bluuebunny/crossref_metadata_2025_split huggingface dataset:
Power Generation Technological Determinants for Fuel Scenario Outlook
Authors: Luby P. , Susta M. R. 
Published: December 2014

Concentration of power market revolutionary changes within the relatively narrow time frame of the last decade will continue for at least another decade.
Too many dynamic factors have been seen in the research & development of new power generation technology as well as commercial realisation.
Too many impulses have been also seen in the independent power market arena. New legislation framework, new financing tools, deregulation, privatisation and liberalisation trends have become typical with many emerging-economy countries but also with countries having highly developed infrastructure supported by stabilised legislation & political system.
Under such circumstances natural gas (NG) has been preferred both by private developers as well as state developers. From the same reason also gas turbines (GT) based technologies have become highly competitive option in the new capacity demand saturation. GT technologies will retain their dominant position also in the future. However, this needn’t inevitably mean that also NG must retain the first choice for the whole period of next generation. NG market may become saturated in middle-range horizon, approximately about 2010–2015. Huge reserves of coal together with appropriate coal-based technologies like IGCC (Integrated Gasification Combined Cycle) or PFBC (Pressurised Fluidised Bed Combustion) will cause subsequent decline from NG towards other fossil fuel commodities. Reasons for such scenario are given in our analysis.
Design and Investigation of Four Low Solidity Vaned Diffusers to Assess the Effect of Solidity and Vane Number
Authors: Engeda Abraham 
Published: December 2014

As part of a continued effort to understand the design and performance of Low Solidity Vaned Diffusers (LSVD), four new LSVDs have been designed and tested.
A centrifugal compressor stage usually consists of the inlet, impeller, diffuser and collector systems. Even though the individual components of the compressor are capable of achieving high efficiency, it is the efficiency of the whole stage that is of great importance. The diffuser system of a centrifugal compressor comes basically in two general categories either as vaneless or vaned diffuser (excluding pipe diffusers). Vaned diffusers can further be subdivided into two depending on channel geometry as straight channel or curved channel, or depending on solidity. It is currently believed that the LSVD offers a compromise between a vaned and a vaneless diffuser by possessing the virtues of each.
This paper discusses the design and experimental investigation of the new four LSVDs. The diffusers had a solidity of 0.9, 0.8, 0.7 and 0.6. These newly designed LSVDs are known as LSVD#5 to LSVD#8.
Development of a Low NOx Combustor for 300kW-Class Ceramic Gas Turbine (CGT302)
Authors: Okuto A. , Kimura T. , Takehara I. , Nakashima T. , Ichikawa Y. , Tatsumi T. 
Published: December 2014

Research and development project of ceramic gas turbines (CGT) was started in 1988 promoted by the Ministry of International Trade and Industry (MITI) in Japan. The target of the CGT project is development of a 300kW-class ceramic gas turbine with a 42 % thermal efficiency and a turbine inlet temperature (TIT) of 1350°C. Three types of CGT engines are developed in this project. One of the CGT engines, which is called CGT302, is a recuperated two-shaft gas turbine for co-generation use. In this paper, we describe the research and development of a combustor for the CGT302.
The project requires a combustor to exhaust lower pollutant emissions than the Japanese regulation level. In order to reduce NOx emissions and achieve high combustion efficiency, lean premixed combustion technology is adopted.
Combustion rig tests were carried out using this combustor. In these tests we measured the combustor performance such as pollutant emissions, combustion efficiency, combustor inlet/outlet temperature, combustor inlet pressure and pressure loss through combustor. Of course air flow rate and fuel flow rate are controlled and measured, respectively.
The targets for the combustor such as NOx emissions and combustion efficiency were accomplished with sufficient margin in these combustion rig tests. In addition, we report the results of the tests which were carried out to examine effects of inlet air pressure on NOx emissions here.
A Rotor Blade Cooling Improvement for Heavy Duty Gas Turbine Using Steam and Mixed Steam/Air Cooling
Authors: Carnevale Ennio , Facchini Bruno , Ferrara Giovanni , Innocenti Luca 
Published: December 2014

This paper proposes a theoretical study of steam cooling application for a typical rotor blade cooling system of heavy duty gas turbine.
The steam cooling introduction is evaluated using open and closed loop configurations; the possible interaction of steam and air cooling is also studied; the simulation is realized with a family of modular codes developed by authors.
The study is conducted with the characteristic cooling parameters (efficiency, effectiveness) analysis and by the evaluation of blade temperature distribution. The results show the possibility of a mass coolant reduction and/or, a maximum cycle temperature increase with the same cooling system used for standard air cooling.
The best results are obtained with an innovative closed-open/steam-air cooling system.
Application of Gas Turbines on Floater Vessel for Power Generation Service
Authors: Waldhelm Chris 
Published: December 2014

