A major technical challenge for modern aero engines is the development of designs which reduce noise and emission whilst increasing aerodynamic efficiency and ensuring aeroelastic stability of low-temperature engine components such as fans and low-pressure compressors. Composites are used in aviation due to their excellent stiffness and strength properties, which also enable additional flexibility in the design process. The weight reduction of the turbomachine components, due to composite materials and lighter engines, is especially relevant for the design and developments of hybrid-electric or distributed propulsion systems [1]. To accomplish this, a representative volume element (RVE) of a glass-fiber reinforced polymer is created, describing the geometrical arrangement of the textile reinforcement structure within the polymer matrix. For both phases, realistic linear elastic properties are assumed. This RVE will be investigated with the finite element method under various loading conditions to assess its anisotropic elastic properties and also its damping behaviour for elastic waves. To study the influence of delamination on the mechanical properties, small defects will be introduced into the model at the interface between reinforcement and matrix. Based on this micromechanical approach, a constitutive model for the composite will be formulated that describes the anisotropic properties as well as the damping behaviour. This constitutive model is then used to describe the material response in a macro-mechanical model, which serves as the basis for an aeroelastic analysis of a 1/3-scaled high-speed fan using a conventional (Ti-6Al-4V) and fiber composite material.

Ceramics matrix composites (CMCs) have higher heat resistance and specific strength than conventional metal. These effects can contribute to not only reducing cooling air and parts weight, but also increasing turbine inlet temperature (TIT). As a result, CMCs have potential to improve aero-engine performance and reducing emission. CMCs also have complicated material characteristics to apply aero engine turbine parts. Stress-strain curve shows not only non-liner behavior in higher stress level but also anisotropy. The behavior and fracture toughness show the anisotropy because of material internal structure. Material strengths indicate anisotropy as well. Low cycle fatigue (LCF) strength indicates dependency of stress gradient. Thus, conventional design methods using linear elastic analysis model and peak stress assessment are too conservative to design CMC parts. IHI is developing SiC-SiC 3D woven fabric which is used for aero engine turbine vane and also building up a fracture prediction model to design the CMC turbine vane. Fracture prediction model is composed of structural analysis model to estimate deformation and fracture evaluation model to predict strength. The material model is assumed as a homogeneous substance and this material model constitutive equation is constructed from the theory of continuum damage mechanics (TCDM). In fracture model, that strength parameter is calculated with averaging stress fields. Multi-axial stress fields are evaluated by engineering equations referred to Hashin’s criteria. To validate our fracture prediction model, specific structural feature test were conducted. Sub-component tests were based on the building block approach that was general to validate structural reliability of composite material parts. Static tests and low cycle and high cycle fatigue tests were carried out at room temperature and high temperature. The validation test results showed good agreement with prediction. Finally we have made sure the validation of this fracture prediction model.

In this paper, the authors present a solid vane concept which uses 3D woven fabric based SiC/SiC CMC and the result of engine testing which was conducted to demonstrate this concept. The authors devised a design concept, in which a vane is made from a folded woven, for the uncooled turbine vanes of the aircraft engines. The advantage of this concept is that there is no structural weak point because a whole vane including outer / inner platform consists of one continuous woven. In order to demonstrate the applicability of this concept to the actual engine parts, CMC turbine vanes were tested with IHI-IM270 that is a small industrial gas turbine engine. After 862 hour testing, there was no defect such as cracks, wear, and deformation.

This paper describes the development of laminated seals for stator-stator sealing in gas turbines. Cloth seals were introduced as stator-stator seals in the 1990’s and resulted in a significant improvement in sealing performance over the rigid seals then in service. Laminated seals presented here are proposed as an improvement to the existing cloth seals. They demonstrate improved leakage performance over cloth seals in aligned and offset conditions. Several versions of laminated seals were developed and tested before arriving at a seal geometry that satisfied the leakage, manufacturability and assembly requirements. These seals therefore provide an alternative to cloth seals that leak less and are durable, cost-effective and robust in assembly.

