Search

Increasing atmospheric carbon dioxide from fossil fuel combustion is raising new interest in using renewable biomass for energy. Modest-scale cogeneration systems using air-blown gasifiers coupled to aeroderivative gas turbines are expected to have high efficiencies and low unit capital costs, making them well-suited for use with biomass. Biomass-gasifier/gas-turbine (BIG/GT) technology is not commercial, but efforts aimed at near-term commercialization are ongoing worldwide. Estimated performance and cost and prospects for commercial development of two BIG/GT systems are described, one using solid biomass fuel (e.g. wood chips), the other using kraft black liquor. At an energy-efficient kraft pulp mill, a BIG/GT cogeneration system could produce over three times as much electricity as is typically produced today. The mill’s on-site energy needs could be met and a large surplus of electricity would be available for export. Using in addition currently unutilized forest residues for fuel, electricity production would be nearly five times today’s level. The total cost to produce the electricity in excess of on-site needs is estimated to be below 4 cents per kWh in most cases. At projected growth rates for kraft pulp production, the associated biomass residue fuels could support up to 100 GW of BIG/GT capacity at kraft pulp mills worldwide in 2020 (30 GW in the US). The excess electricity production worldwide in 2020 would be equivalent to 10% of today’s electricity production from fossil fuels.Copyright © 1991 by ASME

The CW251B10 Gas Turbine has been in service at the Procter & Gamble Paper Mill located at Mehoopany, Pennsylvania since July 1985, and has exhibited outstanding reliability and availability since that time. It operates continuously at base load supplying both electricity and process air for the plant. This paper reviews the operating history of the gas turbine, and describes some of the problems experienced, together with their solutions.Copyright © 1989 by ASME

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.

Vortices generated and designed in internal cooling systems of film cooled turbine blades have a significant influence on the aerodynamic mixing process of the coolant and the main flow. Of course the resulting distribution of the film cooling effectiveness is strongly influenced by the behaviour of the coolant mixing. The vortices are generated by a special design of the cooling channel and film cooling holes and by the comparable flow phenomena coming along with the problem of jets in crossflow. The multi-block Navier-Stokes solver TRACES with special features for the simulation of complex and turbulent mixing phenomena is applied to solve the flow field and the heat fluxes and temperature distribution in the turbine blade structure simultaneously. The code is validated for the simulation of film cooling and heat transfer and was also compared to other codes taking part in the AGARD Working group 26 (Dunham, 1996 [4]) working on the test cases “NASA-Rotor-37” and DLR-Turbine guide vane “VT1B”. As a result of extensive parameter studies (Vogel, 1996 [18]) a vortex mixing model will be established which describes the existing vortices and their effect on the film cooling mixing process in detail. It was found that vortex generation inside the internal cooling channel with an opposite direction of rotation compared with the main kidney shaped jet vortex system can reduce the amount of coolant air significantly without reducing the film cooling effectiveness. All numerical investigations presented in this paper were carried out using a model geometry. No experimental results were available for this geometry. The validation of the code concerning film cooling mixing was presented in [15], [16], [17] and [18] (Vogel, 1994–1996). The geometries applied in those validations were quite similar to those used in this paper. Nevertheless for credibility some comparisons between experimental and numerical data are presented.

We report in this paper a project undertaken at NASA Lewis Research Center with an aim at achieving a timely, reliable, and high-fidelity CFD prediction of aeropropulsion systems. The present paper specifically addresses issues relevant to internal flows in a turbine component. The flows are three dimensional, highly viscous and turbulent and the geometry is complex. We choose to discretize the computation domain with unstructured tetrahedral meshes and approximate the inviscid fluxes with the recent upwind scheme, AUSM+. An implicit discrete system of unknowns is solved by the Gauss-Seidel Jacobi iterative scheme with a coloring strategy to reduce the matrix bandwidth. A one-equation turbulence model is used to represent the Reynolds stresses. To calculate the complex flow in a turbine coolant passage, we first validate the code for unit problems that contain some subset features. The calculations show excellent results for the backward-facing step and the 180-degree-turn duct. Finally we provide a detailed analysis of the flow in the simulated geometry of th turbine coolant passage.

There are various papers relevant to the improvement ideas of gas turbine cycles, which in general discuss only optimum one-point cycle analysis.*1,*2,*6 It is, accordingly, unclear whether such improvement concepts can be applied into existing gas turbines or not. It might be difficult to incorporate such ideas, in the case of yielding significant changes for operation modes. And it may be essential to assess improvement ideas, from view points of applicability to existing gas turbine models.*3 This paper introduces the performance analysis method of simplified small perturbation procedure, showing thermodynamic behaviors based upon the component characteristics, and resultant influences due to settled operation parameters, like ambient temperature & pressure, turbine inlet temperature, etc. The established method might be used as a rule of thumb for the performance prediction when introducing water and/or steam injection into GTs, where operational parameters’ changes are defined under multi-linear differential equations. This is easy to compile in the computer as Lotus 1-2-3 or Exel to evaluate whether every parameter is within the limit or not, offering very helpful performance evaluation tool for the conceptual design stage.Copyright © 1998 by ASME

