The Experts below are selected from a list of 565338 Experts worldwide ranked by ideXlab platform
F. Spinato - One of the best experts on this subject based on the ideXlab platform.
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Reliability of wind Turbine subassemblies
IET Renewable Power Generation, 2009Co-Authors: F. Spinato, G.j.w. Van Bussel, Peter J. Tavner, E. KoutoulakosAbstract:We have investigated the reliability of more than 6000 modern onshore wind Turbines and their subassemblies in Denmark and Germany over 11 years and particularly changes in reliability of generators, gearboxes and converters in a subset of 650 Turbines in Schleswig Holstein, Germany. We first start by considering the average failure rate of Turbine populations and then the average failure rates of wind Turbine subassemblies. This analysis yields some surprising results about which subassemblies are the most unreliable. Then we proceed to consider the failure intensity function variation with time for wind Turbines in one of these populations, using the Power Law Process, of three subassemblies; generator, gearbox and converter. This analysis shows that wind Turbine gearboxes seem to be achieving reliabilities similar to gearboxes outside the wind industry. However, wind Turbine generators and converters are both achieving reliabilities considerably below that of other industries but the reliability of these subassemblies improves with time. The paper also considers different wind Turbine concepts. Then we conclude by proposing that offshore wind Turbines should be subject to more rigorous reliability improvement measures, such as more thorough subassembly testing, to eliminate early failures. The early focus should be on converters and generators.
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reliability analysis for wind Turbines
Wind Energy, 2007Co-Authors: Peter J. Tavner, J. Xiang, F. SpinatoAbstract:Modern wind Turbines are complex aerodynamic, mechanical and electrical machines incorporating sophisticated control systems. Wind Turbines have been erected in increasing numbers in Europe, the USA and elsewhere. In Europe, Germany and Denmark have played a particularly prominent part in developing the technology, and both countries have installed large numbers of Turbines. This article is concerned with understanding the historic reliability of modern wind Turbines. The prime objective of the work is to extract information from existing data so that the reliability of large wind Turbines can be predicted, particularly when installed offshore in the future. The article uses data collected from the Windstats survey to analyse the reliability of wind Turbine components from historic German and Danish data. Windstats data have characteristics common to practical reliability surveys; for example, the number of failures is collected for each interval but the number of Turbines varies in each interval. In this article, the authors use reliability analysis methods which are not only applicable to wind Turbines but relate to any repairable system. Particular care is taken to compare results from the two populations to consider the validity of the data. The main purpose of the article is to discuss the practical methods of predicting large-wind-Turbine reliability using grouped survey data from Windstats and to show how Turbine design, Turbine configuration, time, weather and possibly maintenance can affect the extracted results. Copyright © 2006 John Wiley &Sons, Ltd.
Per-Åge Krogstad - One of the best experts on this subject based on the ideXlab platform.
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experimental investigation of wake effects on wind Turbine performance
Renewable Energy, 2011Co-Authors: Muyiwa S Adaramola, Per-Åge KrogstadAbstract:The wake interference effect on the performance of a downstream wind Turbine was investigated experimentally. Two similar model Turbines with the same rotor diameter were used. The effects on the performance of the downstream Turbine of the distance of separation between the Turbines and the amount of power extracted from the upstream Turbine were studied. The effects of these parameters on the total power output from the Turbines were also estimated. The reduction in the maximum power coefficient of the downstream Turbine is strongly dependent on the distance between the Turbines and the operating condition of the upstream Turbine. Depending on the distance of separation and blade pitch angle, the loss in power from the downstream Turbine varies from about 20 to 46% compared to the power output from an unobstructed single Turbine operating at its designed conditions. By operating the upstream Turbine slightly outside this optimum setting or yawing the upstream Turbine, the power output from the downstream Turbine was significantly improved. This study shows that the total power output could be increased by installing an upstream Turbine which extracts less power than the following Turbines. By operating the upstream Turbine in yawed condition, the gain in total power output from the two Turbines could be increased by about 12%.
