Download or read book On the Use of Large Eddy Simulation and Direct Numerical Simulation to Improve Near Wall Modeling in Porous Media Models of Pebble Bed Reactors written by David Reger and published by . This book was released on 2024 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This work aims to improve capabilities for modeling localized effects in porous media models of Pebble Bed Reactors (PBRs). The wall-channel effect is the primary local phenomena of interest in a PBR, where the presence of the reflector wall disrupts the pebble packing, causing the pebbles near the wall to pack less efficiently and creating large void regions. Accurate modeling of the near-wall region is important as it will affect core bypass flow and temperature predictions. Failing to properly model this region therefore leads to increased uncertainty in the prediction of maximum fuel temperatures and thus larger safety margins are necessary. Porous media models are commonly used for design scoping and plant-level simulations of PBRs. Although these models have some capabilities to model the near-wall region, the correlations that are available in porous media codes are often inaccurate when a multi-region model is used to discretize the near-wall region. A high-to-low methodology is therefore developed in this work to improve local modeling capabilities in porous media codes. NekRS, a spectral-element computational fluid dynamics (CFD) code, is used to generate a large high-fidelity flow dataset with Large Eddy Simulation (LES) and Direct Numerical Simulation (DNS). An analysis of the Turbulent Kinetic Energy (TKE) budget is performed, revealing notable regions of negative TKE production near pebble contact points. Further investigation reveals that the amount of negative production in a given region can be linked to the local porosity of that region. This investigation of the flow physics helps to provide a better understanding of the differences in flow behavior across the various regions of the bed. Porous media models equivalent to the high-fidelity models are created and simulated with Idaho National Laboratory's Pronghorn porous media code. The KTA correlation is used for the pressure drop calculation in Pronghorn and is the correlation that is targeted for improvement. Results between NekRS and Pronghorn are compared to determine areas of discrepancy between the two codes. A method is then developed to extract the form loss coefficients from the high-fidelity dataset where the bed is split into several concentric ring subdomains and flow data is averaged in each region. An improved pressure drop correlation is determined with the extracted form coefficients and is implemented in Pronghorn, reducing the error in the near-wall velocity prediction from greater than 30\% to less than 5\%. A similar high-to-low investigation is performed on the interphase heat transfer closure. Several correlations are compared to the high-fidelity results where it is found that the KTA heat transfer correlation is capable of accurately predicting the local Nusselt numbers that were determined in the high-fidelity simulation. Comparison of the radial solid temperature profiles, however, reveal discrepancies between NekRS and Pronghorn. It is discovered that the implementation of the interphase heat transfer coefficient that exists in many current porous media codes is not valid when local porosities are modeled. Instead, it is suggested that the interphase heat transfer coefficient should be dependent on the local porosity, the Nusselt number, and the local solid surface-to-volume ratio. Implementation of this change produces improvement in the agreement between NekRS and Pronghorn while using the KTA heat transfer correlation.
Download or read book Multiphase Flow and Heat Transfer in Pebble Bed Reactor Core written by Shengyao Jiang and published by Springer Nature. This book was released on 2020-11-19 with total page 510 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book introduces readers to gas flows and heat transfer in pebble bed reactor cores. It addresses fundamental issues regarding experimental and modeling methods for complex multiphase systems, as well as relevant applications and recent research advances. The numerical methods and experimental measurements/techniques used to solve pebble flows, as well as the content on radiation modeling for high-temperature pebble beds, will be of particular interest. This book is intended for a broad readership, including researchers and practitioners, and is sure to become a key reference resource for students and professionals alike.