This paper presents results of experimental as well as numerical investigations of the aerodynamic performance of film-cooled transonic turbine blades. Taking into consideration to non-dimensional similarity, the experiments were performed on a cascade test rig using superheated steam as fluid. The investigated blading corresponds to a typical high pressure turbine vane used in the high subsonic regime. In order to determine the effect of the blown-out cooling fluid on the aerodynamic performance of the cascade, the measurements were performed over a wide range of realistic exit Mach numbers, mass flow rate ratios, coolant injection locations and main-to-coolant flow density ratios. The paper presents the results of the experimental investigation in the form of outlet angles and loss terms, and compares and discusses these for a number of variations. It was found that below a critical mass flow ratio, the kinetic loss coefficient varies only little with flow rate whereas above this critical flow ratio, the loss coefficient increases rapidly. A comparison of the different injection locations shows that the suction side is very sensitive with regard to main flow disturbances while injection on the pressure side and the trailing edge only has a small effect of the loss terms. Consideration of different coolant-to-mainstream density ratios clarifies that the influence of this parameter on the loss terms can be neglected. The paper also addresses a simple numerical code which is based on the „TOTLOS“ model of Hansel and adapted to the above-mentioned problem, and compares and discusses the results of the experimental and numerical investigations.

The first units of the Sequential Combustion System gas turbine family are in commercial operation. The first gas turbine GT24 (60Hz, 165MW-class) started the commercial operation, while the first GT26 (50Hz, 265MW-class) demonstrates its performance at the GT test facility. More engines are presently in the commissioning phase or will be in the near future. These turbines are designed to offer increased output at high GT efficiency. To acheive this, the sequential combustion system, a reheat process with two combustors, has been developed. Whereas the first combustor is based on the proven EV-combustor technology, extensive research and development efforts have been carried out in developing the lean premixed self-igniting second combustor (SEV). This paper is a follow-up of the ASME paper 96-GT-315, which described the basic research work concerning the lean premixing SEV-burners with self-ignition. The present paper reports the experience gained during commissioning of the first engines. The performance of the two combustors, as well as the measured emissions, are discussed and compared with the expected values and rig test results. Finally, the potential of the sequential combustion system to reach low NOx levels is demonstrated by unveiling the results of the extensive testing program during the commissioning phase.

This paper presents an attempt of a quantitative evaluation of deterioration, due to fouling, in the performance of gas turbine units of different schemes (one-shaft, two-shaft and three-shaft) but with axial compressors of the same type and dimensions. This paper also examines the influence of the gas turbine unit initial parameters (inlet turbine temperature and pressure ratio) on the gas turbine unit sensitivity to axial compressor fouling. The evaluation of the gas turbine unit sensitivity to fouling is performed based on the small deviations method. The index of sensitivity to fouling (ISF) proposed in (Tarabrin et al, 1996) is used. It is proposed that not only the ISF characterizing the axial compressor sensitivity to fouling but also the scheme and the initial gas turbine unit parameters influencing the gas turbine unit sensitivity to axial compressor fouling, should be taken into consideration.

This paper identifies the market drivers that have accelerated advanced engine development for use in combined cycles. It also describes experience to date with one such advanced turbine model and details a proven approach to the design of these advanced machines. Details are given of two new models and how the designs are an evolution from previous engines. However, good design alone is not enough to obtain optimum reliability. The paper will discuss those operating practices and maintenance approaches that are necessary for successful and profitable plant operation.

The 60Hz, 165MW gas turbine GT24 and the 50Hz, 240MW gas turbine GT26 are the first two members of ABB’s Sequential Combustion System gas turbine family. These turbines are designed to offer increased output at up to 4% efficiency advantage over today’s engines. Whereas the first combustor is based on the proven EV-combustor technology, an extensive research and development program has been carried out in developing the lean premixed, self-igniting second combustor. This paper reports the basic research work concerning the lean premixing burners with self-ignition. The development of the burner and the combustor was based on wind tunnel and water channel experiments, CFD-calculations and combustion tests at atmospheric and high pressure. Moreover an innovative cooling technology was developed to fullfill all conditions of the self-igniting premix combustor requiring minimal cooling air consumption. Special attention was paid both to a low sensitivity of the cooling effectiveness to variations of the imposed boundary conditions and to a robust hardware construction. Tests of real engine parts at real engine conditions will be demonstrated in detail. Finally the paper demonstrates the potential of the sequential combustion system to reach single digit NOx levels by unveiling the results of the extensive testing program.

