrication capability, yields, and short cycle times at low costs. As these materials and component fabrication processes are maturating, a number of applications are being investigated and demonstrated including hot section turbomachinery components for aircraft auxiliary power units (APU’s), industrial gas turbines, and automotive hybrid electric vehicle turboalternators.

Ceramic Stationary Gas Turbine Development

1993 ◽  
Author(s):  
Mark van Roode ◽  
William D. Brentnall ◽  
Paul F. Norton ◽  
Gregory P. Pytanowski
Keyword(s):  
Silicon Carbide ◽  
Silicon Nitride ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Ceramic Materials ◽  
Ceramic Composites ◽  
Department Of Energy ◽  
Engine Operation ◽  
Component Design ◽  
Combustor Liner

A program has been initiated under the sponsorship of the Department of Energy (DOE), Office of Industrial Technology, to improve the performance of stationary gas turbines in cogeneration through the selective replacement of metallic hot section parts with uncooled ceramic components. 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 program which started in September, 1992, takes an engine of the Solar Centaur family of industrial gas turbines, and modifies the design of the hot section to accept ceramic first stage blades and first stage nozzles, and a ceramic combustor liner. The ceramic materials selected for the blade are silicon nitride, for the nozzle silicon nitride and silicon carbide, and for the combustor liner silicon carbide as well as two continuous fiber reinforced ceramic composites, one with a silicon carbide matrix and another with an oxide matrix. This paper outlines the approach, conceptual component design, and materials selection for the program.

Design Overview of a Three Kilowatt Recuperated Ceramic Turboshaft Engine

2010 ◽  
Vol 132 (9) ◽  
Author(s):  
Michael J. Vick ◽  
Andrew Heyes ◽  
Keith Pullen
Keyword(s):  
Silicon Nitride ◽  
Gas Turbines ◽  
Pressure Ratio ◽  
Cost Effective ◽  
Ceramic Materials ◽  
Combustion Products ◽  
Multistage Turbine ◽  
Ceramic Recuperator ◽  
Ic Engines ◽  
Turboshaft Engine

A three kilowatt turboshaft engine with a ceramic recuperator and turbine has been designed for small unmanned air vehicle (UAV) propulsion and portable power generation. Compared with internal combustion (IC) engines, gas turbines offer superior reliability, engine life, noise and vibration characteristics, and compatibility with military fuels. However, the efficiency of miniature gas turbines must be improved substantially, without severely compromising weight and cost, if they are to compete effectively with small IC engines for long-endurance UAV propulsion. This paper presents a design overview and supporting analytical results for an engine that could meet this goal. The system architecture was chosen to accommodate the limitations of mature, cost-effective ceramic materials: silicon nitride for the turbine rotors and toughened mullite for the heat exchanger and turbine stators. An engine with a cycle pressure ratio below 2:1, a multistage turbine, and a highly effective recuperator is shown to have numerous advantages in this context. A key benefit is a very low water vapor-induced surface recession rate for silicon nitride, due to an extremely low partial pressure of water in the combustion products. Others include reduced sensitivity to internal flaws, creep, and foreign object damage; an output shaft speed low enough for grease-lubricated bearings; and the potential viability of a novel premixed heat-recirculating combustor.

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.

scholarly journals Design and Development of a Landfill Gas Combustion System for the Typhoon Gas Turbine

1996 ◽  
Author(s):  
David J. Ecob ◽  
Michael B. Boyns ◽  
Steve Walsh ◽  
Ken McClave ◽  
A. Allen Hunt
Keyword(s):  
Gas Turbine ◽  
Landfill Gas ◽  
Combustion Products ◽  
Diesel Oil ◽  
Combustion System ◽  
Fuel Injector ◽  
Gas Combustion ◽  
Axial Injection ◽  
Carbon Modification ◽  
Post Test