This paper describes a solar energy collector system for providing process heat to a textile drying process in a WestPoint Pepperell mill in Fairfax, Alabama. The solar collector system uses 24 single axis tracking parabolic trough concentrating collectors to heat water in a high temperature water loop. The high temperature water fuels a steam generator to provide process steam. The process that was solarized is a textile drying process using cylindrical can dryers. The dryers are utilized in the slashing operation, a textile process where yarn is treated with sizing in preparation for weaving.

This paper describes coal-fired, indirectly heated, air turbine combined cycle cogeneration plants that employ atmospheric pressure external combustion of coal, an open cycle gas (air) turbine, and a steam turbine. Air to operate the air turbine is heated indirectly, by hot fluidized solids contained inside tubes. The result is a high efficiency system that burns coal (or almost anything that will burn), does not require extensive operator training or support facilities, and emits low quantities of sulfur, NOx and particulates. The plant is capable of supplying electrical power, process heat, steam, and clean hot air in varying quantities, depending on the application. Uses exist in the chemical, petroleum, mining, metallurgical, paper, and textile industries and in enhanced oil recovery.

Responding to the need for a higher level of through thickness strength, higher damage tolerance, and near net shape manufacturing in structural engine components, there is a worldwide revival in the interest in 3-D fabric preforms. Recent advances in computer aided design, analysis and manufacturing of fully integrated 2-D and 3-D woven, knitted, and braided fibrous structures promises to lead to major advances in composite technology. Through thickness strength imparted to composites by virtue of such integrated reinforcement will open new applications for composites that could not be considered previously, primarily due to the poor transverse strength and interlaminar shear properties of traditional laminated composites. The ability of these structures to conform to shape or assume near net structural shapes promises to simplify manufacturing processes, reduce costs, and enhance design flexibility.

This paper provides a review of the material design concepts for the toughening of ceramic matrix composites by 3-D fiber architecture. To establish a communication link between the structural and the materials engineers, an integrated design methodology is presented with an example. Through a Fabric Geometry Model (FGM), the contribution of 3-D fiber architecture is translated into a stiffness matrix for finite element structural analysis. With the feedback from the structural analysis, this design methodology provides an effective means to screen reinforcement materials systems for 3-D fabric reinforced composite components.

This paper examines some of the major problems connected with cogeneration in some typical industrial sectors. A prior study of the impact of monitorized energy consumption on the choice of cogeneration solution showed that: - In the 0.5–3.0 MW range: Gas turbines with heat recovery represent an appealing solution in terms of overall plant costs. - In the 0.5–0.8 MW range: Industry characteristics must be better clarified before dealing with competition from internal combustion (IC) reciprocating engines. This study served to establish the design guidelines for the NuovoPignone PGT2 gas turbine, rated at 2 MW, with a 25% efficiency at the generator terminals. The design exhaust temperature of 550°C is well suited to cogeneration applications in the types of industry investigated (textile-, cement-, and paper-making). However, in other cases such as nonindustrial cogeneration, where very low electricity costs are desirable, the available regenerative cycle option has a potential electrical efficiency of over 28% at lower exhaust temperatures and heat levels.

This paper examines the tensile behavior of SiC/SiC fabric composites. In the characterization effort, the stress-strain relation and damage evolution are studied with a series of loading and unloading tensile test experiments. The stress-strain relation is linear in response to the initial loading and becomes nonlinear when loading exceeds the proportional limit. Transverse cracking has been observed to be a dominant damage mode governing the nonlinear deformation. The damage is initiated at the inter-tow pores where fiber yarns cross over each other. In the modeling work, the analysis is based upon a fiber bundle model, in which fiber undulation in the warp and fill directions and gaps among fiber yarns have been taken into account. Two limiting cases of fabric stacking arrangements are studied. Closed form solutions are obtained for the composite stiffness and Poisson’s ratio. Transverse cracking in the composite is discussed by applying a constant failure strain criterion.

