An Overview of Droplet Impact Erosion, Related Theory and Protection Measures in Steam Turbines PDF Download
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Author: Mansoor Ahmad
Publisher:
ISBN:
Category : Science
Languages : en
Pages :
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Book Description
Erosion of last-stage steam turbine blades is a well-known problem in the turbine manufacturing industry. Damage of structure and loss of efficiency are the common problems associated with erosion. Understanding of the phenomenon leading to low-pressure blade erosion, erosion protection and erosion prediction has been the topic of scientific research and interest in the steam turbine manufacturing community since the start of the nineteenth century. Although several changes in both the steam turbine stage design and steam properties have been adopted to eliminate this problem, none of them have proved to eradicate this phenomenon completely. The only option left for the scientists and designers is to mitigate the process by utilising materials with high erosion resistance. This requires the development of high erosion-resistive materials and then quantitative confirmation of their erosion resistance by using some precise and accurate laboratory methods reflecting the conditions in the last stage of steam turbines. An overview of droplet impact erosion and related theory has been addressed in this chapter. Moreover, different methods to quantify erosion on a laboratory scale will be presented. In addition, different measures to mitigate erosion in low-pressure stages of steam turbines will be described. In the end, different droplet impact erosion prediction approaches will be discussed.
Author: Mansoor Ahmad
Publisher:
ISBN:
Category : Science
Languages : en
Pages :
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Book Description
Erosion of last-stage steam turbine blades is a well-known problem in the turbine manufacturing industry. Damage of structure and loss of efficiency are the common problems associated with erosion. Understanding of the phenomenon leading to low-pressure blade erosion, erosion protection and erosion prediction has been the topic of scientific research and interest in the steam turbine manufacturing community since the start of the nineteenth century. Although several changes in both the steam turbine stage design and steam properties have been adopted to eliminate this problem, none of them have proved to eradicate this phenomenon completely. The only option left for the scientists and designers is to mitigate the process by utilising materials with high erosion resistance. This requires the development of high erosion-resistive materials and then quantitative confirmation of their erosion resistance by using some precise and accurate laboratory methods reflecting the conditions in the last stage of steam turbines. An overview of droplet impact erosion and related theory has been addressed in this chapter. Moreover, different methods to quantify erosion on a laboratory scale will be presented. In addition, different measures to mitigate erosion in low-pressure stages of steam turbines will be described. In the end, different droplet impact erosion prediction approaches will be discussed.
Author: Wojciech Borek
Publisher: BoD – Books on Demand
ISBN: 1789846528
Category : Science
Languages : en
Pages : 162
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Book Description
Cavitation erosion is one of the most popular phenomena of the destruction of engineering materials working in water conditions and various kinds of liquids. The cavitation effect is defined as a physical effect, induced by a variable field of liquid pressures, where bubbles or other voids (caverns) - containing steams of a given liquid, gas, or a steam-gas mixture - are formed, expanded, and disappear. A better understanding of all aspects related to cavitation wear will allow for more thoughtful analysis in the selection of innovative engineering materials additionally protected by various technologies or techniques in the field of surface engineering, and optimization of the design of constructional elements used in the cavitation environment. The novelty of this book is the presentation of extensive knowledge related to cavitation, erosion, and how to protect engineering materials against this phenomenon supported by the results of thorough research by the authors.
Author: S. M. DeCorso
Publisher:
ISBN:
Category : Heat
Languages : en
Pages : 14
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Book Description
A description of the problem of steam turbine blade erosion is presented along with many of its aspects that remain unexplained.
Author: Adam Charles Plondke
Publisher:
ISBN:
Category :
Languages : en
Pages : 76
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Book Description
In low-pressure steam turbines, water droplet formation on the surfaces of stationary stator blades can lead to erosion on downstream turbine blades and other equipment. One property that affects the size of the droplets that are formed is the adhesive forces between the water and the surface of the stator blade. The adhesive forces hold the droplets to the surface where they may combine, forming increasingly larger droplets. Eventually, the aerodynamic forces will tear the droplets off the surface, carrying them downstream. To study the effect of stator surface properties on the droplet size distribution, four cascades of stator blades were tested with a low-speed, cold-flow steam turbine simulator. A non-intrusive optical system was used to detect and measure the droplets. Of the four cascades tested, the baseline cascade that showed obvious surface roughness had the largest average droplet size. The cascade that had been sandblasted smooth formed smaller average droplets than the baseline cascade but larger average droplets than the cascade that was coated with a proprietary, glass-like coating. This coating was designed to minimize the surface tension between the surface and the water droplet. The fourth cascade was coated in a superhydrophobic granular coating. This coating appeared to work so well to reduce the droplet size that no droplets could be detected by the imaging system. This untested cascade could not be considered in the quantitative analysis.
Author: Hany Kirols
Publisher:
ISBN:
Category :
Languages : en
Pages : 128
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Book Description
Water Droplet Erosion (WDE) is defined as the progressive loss of original material from a solid surface due to continuous impingements of water droplets or jets. In this work, parameters affecting this wear phenomenon are discussed in detail through a literature review. The initial surface roughness as a parameter that may influence WDE process was not given attention in the literature. Therefore, its effect on erosion was studied experimentally. It was concluded that the initial surface roughness has a significant effect on the length of the incubation stage, and may influence the maximum erosion rate. Another point tackled in this work is the WDE results representation. The traditional method of representing erosion results is through a plot between material loss and time. However, this plot neglects important information about the WDE experiment, for instance, the amount of water which has impacted the sample during the test. Therefore, in this work a new representation method of WDE test results was proposed. This new method represents WDE test results with respect to the applied kinetic energy per unit area. WDE erosion result for tests done on 12% Cr stainless steel were successfully represented and analyzed using this method. Finally, the WDE found on ex-service steam turbine blades was studied. The progression of erosion on the surface of the blades was illustrated by the aid of SEM micrographs. This work confirmed that the formation of asperities and depressions are considered the main reasons for pit initiation. In addition, it was also confirmed that the twist angle of the turbine blade around its diagonal, is an important parameter that influences its WDE. Twist angle has an effect on: (a) impact angle, (b) erosion appearance, (c) impact speed, (d) affected area. Furthermore, according to the current experimental results, multi-ray rig erosion tests considered the closest simulation to the actual ex-service blade in terms of damage appearance.