This paper describes the status of the Collaborative Advanced Gas Turbine (CAGT) Program’s initiative to commercialize interCooled AeroDerivative gas turbine (ICAD) technology. CAGT is a consortium of domestic and international electric companies, gas companies and research organizations. ICAD gas turbine technology was selected by CAGT member companies and potential suppliers in a competitive $5 million screening study of various advanced gas turbine options in the 1992–94 time frame. Efforts to commercialize ICAD began in 1994–95. The most attractive ICAD gas turbine options were based on high thrust engines produced by General Electric. Pratt & Whitney and Rolls Royce aircraft divisions. Simple cycle ICAD represents a new intermediate load gas turbine product class with costs and performance unlike any other product available today. Simple cycle efficiencies will approach Chose of many operating combined cycles, but with the low capital costs and rapid start times of a peaking gas turbine. ICAD simple cycle units would be in the 100–130 MW size range with efficiencies in the range of 45–48% + LHV and combined cycle efficiencies potentially as high as 60% + LHV. All efficiencies are presented in the paper in lower heating value (LHV). ICAD gas turbines will eddress a wide range of simple cycle, cogeneration. innovative repowering, combined cycle, distributed generation and renewable energy applications. CAGT members have several projects underway with the goal of the first ICAD unit to begin operation before the year 2000. Industry restructuring has reduced near-term demand for new generation in the United States with a corresponding drop in gas turbine prices. Given the large development cost for any new gas turbine product, potential ICAD suppliers have indicated the need for a launch order to proceed with development. CAGT is pursuing a number of project development and strategic alliance strategies globally to organize a launch order in the range of 10–15 projects. Efforts are also underway to examine options for demonstrating ICAD on a smaller scale (Small ICAD or SICAD) which would address the emerging market for distributed generation. CAGT members feel the low costs and flexibility offered by ICAD could be a significant source of competitive advantage in restructuring electric markets. CAGT members invite others to join the program.Copyright © 1996 by ASME

The U.S. Department of Energy (DOE) has established a government/industry partnership program to greatly improve the capabilities of U.S. gas turbine technology. A new and challenging program named the Advanced Turbine Systems Program (ATS) has been initiated by DOE. The technical and business objectives of this initiative are to challenge the bounds of high performance capabilities of gas turbines, meet stringent environmental requirements, and produce lower cost electric power and cogeneration steam. This program will also yield greater societal benefits through continued expansion of high skilled U.S. jobs and export of U.S. products world wide. A progress report on the ATS program pertaining to program status at DOE will be presented and reviewed in this paper. A preliminary design of an industrial advanced turbine system configuration will also be outlined in the paper. The technical challenges; advanced critical technologies incorporation, analytical and experimental solutions, and test results of an advanced gas turbine meeting the DOE goals will be described and discussed.

This paper will describe how Westinghouse approaches the design of new combustion turbines to ensure the same high reliability and availability as in its present products. The paper describes the risk analysis process, design verification, and methodology used in the design of the 501G combustion turbine together with Westinghouse’s design philosophy for reliable design.Copyright © 1996 by ASME

The continual increase in both efficiency and specific power of power plants determines the complexity of power generation units. Therefore, thermodynamic calculations with a high degree of accuracy and flexibility are required. This paper describes a highly flexible computerized method of calculating thermodynamics in a power cycle. The computerized method analyzed here permits the study of steam, gas and combined plants. Its flexibility is not restricted by any defined cycle scheme. A power plant consists of simple elements (turbine, compressor, combustor chamber, pump, etc.). Each power plant component is represented by its typical equations relating to fundamental mechanical and thermodynamic laws, so a power plant system is represented by algebraic equations, which are the typical equations of components, continuity equations, and data concerning plant conditions. This equation system is not linear, but can be reduced to a linear equation system with variable coefficients. The solution is determined by an iterative process. An example of a simple gas turbine cycle demonstrates the applied technique. This paper also presents the user interface based on MS-Windows. The input data, the results, and any characteristic parameters of a complex cycle scheme are also shown.

The investigation of gas turbine blade failures requires an interdisciplinary approach calling for expertise in gas turbine design, operation and metallurgy. The object of this paper is to show, in the context of blading problems, the interrelationship between design, operation, maintenance, and the operational envelope. This paper presents case studies dealing with a variety of failure modes. The treatment focuses on practical troubleshooting of blading problems augmented, in some cases, by the use of analytical tools.Copyright © 1995 by ASME

The gas turbine industry has adopted the practice of rating engine performance at ISO standard conditions; 15 degrees C, 1.033 ata, 100% methane fuel, and no inlet or exhaust system pressure losses with power output referenced to the generator terminals. (ISO, 1989) While these standards are useful in putting original equipment manufacturers’ (OEM’s) ratings on an equivalent basis it is not likely that an engine would be installed or tested under these types of conditions. To account for variations in engine operating conditions equipment manufacturers’ have utilized performance correction curves to show the influence of changing one operating parameter while holding all others constant. The purpose of this paper is to review the correction curves that are used for initial project application studies, and the variations to the curves that occur when a unit is put into service as a result of the methods used to control engine operation. Sample corrections curves and a brief explanation of the correction curves are presented to illustrate the variations in the curves. The paper also presents a new method for illustrating the influence of fuel heating value and composition on engine performance for natural gas and oil fuel. All data presented is for a single shaft, constant speed gas turbine. Two shaft or three shaft gas turbines will not have these correction curves.

