Design Fabrication Testing And Modeling Of A High Temperature Printed Circuit Heat Exchanger
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Design Fabrication Testing And Modeling Of A High Temperature Printed Circuit Heat Exchanger
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Author : Minghui Chen
language : en
Publisher:
Release Date : 2015
Design Fabrication Testing And Modeling Of A High Temperature Printed Circuit Heat Exchanger written by Minghui Chen and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2015 with categories.
One of the very-high-temperature reactor (VHTR) missions is to produce electricity and/or to provide process heat for applications with high efficiency. The electricity generation or process heat applications of these advanced reactors greatly rely on an effective intermediate heat exchanger (IHX) that transfers heat from the primary fluid (i.e., helium) to the secondary fluid, which can be helium, molten salt, water/steam, or supercritical carbon dioxide. The IHX performance is directly related to the efficiency and safety of the overall nuclear system. A printed circuit heat exchanger (PCHE) is one of the leading IHX candidates due to its high effectiveness and compactness, as well as its robustness. In the current study, a scaled-down PCHE was fabricated using Alloy 617 plates and Alloy 800H headers. The PCHE fabrication processes, i.e., photochemical etching, diffusion bonding and brazing, are described. This PCHE has eight hot and eight cold plates with 11 semicircular wavy (zigzag) channels in each plate with the following channel dimensions: 1.2 mm hydraulic diameter, 24.6 mm pitch in the flow (stream-wise) direction, 2.5 mm pitch in the span-wise direction, and 15o wavy pitch angle. The thermal-hydraulic performance of the PCHE is investigated experimentally in the high-temperature helium test facility (HTHF) at The Ohio State University. The PCHE inlet temperatures and pressures are varied up to 350 oC/2 MPa for the cold side and 700 oC/2 MPa for the hot side, respectively, while the maximum mass flow rate of helium reaches 30 kg/h. The corresponding maximum channel Reynolds number for both the hot and cold sides is about 3,000, including the laminar flow and laminar-to-turbulent transitional flow regimes. Comparisons between the obtained experimental data and available empirical correlations in the literature have been carried out. Both hot-side and cold-side friction characteristics of the PCHE with the wavy channels follow the trend established in the empirical model well, while large deviation is presented in the low Reynolds number region. Heat transfer characteristics obtained from model available in the literature show a discrepancy from the experimental results. Large deviation appears in the low Reynolds number region as well. A new heat transfer correlation based on experimental data has been subsequently proposed for the current wavy-channel PCHE. Finally, transients that involve variations of the mass flow rate and temperature on the hot and cold sides of the scaled-down PCHE are investigated by numerical method. A dynamic model has been verified using a commercial software DYNSIM and validated using the experimental data. The model predicts the dynamic trends well and is available for use in the future.
Numerical Modeling And Performance Analysis Of Printed Circuit Heat Exchanger For Very High Temperature Reactors
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Author : Justin T. Figley
language : en
Publisher:
Release Date : 2009
Numerical Modeling And Performance Analysis Of Printed Circuit Heat Exchanger For Very High Temperature Reactors written by Justin T. Figley and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2009 with Heat exchangers categories.
Abstract: Very High Temperature Reactors (VHTRs) operate at high temperatures (1,173-1,223 K) and require intermediate heat exchangers to transfer thermal energy to a hydrogen production plant or power conversion system. A promising plate-type compact heat exchanger for these applications is the Printed Circuit Heat Exchanger (PCHE). The objective of this study is to numerically model an Alloy 617 PCHE core with Helium as the working fluid using Fluent(TM)computational fluid dynamics software. The PCHE dimensions and operating conditions are those of a high-temperature helium test facility under construction at The Ohio State University. The test conditions considered are based upon the nominal design conditions of the test facility: operating pressure up to 3 MPa, mass flow rates of 10 to 80 kg/h, and hot and cold side inlet temperatures of 1,173 and 813 K, respectively. These operating conditions correspond to laminar and laminar-to-turbulent transitional flows within the fluid passages of the PCHEs being fabricated and modeled. The overall heat transfer coefficient ranges from 563-1697 W/m2K. The maximum effectiveness achieved is 85%. The maximum pressure drop of this PCHE is found to be approximately 1.5% of the operating pressure. The thermal duty of the heat exchanger ranges from 4.45 to 28.73 kW. The critical Reynolds number is found to be approximately 2800 for the semicircular channel as opposed to 2300 for a circular channel. CFD simulations carried out for laminar flow operating conditions are within good agreement with the predictions made using published correlations and empirical data. CFD simulations carried out for low Reynolds number laminar-to-turbulent transition cases are not accurately predicted by the correlations recommended in the published literature.