Author: Tadashi Tanuma
Publisher: Woodhead Publishing
ISBN: 0081003250
Category : Technology & Engineering
Languages : en
Pages : 569
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Book Description
Advances in Steam Turbines for Modern Power Plants provides an authoritative review of steam turbine design optimization, analysis and measurement, the development of steam turbine blades, and other critical components, including turbine retrofitting and steam turbines for renewable power plants. As a very large proportion of the world’s electricity is currently generated in systems driven by steam turbines, (and will most likely remain the case in the future) with steam turbines operating in fossil-fuel, cogeneration, combined cycle, integrated gasification combined cycle, geothermal, solar thermal, and nuclear plants across the world, this book provides a comprehensive assessment of the research and work that has been completed over the past decades. Presents an in-depth review on steam turbine design optimization, analysis, and measurement Written by a range of experts in the area Provides an overview of turbine retrofitting and advanced applications in power generation
Author: Wolfgang E. Nagel
Publisher: Springer Science & Business Media
ISBN: 3642333745
Category : Computers
Languages : en
Pages : 587
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Book Description
This book presents the state-of-the-art in simulation on supercomputers. Leading researchers present results achieved on systems of the High Performance Computing Center Stuttgart (HLRS) for the year 2012. The reports cover all fields of computational science and engineering ranging from CFD via computational physics and chemistry to computer science with a special emphasis on industrially relevant applications. Presenting results for both vector-systems and micro-processor based systems the book allows to compare performance levels and usability of various architectures. As HLRS operates not only a large cluster system but also one of the largest NEC vector systems in the world this book gives an excellent insight also into the potential of vector systems. The book covers the main methods in high performance computing. Its outstanding results in achieving highest performance for production codes are of particular interest for both the scientist and the engineer. The book comes with a wealth of coloured illustrations and tables of results.
Author: R. G. Hoagland
Publisher:
ISBN:
Category :
Languages : en
Pages : 78
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Book Description
The impact of a water drop on a solid surface produces a transient stress pulse which can damage the surface by plastic deformation and cracking. The consequence of this damage has important technological implications in diverse areas. Water droplet damage, like cavitation damage, is most typically characterized as an erosion process reflecting material removed with time. Indeed, measurements of material removal rates during repetitive impacting under standardized conditions are a common means of ranking materials for comparison of erosion resistance. However, the development of surface roughness (due to deformation or material removal) and damage in the surface layer during repetitive impacting greatly complicates a detailed analysis of individual impact events. In fact, qualitative descriptions of erosion show that several mechanisms may be involved at different times in the erosion process, leading to distinct stages. It is also clear that the conditions which will eventually lead to material removal are developed by sonic and subsonic droplets in the initial stage of erosion when the density of impacts is low.
Author: Augusto Di Gianfrancesco
Publisher: Woodhead Publishing
ISBN: 008100558X
Category : Business & Economics
Languages : en
Pages : 902
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Book Description
Materials for Ultra-Supercritical and Advanced Ultra-Supercritical Power Plants provides researchers in academia and industry with an essential overview of the stronger high-temperature materials required for key process components, such as membrane wall tubes, high-pressure steam piping and headers, superheater tubes, forged rotors, cast components, and bolting and blading for steam turbines in USC power plants. Advanced materials for future advanced ultra-supercritical power plants, such as superalloys, new martensitic and austenitic steels, are also addressed. Chapters on international research directions complete the volume. The transition from conventional subcritical to supercritical thermal power plants greatly increased power generation efficiency. Now the introductions of the ultra-supercritical (USC) and, in the near future, advanced ultra-supercritical (A-USC) designs are further efforts to reduce fossil fuel consumption in power plants and the associated carbon dioxide emissions. The higher operating temperatures and pressures found in these new plant types, however, necessitate the use of advanced materials. Provides researchers in academia and industry with an authoritative and systematic overview of the stronger high-temperature materials required for both ultra-supercritical and advanced ultra-supercritical power plants Covers materials for critical components in ultra-supercritical power plants, such as boilers, rotors, and turbine blades Addresses advanced materials for future advanced ultra-supercritical power plants, such as superalloys, new martensitic and austenitic steels Includes chapters on technologies for welding technologies
Author: Tony Giampaolo
Publisher: The Fairmont Press, Inc.
ISBN: 0881734136
Category : Gas-turbines
Languages : en
Pages : 426
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Book Description
The second edition of a bestseller, this comprehensive reference provides the fundamental information required to understand both the operation and proper application of all types of gas turbines. The completely updated second edition adds a new section on use of inlet cooling for power augmentation and NOx control. It explores the full spectrum of gas turbines hardware, typical application scenarios, and operating parameters, controls, inlet treatments, inspection, trouble-shooting, and more. The author discusses strategies that can help readers avoid problems before they occur and provides tips that enable diagnosis of problems in their early stages and analysis of failures to prevent their recurrence.
