Simulation of Large State Variations in Steam Power Plants

Simulation of Large State Variations in Steam Power Plants PDF Author: Richard Dolezal
Publisher: Springer Science & Business Media
ISBN: 3642831524
Category : Science
Languages : en
Pages : 120

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Book Description
The present simulation method has been developed at the Institute for Power Technology and Steam Generation (IVD) of the University of Stuttgart. It is being successfully employed in the analysis of processes involving large state changes such as start-ups, shut downs, malfunctions and failures in steam power generating unit, which is a large scale system consisting of several subsystems with distributed parameters, to which the steam generator also belongs. This research resulted from the increasing use of the once-through boiler, while simultaneously raising the steam parameters into the region of the supercritical state, using sliding pressure operation, combined processes with gas and steam turbines etc. The objective of this system simulation is to reduce losses of heat and condensate and to minimise unavoidable thermal stresses. The project was financed between 1979 and 1983 by the German Research Society (DFG) as part of the special research section Nr. 157 'Thermal power plants'. The Westfalen Power Company Inc. (VEW) sponsored the start-up code 'DYSTAR'. We would like to express our thanks for this support. The following members of the IVD were involved in this research project: Dr.-Ing. J. Kley Dipl.-Ing. G. Riemenschneider Dr.-Ing. A. Rolf Dipl.-Ing. U. Mayer Dipl.-lng. E. Dr.-lng. M. Klug Pfleger Dr.-Ing. G. Berndt Presently it is intended to use this non-linear, time-variant model of a power generating unit with a variable process and system struc ture as the basis for simple code versions, which one can employ e.g.

Simulation of Large State Variations in Steam Power Plants

Simulation of Large State Variations in Steam Power Plants PDF Author: Richard Dolezal
Publisher: Springer Science & Business Media
ISBN: 3642831524
Category : Science
Languages : en
Pages : 120

Get Book Here

Book Description
The present simulation method has been developed at the Institute for Power Technology and Steam Generation (IVD) of the University of Stuttgart. It is being successfully employed in the analysis of processes involving large state changes such as start-ups, shut downs, malfunctions and failures in steam power generating unit, which is a large scale system consisting of several subsystems with distributed parameters, to which the steam generator also belongs. This research resulted from the increasing use of the once-through boiler, while simultaneously raising the steam parameters into the region of the supercritical state, using sliding pressure operation, combined processes with gas and steam turbines etc. The objective of this system simulation is to reduce losses of heat and condensate and to minimise unavoidable thermal stresses. The project was financed between 1979 and 1983 by the German Research Society (DFG) as part of the special research section Nr. 157 'Thermal power plants'. The Westfalen Power Company Inc. (VEW) sponsored the start-up code 'DYSTAR'. We would like to express our thanks for this support. The following members of the IVD were involved in this research project: Dr.-Ing. J. Kley Dipl.-Ing. G. Riemenschneider Dr.-Ing. A. Rolf Dipl.-Ing. U. Mayer Dipl.-lng. E. Dr.-lng. M. Klug Pfleger Dr.-Ing. G. Berndt Presently it is intended to use this non-linear, time-variant model of a power generating unit with a variable process and system struc ture as the basis for simple code versions, which one can employ e.g.

Power Systems: Modelling and Control Applications

Power Systems: Modelling and Control Applications PDF Author: A. J. Calvaer
Publisher: Elsevier
ISBN: 1483298914
Category : Technology & Engineering
Languages : en
Pages : 549

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Book Description
The control of power systems and power plants is a subject of worldwide interest which continues to sustain a high level of research, development and application. Papers pertaining to areas directly related to power systems and representing the state-of-the-art methods are included in this volume. The topics covered include security analysis, dynamic state estimation, voltage control, power plant control, stability analysis, data communication, expert systems and training simulators for power plants. This interchange between those involved in the research and those involved in the practical applications of new ideas and developments provide a comprehensive reference source for all involved in the power industry.

Difference Equations from Differential Equations

Difference Equations from Differential Equations PDF Author: Wilbert J. Lick
Publisher: Springer Science & Business Media
ISBN: 3642837018
Category : Technology & Engineering
Languages : en
Pages : 296

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Book Description
In computational mechanics, the first and quite often the most difficult part of a problem is the correct formulation of the problem. This is usually done in terms of differential equations. Once this formulation is accomplished, the translation of the governing differential equations into accurate, stable, and physically realistic difference equations can be a formidable task. By comparison, the numerical evaluation of these difference equations in order to obtain a solution is usually much simpler. The present notes are primarily concerned with the second task, that of deriving accurate, stable, and physically realistic difference equations from the governing differential equations. Procedures for the numerical evaluation of these difference equations are also presented. In later applications, the physical formulation of the problem and the properties of the numerical solution, especially as they are related to the numerical approximations inherent in the solution, are discussed. There are numerous ways to form difference equations from differential equations.