Numerical Modeling Of A Printed Circuit Heat Exchanger Based On Experimental Results From The High Temperature Helium Test Facility
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Author : Kevin R. Wegman
language : en
Publisher:
Release Date : 2016
Numerical Modeling Of A Printed Circuit Heat Exchanger Based On Experimental Results From The High Temperature Helium Test Facility written by Kevin R. Wegman and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2016 with categories.
The U.S. Department of Energy’s Generation IV Program has identified six advanced reactor technologies to be investigated for possible deployment in both energy and process heat generation. Most of these reactor concepts, such as the Very-High-Temperature Reactor (VHTR) and the Molten Salt Reactor (MSR), operate at high temperatures and/or pressures, requiring intermediate heat exchangers (IHXs) to transfer heat from the primary loop to secondary and tertiary loops. The VHTR has a design core outlet temperature of up to 1000 °C, and thus a robust high temperature IHX is required for full VHTR technology maturity. One such candidate for the IHX in these advanced reactors is the printed circuit heat exchanger (PCHE). The PCHE has an extremely high effectiveness and compactness, and the fabrication methods lead to great robustness as well. In this study, numerical simulations using a commercial code, COMSOL Multiphysics, were investigated and compared to the experimental results obtained from straight channel PCHE testing at the High-Temperature Helium test Facility (HTHF) at The Ohio State University (OSU). A post-machining analysis was completed for the frontal face geometry of the PCHE flow channels, and the results were compared to the nominal geometric values. The actual channel diameter was found to be 2.04±0.12 mm, compared to the nominal value of 2.0 mm, and the actual channel height was found to be 0.9±0.11 mm, compared to the nominal value of 1.0 mm. These new values were tested in the numerical model geometry as well as the nominal values. Three model were created for numerical investigation of the experimental results; a two-channel model, a two-plate model and a full-geometry model. A grid sensitivity study was completed for the two-channel model using a laminar flow model. Results were obtained for the two-channel model and was compared to the results obtained in the experiment. The heat transfer characteristics were over predicted in the numerical results, while the numerical pressure drops predicted the experimental values well. Preliminary results using a coarsened mesh were obtained for the two-plate and full-geometry model. A methodology for calculations of local friction factor and Nusselt number effects from numerical data is presented, and the resulting analyses are discussed. The globally calculated values are compared to the locally calculated values. The global and locally calculated results do not always match, explained by numerical errors related to the use of differentials for first ordered mesh cell elements.
Design Fabrication Performance Testing And Modeling Of Diffusion Bonded Compact Heat Exchangers In A High Temperature Helium Test Facility
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Author : Sai Kiran Mylavarapu
language : en
Publisher:
Release Date : 2011
Design Fabrication Performance Testing And Modeling Of Diffusion Bonded Compact Heat Exchangers In A High Temperature Helium Test Facility written by Sai Kiran Mylavarapu and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2011 with categories.
PCHEs are plate-type heat exchangers, fabricated by photochemical machining and diffusion bonding. In the current research work, both these fabrication techniques have been demonstrated on Alloy 617 plates, a high-temperature candidate material for VHTR structural components. Two counter-current flow PCHEs have been designed and fabricated using Alloy 617 plates and are installed in a small-scale high-temperature helium test facility (HTHF). The HTHF has been designed and constructed at The Ohio State University as part of this research to facilitate experiments at temperatures and pressures up to 800oC and 3 MPa, respectively.
Development Of Compact Heat Exchangers For Very High Temperature Gas Cooled Reactors
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Author : Sai K. Mylavarapu
language : en
Publisher:
Release Date : 2008
Development Of Compact Heat Exchangers For Very High Temperature Gas Cooled Reactors written by Sai K. Mylavarapu and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2008 with Gas cooled reactors categories.