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Experimental investigation of wake effects on wind Turbine performance
Renewable Energy, 2011Co-Authors: Muyiwa S Adaramola, Per-Åge KrogstadAbstract:The wake interference effect on the performance of a downstream wind Turbine was investigated experimentally. Two similar model Turbines with the same rotor diameter were used. The effects on the performance of the downstream Turbine of the distance of separation between the Turbines and the amount of power extracted from the upstream Turbine were studied. The effects of these parameters on the total power output from the Turbines were also estimated. The reduction in the maximum power coefficient of the downstream Turbine is strongly dependent on the distance between the Turbines and the operating condition of the upstream Turbine. Depending on the distance of separation and blade pitch angle, the loss in power from the downstream Turbine varies from about 20 to 46% compared to the power output from an unobstructed single Turbine operating at its designed conditions. By operating the upstream Turbine slightly outside this optimum setting or yawing the upstream Turbine, the power output from the downstream Turbine was significantly improved. This study shows that the total power output could be increased by installing an upstream Turbine which extracts less power than the following Turbines. By operating the upstream Turbine in yawed condition, the gain in total power output from the two Turbines could be increased by about 12%. © 2011 Elsevier Ltd.
Yurii Govoruschenko - One of the best experts on this subject based on the ideXlab platform.
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study on applicability of radial outflow Turbine type for 3 mw whr organic rankine cycle
Energy Procedia, 2017Co-Authors: Dmytro Maksiuta, Leonid Moroz, Maksym Burlaka, Yurii GovoruschenkoAbstract:Abstract The article presents the results of study on the reasonability of using radial-outflow Turbines in ORC. Peculiarities of radial-outflow Turbine design utilizing modern design technologies and application to ORC was considered in the first part of the paper. The second part of the paper describes the selection process of the best Turbine type for a 3 MW WHR ORC power unit for an internal combustion engine. The selection was performed among different Turbine types, like radial-inflow, axial and radial-outflow Turbines which were designed with given boundary conditions. The advantages and disadvantages of their application were shown. Eventually, the recommendations regarding application of different Turbine types for a 3 MW WHR Organic Rankine Cycle were given. For this particular cycle design, Turbines of radial-outflow type were chosen. Their application enables the increase of mechanical output power by 11 % compared to original radial-inflow Turbines.
Peter J. Tavner - One of the best experts on this subject based on the ideXlab platform.
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Reliability of wind Turbine subassemblies
IET Renewable Power Generation, 2009Co-Authors: F. Spinato, G.j.w. Van Bussel, Peter J. Tavner, E. KoutoulakosAbstract:We have investigated the reliability of more than 6000 modern onshore wind Turbines and their subassemblies in Denmark and Germany over 11 years and particularly changes in reliability of generators, gearboxes and converters in a subset of 650 Turbines in Schleswig Holstein, Germany. We first start by considering the average failure rate of Turbine populations and then the average failure rates of wind Turbine subassemblies. This analysis yields some surprising results about which subassemblies are the most unreliable. Then we proceed to consider the failure intensity function variation with time for wind Turbines in one of these populations, using the Power Law Process, of three subassemblies; generator, gearbox and converter. This analysis shows that wind Turbine gearboxes seem to be achieving reliabilities similar to gearboxes outside the wind industry. However, wind Turbine generators and converters are both achieving reliabilities considerably below that of other industries but the reliability of these subassemblies improves with time. The paper also considers different wind Turbine concepts. Then we conclude by proposing that offshore wind Turbines should be subject to more rigorous reliability improvement measures, such as more thorough subassembly testing, to eliminate early failures. The early focus should be on converters and generators.