Fibers such as fabric and bristles can be readily fabricated into a variety of seal configurations that are compliant and responsive to high speed or lightly loaded systems. A linear, circular, or contoured brush seal system is a contact seal consisting of the bristle pattern and hardened interface. When compared to a labyrinth seal the brush seal system is superior and features low leakage, dynamic stability, and permits compliant structures. But in turn the system usually requires a hardened smooth interface, permits only limited pressure drops. Wear life and wear debris for operations with static or dynamic excitation are largely undetermined. A seal system involves control of fluid within specific boundaries. The brush and rub ring (or rub surface) form a seal system. In this paper, design similitudes, a bulk flow model, and rub ring (interface) coatings are discussed. The bulk flow model calculations are based on flows in porous media and filters. The coatings work is based on our experience and expanded to include current practice.

This paper reviews the properties of high temperature ceramic fibers and relates why strength, thermal shock resistance, chemical inertness, and high temperature capability are important properties for high temperature filter media. The use of candle filters, fabric filters, and composite filters will be discussed for removal of particulates from hot gas streams in electrical power generation systems, metal refining, chemical processing, and Diesel engine exhaust applications.

Ceramic composite materials have the capability to sustain high stress in the presence of high temperatures and aggressive atmospheres. Such materials are being considered for application as cumbustors, burner tubes, heat exchangers, headers, hot-gas filters, and even rotors of stationary gas turbine engines. In the present program, Nicalon preforms of tubular geometry were fabricated with different fiber architectures (filament winding, 3D braiding, or cloth winding) to tailor the mechanical properties for specific applications. However, these applications require that candidate materials be carefully characterized. Mechanical characterization must establish the properties and performance that are essential for structural design of the turbine components. For this purpose, a full complement of properties is needed, i.e., the stiffness and strengths of the composite materials at a range of temperatures, and the fatigue and creep behavior of the materials under the stress states anticipated by the user. This mechanical characterization requires specialized equipment and methodologies, which are now under development by the authors. This paper will present a description of the methodologies required for ceramic composite characterization, and will describe initial results for ceramic composite tubes, a representative geometry for gas turbine components. Future needs and opportunities will also be discussed.

The PGT2 is a single-shaft gas turbine with a 2 MW ISO electric output that, after an extensive factory development program has been launched into industrial service with a number of cogeneration applications in small-medium size industries. The two-stage high pressure ratio compressor combined with the single-can combustor and the two-stage air-cooled transonic turbine provides a compact and rugged architecture. The turbine inlet temperature in the 1050–1100 °C class and the 12.5:1 pressure ratio provide a 25% electrical efficiency and a high exhaust temperature that make this machine attractive for a variety of both civil and industrial applications like hospitals and pulp and paper mills, textile, tiles, cement, glass and food production. The exhaust heat recovery boiler can be either a commercial unit or compact once-through type of proprietary design that is housed in a vertical exhaust duct to substantially reduce powerplant footprint area when space is limited. The first application that has provided the most extensive operating experience so far is cogeneration in a paper mill in central Italy. Detailed studies on the potential energy saving and on the return of investment cycle were made in collaboration with the client, and provided a valuable basis for further studies that led to additional orders for paper mills, textile and tile industries. The first installed unit is a package comprising a once-through-flow boiler that was full-load tested at the factory before shipping. Commissioning of the cogeneration plant was started in 30 days after shipment and the plant was taken over by the client in less than three months. A dedicated telephone line allows the power plant to be monitored directly from Florence, thus making it possible to gather operational data in real time and to provide this first customer with prompt assistance during the 4-year service and maintenance contract period. This paper describes the PGT2 design and performance features, the technical and economic evaluations made for the first application, the cogeneration plant layout and a summary of the most significant operational data collected in the initial months or regular service in the paper mill.