Download or read book Convective Heat Transfer in Porous Media written by Yasser Mahmoudi and published by CRC Press. This book was released on 2019-11-06 with total page 399 pages. Available in PDF, EPUB and Kindle. Book excerpt: Focusing on heat transfer in porous media, this book covers recent advances in nano and macro’ scales. Apart from introducing heat flux bifurcation and splitting within porous media, it highlights two-phase flow, nanofluids, wicking, and convection in bi-disperse porous media. New methods in modeling heat and transport in porous media, such as pore-scale analysis and Lattice–Boltzmann methods, are introduced. The book covers related engineering applications, such as enhanced geothermal systems, porous burners, solar systems, transpiration cooling in aerospace, heat transfer enhancement and electronic cooling, drying and soil evaporation, foam heat exchangers, and polymer-electrolyte fuel cells.
Download or read book Design for Reactor Core Safety in Nuclear Power Plants written by International Atomic Energy Agency and published by . This book was released on 1986 with total page 72 pages. Available in PDF, EPUB and Kindle. Book excerpt: Covers the mechanical, chemical, thermal, hydraulic, neutronic and irradiation considerations important to the safe design of a nuclear reactor core. The core features of commonly used reactor types including light and heavy water reactors, as well as gas cooled reactors, are addressed.
Download or read book Advances in High Temperature Gas Cooled Reactor Fuel Technology written by International Atomic Energy Agency and published by . This book was released on 2012-06 with total page 639 pages. Available in PDF, EPUB and Kindle. Book excerpt: This publication reports on the results of a coordinated research project on advances in high temperature gas cooled reactor (HTGR) fuel technology and describes the findings of research activities on coated particle developments. These comprise two specific benchmark exercises with the application of HTGR fuel performance and fission product release codes, which helped compare the quality and validity of the computer models against experimental data. The project participants also examined techniques for fuel characterization and advanced quality assessment/quality control. The key exercise included a round-robin experimental study on the measurements of fuel kernel and particle coating properties of recent Korean, South African and US coated particle productions applying the respective qualification measures of each participating Member State. The summary report documents the results and conclusions achieved by the project and underlines the added value to contemporary knowledge on HTGR fuel.
Download or read book Advances of Computational Fluid Dynamics in Nuclear Reactor Design and Safety Assessment written by Jyeshtharaj Joshi and published by Woodhead Publishing. This book was released on 2019-06-11 with total page 888 pages. Available in PDF, EPUB and Kindle. Book excerpt: Advances of Computational Fluid Dynamics in Nuclear Reactor Design and Safety Assessment presents the latest computational fluid dynamic technologies. It includes an evaluation of safety systems for reactors using CFD and their design, the modeling of Severe Accident Phenomena Using CFD, Model Development for Two-phase Flows, and Applications for Sodium and Molten Salt Reactor Designs. Editors Joshi and Nayak have an invaluable wealth of experience that enables them to comment on the development of CFD models, the technologies currently in practice, and the future of CFD in nuclear reactors. Readers will find a thematic discussion on each aspect of CFD applications for the design and safety assessment of Gen II to Gen IV reactor concepts that will help them develop cost reduction strategies for nuclear power plants.
Download or read book Transport Phenomena in Porous Media II written by I. Pop and published by Elsevier. This book was released on 2002-06-20 with total page 469 pages. Available in PDF, EPUB and Kindle. Book excerpt: Transport phenomena in porous media continues to be a field which attracts intensive research activity. This is primarily due to the fact that it plays an important and practical role in a large variety of diverse scientific applications. Transport Phenomena in Porous Media II covers a wide range of the engineering and technological applications, including both stable and unstable flows, heat and mass transfer, porosity, and turbulence.Transport Phenomena in Porous Media II is the second volume in a series emphasising the fundamentals and applications of research in porous media. It contains 16 interrelated chapters of controversial, and in some cases conflicting, research, over a wide range of topics. The first volume of this series, published in 1998, met with a very favourable reception. Transport Phenomena in Porous Media II maintains the original concept including a wide and diverse range of topics, whilst providing an up-to-date summary of recent research in the field by its leading practitioners.