Filtering Techniques for Turbulent Flow Simulation

Filtering Techniques for Turbulent Flow Simulation PDF Author: Alvaro A. Aldama
Publisher: Springer Science & Business Media
ISBN: 3642840914
Category : Science
Languages : en
Pages : 410

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Book Description
1. 1 Scope of the Study The detailed and reasonably accurate computation of large scale turbulent flows has become increasingly important in geophysical and engi neering applications in recent years. The definition of water quality management policies for reservoirs, lakes, estuaries, and coastal waters, as well as the design of cooling ponds and solar ponds, requires an ade quate quantitative description of turbulent flows. When the diffusion of some tracer (be it active, such as temperature or salinity, or passive, such as dissolved oxygen) is of relevance to a specific application, the proper determination of the effects of turbulent transport processes has paramount importance. Thus, for instance, the proper understanding of lake and reservoir dynamics requires, as a first step, the ability to simulate turbulent flows. Applications in other areas of geophysical research, such as meteorology and oceanography are easily identified and large in number. It should be stressed that, in this context, the analyst seeks predictive ability to a certain extent. Accordingly, the need for simulation models that closely resemble the natural processes to be repre sented has recently become more evident. Since the late 1960s considerable effort has been devoted to the development of models for the simulation of complex turbulent flows. This has resulted in the establishment of two approaches which have been, or 2 have the potential for being, applied to problems of engineering and geophysical interest.

Discretization Methods and Structural Optimization — Procedures and Applications

Discretization Methods and Structural Optimization — Procedures and Applications PDF Author: Hans A. Eschenauer
Publisher: Springer Science & Business Media
ISBN: 3642837077
Category : Technology & Engineering
Languages : en
Pages : 377

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Book Description
In recent years, the Finite Element Methods FEM were more and more employed in development and design departments as very fast working tools in order to determine stresses, deformations, eigenfrequencies etc. for all kinds of constructions under complex loading conditions. Meanwhile. very effective software systems have been developed by various research teams although some mathematical problems (e. g. convergence) have not been solved satisfac torily yet. In order to make further advances and to find a common language between mathe maticians and mechanicians the "Society for Applied Mathematics and Mechanics" (GAMM) agreed on the foundation of a special Committee: "Discretization Methods in Solid Mechanics" focussing on the following problems: - Structuring of various methods (displacement functions, hybrid and mixed approaches, etc. >, - Survey of approach functions (Lagrange-/Hermite-polynominals, Spline-functions), - Description of singularities, - Convergence and stability, - Practical and theoretical optimality to all mentioned issues (single and interacting). One of the basic aims of the GAMM-Committee is the interdisciplinary cooperation between mechanicians, mathematicians, and users which shall be intensified. Thus, on September 22, 1985 the committee decided to hold a seminar on "Structural Optimization" in order to allow an exchange of experiences and thoughts between the experts of finite element methods and those of structural optimization. A GAMM-seminar entitled "Discretization Methods and Structural Optimization - Procedures and Applications" was hold on October 5-7, 1988 at the Unversity of Siegen.

Dynamic Analysis of Non-Linear Structures by the Method of Statistical Quadratization

Dynamic Analysis of Non-Linear Structures by the Method of Statistical Quadratization PDF Author: M.G. Donley
Publisher: Springer Science & Business Media
ISBN: 3642467156
Category : Technology & Engineering
Languages : en
Pages : 184

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Book Description
1. 1 Introduction As offshore oil production moves into deeper water, compliant structural systems are becoming increasingly important. Examples of this type of structure are tension leg platfonns (TLP's), guyed tower platfonns, compliant tower platfonns, and floating production systems. The common feature of these systems, which distinguishes them from conventional jacket platfonns, is that dynamic amplification is minimized by designing the surge and sway natural frequencies to be lower than the predominant frequencies of the wave spectrum. Conventional jacket platfonns, on the other hand, are designed to have high stiffness so that the natural frequencies are higher than the wave frequencies. At deeper water depths, however, it becomes uneconomical to build a platfonn with high enough stiffness. Thus, the switch is made to the other side of the wave spectrum. The low natural frequency of a compliant platfonn is achieved by designing systems which inherently have low stiffness. Consequently, the maximum horizontal excursions of these systems can be quite large. The low natural frequency characteristic of compliant systems creates new analytical challenges for engineers. This is because geometric stiffness and hydrodynamic force nonlinearities can cause significant resonance responses in the surge and sway modes, even though the natural frequencies of these modes are outside the wave spectrum frequencies. High frequency resonance responses in other modes, such as the pitch mode of a TLP, are also possible.

