Phase Change with Convection: Modelling and Validation

Phase Change with Convection: Modelling and Validation PDF Author: Tomasz A. Kowalewski
Publisher: Springer
ISBN: 3709127645
Category : Technology & Engineering
Languages : en
Pages : 277

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Book Description
This unique volume offers a review of state-of-the-art modelling methods of phase change problems, numerical and experimental methods used in the field. It combines the experience of theoreticians with those using numerical tools for modelling problems of solidification.

Phase Change with Convection: Modelling and Validation

Phase Change with Convection: Modelling and Validation PDF Author: Tomasz A. Kowalewski
Publisher: Springer
ISBN: 3709127645
Category : Technology & Engineering
Languages : en
Pages : 277

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Book Description
This unique volume offers a review of state-of-the-art modelling methods of phase change problems, numerical and experimental methods used in the field. It combines the experience of theoreticians with those using numerical tools for modelling problems of solidification.

AMIF-ESF Workshop on Phase Change with Convection

AMIF-ESF Workshop on Phase Change with Convection PDF Author: Tomasz A Kowalewski
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Book Description


MODELING OF THE PHASE CHANGE MATERIAL OF A HYBRID STORAGE USING THE FINITE ELEMENT METHOD

MODELING OF THE PHASE CHANGE MATERIAL OF A HYBRID STORAGE USING THE FINITE ELEMENT METHOD PDF Author: Lukas Kasper
Publisher: TU Wien Academic Press
ISBN: 3854480377
Category : Technology & Engineering
Languages : en
Pages : 149

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Book Description
To increase the efficiency of energy-intensive industrial processes, thermal energy storages can offer new possibilities. A novel approach is investigated in the project HyStEPs. In this concept, containers filled with PCM are placed at the shell surface of a Ruths steam storage, to increase storage efficiency. In this work, a two-dimensional model using the finite element method is developed to simulate the PCM of the hybrid storage as designed in the HyStEPs project. The apparent heat capacity method is applied in a MATLAB implementation, considering heat transfer by both conduction and natural convection. This successfully validated code can handle any desired layout of materials arranged on a rectangular domain. Furthermore, a parameter study of different dimensions and orientations of the PCM cavity was conducted. The impact of natural convection was found to lead to significantly varying behaviour of the studied cavities with different orientation during the charging process, while it was found to be negligible during the discharging process.

Simultaneous Charging/Discharging of Phase Change Materials

Simultaneous Charging/Discharging of Phase Change Materials PDF Author: Mahmood Mastani Joybari
Publisher:
ISBN:
Category :
Languages : en
Pages : 285

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Book Description
In recent decades, latent heat storage in phase change materials (PCMs) received considerable attention. This is due to their high latent heat capacity, which is essentially required for managing and overcoming the temporal mismatch between energy supply and demand. Thus, at the time of energy availability at supply side, it is stored in PCMs so as to be extracted later on when it is needed. In order to provide continuous operation, there are some periods when a thermal storage has to be simultaneously charged and discharged. Most studies focused either on charging, discharging, or consecutive charging and discharging process, while limited work has been conducted for the case of simultaneous charging and discharging (SCD). The first objective of this dissertation is to develop a numerical model to analyze the heat transfer mechanism within a horizontal PCM storage under SCD. Since the possible heat transfer mechanisms within PCMs are conduction, convection or a combination of both, two models are used to identify the mechanism under SCD; i.e. the pure conduction (PC) model and combined conduction and natural convection (CCNC) model. The PC model is a hypothetical model, which neglects the natural convection during phase change process; however, the CCNC model is the real case one. Validation of the model results by comparison with experimental data shows an acceptable agreement both under melting and solidification. Therefore, the developed model can be used to numerically study the phase change process in PCMs.Natural convection is the result of density changes, which create buoyancy forces within melted PCM and plays a significant role during melting. Currently, the most widely used method to account for natural convection is the effective thermal conductivity method. The method considers an artificial increase in thermal conductivity values to take into consideration the effect of natural convection by comparing the results with experimental data. Two major shortcomings of this method are that first, it is tedious to obtain the proper value and second, the method does not provide information about the melting front location. In this dissertation, a novel simplified front tracking method is presented to replace the thermal conductivity method. The novel method is based on considering two separate melting fronts for the upper and lower halves of a horizontal thermal storage system. Therefore, two dimensionless correlations are developed to map the results of the simple PC model to that of the complicated CCNC model based on the presented logic. The method essentially creates a link between CCNC and PC models, which is also missing in the literature. Based on verification, the correlations can provide results within ±15% discrepancy.

Computational Thermo-Fluid Dynamics

Computational Thermo-Fluid Dynamics PDF Author: Petr A. Nikrityuk
Publisher: John Wiley & Sons
ISBN: 3527636080
Category : Technology & Engineering
Languages : en
Pages : 353

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Book Description
Combining previously unconnected computational methods, this monograph discusses the latest basic schemes and algorithms for the solution of fluid, heat and mass transfer problems coupled with electrodynamics. It presents the necessary mathematical background of computational thermo-fluid dynamics, the numerical implementation and the application to real-world problems. Particular emphasis is placed throughout on the use of electromagnetic fields to control the heat, mass and fluid flows in melts and on phase change phenomena during the solidification of pure materials and binary alloys. However, the book provides much more than formalisms and algorithms; it also stresses the importance of good, feasible and workable models to understand complex systems, and develops these in detail. Bringing computational fluid dynamics, thermodynamics and electrodynamics together, this is a useful source for materials scientists, PhD students, solid state physicists, process engineers and mechanical engineers, as well as lecturers in mechanical engineering.