Four key parameters, the 4 S’s, determine the technoeconomical performance of the steam bottoming cycle to a given gasturbine: [S1], the temperature of the heat Source, [S2], the temperature of the heat Sink, [S3] cycle Structure and [S4] component Specifications. The first two are given by the gasturbine exhaust gas temperature (TEX) and ambient water/air temperatures respectively; the last two are designer’s choice but depend on economics: how much can you afford to pay for an extra kW? (parity factor or differential capital outlay). The paper analyses the effect of current trends in the first two S’s on the latter two: «S1», the higher TIT (turbine inlet temperature) of advanced GT’s generally leads to higher TEX, especially when coupled with Sequential Combustion; and [S2]«S2», the trend from fresh water cooling to cooling towers — and again from wet to dry types — due to environmental considerations and/or water shortages leads to higher condenser pressures. These trends change the economics of «S3», the structure (one-, two- or three-pressure, reheat, supercritical etc.); finally, macro-economical trends (fuel cost, cost of capital, more Independent Power Producers or IPP’s) determine «S4», equipment specifications (delta-T’s, delta-P’s, number of stages or exhaust flows etc.). In this written paper the authors report on their technoeconomical analysis; at the conference they will present hands-on solutions, optimized for ABB’s Type GT24 (60Hz, 165 MW) and GT26 (50 Hz, 240 MW) gasturbines. (Note that throughout the paper definite figures are only given for ABB gasturbines and steam turbines, as the authors cannot vouch for information published by other manufacturers or third parties).

This paper describes the design of an uprated turbine for the GT8 gas turbine. The new turbine is installed in the GT8C gas turbine unit. The entire aero-thermal performance of the old turbine has been re-assessed and the new design improves upon the old unit by a 3.5% point increase in gas turbine efficiency. Additionally, the heat transfer and cooling of the turbine has been improved with the blading having more uniform thermal loading resulting in improved thermo-mechanical life-time. This has been achieved with better cooling technology whilst still maintaining the same cooling air mass flow. The paper describes the steps involved in the uprating.Copyright © 1994 by ASME

This paper covers the design of heat recovery steam generators (HRSG). The design of the HRSG plays an important role in overall design of a combined cycle unit. The primary focus of the paper is the influence of the boiler on the total efficiency of the combined cycle.

This paper reviews the evolution of heavy-duty power generation and industrial combustion turbines in the United States from a Westinghouse Electric Corporation perspective. Westinghouse combustion turbine genealogy began in March of 1943 when the first wholly American designed and manufactured jet engine went on test in Philadelphia, and continues today in Orlando, Florida with the 160 MW, 501F Advanced Combustion Turbine. In this paper, advances in thermodynamics, materials, cooling, and unit size will be described. Many basic design features such as two-bearing rotor, cold-end drive, can-annular internal combustors, CURVIC2 clutched turbine discs, and tangential exhaust struts have endured successfully for over 40 years. Progress in turbine technology includes the clean coal technology and advanced turbine systems initiatives of the U.S. Department of Energy.Copyright © 1994 by ASME

Most engine health monitoring systems used for land based systems are based on steady state operation. Diagnostic analysis has traditionally been conducted under steady state conditions with on-line systems tending to concentrate on map based performance diagnostics using pattern analysis, fault matrices or expert systems. Transient analysis is a relatively a new technique and is being applied to some aeroengines. There is significant diagnostic content in turbine startup and shutdown data and in data obtained during power or speed changes. This data can be captured if an automatic on-line system is employed. This paper provides an overview of the use of both performance and mechanical transient analysis as a means to detect gas turbine problems. The paper covers the need for transient analysis and covers transient analysis techniques. Examples and a discussion of how transient analysis can be integrated within an existing on-line monitoring system is made.Copyright © 1992 by ASME

Reliability performance is currently receiving significant attention in the bid requests for new gas turbine generating units. Reliability guarantees backed by liquidated damages clauses are becoming the rule rather than the exception. But the power generation industry does not have a universally accepted set of reliability measurements and the more commonly used measurements are not sufficiently refined for the warranty situation. This paper is intended to provide the guidance, structure and refinement needed for meaningful reliability warranties. Four key areas of reliability measurement: starting reliability, running reliability, availability and equivalent availability are separately addressed. And within each of these areas there is the flexibility, the methodology and the need to adapt the measurement system to the varied operating regimes and philosophies encountered such as: peaking vs. continuous service, attended vs. unattended sites, different levels of maintenance intensity, chargeable vs. non-chargeable outage events and emotional/political/optical acceptability (i.e., 3% Forced Outage Factor vs. 40% Forced Outage Rate). Warranty structuring rationale and suggested contract language are provided to address such needs as a rigorous and explicit operating log, certification of data, measurement accuracy, statistical confidence, assurance of readiness and risk assessment. The suggestions presented herein have been constructed with logic and fairness. This paper will be beneficial to all Architect Engineers, Utilities, Independent Power Producers and OEM’s that become involved with the structuring of reliability warranties.

