CFD Model Development and Validation for High Temperature Gas Cooled Reactor Cavity Cooling System (RCCS) Applications PDF Download
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Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 320
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Book Description
The Reactor Cavity Cooling Systems (RCCS) is a passive safety system that will be incorporated in the VTHR design. The system was designed to remove the heat from the reactor cavity and maintain the temperature of structures and concrete walls under desired limits during normal operation (steady-state) and accident scenarios. A small scale (1:23) water-cooled experimental facility was scaled, designed, and constructed in order to study the complex thermohydraulic phenomena taking place in the RCCS during stead-state and transient conditions. The facility represents a portion of the reactor vessel with nine stainless steel coolant risers and utilizes water as coolant. The facility was equipped with instrumentation to measure temperatures and flow rates and a general verification was completed during the shakedown. A model of the experimental facility was prepared using RELAP5-3D and simulations were performed to validate the scaling procedure. The experimental data produced during the stead-state run were compared with the simulation results obtained using RELAP5-3D. The overall behavior of the facility met the expectations. The facility capabilities were confirmed to be very promising in performing additional experimental tests, including flow visualization, and produce data for code validation.
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 320
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Book Description
The Reactor Cavity Cooling Systems (RCCS) is a passive safety system that will be incorporated in the VTHR design. The system was designed to remove the heat from the reactor cavity and maintain the temperature of structures and concrete walls under desired limits during normal operation (steady-state) and accident scenarios. A small scale (1:23) water-cooled experimental facility was scaled, designed, and constructed in order to study the complex thermohydraulic phenomena taking place in the RCCS during stead-state and transient conditions. The facility represents a portion of the reactor vessel with nine stainless steel coolant risers and utilizes water as coolant. The facility was equipped with instrumentation to measure temperatures and flow rates and a general verification was completed during the shakedown. A model of the experimental facility was prepared using RELAP5-3D and simulations were performed to validate the scaling procedure. The experimental data produced during the stead-state run were compared with the simulation results obtained using RELAP5-3D. The overall behavior of the facility met the expectations. The facility capabilities were confirmed to be very promising in performing additional experimental tests, including flow visualization, and produce data for code validation.
Author: Nuclear Engineering Division
Publisher:
ISBN:
Category :
Languages : en
Pages :
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Book Description
As part of the Department of Energy (DOE) Generation IV roadmapping activity, the Very High Temperature gas cooled Reactor (VHTR) has been selected as the principal concept for hydrogen production and other process-heat applications such as district heating and potable water production. On this basis, the DOE has selected the VHTR for additional R & D with the ultimate goal of demonstrating emission-free electricity and hydrogen production with this advanced reactor concept. One of the key passive safety features of the VHTR is the potential for decay heat removal by natural circulation of air in a Reactor Cavity Cooling System (RCCS). The air-cooled RCCS concept is notably similar to the Reactor Vessel Auxiliary Cooling System (RVACS) that was developed for the General Electric PRISM sodium-cooled fast reactor. As part of the DOE R & D program that supported the development of this fast reactor concept, the Natural Convection Shutdown Heat Removal Test Facility (NSTF) was developed at ANL to provide proof-of-concept data for the RVACS under prototypic natural convection flow, temperature, and heat flux conditions. Due to the similarity between RVACS and the RCCS, current VHTR R & D plans call for the utilization of the NSTF to provide RCCS model development and validation data, in addition to supporting design validation and optimization activities. Both air-cooled and water-cooled RCCS designs are to be included. In support of this effort, ANL has been tasked with the development of an engineering plan for mechanical and instrumentation modifications to NSTF to ensure that sufficiently detailed temperature, heat flux, velocity and turbulence profiles are obtained to adequately qualify the codes under the expected range of air-cooled RCCS flow conditions. Next year, similar work will be carried out for the alternative option of a water-cooled RCCS design. Analysis activities carried out in support of this experiment planning task have shown that: (a) in the RCCS, strong 3-D effects result in large heat flux, temperature, and heat transfer variations around the tube wall; (b) there is a large difference in the heat transfer coefficient predicted by turbulence models and heat transfer correlations, and this underscores the need of experimental work to validate the thermal performance of the RCCS; and (c) tests at the NSTF would embody all important fluid flow and heat transfer phenomena in the RCCS, in addition to covering the entire parameter ranges that characterize these phenomena. Additional supporting scaling study results are available in Reference 2. The purpose of this work is to develop a high-level engineering plan for mechanical and instrumentation modifications to NSTF in order to meet the following two technical objectives: (1) provide CFD and system-level code development and validation data for the RCCS under prototypic (full-scale) natural convection flow conditions, and (2) support RCCS design validation and optimization. As background for this work, the report begins by providing a summary of the original NSTF design and operational capabilities. Since the facility has not been actively utilized since the early 1990's, the next step is to assess the current facility status. With this background material in place, the data needs and requirements for the facility are then defined on the basis of supporting analysis activities. With the requirements for the facility established, appropriate mechanical and instrumentation modifications to NSTF are then developed in order to meet the overall project objectives. A cost and schedule for modifying the facility to satisfy the RCCS data needs is then provided.
