Features of Design and Results of Function Tests at Tomari Unit 3

2009 ◽  
Author(s):  
Ichiro Sakai ◽  
Takashi Yano ◽  
Takashi Takemura ◽  
Kousei Yamada
Keyword(s):  
Steam Turbine ◽  
Human Error ◽  
Mental Workload ◽  
Control Board ◽  
3 Dimensional ◽  
Operator Console ◽  
Hydraulic Design ◽  
The World ◽  
Zn Injection ◽  
Lp Turbine

Tomari Unit 3 is not APWR but many advanced and latest technologies such as integrated I&C system including advanced main control board, advanced steam turbine and zinc injection are introduced into it. These three technologies are the fist application in Japan or in the world. Advanced main control board consists of large display panel, operator console and shift supervisor console and improved alarm system is introduced into it. Operator’s mental workload and human error probability is each improved 27% and 59% by introducing advanced main control board. Also maintainability and construction cost is improved by introducing integrated I&C system. MTTR is less than 30 minutes. 54-inch last blade in LP turbine, 3-dimensional hydraulic design blade, integral shroud blade and advanced bearing are applied to advanced steam turbine. Improvement of turbine efficiency by introducing 54-inch and 3-dimensional hydraulic design blade is evaluated to be approximately 0.3%. Vibration amplitude of bearings in turbine-generator during HFT was very small due to advanced bearing. Zinc injection was started from HFT for the first time in the world. Measured zinc consumption is consistent with anticipated. According to result of Zn injection during HFT, radiation sources are approximately 10–20% reduced in comparison with no injection.

Sir Charles Parsons and Electrical Power Generation—a Turbine Designer's Perspective

1994 ◽  
Vol 208 (3) ◽  
pp. 159-176 ◽  
Author(s):  
J R Bolter
Keyword(s):  
Power Generation ◽  
Steam Turbine ◽  
Gas Turbine ◽  
Electrical Power Generation ◽  
Analytical Methods ◽  
State Of The Art ◽  
Electrical Power ◽  
Turbine Generator ◽  
Current State ◽  
The World

Sir Charles Parsons died some three years after the author was born. In this paper the author looks back at the pioneering work of Parsons in the field of power generation. It shows how he was able to increase output of the steam turbine generator from 7.5 kW in 1884 to 50000 kW in 1930 while increasing efficiency from 1.6 to 36 per cent, and relates these achievements to the current state of the art. Blading design, rotor construction and other aspects of turbine engineering are considered. The conclusion is that Parsons and his associates charted the course which manufacturers and utilities throughout the world have continued to follow, although increasingly sophisticated design and analytical methods have succeeded the intuitive approach of Parsons. His constant search for improved efficiency was and is highly relevant to today's concern for the environment. Finally, although it did not become a practical proposition in his lifetime, the paper reviews Parsons' vision of, and continuing interest in, the gas turbine, first mentioned in his 1884 patents.

Design Optimization of a Low Pressure Steam Turbine Radial Diffuser Using an Evolutionary Algorithm and 3D CFD

2012 ◽  
Author(s):  
Tom Verstraete ◽  
Johan Prinsier ◽  
Alberto Di Sante ◽  
Stefania Della Gatta ◽  
Lorenzo Cosi
Keyword(s):  
Design Optimization ◽  
Steam Turbine ◽  
Differential Evolution Algorithm ◽  
Low Pressure ◽  
Pressure Recovery ◽  
Strong Impact ◽  
Optimized Design ◽  
Steam Turbines ◽  
Recovery Coefficient ◽  
Lp Turbine

The design of the radial exhaust hood of a low pressure (LP) steam turbine has a strong impact on the overall performance of the LP turbine. A higher pressure recovery of the diffuser will lead to a substantial higher power output of the turbine. One of the most critical aspects in the diffuser design is the steam guide, which guides the flow near the shroud from axial to radial direction and has a high impact on the pressure recovery. This paper presents a method for the design optimization of the steam guide of a steam turbine for industrial power generation and mechanical drive of centrifugal compressors. This development is in the frame of a continuous effort in GE Oil and Gas to develop more efficient steam turbines. An existing baseline exhaust and steam guide design is first analyzed together with the last LP turbine stage with a frozen rotor full 3D Computational Fluid Dynamics (CFD) calculation. The numerical prediction is compared to available steam test turbine data. The new exhaust box and a first attempt new steam guide design are then first analyzed by a CFD computation. The diffuser inlet boundary conditions are extracted from this simulation and used for improving the design of the steam guide. The maximization of the pressure recovery is achieved by means of a numerical optimization method that uses a metamodel assisted differential evolution algorithm in combination with a 3D CFD solver. The profile of the steam guide is parameterized by a Bezier curve. This allows for a wide variety of shapes, respecting the manufacturability constraints of the design. In the design phase it is mandatory to achieve accurate results in terms of performance differences in a reasonable time. The pressure recovery coefficient is therefore computed through the 3D CFD solver excluding the last stage, to reduce the computational burden. Steam tables are used for the accurate prediction of the steam properties. Finally, the optimized design is analyzed by a frozen rotor computation to validate the approach. Also off-design characteristics of the optimized diffuser are shown.