This paper presents design, initial combustion development testing and engine validation results of a combustion system which is capable of burning a medium CV landfill gas or conventional diesel oil in a 5MW gas turbine. Initial rig testing of the original combustion system burning a simulated medium CV gas revealed stability problems and inherently poor combustion efficiencies. A study of primary zone flow patterns and fuel placement led to the conclusion that the problems were due to axial injection of the gas. Subsequently a modified dual fuel injector was designed which relied on swirled instead of axial injection. The modified injector design also embodies a passive purge feature, which uses combustor wall pressure drop to feed air directly into the gas swirler passages. This prevents ingestion of harmful combustion products when running on diesel oil. Extensive rig testing demonstrated encouraging combustion efficiencies and emissions using 40% and 54% methane landfill gas compositions across a simulated engine load profile. Operation of the modified injector on diesel oil however, demonstrated a need for the incorporation of an anti-carbon feature. The effectiveness of this anti-carbon modification was verified as part of a ‘validation engine cycle’ simulating the actual engine operating procedure from light up to shutdown. Post test inspection revealed carbon deposition to be significantly reduced. Combustion efficiencies, emissions, traverse quality, metal temperatures, stability and noise were all found to be satisfactory.

scholarly journals Compact Metallic and Ceramic Recuperators for Gas Turbines

1978 ◽  
Author(s):  
S. Förster ◽  
M. Kleemann
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Power Plants ◽  
Ceramic Materials ◽  
Experimental Heat ◽  
Tube Type ◽  
Recuperative Heat Exchanger ◽  
Gas Turbine Cycle ◽  
Typical Design ◽  
Plate Type

A compact plate-type recuperative heat exchanger feasible in metal or ceramic materials and suitable for stationary and vehicular gas turbines is described. The flow schemes and fabrication techniques of the heat exchanging matrices are illustrated. Metallic and ceramic prototype matrices are shown which have been fabricated successfully. On the bases of experimental heat transmission and friction data for the metallic matrices, typical design solutions are shown for complete recuperators. Design examples for metallic recuperators are given for large nuclear closed-cycle helium turbine power plants and for stationary and vehicular open-cycle gas turbines. For vehicular application, sizes for turbines of several hundred kilowatts are discussed. Two design examples are given of ceramic recuperators for a 70-kw vehicular gas turbine having small overall dimensions when compared to a piston engine. Some cost aspects of the compact recuperators are discussed. Compact metallic recuperators, such as described in the paper, may replace advantageously the tube type or other plate type recuperators for large stationary and vehicular gas turbine cycle applications. Furthermore, the ceramic compact recuperator also described in the paper may be a satisfying practical solution for small vehicular gas turbines, especially for the so-called “ceramic” gas turbines with gas temperatures at the turbine inlet of about 1300 C.

Quantitative Phase Analysis of Synthetic Silicon Nitride by X-Ray Diffraction

1979 ◽  
Vol 23 ◽  
pp. 375-379
Author(s):  
Z. Mencik ◽  
M. A. Short ◽  
C. R. Peters
Keyword(s):  
Silicon Nitride ◽  
Phase Analysis ◽  
Gas Turbines ◽  
Ceramic Materials ◽  
Silicon Oxynitride ◽  
Quantitative Phase Analysis ◽  
X Ray Diffraction ◽  
X Ray ◽  
Quantitative Phase ◽  
Typical Material

Synthetically prepared silicon nitride is one of the more promising ceramic materials for structural components of gas turbines. Typical material may contain a-silicon nitride, Si3N4 (which is believed to always contain oxygen and therefore, according to Grievson, Jack and Wild, is more properly written as Si11.5N15O0.5), β-silicon nitride, Si3N4, silicon oxynitride, Si2ON2, silicon metal, Si, and α-cristobalite, SiO2. Because the physical properties of the ceramic parts are dependent on their phase composition, it is essential that a technique be available for performing a phase analysis. An X-ray diffraction procedure has been, developed for the quantitative phase analysis of synthetically prepared silicon nitride. This procedure converts experimentally measured intensities of selected X-ray diffraction peaks to weight fractions of components using empirically determined intensity coefficients.

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