Download or read book Thermal Hydraulics of Water Cooled Nuclear Reactors written by Francesco D'Auria and published by Woodhead Publishing. This book was released on 2017-05-18 with total page 1200 pages. Available in PDF, EPUB and Kindle. Book excerpt: Thermal Hydraulics of Water-Cooled Nuclear Reactors reviews flow and heat transfer phenomena in nuclear systems and examines the critical contribution of this analysis to nuclear technology development. With a strong focus on system thermal hydraulics (SYS TH), the book provides a detailed, yet approachable, presentation of current approaches to reactor thermal hydraulic analysis, also considering the importance of this discipline for the design and operation of safe and efficient water-cooled and moderated reactors. Part One presents the background to nuclear thermal hydraulics, starting with a historical perspective, defining key terms, and considering thermal hydraulics requirements in nuclear technology. Part Two addresses the principles of thermodynamics and relevant target phenomena in nuclear systems. Next, the book focuses on nuclear thermal hydraulics modeling, covering the key areas of heat transfer and pressure drops, then moving on to an introduction to SYS TH and computational fluid dynamics codes. The final part of the book reviews the application of thermal hydraulics in nuclear technology, with chapters on V&V and uncertainty in SYS TH codes, the BEPU approach, and applications to new reactor design, plant lifetime extension, and accident analysis. This book is a valuable resource for academics, graduate students, and professionals studying the thermal hydraulic analysis of nuclear power plants and using SYS TH to demonstrate their safety and acceptability. - Contains a systematic and comprehensive review of current approaches to the thermal-hydraulic analysis of water-cooled and moderated nuclear reactors - Clearly presents the relationship between system level (top-down analysis) and component level phenomenology (bottom-up analysis) - Provides a strong focus on nuclear system thermal hydraulic (SYS TH) codes - Presents detailed coverage of the applications of thermal-hydraulics to demonstrate the safety and acceptability of nuclear power plants
Download or read book Fundamentals of Transport Phenomena in Porous Media written by Jacob Bear and published by Springer. This book was released on 1984-11-30 with total page 1018 pages. Available in PDF, EPUB and Kindle. Book excerpt: Proceedings of the NATO Advanced Study Institute, Newark, Delaware, July 18-27, 1982
Download or read book Magnetic Fusion Technology written by Thomas J. Dolan and published by Springer Science & Business Media. This book was released on 2014-02-10 with total page 816 pages. Available in PDF, EPUB and Kindle. Book excerpt: Magnetic Fusion Technology describes the technologies that are required for successful development of nuclear fusion power plants using strong magnetic fields. These technologies include: • magnet systems, • plasma heating systems, • control systems, • energy conversion systems, • advanced materials development, • vacuum systems, • cryogenic systems, • plasma diagnostics, • safety systems, and • power plant design studies. Magnetic Fusion Technology will be useful to students and to specialists working in energy research.
Download or read book Contaminants in the Subsurface written by National Research Council and published by National Academies Press. This book was released on 2005-04-23 with total page 371 pages. Available in PDF, EPUB and Kindle. Book excerpt: At hundreds of thousands of commercial, industrial, and military sites across the country, subsurface materials including groundwater are contaminated with chemical waste. The last decade has seen growing interest in using aggressive source remediation technologies to remove contaminants from the subsurface, but there is limited understanding of (1) the effectiveness of these technologies and (2) the overall effect of mass removal on groundwater quality. This report reviews the suite of technologies available for source remediation and their ability to reach a variety of cleanup goals, from meeting regulatory standards for groundwater to reducing costs. The report proposes elements of a protocol for accomplishing source remediation that should enable project managers to decide whether and how to pursue source remediation at their sites.
Download or read book PbZn 2020 9th International Symposium on Lead and Zinc Processing written by A. Siegmund and published by Springer Nature. This book was released on 2020-01-24 with total page 937 pages. Available in PDF, EPUB and Kindle. Book excerpt: Established in 1970, the PbZn symposium series is considered the leading international technical forum for the lead and zinc processing industries. The PbZn 2020 volume addresses all aspects of current processing technologies for primary and secondary lead and zinc, as well as emerging technologies for both metals.