The heat recovery steam generator (HRSG) is an integral part of the combined cycle power plant which includes combustion turbine and steam turbine in addition to heat recovery steam generator. The start-up of the heat recovery steam generator, therefore, has an influence on the start-up of the total plant. The paper discusses various constraints, both external and internal, which affect the Steam Generator start-up and in turn influence the start-up of the total plant. Considerations in the design of the steam generator to accommodate the plant start-up requirements, along with the effect of the cyclic or base loaded operation are also discussed. The paper also presents a procedure which may be adopted in the conceptual design of the plant for an optimized system, a system which can accommodate the total plant start-up requirements without undue constraints on the availability of the full plant output.

The first CW251B12 engine has been operating for about a year at a paper mill in a cogeneration application. The engine generates electricity, and the exhaust heat is used in a supplementary fired Heat Recovery Steam Generator (HRSG) to produce steam. The steam generated in the HRSG plus additional process steam is used to produce electrical power in a condensing steam turbine. Steam extracted from the steam turbine is in turn used in the paper mill. This paper describes the operating experience of the gas turbine and provides some details of the site performance test.Copyright © 1992 by ASME

This paper discusses development, installation, and analysis of instrumentation systems for reliably measuring casing, thermal distortion, and alignment deviation on a large combustion turbine in power utility service. A variety of redundant measurement systems were installed to document casing distortion during the cool-down period after firing. The operating principles of each measurement system are described and presented with the rationale developed for installing and locating sensors. A vertical deflection sensor used for casing bow and bearing misalignment measurements is highlighted in the paper to illustrate its potential for use in other investigations. Additional sensors used include an array of shaft proximity probes, blade tip proximity probes, thermocouples, and axial growth probes, blade tip proximity probes, thermocouples, and axial growth probes. A measurement system for casing ovalization was developed using LVDTs mounted from a thermally stabilized ring. An automated data acquisition system was developed and installed to facilitate the recording of turbine cool-down events over the complete operating season without the need for constant on-site attention. Preliminary results define the turbine cylinder bow and ovalization response during the cool-down event following normal unit operation and correlated casting distortions with thermal gradients.

In the increasingly competitive global marketplace the users of industrial products face the challenge of predicting accurate life-cycle costs of their equipment and machinery. The deregulation of many industries resulted in inability of operating companies to pass over to the customer the increased costs of their products, which may have been caused by inaccurate predictions of the equipment operating costs. This evolution in the 1980’s have emphasized the need for accurate predictions of the equipment operating costs and have meant the difference between profit and loss. This paper presents the concept of equipment Durability to be used in the process of evaluation the equipment life cycle cost and subsequent equipment selection. It is also the first part or primer to the paper which describes the Durability Surveillance Program on the Advanced Gas Turbines sponsored by EPRI titled “Durability Surveillance Program on the Advanced Gas Turbine GE Frame 7 F” (1).Copyright © 1992 by ASME

The paper will deal with new developments on basis of the ideas, laid down in ASME paper 90-GT-180, presented at the Brussels Conference. In this former paper a combination of incinerators and cogen systems was described. New development show, that some of these ideas can also be used in cogen plants, in which all steam is raised and superheated in a waste heat boiler behind a high grade fuel fired gas turbine (natural gas or equivalent). This paper will deal give a description of the new system. A comparison will be made with conventional cogen systems, comprising of a gas turbine, a dual pressure non-fired waste heat boiler and a condensing steam turbine. On basis of a particular case study both the technical and financial performances will be compared with each other.Copyright © 1992 by ASME

The need for high purity water for both water and steam injection into gas turbines has become more evident over the past twenty years. Changing environmental concerns and the need for highly trained personnel have prompted a closer look at permanently installed water treatment systems versus leased, mobile systems. Water availability, water quality, discharge limitations, and licensing have all become key issues in new system development. Traditional permanently installed water treatment systems with on site regeneration of resins must now be evaluated against new options available to developers and operators of gas turbine installations. The leased mobile systems, as evaluated in this paper, are trailer mounted, self contained units, which will have all regeneration of resins done off site at the vendor’s facility. The units are under the direct control of the vendor, with the only responsibility of the site being the delivery of power and water to the trailers. For clarity, this paper will use the term “Permanent System” to refer to a traditional water treatment plant installation under the control of the plant, and the term “Mobile System” to refer to a leased mobile system under the control of the system vendor. This paper will provide conceptual designs for water treatment systems at two sites, for both permanently installed and leased mobile water treatment systems. It will examine the cost impact that each option has on installation, operation and maintenance. Different modes of operation will be examined to determine the optimal system. The results of this optimization will consist of an illustration of equipment, operating cost, capital cost, and advantages and disadvantages of purchasing versus leasing. This paper does not address the leasing of a permanent water treatment system in lieu of purchasing the permanent equipment outright, as that would merely be an exercise in financing options.