Author:
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ISBN:
Category :
Languages : en
Pages :
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Book Description
The Very High Temperature gas cooled reactor (VHTR) is one of the GEN IV reactor concepts that have been proposed for thermochemical hydrogen production and other process-heat applications like coal gasification. The USDOE has selected the VHTR for further research and development, aiming to demonstrate emissions-free electricity and hydrogen production at a future time. One of the major safety advantages of the VHTR is the potential for passive decay heat removal by natural circulation of air in a Reactor Cavity Cooling System (RCCS). The air-side of the RCCS is very similar to the Reactor Vessel Auxiliary Cooling System (RVACS) that has been proposed for the PRISM reactor design. The design and safety analysis of the RVACS have been based on extensive analytical and experimental work performed at ANL. The Natural Convective Shutdown Heat Removal Test Facility (NSTF) at ANL that simulates at full scale the air-side of the RVACS was built to provide experimental support for the design and analysis of the PRISM RVACS system. The objective of this work is to demonstrate that the NSTF facility can be used to generate RCCS experimental data: to validate CFD and systems codes for the analysis of the RCCS; and to support the design and safety analysis of the RCCS.
Author: Wenxi Tian
Publisher: Frontiers Media SA
ISBN: 2832533264
Category : Technology & Engineering
Languages : en
Pages : 219
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Book Description
High fidelity nuclear reactor thermal hydraulic simulations are a hot research topic in the development of nuclear engineering technology. The three-dimensional Computational Fluid Dynamics (CFD) and Computational Multi-phase Fluid Dynamics (CMFD) methods have attracted significant attention in predicting single-phase and multi-phase flows under steady-state or transient scenarios in the field of nuclear reactor engineering. Compared with three-dimensional thermal hydraulic methods, the traditional one-dimensional system analysis method contains inherent defects in the required accuracy and spatial resolution for a number of important nuclear reactor thermal-hydraulic phenomena. At present the CFD method has been widely adopted in the nuclear industry, across both light water reactors and liquid metal cooled fast reactors, providing an effective solution for complex issues of thermal hydraulic analysis. However, the CFD method employs empirical models for turbulence simulation, heat transfer, multi-phase interaction and chemical reactions. Such models must be validated before they can be used with confidence in nuclear reactor applications. In addition, user practice guidelines play a critical role in achieving reliable results from CFD simulations.
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Category :
Languages : en
Pages :
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Book Description
The objective of this project is to study the fundamental physical phenomena in the reactor cavity cooling system (RCCS) of very high-temperature reactors (VHTRs). One of the primary design objectives is to assure that RCCS acts as an ultimate heat sink capable of maintaining thermal integrity of the fuel, vessel, and equipment within the reactor cavity for the entire spectrum of postulated accident scenarios. Since construction of full-scale experimental test facilities to study these phenomena is impractical, it is logical to expect that computational fluid dynamics (CFD) simulations will play a key role in the RCCS design process. An important question then arises: To what extent are conventional CFD codes able to accurately capture the most important flow phenomena, and how can they be modified to improve their quantitative predictions? Researchers are working to tackle this problem in two ways. First, in the experimental phase, the research team plans to design and construct an innovative platform that will provide a standard test setting for validating CFD codes proposed for the RCCS design. This capability will significantly advance the state of knowledge in both liquid-cooled and gas-cooled (e.g., sodium fast reactor) reactor technology. This work will also extend flow measurements to micro-scale levels not obtainable in large-scale test facilities, thereby revealing previously undetectable phenomena that will complement the existing infrastructure. Second, in the computational phase of this work, numerical simulation of the flow and temperature profiles will be performed using advanced turbulence models to simulate the complex conditions of flows in critical zones of the cavity. These models will be validated and verified so that they can be implemented into commercially available CFD codes. Ultimately, the results of these validation studies can then be used to enable a more accurate design and safety evaluation of systems in actual nuclear power applications (both during normal operation and accident scenarios).