Application of gas turbines for power generation services aboard special classed floater vessels for mobile oil and gas exploration platforms has been demonstrated and certified by classification societies. A floating platform, designed by Kerr McGee UK PLC, in operation in the North Sea on purpose-built vessel, Tentech 850, has incorporated a pair of Mars T-12,000 gas turbine generator sets designed and supplied by Solar Turbines. The system has been registration classed and certified by Det Norske Veritas in mid 1993 for all of the power generating services required for extended oil extraction and pre-production processing, as well as, auxiliary electric power required for operations.
This paper presents the selection and certification process required for this application and an update of the operating experience during the first years of operation.
Investigations of Turbulent Flow in a Centrifugal Compressor Vaned Diffuser by 3-Component Laser Velocimetry
Authors: Stahlecker D. , Gyarmathy G. 
Published: December 2014

The unsteady 3D impeller exit and vaned diffuser flow of a high-subsonic centrifugal compressor has been investigated with an LDV system. Time-resolved 3D velocity measurements were taken along a streampath at 8 positions from impeller exit downwards through the vaned diffuser and at 18 positions from hub to casing at each station. The compressor was operated at its best point at a rim Mach number of Mu = 0.75.
Time-resolved (phase averaged) angle and velocity profiles are presented for 2 positions along the streampath. The time-averaged velocity, deterministic fluctuation intensity, turbulence intensity, and in-plane Reynolds sheer stress profiles, presented for all stations, show the evolution of flow and permit comparisons to in-house CFD calculations to be made.
The flow leaving the impeller enters the diffuser with an asymmetric and distorted velocity profile. It is shown that the deterministic fluctuations caused by the jet/wake are quickly damped along the streampath. The results illustrate the deceleration of the flow arriving near the hub in the diffuser channel. The deceleration is accompanied by a sharp increase of turbulence. Near the casing, where the approach velocity is low, no deceleration occurs and the Reynolds stresses are high. Turbulence in the in-plane flow can be regarded as isotropic whereas the axial fluctuations clearly show a high amount of anisotropicity.
The narrow diffuser passage required special optical measures for permitting close-to-wall LDV measurements. The experiences are described.
Mechanical Property Scatter in CFCCs
Authors: Steen Marc , Filiou Constantina 
Published: December 2014

The tensile response of continuous fibre reinforced ceramic matrix composites (CFCCs) is not expected to show the large variation in strength properties commonly observed for monolithic ceramics. Results of recent investigations on a number of 2D reinforced CFCCs have nevertheless revealed a considerable scatter in the initial elastic modulus, in the first matrix cracking stress and in the failure stress. One school of thought considers that the observed variability is caused by experimental factors. Elaborate testing programmes have been set up to clarify the origins of this scatter by investigation of the effects of control mode, loading rate, specimen shape, etc.. Another school explains the scatter by the presence of (axial) residual stresses in the fibres and in the matrix. Although plausible, this hypothesis is difficult to verify because experimental determination of the residual stress state in CFCCs is not straightforward. In addition, with the available methods it is impractical to determine the residual stresses in every test specimen. This approach is indeed required for establishing the relationship between the magnitude of the residual stresses and the experimentally observed scatter.
At IAM a method has been developed and validated which allows to quantify the axial residual stress state in individual CFCC specimens by subjecting them to intermittent unloading-reloading cycles. The method as well as the derived relationship between residual stress state and scatter in mechanical response will be presented.
High Pressure Test Results of a Catalytically Assisted Ceramic Combustor for a Gas Turbine
Authors: Ozawa Yasushl , Tochihara Yoshihisa , Mori Noriyuki , Yuri Isao , Kanazawa Takaaki , Sagimori Katsuhiro 
Published: December 2014

A catalytically assisted ceramic combustor for a gas turbine was designed to achieve low NOx emission under 5ppm at a combustor outlet temperature over 1300°C. This combustor is composed of a burner system and a ceramic liner behind the burner system. The burner system consists of 6 catalytic combustor segments and 6 premixing nozzles, which are arranged in parallel and alternately. The ceramic liner is made up of the layer of outer metal wall, ceramic fiber and inner ceramic tiles.
Fuel flow rates for the catalysts and the premixing nozzles are controlled independently. Catalytic combustion temperature is controlled under 1000°C, premixed gas is injected from the premixing nozzles to the catalytic combustion gas and lean premixed combustion over 1300°C is carried out in the ceramic liner. This system was designed to avoid catalytic deactivation at high temperature and thermal and mechanical shock fracture of the honeycomb monolith of the catalyst.
A combustor for a 10MW class, multi-can type gas turbine was tested under high pressure conditions using LNG fuel. Measurements of emission, temperature, etc. were made to evaluate combustor performance under various combustion temperatures and pressures.
This paper presents the design features and the test results of this combustor.
A Systematic Experimental Study on the Aerodynamics of Leading Edge Film Cooling on a Large Scale High Pressure Turbine Cascade
Authors: Ardey Sabine , Fottner Leonhard 
Published: December 2014