A high temperature flow through a gas-turbine produces a high rate of turbulent heat transfer between the fluid flow field and the turbine components. The heat transfer process through rotor disks causes thermal stress due to the thermal gradient as well as the centrifugal force causes mechanical stresses; thus an accurate analysis for the evaluation of thermal behavior is needed. This paper presents a numerical study of thermal flow analysis in a two-stage turbine in order to better understand the detailed flow and heat transfer mechanisms through the cavity and the rotating rotor-disks. The numerical computations were performed to predict thermal fields throughout the rotating disks. The method used in this paper is the ‘segregation’ method which requires a much smaller number of grids than actually employed in the computations. The results are presented for temperature distributions through the disk and the velocity fields which illustrate the interaction between the cooling air flow and gas flow created by the disk rotation. The temperature distribution in the disks shows a reasonable trend. The numerical method developed in this study shows that it can be easily adapted for similar computations for air cooling flow patterns through any rotating blade disks in a gas turbine.

This paper describes the methods developed to optimize the mechanical design of a free standing exhaust stack and its supporting structure. These particular methods have been used for the design of three gas turbine exhaust systems on a UK sector offshore platform currently under construction. The driving force behind the choice of a free standing stack was to save weight and therefore cost. The move towards the development of marginal fields in deeper waters will only increase the need for lighter, and therefore more cost effective design solutions. Although national standards which cover the basic design philosophy are available, these have serious limitations when applied to this type of structure. The aim of this paper is to demonstrate how the limitations may be overcome by undertaking fundamental design analysis, and also to indicate those critical areas which demand special consideration. The detailed design analysis presented here considers the possibility of failure due to local instability, the effect on the dynamic response of the flexible foundation provided by the platform, and the determination of thermal stresses at critical locations. Although this design has been developed for offshore use, the techniques utilized can be applied equally to onshore applications.

In this paper, the use of various gaseous fuels in aero-derivative gas turbine engines is analysed. The gases investigated are natural gas and three coal synthetic gases of calorific values which are significantly lower than that of natural gas. The analysis is carried out employing natural gas fuel as a yardstick for comparison. Due to the lower calorific values of synthetic gases, the mass flow balance between compressors and turbines is altered. This in turn affects the matching of the components and the overall performance of a gas turbine engine. The engines examined are a single spool gas generator with a free power turbine and the double engine described in a previous paper. The main conclusion drawn from this analysis is that, for a given power output, the use of synthetic gases will result in an erosion of surge margins and in a reduction of the overall efficiency of the power plant.

This paper is a continuation of investigation into the possibilities of industrial application of the modified exhaustheated gas turbine installation with increased thermal efficiency, described in the ASME-Paper 90-GT-369. According to the author’s conception this turbine installation may be very useful when interacting with some chemical processing installations, e.g. by feeding a coal gasifier with pre-heated compressed air. It would then be a turbine system with an air extraction, performing a double duty. The heat contained in the air extracted from the gas turbine system plus the mechanical/electrical power produced create permanent full load conditions yielding the maximum thermal efficiency of the system. It has been found that for some point of extraction from a gas turbine plant of 33 % efficiency (without air extraction) the overall efficiency may raise to some 60 or even 73 %. This is possible due to the fact that the enthalpy increase of the extracted air is calculated with respect to that of the compressor inlet air. Moreover the air supplied to the gasifier does not expand in the turbine and does not perform any mechanical work.Copyright © 1991 by ASME

Today the Heat Recovery Steam Generator (HRSG) has become an integral part of the combined cycle or Cogen plant because of its influence on other equipment. Therefore, the optimization of the HRSG has become one of the prime targets to improve the overall efficiency. The paper presents recent developments and concepts used in HRSG design which improve either the efficiency or the range of performance or both. The paper discusses three major areas of a HRSG - Superheater/Reheater, Economizer, and LP Evaporator/Feedwater Preheater. Depending upon the requirement, the user can implement one or more of the concepts to improve the total performance and/or the reliability.

This paper describes existing, developing, and needed methods for detection, identification, and diagnosis of problems in combustion turbines. The use of combustion turbines for electrical power generation is growing, and advanced models of large industrial turbines are now starting to enter service. In view of the harsh operating conditions and severe service to which these new turbines will be exposed, this paper evaluates sensors and signal analysis methods to detect and diagnose the problems which may surface in operation. Generic problems which have been observed in combustion turbine installations in the recent past are identified, and methods for detecting these problems, quantifying them, and isolating their causes are analyzed.Copyright © 1990 by ASME

In this paper a new process is described to improve the efficiency of power generation in waste incineration plants. It is proposed to superheat the steam in a gas turbine/waste heat boiler combination rather than in the incinerator boiler. Although this is not discussed in this paper the same process may be applied in nuclear power stations where the superheating of steam is also a problem. A global risk-analysis of the addition of equipment is made in this paper. On basis of a case-study the financial advantages are demonstrated.