World is now endangered by the threat of fuel source scarcity and environmental degradation. Researchers all over the world are searching for the alternative energy resources to supplement the present energy needs and to conserve the conventional resources from depletion which are less costly and environmentally friendly. Harnessing the wind power and its utilization is one of the best possible answers. Investigations for recent years have revealed that wind energy has been the great deals to the rural farmers for their water pumping. Wind power can be used effectively in maintaining livestock, water supply, fish & ice farming, water desalination, sawing wood, irrigation, electrification, agricultural operations etc. If all possible considerations are given in exploiting wind energy, in the coming 4 to 5 decades it can meet 30% to 45% of the world’s total energy demand contributing no unwanted emissions into the atmosphere. It can adjust more jobs and occupies fewer lands. It is cheaper than any other sources. Bangladesh possesses flat terrain, hilly & mountainous regions, open river banks & harbors, and a vast lengthy coastal belt by the sea “the Bay of Bengal” where reasonable wind flow round the year available. For most of the said areas, electricity supply from the mother grid is almost inaccessible due to various difficulties and limitations. Moreover, a total of 2105 MW national generation capability absolutely unable to meet the present suppressed peak demand of 2114 MW for the consumers already in the grid. This continuously causing a severe regular load shedding up to 30% of the peak demand. The large sized population of the above areas is being maintained over decades mostly from fuel wood, charcoal plant & agricultural residues, dung and very few from imported petroleum and derivatives as the only energy sources. The energy scarcity let the locality remained economically backward and noncontributing to the GDP. In some of the areas namely Chittagong Harbor, Coastal belts & City periphery, from recent observations the monthly mean wind speeds (m/s) ranging between 4.5 and 8.5 are recorded which show the genius prospect of reaping wind power in Bangladesh. Despite a promising future of this free fuel, benefits for utilizing this energy in Bangladesh are being missed because too little is known about either the resource or the technology. Wind energy can successfully be utilized in utility for supplementing our generation and to meet decentralized needs or wind-solar hybrids for Bangladeshi modern multistory buildings which are now meeting their energy deficit by individual diesel generators at higher money and environmental costs. In the context of Bangladesh, wind power to come to use, this paper is an attempt to describe the methodologies for site selection; wind data collection & regime modeling; power availability, conversion & storage; turbine performance monitoring & augmenting wind speed using cloth scoops including costs and environmental impact Assessment. This paper also discusses Bangladesh energy scenario and strategies for meeting deficit demand and summarizes global wind development and proposes that Bangladesh government and other agencies must take immediate initiatives towards implementing wind projects.

This paper presents effective extensional stiffness of plain-weft knitted fabric reinforced composites obtained from finite element analysis and analytical calculations. For micro-mechanical analyses, a unit cell, enclosing the characteristic periodic repeat pattern in the knitted fabric, is isolated and modeled. Psuedo three-dimensional finite element model is constructed using laminated shell elements. Composite extensional stiffness is estimated for plane-stress and plane-strain conditions. Further, stiffness and compliance averaging methods have been used to determine the upper and lower limits of composite stiffness. The models are explicitly based on the properties of fiber and matrix materials and orientation of yarns. Results obtained from the models are compared with experimental values.

Zorlu Enerji needed 35 MW of reliable power at a stable frequency to maintain constant speed on the spindles producing thread at its parent company’s textile plant in Bursa, Turkey. In December of 1996, Zorlu selected an LM2500+ combined cycle plant to fill its power-generating requirements. The LM2500+ has output of 26,810 KW at a heat rate of 9,735 Kj/Kwh. The combined cycle plant has an output of 35,165 KW and a heat rate of 7,428 Kj/Kwh. The plant operates in the simple cycle mode utilizing the LM2500+ and a bypass stack and in combined cycle mode using the 2-pressure heat recovery steam generator and single admission, 9.5 MW condensing steam turbine. The generator is driven through a clutch by the steam turbine from the exciter end and by the gas turbine from the opposing end. The primary fuel for the plant is natural gas; the backup fuel is naphtha. Utilizing a load bank, the plant is capable of accepting a 12 MW load loss when the utility breaker trips open; it can sustain this loss while maintaining frequency within 1% on the mill load. The frequency stabilizing capability prevents overspeeding of the spindles, breakage of thousands of strands of thread and a costly shutdown of the mill. A description of the equipment, operation and performance illustrates the unique features of this versatile, compact and efficient generating unit.