Systematic isothermal investigations on the aerodynamic effects of leading edge film cooling were carried out on a large scale high pressure turbine cascade named AGTB. In the vicinity of the stagnation point the AGTB turbine cascade has one injection site on the suction side and one on the pressure side. Three injection geometries were tested: Slots (two dimensional geometry), streamwise inclined holes (symmetrical three dimensional geometry) and compound angle holes (fully three dimensional geometry). The injection angle in streamwise direction, the blowing ratio, the inlet turbulence intensity, the inlet Mach number, and the inlet Reynolds number were kept constant at values typically found in modern gas turbines.
The measured data comprise the coolant plenum state, the cascade inlet conditions, the flow field in the cascade exit plane including secondary flows, the static pressure distribution in the mid span section of the blade and in the near hole region, the coolant flow field close to the injection site on the leading edge, Schlieren images of the coolant penetration height and oil-and-dye flow visualizations of the blade surface. The experimental data are summarized and documented as a test case that can be used for validation purposes of prediction methods.
Results of the GT Prime Program Improvements to General Electric MS7001B Gas Turbines at the Houston Light and Power T.H. Wharton Site
Authors: Svatek Jerome , Elliott Michael , Crabtree Paul , Jurczynski Gerald E. , Johnston John R. (Bob) 
Published: December 2014

At the time of the start of the GT PRIME upgrade project, the eight General Electric MS7001 gas turbines in combined cycle service at the Wharton Station of Houston lighting and Power each had 85,000 hours of operation with 2000 starts. The units were ready for their second major overhaul. A number of hot gas path components required replacement at that time. Rather than replacing components one by one, the user devised a Program for Reliability, Improved Maintenance, and Efficiency (GT PRIME). We will discuss turbine condition, design changes, reduced emissions, and increased output in the paper.
Actual user experience on maintenance and operating costs resulted in some special requirements to be satisfied in addition to the expected parts replacement. General Electric had developed many improved parts for newer units, all of which could be easily applied to older machines. The use of these newer production MS7001EA parts increase component life, parts availability, inspection intervals, system reliability and performance. These will be described in the paper.
These 1972 vintage turbines achieved a 50PPM NOx level by injecting water at a high rate of flow which resulted in the need for more frequent combustion inspection intervals. The development of a dry low NOx system for the unit allowed the combustion inspection interval to double while reducing NOx to 25PPM.
The improvement in component efficiencies in the gas path resulted in increased output and improved the heat rate. These changes had a significant impact on customer operating costs which resulted in a very attractive payback period. We will discuss expected versus actual output, heat rate and emissions results for all eight units. The upgrade of the first unit started in 1992 and the last unit was completed in 1996. A detailed listing of uprate program schedule by unit is listed in Figure #1.
Fast-Track Redeployment of AVON Quad-Pack Improves Island’s Backup Power System
Authors: Blomberg Björn , Liljigren Christer , Jameison Ian 
Published: December 2014

Moving power generation equipment is a major undertaking under the best of circumstances. This paper documents the project to provide more reliable backup power for the island of Gotland, off the coast of Sweden in the Baltic Sea. All the power for this scenic island is normally supplied by two sub-sea, HVDC cables from the Swedish mainland. In the early 1990’s, the power company started the planning to redeploy some of their peaking generation assets more effectively on Gotland. Providing the island with more generating capacity and faster recovery in the event of a partial or total loss of the DC tie-line was deemed a worthy endeavor.
Preparations to move the two 60 MW AVON Quad-pack gas turbine-generators were initiated late in 1994. In addition to commencing green-field site construction to receive the units, the company initiated a controls retrofit of the 1970-vintage units with new fault-tolerant combustion and generation automatic voltage regulation control systems to the relocated turbines.
The scope and timeline for this complex, fast-track project are described along with specific challenges. Results versus expectations are also documented.
On-Line and Off-Line Steam Turbine Component Strain States Monitoring for the Diagnostic System
Authors: Kosman Gerard P. , Rusin Andrzej M. , Nowak Grzegorz M. 
Published: December 2014

This paper presents the main assumptions and targets of the strain and stress states modelling of the steam turbine components. The analysis is undertaken due to the main components of HP and IP turbine sections (inner and outer casings, valve bodies and rotors) working under a significant load. Stress modelling has been divided into two parts: a simplified analysis and the detailed one. The former has been proposed in this way that the on-line calculations can be done. It’s based on special functions built upon multi-variant heat process simulations. The functions mentioned make it possible to describe the maximum component stress from some measured temperatures. This part should meet the requirements due to the stress state modelling during a usual turbine operation.
The detailed analysis comprises the unsteady operating conditions, bearing the stamp of intensive heating or cooling processes. As a result of the advanced calculation methods and full stress models being used the analyses is carried off-line.
Update on the Progress of the Brazilian Wood BIG-GT Demonstration Project
Authors: Waldheim L. , Carpentieri E. 
Published: December 2014