Common Mistakes in Delivering Cybersecurity Awareness

2019 ◽  
pp. 19-32
Author(s):  
Joshua Crumbaugh
Keyword(s):  
Training Program ◽  
Real World ◽  
Human Error ◽  
Cyber Attacks ◽  
Security Awareness ◽  
Complete Control ◽  
Data Breaches ◽  
The World ◽  
Gain Access ◽  
Successes And Failures

Human error is the cause of over 95% of data breaches and the weakest aspect of cybersecurity in nearly all organizations. These errors guarantee that hackers can easily gain access to almost any network in the world and take complete control of systems, data, and more. This chapter outlines the top mistakes organizations make in security awareness and why most companies are failing to properly prepare their users for cyber-attacks. Each point is accompanied by actionable data derived from real-world training program successes and failures.

CMU-WEB

2002 ◽  
pp. 219-242
Author(s):  
Akhilesh Bajaj ◽  
Ramayya Krishnan
Keyword(s):  
World Wide Web ◽  
Conceptual Model ◽  
World Wide ◽  
Web Applications ◽  
Internet Access ◽  
Empirical Testing ◽  
Design Metrics ◽  
3 Dimensional ◽  
Dimensional Classification ◽  
The World

With the ubiquitous availability of browsers and internet access, the last few years have seen a tremendous growth in the number of applications being developed on the world wide web (WWW). Models for analyzing and designing these applications are only just beginning to emerge. In this work, we propose a 3-dimensional classification space for WWW applications, consisting of a degree of structure of pages dimension, a degree of support for interrelated events dimension and a location of processing dimension. Next, we propose usability design metrics for WWW applications along the structure of pages dimension. To measure these ,we propose CMU-WEB: a conceptual model that can be used to design WWW applications, such that its schemas provide values for the design metrics. This work represents the first effort, to the best of our knowledge, to provide a conceptual model that measures quantifiable metrics that can be used for the design of more usable web applications, and that can also be used to compare the usability of existing web applications, without empirical testing.

Low Pressure Steam Turbine Exhaust Flow: Part 1 — CFD Coupling of LP Turbine and Condenser Neck

2016 ◽  
Author(s):  
Peter Stein ◽  
Dirk Telschow ◽  
Frederic Lamarque ◽  
Nuncio Colitto
Keyword(s):  
Steam Turbine ◽  
Measurement Data ◽  
Low Pressure ◽  
Computational Time ◽  
Feed Water ◽  
Cfd Modelling ◽  
Design Changes ◽  
Plant Level ◽  
Lp Turbine ◽  
Modelling Approach

Since many years the diffuser and exhaust of low pressure (LP) turbines have been in the focus of turbine development and accordingly broadly discussed within the scientific community. The pressure recovery gained within the diffuser significantly contributes to the turbine performance and therefore plenty of care is taken in investigations of the flow as well as optimization within this part of the turbine. However on a plant level the component following the LP turbine is the condenser, which is connected by the condenser neck. Typically the condenser neck is not fully designed to provide additional enthalpy recovery. Due to plant arrangement reasons, often it is full of built-ins like stiffening struts, feed-water heaters, extraction pipes, steam dump devices and others. It is vital to minimize the pressure losses across the condenser neck, in order to keep performance benefit, previously gained within the diffuser. As a general rule, each mbar of total pressure loss in a condenser neck may reduce the gross power output up to 0.1%. While turbines usually follow a modular approach, the condenser is typically designed plant specific. Therefore, on a plant level it is crucial to identify and evaluate the loss contributors and develop processes and tools which allow an accurate and efficient design process for an optimized condenser neck design. This needs to be performed as a coupled modelling approach, as both, turbine and condenser flow interact with each other. 3-D CFD tools enable a deep insight into the flow field and help to locally optimize the design, as they help to identify local losses and this even for small geometrical design changes. Unfortunately these tools are costly with respect to computational time and resources, if they are used to analyze a full condenser neck with all built-ins. Here 1-D modelling approaches can help to close the gap, as they can provide fast feedback, e.g. in a project tender phase, or can allow to quickly analyze design changes. For this they need a proper calibration and validation. This publication discusses the CFD modelling of a LP steam turbine coupled to a condenser neck and the validity of such calculations against measurement data. In the second publication (Part 2) a simplification of the gained information to a 1-D modelling approach will be discussed.