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reliability analysis for wind Turbines
Wind Energy, 2007Co-Authors: Peter J. Tavner, J. Xiang, F. SpinatoAbstract:Modern wind Turbines are complex aerodynamic, mechanical and electrical machines incorporating sophisticated control systems. Wind Turbines have been erected in increasing numbers in Europe, the USA and elsewhere. In Europe, Germany and Denmark have played a particularly prominent part in developing the technology, and both countries have installed large numbers of Turbines. This article is concerned with understanding the historic reliability of modern wind Turbines. The prime objective of the work is to extract information from existing data so that the reliability of large wind Turbines can be predicted, particularly when installed offshore in the future. The article uses data collected from the Windstats survey to analyse the reliability of wind Turbine components from historic German and Danish data. Windstats data have characteristics common to practical reliability surveys; for example, the number of failures is collected for each interval but the number of Turbines varies in each interval. In this article, the authors use reliability analysis methods which are not only applicable to wind Turbines but relate to any repairable system. Particular care is taken to compare results from the two populations to consider the validity of the data. The main purpose of the article is to discuss the practical methods of predicting large-wind-Turbine reliability using grouped survey data from Windstats and to show how Turbine design, Turbine configuration, time, weather and possibly maintenance can affect the extracted results. Copyright © 2006 John Wiley &Sons, Ltd.
Meherwan P. Boyce - One of the best experts on this subject based on the ideXlab platform.
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An Overview of Gas Turbines
Gas Turbine Engineering Handbook, 2020Co-Authors: Meherwan P. BoyceAbstract:The gas Turbine is a power plant that produces a great amount of energy depending on its size and weight. It has found increasing service in the past 60 years in the power industry among both utilities and merchant plants, as well as in the petrochemical industry. Its compactness, low weight and multiple fuel application make it a natural power plant for offshore platforms. Today there are gas Turbines that run on natural gas, diesel fuel, naphtha, methane, crude, low-BTU gases, vaporized fuel oils and biomass gases. The last 20 years have seen a large growth in gas Turbine technology, spearheaded by the growth in materials technology, new coatings, new cooling schemes and combined cycle power plants. This chapter presents an overview of the development of modern gas Turbines and gas Turbine design considerations. The six categories of simple-cycle gas Turbines (frame type heavy-duty; aircraft-derivative; industrial-type; small; vehicular; and micro) are described. The major gas Turbine components (compressors; regenerators/recuperators; fuel type; and combustors) are outlined. A gas Turbine produces various pollutants in the combustion of the gases in the combustor and the potential environmental impact of gas Turbines is considered. The two different types of combustor (diffusion; dry low NO x , (DLN) or dry low emission (DLE)), the different methods to arrange combustors on a gas Turbine, and axial-flow and radial-inflow Turbines are described. Developments in materials and coatings are outlined.
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Radial-Inflow Turbines
Gas Turbine Engineering Handbook, 2020Co-Authors: Meherwan P. BoyceAbstract:This chapter focuses on radial-inflow Turbines, which first appeared as a practical power-producing unit in the hydraulic Turbine field. A radial-inflow Turbine is basically a centrifugal compressor with reversed flow and opposite rotation, and it was first used in jet engine flight in the late 1930s. It was considered as the natural combination for a centrifugal compressor used in the same engine. In transportation, it is used in turbochargers for both spark ignition and diesel engines, and in aviation, it is used as an expander in environmental control systems. It is used in expander designs, gas liquefaction expanders, and other cryogenic systems in the petrochemical industry. It is also used in various small gas Turbines to power helicopters, and as standby generating units. The greatest advantage of radial-inflow Turbine is that the work produced by a single stage is equivalent to that of two or more stages in an axial Turbine. This phenomenon occurs because a radial-inflow Turbine usually has a higher tip speed than an axial Turbine. Its cost is also much lower than that of a single or multistage axial-flow Turbine. Although the radial-inflow Turbine has a lower Turbine efficiency than the axial-flow Turbine, its lower initial costs may work as an incentive for choosing it. There are two types of radial-inflow Turbines: the cantilever radial-inflow Turbine and the mixed-flow radial-inflow Turbine. The cantilever-type radial-inflow Turbine is infrequently used because of its low efficiency, production difficulties, and rotor blade flutter problems. On the other hand, the mixed-flow radial-inflow Turbine is a widely used design.