Author: Afaque Shams
Publisher: Springer Nature
ISBN: 3031643623
Category :
Languages : en
Pages : 849
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Book Description
Author: Kurt D. Hamman
Publisher:
ISBN: 9781339321523
Category : Nuclear reactors
Languages : en
Pages : 412
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Book Description
Current research in advanced reactor designs has focused on passive safety systems, where in the event of a loss of cooling to the reactor core, excess heat will be removed by a passive safety heat removal system. A safety system is classified as 'passive' because it does not require a pump to circulate the fluid (i.e., forced circulation) or operator action to maintain cooling. The system relies on the natural circulation of a fluid (i.e., fluid density differences and gravity) to transfer the heat. Passive safety system designs include features that enhance natural circulation, such as using smooth pipes, minimizing flow obstructions, and maximizing density differences, which increase fluid velocity and hence the removal of more heat. This research consisted of a CFD study of wall-bounded transitional flows and a passive reactor cavity cooling system. Yet in an effort to better understand fundamental phenomena, relative to the limits of natural circulation turbulence modeling, only forced circulation CFD analyses were performed. The initial phase of this research consisted of two types of CFD studies: 2D entropy generation rate boundary layer analyses of an isothermal transitional fluid flow over a flat plate, and 3D thermal performance analyses of a 1/4-scale experimental air reactor cavity cooling system. The 2D flat plate boundary layer studies were important in that they provided insight into flow features, such as boundary layer development and entropy generation rate, in the 3D RCCS ducts as the air transitions from laminar to turbulent flow. Using the results of the initial study as a baseline, this work analyzed the viscous and thermal boundary layer development, including estimating the entropy generation rate, in the heated duct section of the RCCS, which is characterized by nonuniform flow and heat transfer. A new engineering design process was developed, which incorporates not only traditional heat transfer and fluid flow (HTFF) analysis techniques but entropy generation minimization (EGM) concepts as well. This analysis process was successfully applied to the existing 1/4-scale experimental air RCCS, resulting in the identification of the primary entropy dissipation mechanism and an improved design.
Author: Robin Elder
Publisher: John Wiley & Sons
ISBN: 9781860583537
Category : Science
Languages : en
Pages : 258
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Book Description
In the past Computational Fluid Dynamics (CFD) was confined to large organisations capable of developing and supporting their own codes. But recently there has been a rapid increase in the availability of reasonably priced commercial codes, and many more industrial organisations are now able to routinely use CFD. Advances of CFD in Fluid Machinery Design provide the perfect opportunity to find out what industry is doing and this book addresses how CFD is now being increasingly used in the design process, rather than as a post-design analysis tool. COMPLETE CONTENTS Trends in industrial use of CFD Challenges and methodologies in the design of axial flow fans for high-bypass-ratio, gas turbine engines using steady and unsteady CFD A three-dimensional inverse method based on pressure loading for the design of turbomachinery blades Application of CFD to the design and analysis of axial and centrifugal fans and compressors The design and performance of a transonic flow deswirling system – an application of current CFD design techniques tested against model and full-scale experiments Recent developments in unsteady flow modelling for turbomachinery aeroelasticity Computational investigation of flow in casing treatments for stall delay in axial flow fans Use of CFD for the three-dimensional hydrodynamic design of vertical diffuser pumps Recommendations to designers for CFD pump impeller and diffuser simulations Three dimensional CFD – a possibility to analyse piston pump flow dynamics CFD analysis of screw compressor performance Prediction of aerothermal phenomena in high-speed discstator systems Use of CFD in the design of a shaft seal for high-performance turbomachinery Users and potential users, of CFD for the design of fluid machinery, managers, designers, and researchers working in the field of ‘industrial flows’, will all find Advances of CFD in Fluid Machinery Design a valuable volume discussing state-of-the-art developments in CFD.
Author: Zied Driss
Publisher: Springer
ISBN: 3319709453
Category : Science
Languages : en
Pages : 208
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Book Description
This book focuses on CFD (Computational Fluid Dynamics) techniques and the recent developments and research works in thermo-mechanics applications. It is devoted to the publication of basic and applied studies broadly related to this area. The chapters present the development of numerical methods, computational techniques, and case studies in the thermo-mechanics applications. They offer the fundamental knowledge for using CFD in real thermo-mechanics applications and complex flow problems through new technical approaches. Also, they discuss the steps in the CFD process and provide benefits and issues when using the CFD analysis in understanding of complicated flow phenomena and its use in the design process. The best practices for reducing errors and uncertainties in CFD analysis are also discussed. The presented case studies and development approaches aim to provide the readers, such as engineers and PhD students, the fundamentals of CFD prior to embarking on any real simulation project. Additionally, engineers supporting or being supported by CFD analysts can benefit from this book.
Author: Zied Driss
Publisher: Springer
ISBN: 331970950X
Category : Technology & Engineering
Languages : en
Pages : 199
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Book Description
This book focuses on CFD (Computational Fluid Dynamics) techniques and the recent developments and research works in energy applications. It is devoted to the publication of basic and applied studies broadly related to this area. The chapters present the development of numerical methods, computational techniques, and case studies in the energy applications. Also, they offer the fundamental knowledge for using CFD in energy applications through new technical approaches. Besides, they describe the CFD process steps and provide benefits and issues for using CFD analysis in understanding the flow complicated phenomena and its use in the design process. The best practices for reducing errors and uncertainties in the CFD analysis are further described. The book reveals not only the recent advances and future research trends of CFD Techniques but also provides the reader with valuable information about energy applications. It aims to provide the readers, such as engineers and PhD students, with the fundamentals of CFD prior to embarking on any real simulation project. Additionally, engineers supporting or being supported by CFD analysts can take advantage from the information of the book’s different chapters.