Some Aspects of Steam Turbine Valves: Materials, Operations and Maintenance

2013 ◽  
Author(s):  
Kuda R. Mutama
Keyword(s):  
Power Plant ◽  
Steam Turbine ◽  
Solid Particle ◽  
Solid Particle Erosion ◽  
Particle Erosion ◽  
Pull Out ◽  
Essential Components ◽  
The World ◽  
Maintenance Cycle ◽  
Main Steam

Steam turbine valves are the most essential components of modern steam turbines from an operation, performance, reliability and safety aspects of a modern power plant. Current designs are pushing the operational envelope and it is not uncommon for large ultracritical plants to run on pressures exceeding 4500 psi and 1200 °F. These conditions are not only challenging for materials of construction for turbines and boilers but also for main steam turbine valves. The tendency of materials to oxidize at these temperatures is all too common causing problems for valve heads, stems, discs, bushings and seats. OEMs around the world are pushing to develop valve components with 9–12% Cr martensitic steels and nickel based alloys which offer better creep strength at elevated temperatures. For existing power plants at temperatures of a 1000 to 1050 °F range there is a push to retrofit valve components with Incolloy 901 type, Inconel 718 and Stellite alloys. Scale build up in traditional alloys happens too quickly for the usual two year maintenance cycle. The application of better alloys for steam turbine valves makes it possible to increase the maintenance cycle from two to four or even six years, while increasing the operational reliability of the valve. Elimination of main steam valve failures removes risks of turbine overspeed events and increases plant availability. Solid particle erosion is not forgiving on valve parts such as stems, discs and valve seats and over a period of time, excessive wear causes the valve to be rendered unsafe to continued service. Nitrided materials and chrome-carbide-coated materials are much harder than the stem base material; and to slow down wear, a nitriding process is used to develop a thin, hard, wear-resistant surface. Some of the material often used for Stellite liners are Nitralloy 135M, 410 SS, 422 SS Nitrided, Incolloy 901 Nitrided, 347 SS, 13Cr-13Ni-10Co-3Nb-2.5W-2Mo. Different OEMs use a variety of alloys for valve seats, discs and stems. Antigalling characteristics are particularly favorable. Valve casings are cast materials and usually specifications include the ASTM A217 and ASTM A356. The ASTM A217 cast steels are typically, 1.25Cr-0.5Mo Grade WC6 and the 2.25Cr-1Mo Grade WC9 materials. Some of the problems experienced with steam turbine valves, are sticking to the valve seat requiring excessive pull-out force, wear of the seat surface, valves not closing properly due to oxidation build up, Stellite weld cracking, cutting or gouging due to solid particle erosion. The material presented in this paper is of interest to fossil power plant personnel experiencing challenges on valve performance and maintenance. The paper looks at all aspects of steam turbine valves as far as current trends in valve material, operation and maintenance and lastly, looks at recent occurrences of valve failures leading to steam turbine overspeed catastrophic failures around the world.

scholarly journals Unconventionals in Europe: Best Practice vs. Worst Case - The Conflict Between Facts and Public Perception

2016 ◽  
Vol 23 (3) ◽  
pp. 377-386 ◽  
Author(s):  
Peter Burri
Keyword(s):  
Natural Gas ◽  
Public Perception ◽  
Human Error ◽  
Fossil Fuels ◽  
Fossil Fuel ◽  
Hydrocarbon Exploration ◽  
Negative Consequences ◽  
Rapid Improvement ◽  
Worst Case ◽  
The World