Download or read book Numerical Simulation of Power Plants and Firing Systems written by Heimo Walter and published by Springer. This book was released on 2017-04-18 with total page 851 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book comprises the fundamentals of the numerical simulation of fluid flows as well as the modelling of a power plant and plant components. The fundamental equations for heat and mass transfer will be prepared for the application in the numerical simulation. Selected numerical methods will be discussed in detail. The book will deal with the gas as well as with the water/steam flow. Regulation and controller, simplified models and hybrid models as well as the validation of measurement data are also included in the book.
Download or read book Elementary Chemical Reactor Analysis written by Rutherford Aris and published by Butterworth-Heinemann. This book was released on 2013-09-03 with total page 367 pages. Available in PDF, EPUB and Kindle. Book excerpt: Elementary Chemical Reactor Analysis focuses on the processes, reactions, methodologies, and approaches involved in chemical reactor analysis, including stoichiometry, adiabatic reactors, external mass transfer, and thermochemistry. The publication first takes a look at stoichiometry and thermochemistry and chemical equilibrium. Topics include heat of formation and reaction, measurement of quantity and its change by reaction, concentration changes with a single reaction, rate of generation of heat by reaction, and equilibrium of simultaneous and heterogeneous reactions. The manuscript then offers information on reaction rates and the progress of reaction in time. Discussions focus on systems of first order reactions, concurrent reactions of low order, general irreversible reaction, variation of reaction rate with extent and temperature, and heterogeneous reaction rate expressions. The book examines the interaction of chemical and physical rate processes, continuous flow stirred tank reactor, and adiabatic reactors. Concerns include multistage adiabatic reactors, adiabatic stirred tank, stability and control of the steady state, mixing in the reactor, effective reaction rate expressions, and external mass transfer. The publication is a dependable reference for readers interested in chemical reactor analysis.
Download or read book Onsite Wastewater Treatment Systems Manual written by and published by . This book was released on 2002 with total page 378 pages. Available in PDF, EPUB and Kindle. Book excerpt: "This manual contains overview information on treatment technologies, installation practices, and past performance."--Introduction.
Download or read book Industrial and Process Furnaces written by Barrie Jenkins and published by Butterworth-Heinemann. This book was released on 2013-10-23 with total page 677 pages. Available in PDF, EPUB and Kindle. Book excerpt: Furnaces sit at the core of all branches of manufacture and industry, so it is vital that these are designed and operated safely and effi-ciently. This reference provides all of the furnace theory needed to ensure that this can be executed successfully on an industrial scale. Industrial and Process Furnaces: Principles, 2nd Edition provides comprehensive coverage of all aspects of furnace operation and design, including topics essential for process engineers and operators to better understand furnaces. This includes: the combustion process and its control, furnace fuels, efficiency, burner design and selection, aerodynamics, heat release profiles, furnace atmosphere, safety and emissions. These elements and more are brought together to illustrate how to achieve optimum design and operation, with real-world case studies to showcase their application. - Up-to-date and comprehensive reference encompassing not only best practice of operation but the essential elements of furnace theory and design, essential to anyone working with furnaces, ovens and combustion-based systems. - More case studies, more worked examples. - New material in this second edition includes further application of Computational Fluid Dynamics (CFD), with additional content on flames and burners, costs, efficiencies and future trends.
Download or read book Reservoir Sedimentation Handbook written by Gregory L. Morris and published by McGraw Hill Professional. This book was released on 1998 with total page 864 pages. Available in PDF, EPUB and Kindle. Book excerpt: Focusing on reservoir sedimentation management and control, this work defines the nature and severity of sedimentation, reviews relevant physical processes, describes techniques used to combat sedimentation, and presents detailed case studies.