Abstract: The U.S. Department of Energy's Generation IV Program has generated considerable interest for High-Temperature Gas-Cooled Reactors (HTGR), in particular, the Very-High-Temperature Reactor (VHTR). VHTR is one of the six reactor concepts selected by the Generation IV International Forum and is anticipated to be reactor type for the Next Generation Nuclear Plant (NGNP). The VHTR concept, with a projected plant design service life of 60 years, is being actively researched not only due to its near-term deployment potential but also because it offers a broad range of process heat applications ranging from electricity generation to hydrogen co-generation. To efficiently and reliably transfer the thermal output from the reactor core, VHTRs require high temperature (900-950 0C) and high integrity heat exchangers with high effectiveness during normal and off-normal conditions. A class of compact plate-type heat exchangers, namely, Printed Circuit Heat Exchangers (PCHEs), made of high-temperature materials and found to have these above characteristics are being increasingly pursued for heavy duty applications. The current thesis work is a part of a larger research project aimed at investigating the design, fabrication, testing, modeling, and optimization of PCHEs at operating temperatures proposed to be realized in VHTRs. In the present work, two PCHEs were designed and fabricated. In addition, a detailed design of a high-temperature helium test facility to test the thermal-hydraulic performance of these PCHEs was completed. Owing to the high operating temperatures and pressures, a detailed investigation on various high-temperature materials was carried out to aid in the design of the test facility and the heat exchangers. The study showed that Alloys 617 and 230 are the leading candidate materials for high-temperature applications. However, economics and material availability in the required form dictated the final design operating conditions. The helium test facility is of Alloy 800HT construction and is currently being constructed at The Ohio State University. It is intended to facilitate experiments at operating temperatures and pressures up to 900 0C and 3 MPa, respectively. Two PCHEs, each having 10 hot and 10 cold plates with 12 channels in each plate, were fabricated using Alloy 617 plates. In addition, the processes related to the fabrication of PCHEs, namely photochemical machining and diffusion bonding techniques were investigated and successfully established for Alloy 617 plates. The PCHEs will be tested in the helium test facility for their heat transfer and pressure drop characteristics at various operating temperatures and pressures. The experimental database generated from the test facility will then be used for model development and computer code validation. In summary, the current thesis focuses on the study of the high-temperature materials, design of the helium test facility, design, development, and fabrication of the high-temperature PCHEs.
Compact Heat Exchangers
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Author : C. Ranganayakulu
language : en
Publisher: John Wiley & Sons
Release Date : 2018-02-02
Compact Heat Exchangers written by C. Ranganayakulu and has been published by John Wiley & Sons this book supported file pdf, txt, epub, kindle and other format this book has been release on 2018-02-02 with Technology & Engineering categories.
A comprehensive source of generalized design data for most widely used fin surfaces in CHEs Compact Heat Exchanger Analysis, Design and Optimization: FEM and CFD Approach brings new concepts of design data generation numerically (which is more cost effective than generic design data) and can be used by design and practicing engineers more effectively. The numerical methods/techniques are introduced for estimation of performance deteriorations like flow non-uniformity, temperature non-uniformity, and longitudinal heat conduction effects using FEM in CHE unit level and Colburn j factors and Fanning friction f factors data generation method for various types of CHE fins using CFD. In addition, worked examples for single and two-phase flow CHEs are provided and the complete qualification tests are given for CHEs use in aerospace applications. Chapters cover: Basic Heat Transfer; Compact Heat Exchangers; Fundamentals of Finite Element and Finite Volume Methods; Finite Element Analysis of Compact Heat Exchangers; Generation of Design Data by CFD Analysis; Thermal and Mechanical Design of Compact Heat Exchanger; and Manufacturing and Qualification Testing of Compact Heat Exchanger. Provides complete information about basic design of Compact Heat Exchangers Design and data generation is based on numerical techniques such as FEM and CFD methods rather than experimental or analytical ones Intricate design aspects included, covering complete cycle of design, manufacturing, and qualification of a Compact Heat Exchanger Appendices on basic essential fluid properties, metal characteristics, and derivation of Fourier series mathematical equation Compact Heat Exchanger Analysis, Design and Optimization: FEM and CFD Approach is ideal for senior undergraduate and graduate students studying equipment design and heat exchanger design.
Thermohydraulic And Mechanical Modeling Of Printed Circuit Heat Exchangers For Next Generation Nuclear Service
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Author : Ian William Jentz
language : en
Publisher:
Release Date : 2021
Thermohydraulic And Mechanical Modeling Of Printed Circuit Heat Exchangers For Next Generation Nuclear Service written by Ian William Jentz and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2021 with categories.