Phase Change Material-Based Heat Sinks

Phase Change Material-Based Heat Sinks PDF Author: Srikanth Rangarajan
Publisher: CRC Press
ISBN: 1000752836
Category : Science
Languages : en
Pages : 223

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Book Description
Phase-change Material based heat sinks and associated optimization remains a topic of great interest, as evident from the increasing number of citations and new applications and miniaturization. Often the multi objective perspective of such heat sinks is ignored. This book introduces the readers to the PCM based heat sinks and Multi objective optimization. The authors have also included interesting in house experimental results on the "Rotating heat sinks" which is a first of a kind work. Useful to budding thermal researchers and practicing engineers in the field, this book is also a great start for students to understand the cooling applications in electronics and an asset to every library in a technical university. Since this book not only gives a critical review of the state of the art but also presents the authors' own results. The book will encourage, motivate and let the reader consider pursuing a research career in electronic cooling technologies.

The Classical Stefan Problem

The Classical Stefan Problem PDF Author: S.C. Gupta
Publisher: Elsevier
ISBN: 008052916X
Category : Science
Languages : en
Pages : 404

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Book Description
This volume emphasises studies related to classical Stefan problems. The term "Stefan problem" is generally used for heat transfer problems with phase-changes such as from the liquid to the solid. Stefan problems have some characteristics that are typical of them, but certain problems arising in fields such as mathematical physics and engineering also exhibit characteristics similar to them. The term ``classical" distinguishes the formulation of these problems from their weak formulation, in which the solution need not possess classical derivatives. Under suitable assumptions, a weak solution could be as good as a classical solution. In hyperbolic Stefan problems, the characteristic features of Stefan problems are present but unlike in Stefan problems, discontinuous solutions are allowed because of the hyperbolic nature of the heat equation. The numerical solutions of inverse Stefan problems, and the analysis of direct Stefan problems are so integrated that it is difficult to discuss one without referring to the other. So no strict line of demarcation can be identified between a classical Stefan problem and other similar problems. On the other hand, including every related problem in the domain of classical Stefan problem would require several volumes for their description. A suitable compromise has to be made. The basic concepts, modelling, and analysis of the classical Stefan problems have been extensively investigated and there seems to be a need to report the results at one place. This book attempts to answer that need.

FUNDAMENTALS OF HEAT AND MASS TRANSFER, 6TH ED

FUNDAMENTALS OF HEAT AND MASS TRANSFER, 6TH ED PDF Author: Incropera
Publisher:
ISBN: 9788126527649
Category :
Languages : en
Pages : 1028

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Book Description
Market_Desc: Mechanical, Chemical and Aerospace Engineers and Students and Instructors of Engineering. Special Features: · Covers new applications in bioengineering, fuel cells, and nanotechnology. · Incorporates 220 new problems to help reinforce key concepts. · Presents revised and streamlined content, including the removal of more advanced topics. · Explains how to develop representative models of real processes and systems and draw conclusions concerning process/systems design or performance from the attendant analysis. · Integrates extensive use of the first law of thermodynamics. About The Book: This bestselling book in the field provides a complete introduction to the physical origins of heat and mass transfer. Noted for its crystal clear presentation and easy-to-follow problem solving methodology, Incropera and Dewitt's systematic approach to the first law develops reader confidence in using this essential tool for thermal analysis. Readers will learn the meaning of the terminology and physical principles of heat transfer as well as how to use requisite inputs for computing heat transfer rates and/or material temperatures.

Special Issue Containing Papers Presented at AMIF-ESF Workshop on Phase Change with Convection: Modelling and Validation

Special Issue Containing Papers Presented at AMIF-ESF Workshop on Phase Change with Convection: Modelling and Validation PDF Author: Workshop on Phase Change with Convection: Modelling and Validation
Publisher:
ISBN:
Category :
Languages : en
Pages : 178

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Book Description


Reduced Order Methods for Modeling and Computational Reduction

Reduced Order Methods for Modeling and Computational Reduction PDF Author: Alfio Quarteroni
Publisher: Springer
ISBN: 3319020900
Category : Mathematics
Languages : en
Pages : 338

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Book Description
This monograph addresses the state of the art of reduced order methods for modeling and computational reduction of complex parametrized systems, governed by ordinary and/or partial differential equations, with a special emphasis on real time computing techniques and applications in computational mechanics, bioengineering and computer graphics. Several topics are covered, including: design, optimization, and control theory in real-time with applications in engineering; data assimilation, geometry registration, and parameter estimation with special attention to real-time computing in biomedical engineering and computational physics; real-time visualization of physics-based simulations in computer science; the treatment of high-dimensional problems in state space, physical space, or parameter space; the interactions between different model reduction and dimensionality reduction approaches; the development of general error estimation frameworks which take into account both model and discretization effects. This book is primarily addressed to computational scientists interested in computational reduction techniques for large scale differential problems.