Lecture Notes in Engineering

Lecture Notes in Engineering PDF Author: Ghodratollah Karami
Publisher: Springer Science & Business Media
ISBN: 3642838979
Category : Technology & Engineering
Languages : en
Pages : 256

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Book Description
The Boundary Element Method (BEM) has been established as a powerful numerical tool for the analysis of continua in recent years. The method is based on an attempt to transfer the governing differential equations into integral equations over the boundary. Thus, the discretization scheme or the intro duction of any approximations must be done over the boundary. This book presents a BEM for two-dimensional elastic, thermo -elastic and body-force contact problems. The formulation is implemented for the general case of contact with various fric tional conditions. The analysis is limited to linear elasto statics and small strain theory. Following a review of the basic nature of contact problems, the analytical basis of the direct formulation of the BEM method is described. The numerical implementation employs three-noded isoparametric line elements for the representa tion of the boundary of the bodies in contact. Opposite nodal points in equi-Iength element-pairs are defined on the two surfaces in the area which is expected to come into contact under an increasing load. The use of appropriate contact IV conditions enables the integral equations for the two bodies to be coupled together. To find the proper contact dimensions and the contact load a combined incremental and iterative approach is utilised. With this approach, the loads are applied progressively, and the sliding and adhering portion of the contact region is established for each load increment using an iterative procedure. A coulomb type of friction law is assumed.

Thermal Power Plant Simulation and Control

Thermal Power Plant Simulation and Control PDF Author: Damian Flynn
Publisher: IET
ISBN: 0852964196
Category : Science
Languages : en
Pages : 447

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Book Description
An exploration of how advances in computing technology and research can be combined to extend the capabilities and economics of modern power plants. The contributors, from academia as well as practising engineers, illustrate how the various methodologies can be applied to power plant operation.

Computational Tensor Analysis of Shell Structures

Computational Tensor Analysis of Shell Structures PDF Author: Steve Naomis
Publisher: Springer Science & Business Media
ISBN: 3642842437
Category : Technology & Engineering
Languages : en
Pages : 321

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Book Description
This book presents a method which is capable of evaluating the deformation characteristics of thin shell structures A free vibration analysis is chosen as a convenient means of studying the displacement behaviour of the shell, enabling it to deform naturally without imposing any particular loading conditions. The strain-displacement equations for thin shells of arbitrary geometry are developed. These relationships are expressed in general curvilinear coordinates and are formulated entirely in the framework of tensor calculus. The resulting theory is not restricted to shell structures characterized by any particular geometric form, loading or boundary conditions. The complete displacement and strain equations developed by Flugge are approximated by the curvilinear finite difference method and are applied to computing the natural frequencies and mode shapes of general thin shells. This approach enables both the displacement components and geometric properties of the shell to be approximated numerically and accurately. The selection of an appropriate displacement field to approximate the deformation of the shell within each finite difference mesh is discussed in detail. In addition, comparisons are made between the use of second and third-order finite difference interpolation meshes.

Slope Analysis Using Boundary Elements

Slope Analysis Using Boundary Elements PDF Author: Yansheng Jiang
Publisher: Springer Science & Business Media
ISBN: 3642839185
Category : Science
Languages : en
Pages : 184

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Book Description
The aim of this book is to provide a new angle on the analysis of slope stability with the Boundary Element Method. The main advantages of BEM are the reduction of the dimensionality of the problem to be solved and accurate selective calculation of internal stresses. This makes it possible, as shown in the book, to develop the algorithms of slip surface analysis of slope more accurate, more rigorous and more easy to be used than in the conventional limit equilibrium methods. The full elastoplastic analysis of slope is also investigated. Besides, the interested reader can find a detailed study of Melan's fundamental solution such as its displacements, its corresponding Galerkin tensor and the treatment of body forces in the half-plan. The basic theory of BEM is outlined in the book so that undergraduate and graduate students of civil engineering, mining engineering and engineering geology can read it without difficulty.