Each combustion turbine installation has peculiar to it site-related characteristics that, if considered carefully, will define the type of inlet system that best fits the operational requirements. Historically, and unless owner specified, the OEM/Packager supplies his standard, all-purpose air filter configuration as an integral part of the package. The standard may or may not be the best selection for filtering combustion inlet air at the intended specific site location. This technical paper will match inlet air filtration systems to several typical ambient conditions, using laboratory tests and actual site experience. This paper can also be used as a technically current selection guide for those considering various inlet air filtration requirements for new and retrofit systems.Copyright © 1990 by ASME

A decade ago several important fundamental heat transfer phenomena were identified which were considered basic to the ability to predict heat transfer loads in aircraft gas turbines. The progress in addressing these fundamentals over the past ten years is assessed in this paper. Much research effort has been devoted to their study in university, industry and government laboratories and significant progress has been achieved. Advances in computer technology have enabled the modeling of complex three-D fluid flow in gas turbines so necessary for heat transfer calculations. Advances in instrumentation plus improved data acquisition have brought about more reliable data sets. While much has advanced in the ‘80’s, much challenging research remains to be done. Several of these areas are suggested in the paper.

The gear coupling was the primary flexible coupling for industrial gas turbines for almost twenty-five years. As advancements in the industrial gas turbine have occurred so have advancements in gear couplings. There are many variables in gear couplings that can affect their characteristics, including tooth design, materials, and lubrication methods. All couplings react on connected equipment. The system designer must consider these reactions when designing the system. If a gear coupling is chosen, there are many characteristics which can make a designer’s life easier. This paper compares the characteristics of diaphragm couplings versus gear type couplings used in industrial gas turbine applications including applications of couplings for turbine to generator, turbine to mechanical drives (compressors, pumps, and gear) and also couplings used between the turbine and accessory gears. The methods used to analyze the design and the forces and moments generated by both the gear coupling and the diaphragm coupling are also provided. These analysis are used to show that the forces and moments generated by a diaphragm coupling are not only predictable, but usually lower than those of a gear coupling. The paper shows that a diaphragm coupling can be more predictable and reliable than a gear coupling for most industrial gas turbine applications.Copyright © 1989 by ASME

This paper presents a discussion of the computer model developed to quantify the effects of transient processes occurring during injection, storage and withdrawal of compressed air from underground storage in a salt dome. The following mechanisms are considered when modelling the thermodynamic behavior of the compressed air within the cavern: 1) Temperature variations due to the compression and expansion of the air. 2) Heat transfer by convection at the cavern wall. 3) Heat transfer by conduction inside the salt formation. 4) Enthalpy changes as air is injected into and withdrawn from the cavern. The paper presents a description of the physical processes in the storage cavern, the calculation methodology, and results of the model as applied to the conditions of the storage cavern designed for the Alabama Electric Cooperative 100 MW CAES plant.

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.

The different aspects of the CW251B12 compressor redesign intended for possible upgrading of currently installed B10 engines and for the B12 model are described in this paper. The design philosophy is based upon experience with previous compressor upratings. Aerodynamic and mechanical considerations as well as description of the new features introduced into the redesigned compressor are included in the paper. Generalized compressor design rules are also presented.Copyright © 1989 by ASME

Higher turbine inlet temperatures are a common method of increasing the thermal efficiency of modern gas turbines. This development not only generates the need for more efficient turbine blade cooling but also demands a more profound knowledge of the mechanically and thermally stressed parts of the rotor. In order to determine thermal stresses from the temperature distribution in the rotor of a gas turbine, one has to encounter the convective heat transfer in rotor cavities. In the special case of a completely closed gas-filled rotating annulus the convective flow is governed by strong natural convection. As shown in a previous paper by the authors, and for example by Owen, the presence of turbulence and its inclusion in the modeling of the flow has been found to cause significant differences in the flow development in rotating annuli. This influence in the special case of a closed rotating annulus has been recently investigated by the authors for a moderately high Rayleigh-Number. Based on this work an investigation was undertaken focusing on the development of turbulence and turbulence related changes in the flow structure for increasing Rayleigh-Numbers. The flow is investigated numerically using a three-dimensional Navier-Stokes solver, based on a pressure correction scheme. To account for the turbulence, a low-Reynolds-number k-ε-model is employed. This model is complemented by an additional term for turbulence production due to buoyancy. The results are compared with experiments performed at the Institute of Steam and Gas Turbines. The computations demonstrate the considerable influence on the overall heat transfer as well as on the local heat transfer distribution.