Abstract In spite of great progress in energy efficiency and in the development of renewable energy the world is likely to need significant amounts of fossil fuel throughout this century and beyond (the share of fossil fuels in the world mix has remained at about 86% of primary energy from 1990 to today). Gas, being the by far cleanest fossil fuel is the ideal bridging fuel to a world with predominantly renewable supplies. Thanks to the recent perfection of unconventional technologies there is no shortage of gas for this bridging function for at least the next 100-200 years. EASAC and several other European Institutions, notably the German Academy of Technical Sciences (acatech) have in the last few years carried out expert studies to assess the alleged environmental risks of unconventional hydrocarbon exploration and production. All these studies have, in agreement with other competent studies worldwide, come to the conclusion that there exists no scientific reason for a ban on hydraulic fracturing. With good practices, clear standards and adequate control the method causes no enhanced risks to the environment or the health of humans. Special attention has to be paid to the surface handling of drilling and fracking fluids. In Europe alone many thousand frac jobs have been carried out by the industry in the last 60 years without any severe accidents. The mishaps in North America have largely been the cause of unprofessional operations and human error. Especially in places with high air pollution, like many megacities of Asia, natural gas has to be seen as a unique chance to achieve a rapid improvement of the air quality and a significant reduction of CO2 emissions. This is also true for Europe where especially the use of domestic natural gas brings important benefits to the environment. The alternative to gas is in many regions of the world an increased consumption of coal, with all negative consequences.

Climatological Biomass Burning CO – Where it comes from and where it goes.

2020 ◽  
Author(s):  
Nikos Daskalakis ◽  
Maria Kanakidou ◽  
Mihalis Vrekoussis ◽  
Laura Gallardo
Keyword(s):  
Biomass Burning ◽  
Transport Model ◽  
Source Region ◽  
Atmospheric Composition ◽  
Anthropogenic Sources ◽  
3 Dimensional ◽  
Source Regions ◽  
The World ◽  
Transport Patterns ◽  
The Impact

<p>Carbon Monoxide (CO) is an important atmospheric trace gas, and among the key O<sub>3</sub> precursors in the troposphere, alongside NO<sub>x</sub> and VOCs. It is among the most important sinks of OH radical in the atmosphere, which controls lifetime of CH<sub>4</sub> — a major greenhouse gas. Biomass burning sources contribute about 25% to the global emissions of CO, with the remaining CO being either emitted from anthropogenic sources, or being chemically formed in the atmosphere. Because of CO tropospheric lifetime is about two months; it can be transported in the atmosphere thus its sources have a hemispheric impact on atmospheric composition.</p><p>The extent of the impact of biomass burning to remote areas of the world through long range transport is here investigated using the global 3-dimensional chemistry transport model TM4-ECPL. For this, tagged biomass burning CO tracers from the 13 different HTAP (land) source regions are used in the model in order to evaluate the contribution of each source region to the CO concentrations in the 170 HTAP receptor regions that originate from biomass burning. The global simulations cover the period 1994—2015 in order to derive climatological transport patterns for CO and assess the contribution of each of the source regions to each of the receptor regions in the global troposphere. The CO simulations are evaluated by comparison with satellite observations from MOPITT and ground based observations from WDCGG. We show the significant impact of biomass burning emissions to the most remote regions of the world.</p>

Numerical Investigation of the 3D Flow Field in a Steam Turbine Axial Exhaust Diffuser: Comparison With Experimental Data and Performance Evaluation

2013 ◽  
Author(s):  
Federico Daccà ◽  
Claudio Canelli ◽  
Stefano Cecchi
Keyword(s):  
Experimental Data ◽  
Performance Evaluation ◽  
Flow Field ◽  
Steam Turbine ◽  
Three Dimensional ◽  
Measured Data ◽  
Accurate Performance ◽  
And Performance ◽  
Lp Turbine ◽  
Actual Geometry

The purpose of this paper is to present a numerical analysis carried out for the performance evaluation of the axial exhaust diffuser of a LP steam turbine. A set of measured data in an actual real scale steam turbine is available for direct comparison. The three dimensional exhaust flow in a LP steam turbine provided with a 48″ LSB is numerically investigated in different real working conditions by means of 3D CFD analysis. A detailed 3D model of the actual geometry is used in order to catch the highly 3D features of the flow field, avoiding the use of numerical periodicity conditions. Boundary conditions are derived both from experimental data and from specific validated 3D simulations of the main flow of the entire LP turbine section from front stages up to the LSN. The comparison with measured data allows to validate the performed CFD simulations and to provide a reliable complete performance curve of the exhaust diffuser geometry coupled with the 48″ LSB design. An important outcome of the work consists also in a generalized method for accurate performance evaluation of axial diffusers.

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