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Radial-Inflow Turbines
Gas Turbine Engineering Handbook, 2012Co-Authors: Meherwan P. BoyceAbstract:Publisher Summary The inward-flow radial Turbine covers tremendous ranges of power, rates of mass flow, and rotational speeds from very large Francis Turbines used in hydroelectric power generation and developing hundreds of megawatts down to tiny closed cycle gas Turbines for space power generation of a few kilowatts. The widespread adoption of variable geometry Turbines for diesel engine turbochargers has been the major factor in increasing the commercial use of this technology. Variable area is commonly, but not exclusively, achieved by pivoting the nozzle vanes about an axis disposed in the span-wise direction. The most common radial-inflow Turbine applications are turbochargers for internal combustion engines, natural gas, diesel, and gasoline powered units. The advantage of a turbocharger is that it compresses the air, thus letting the engine squeeze more air into a cylinder, and more air means that more fuel can be added. Applications of turbo expanders in the chemical industry abound in the petrochemical and chemical industries. Turbo expanders using radial-inflow Turbines have a much higher ruggedness than turbo expanders using axial-flow Turbines. The radial-inflow Turbine for gas Turbine application is basically a centrifugal compressor with reversed flow and opposite rotation. The performance of the radial-inflow Turbine is being investigated with increased interest by the transportation and chemical industries. In the petrochemical industry, it is used in expander designs, gas liquefaction expanders and other cryogenic systems. The radial-inflow Turbine’s greatest advantage is that the work produced by a single stage is equivalent to that of two or more stages in an axial Turbine. Its cost is also much lower than that of a single- or multi-stage axial-flow Turbine. The configurations and designs of the two types of radial-inflow Turbine (cantilever and mixed-flow) are described. The thermodynamic and aerodynamic principles governing a radial-inflow Turbine are summarized. The design and performance of a radial-inflow Turbine are discussed. The potential problems (erosion; exducer blade vibration; noise) and types of losses in a radial-inflow Turbine are described. Applications of radial-inflow Turbines (e.g. turbochargers) are discussed.
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Axial-Flow Turbines
Gas Turbine Engineering Handbook, 2011Co-Authors: Meherwan P. BoyceAbstract:This chapter focuses on axial-flow Turbines that are the most widely employed Turbines using a compressible fluid. Axial-flow Turbines power most of the gas Turbine units and they are more efficient than radial-inflow Turbines in most operational ranges. They are also used in steam Turbine design; however, there are some significant differences between the axial-flow Turbine design for a gas Turbine and the design for a steam Turbine. Axial-flow Turbines are now designed with a high work factor to obtain lower fuel consumption and reduce the noise from the Turbine. Lower fuel consumption and lower noise requires the design of higher by-pass ratio engines, and a high by-pass ratio engine in turn requires various Turbine stages to drive the high-flow, low-speed fan. The flow in axial-flow Turbines enters and leaves in the axial direction. There are two types of axial Turbines: impulse type and reaction type. Most axial flow Turbines consist of more than one stage. The front stages are usually impulse (zero reaction) and the later stages have about 50% reaction. The impulse stages produce about twice the output of a comparable 50% reaction stage, while the efficiency of an impulse stage is less than that of a 50% reaction stage. The high temperatures that are available in the Turbine section have resulted from the improvements of the metallurgy of the blades in the Turbines. Development of directionally solidified blades as well as the new single-crystal blades, with the new coating cooling schemes, is responsible for the increase in firing temperatures. The high pressure ratio in the compressor also causes the cooling air used in the first stages of the Turbine to become hot.