The general approach which has been taken toward cooling aircraft turbine combustor liners is to utilize a portion of incoming combustor air for film-cooling. In this paper an alternate cooling method is considered, which is referred to as Heat Pipe Combustor Cooling. The conventional film-cooled combustor liner is replaced by a thin, metallic heat pipe liner. Incident heat is transported upstream, and then into to an adjacent compressor discharge air stream. After first acting as a heat sink to cool the liner, the compressor discharge air stream enters the combustor and serves as a supplementary combustion air supply/combustion gas diluent. This dual-use capability effectively doubles the available air supply for liner cooling, extending the turbine inlet temperature range for which metallic construction of the combustor liner is feasible.Copyright © 1998 by ASME

This paper deals with the modeling of the flow in the leakage cavity between shroud and stator of a radial pump and the design of optimized swirl brakes at the inlet of the seal. As pressure losses were of no importance in this application, the only criterion for optimization was to minimize the swirl at the seal inlet in order to enhance the rotordynamic stability of it. The design investigation was performed by means of a 3D Navier-Stokes solver. A variety of vane designs were analyzed. It was shown that the three-dimensional vortical structure of the flows plays a dominant role and can be efficiently used to reduce or even invert the swirl at the seal inlet.Copyright © 1998 by ASME

The use of gas turbines in relatively small grids is often connected with an additional requirement from the grid side. Such a requirement can be the increase of power production within seconds to support the stability of a grid. This topic was investigated thoroughly in 1985 for several types of power plants. In 1992 ABB received an order for a gas turbine power plant on the island of Puerto Rico where a fast loading response with 40% load increase within 3 seconds was required. Based on earlier investigations the order was accepted. The powerplant built a „Steam Enhanced Power (SEP) plant“, each consisting of three powertrains each with a gas turbine, a once through steam generator and an exhaust system with an SCR for emission control. This paper describes the control functions necessary to meet the requirements and the consequences for the operation of the plant. Results from the acceptance tests where the rapid loading from a standby mode at 60% load was simulated will be shown and discussed in detail.

An experimental research program was performed in a pressurized hot component test rig to evaluate surface temperatures, cooling effectiveness and heat transfer coefficients on a convective cooled turbine vane at near engine conditions. The results were obtained in a 40° five-vane sector cascade at exit Reynolds numbers of 0.98*106 and 2.28*106 at a turbulence level of 4 %. The tests were performed both in steady state and in transient modes. The temperature solving part of a cooling design system was used to evaluate the heat transfer coefficients. A two-dimensional boundary layer program and the commercial Navier-Stokes code Rampant were used for obtaining the numerical results. This paper describes the experimental procedure, the evaluation model and method and the comparison of the first experimental results with numerical calculations.Copyright © 1998 by ASME

In this paper, a thermoeconomic analysis is carried out for two and three pressure level combined cycles derived from existing steam power plants. The considered steam power plants are among the most widespread in the Italian territory (70 MW, 160 MW, 320 MW power output). First of all, the gas turbine plants that best match the steam power plants’ requirements are selected among existing units. Subsequently, the thermodynamic analysis for the repowered plants is performed, taking into account the off-design working condition of some components such as, the steam turbines and the condenser. Then, the economic evaluation for the repowered plants is carried out by determining the cost per kWh, the pay back period and the internal rate of return. The analysis permits the most economic choice to be made. The thermoeconomic investigation was also performed for a new combined cycle power plant. The study has revealed that the repowering of the three existing steam power plants in two or three pressure level combined cycle plants is more convenient than building a new combined cycle with higher efficiency. It has also pointed out that the repowering of the 320 MW existing steam power plant in a three pressure level reheat combined cycle plant supplies the lowest cost per kWh among all the other repowered plants analyzed. The revamping and environment effect on the above mentioned existing steam power plants was also investigated and it resulted that this solution has a cost per kWh that is much higher than that of the repowered steam plants and the new combined cycle.

Three important subjects of the physics of air systems have been chosen: Part 1: Labyrinth Seals Part 2: Rotating Holes and Two Phase Flow In these fields many new papers are available. Correlations out of the literature for the discharge coefficients of rotating holes which include the most important parameters are compared and discussed. For two phase flow simple correlations for engineering purposes are recommended, especially for vent lines of aero engines. It is concluded that much more effort is required in order to push knowledge beyond the state of current literature which is partly controversial and not comprehensive enough for computerized engineering.

This paper describes the FT8 gas generator (GG8) development history, including required design modifications to the JT8D aircraft engine, initial field experience and the latest reliability improvements incorporated into the GG8. The modifications include improvements to bearing compartment operating temperature, bearing compartment seals, and increases to bearing life. Turbine durability improvements are also discussed. The incorporation and control of a cold air buffer system to control bearing compartment oil coke formation is provided. Improvements to bearing compartment carbon seals are reviewed and the benefits of this design are discussed. Rotor system thrust bearing life improvements are achieved through the incorporation of modified compressor seals and turbine aerodynamics.