Recent advances in COI’s oxide-oxide CMC materials will be presented including basic processing steps, updated material properties, and fabrication techniques. Material properties of COI’s alumino-silicate system reinforced with various oxide fabrics will be compared, along with progress in developing a 1200°C oxide matrix system for future turbine system applications. Examples of fabricated hardware, including a subscale combustion liner, will be shown. Recent test and evaluation data will be provided.

The layer of non-impregnated aramid fibers is widely used in the containment systems of aircraft gas turbine engines. Such systems are found to be especially cost-effective and light weight for mitigating engine debris during a fan blade-out event. This is mostly because non-impregnated aramid fibers have a high strength per unit weight. Moreover, it is inexpensive to manufacture such a containment system compared to traditional metallic systems. To properly utilize this advantage, it is necessary to have a finite element (FE) analysis modeling methodology for daily design tasks. Non-impregnated aramid fibers winding for fan case modeling for engine containment systems is a difficult task. This research implied both experimental and modeling techniques, and data characterizing the behavior of fabric materials for engine containment systems. This research was aimed at addressing engine containment modeling issues. Thus this work has resulted in the following major accomplishments: • Experimental Characterization of Non-impregnated Aramid Fibers: the fabric material model originally was created during this phase. The independent laboratory tests conducted at NPO Saturn form the basis of this model. These material models are general enough to be used as the constitutive model for both static and dynamic/explicit FE analyses. • Static Ring Tests: Static tests of containment wraps subjected to loads through a blunt nose impactor were performed at NPO Saturn. Ballistic tests of containment wraps subjected to a high-velocity projectile were performed at NPO Saturn. These tests provided the test cases (the benchmark results) to validate the developed FE methodology. • FE Material Model Development: The material models were used by the research team in the FE simulation of static and ballistic tests. The static test results have been validated by NPO Saturn using the ANSYS FE program. The ballistic test results were validated by NPO Saturn using the LS-DYNA FE program. • Engine Fan Blade-Out (FBO) Simulation: The knowledge gained from previous tasks was used by NPO Saturn for the the numerical simulation of real engine FBO events involving the existing production engine models and compared to the test results (employing thelayer of non-impregnated aramid fibers containment). • Combined Fan and Metal Case Comparison: The relative comparison between the non-impregnated aramid fibers and the metal materials in engine FBO containment systems has been carried out in order to ascertain that the non-impregnated aramid fibers case is more advantageous.

Ceramic Matrix Composite (CMC) materials are an attractive design option for various high-temperature structural applications. In particular, the use of CMC materials as a replacement for state-of-the-art nickel-based superalloys in hot gas path turbomachinery components offers the potential for significant increases in turbine system efficiencies, due largely to reductions in cooling requirements afforded by the increased temperature capabilities inherent to the ceramic material. However, two-dimensional fabric-laminated CMCs typically exhibit low tensile strengths in the thru-thickness (interlaminar) direction, and interply delamination is a concern for some targeted applications. Currently, standardized test methods only address the characterization of interlaminar tensile strengths at ambient temperatures; this is problematic given that nearly all CMCs are slated for service in high-temperature operating environments. This work addresses the development of a new test technique for the high-temperature measurement of interlaminar tensile properties in CMCs, allowing for the characterization of material properties under conditions more analogous to anticipated service environments in order to yield more robust component designs.