Biomass integrated gasification-gas turbine (BIG-GT) technology offers the opportunity for efficient and environmentally sound power generation from biomass fuels. Since biomass is ‘carbon-neutral’ it can be used in power generation equipment without contributing to the ‘greenhouse effect’ if it is grown sustainably.
The Brazilian BIG-GT initiative is one of a number of initiatives world-wide aimed at demonstrating, and thereby establishing, biomass as an energy resource for power production. The goal of the Brazilian BIG-GT project is to confirm the commercial viability of producing electricity from wood through the use of biomass-fuelled integrated gasification combined-cycle (BIG-GT) technology. To fulfil this goal a 32 MWe eucalyptus-fuelled demonstration power plant will be built in Brazil on the basis of a design made by TPS Termiska Processer AB (TPS).
The first two phases of the project, which included experimental and engineering studies and the basic engineering of the plant, were completed in 1997. The next phase of the project, the construction and commissioning of the plant, is the recipient of a U.S. $35 million grant from the Global Environmental Facility (GEF) of the United Nations Development Programme (UNDP), in addition to financing from the World Bank (WB).
The plant will be built in Bahia, north-eastern Brazil. The customer of the plant is a consortium, SER - Sistemas de Energia Renovável, comprising of CHESF (Companhia Hidro Elétrica do São Francisco), a federally-owned electricity generation and distribution company, Eletrobras (Centrais Elétricas Brasileiras), a holding company comprising of the main Brazilian companies from the electric generation and distribution sector, and Shell Brasil. Start-up of the plant is scheduled for the year 2000.
The plant will be based on a TPS designed atmospheric-pressure gasification/gas cleaning process. The product gas will be fired in a modified GE LM 2500 gas turbine. The gasification and gas cleaning process is based on the use of a circulating fluidised bed gasifier, secondary stage catalytic tar cracker and conventional cold filter and wet scrubbing technology. The feedstock to the plant will be mainly eucalyptus wood from a dedicated plantation which is harvested on a three-year cycle.
This paper describes the background of the project leading up to the technology selection, the technology that will be employed in the plant and the outline of the economics of this ‘first-of-a-kind’ plant. The progress made in establishing the organisation and the formal framework (e.g. securing the electricity and fuel contracts) are also reported. Future projections of likely technological improvements and cost reductions, and their effect on the overall economics of an ‘Nth’ plant, are presented.
A Metallographic Technique for High Temperature Creep Damage Assessment in Single Crystal Alloys
Authors: Henderson Pamela , Komenda Jacek 
Published: December 2014

The use of single crystal (SX) nickel-base superalloys will increase in the future with the introduction of SX blades into large gas turbines for base-load electricity production. Prolonged periods of use at high temperatures may cause creep deformation and the assessment of damage can give large financial savings. A number of techniques can be applied for life assessment, e.g. calculations based on operational data, non-destructive testing or material interrogation, but because of the uncertainties involved the techniques are often used in combination. This paper describes a material interrogation (metallographic) technique for creep strain assessment in SX alloys.
Creep tests have been performed at 950°C on the SX alloy CMSX-4 and quantitative microstructural studies performed on specimens interrupted at various levels of strain. It was found that the strengthening γ′-particles, initially cuboidal in shape, coalesced to form large plates or rafts normal to the applied stress. The γ-matrix phase also formed plates. CMSX-4 contains ∼ 70 vol % γ′-particles and after creep deformation the microstructure turned itself inside out, i.e. the gamma “matrix” became the isolated phase surrounded by the γ′-“particles”. This can cause problems for computerised image analysis, which in this case, were overcome with the choice of a suitable measurement parameter.
The rafts reached their maximum length before 2% strain, but continued to thicken with increasing strain. Although of different dimensions, the aspect ratios (length/thickness ratio) of the gamma-prime rafts and the gamma plates were similar at similar levels of strain, increasing from ∼1 at zero strain to a maximum of ∼3 at about 1–2 % strain.
Analysis of microstructural measurements from rafting studies on SX alloys presented in the literature showed that the aspect ratios of the γ- and γ′-phases were similar and that at a temperature of 950–1000°C a maximum length/thickness ratio of about 2.5–3.5 is reached at 1 to 2% creep strain. Measurement of gamma-prime raft or (or gamma plate) dimensions on longitudinal sections of blades is thus a suitable method for high temperature creep damage assessment of SX alloys. This gives a considerable advantage over conventional Ni-base superalloys whose microstructures are usually very stable with respect to increasing creep strain.