In this work an approach to thermodyraulic and mechanical modeling of a full 3-dimensional Printed Circuit Heat Exchanger is presented. A new approach to Finite Element analysis of the fluid and structure using homogenization of micro-channel behavior is developed. The accuracy of the thermohydrualic model is verified against experiment for a large range of flow conditions. Using the results from the thermohydraulic model as input to the mechanical FE model allows loading and stress within the PCHE to by resolved. Coupling of the thermodynamic and mechanical models allows the performance and mechanical integrity of all parts of the PCHE to be evaluated simultaneously. Motivation for using airfoil PCHEs in s-CO2 applications is given and the design of PCHEs are briefly discussed. A thermohydraulic model using a homogenized heat exchanger thermohydraulics (HHXT) approach has been developed for PCHE applications. The HHXT model provides a fully resolved PCHE model without the complexity inherent in resolving all facets of the micro-channel geometry throughout the core. The HHXT approach expands on previous work by Urquiza in homogenizing the PCHE micro-channel core as an anisotropic media. Flow distribution in the PCHE is determined using a porous media approach. Heat transfer between fluids is modeled using heat transfer coefficients and is coupled to a conduction model of the solid PCHE body. The Homogenized Heatexchanger Thermohydraulics model properly resolves American Society of Mechanical Engineers Boiler and Pressure Vessel Code (BPVC) Sec-3 loading conditions without the complexity inherent in resolving all facets of the PCHE geometry. The accuracy of the model is verified through experimental validation. A purpose designed zig-zag channel test PCHE was tested over a wide range of flow, using 60 separate tests with Reynolds number ranging from 1,790 to 64,200. Embedded fiber-optic temperature sensors measured 2-dimensional temperature distribution within the test recuperator. Along with measurement of inlet and outlet conditions, the internal temperature measurements provide 7,542 distributed measurements for each flow rate tested. This allowed the verification of HHXT against a large set of data. Combined modelling and measurement allowed for better insight into PCHE performance. The interaction of side entrance and transition regions could be resolved. Flow redistribution within the cold CO2 of the zig-zag PCHE was found to be a major factor in the distribution of temperature. Mechanical analysis per BPVC section III design by analysis rules is demonstrated. Linearized stress analysis was used to break the stress within micro-channel walls into membrane and bending components needed in BPVC stress intensity calculations. A homogenized approach to modeling mechanical loads in the full 3-dimensional PCHE is used. The method consisted of separate micro-channel structure and PCHE structure analyses. The resulting model resolved pressurization and thermal stresses within the zig-zag test PCHE. Stress intensities within 108,000 distinct micro-channel walls could be determined. Thermal stress arising from the differential expansion of the PCHE body was found to contribute the most stress. The zig-zag test PCHE meets BPVC section III stress intensity limits at design operating conditions. Additionally the measurement of airfoil micro-channel heat transfer and hydraulic performance is made. As direct internal measurement of bulk CO2 or fluid-wall temperatures within the channels of the airfoil PCHE is not possible, convective heat transfer is calculated from inlet and outlet CO2 conditions and simple models of heat transfer within the recuperator. Since CO2 properties changed over the length of the recuperator, a 1D discrete model of the recuperator for calculating localized values of j and f is presented.
Heat Exchangers
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Author : S. M. Sohel Murshed
language : en
Publisher: BoD – Books on Demand
Release Date : 2017-04-27
Heat Exchangers written by S. M. Sohel Murshed and has been published by BoD – Books on Demand this book supported file pdf, txt, epub, kindle and other format this book has been release on 2017-04-27 with Technology & Engineering categories.
Presenting contributions from renowned experts in the field, this book covers research and development in fundamental areas of heat exchangers, which include: design and theoretical development, experiments, numerical modeling and simulations. This book is intended to be a useful reference source and guide to researchers, postgraduate students, and engineers in the fields of heat exchangers, cooling, and thermal management.
Exploratory Development Of High Temperature Heat Exchangers
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Author : O. A. Buchmann
language : en
Publisher:
Release Date : 1966
Exploratory Development Of High Temperature Heat Exchangers written by O. A. Buchmann and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1966 with categories.
The objective of this program is to establish and verify design concepts for heat exchangers that process air at temperatures that are considerably in excess of the melting points of conventional, or practical, heat exchanger materials. All design and fabrication associated with the program will be based on the use of uncoated L-605, operating at a maximum metal temperature of 1800 F. The approach being used in the program involves (1) definition and layout of a reference design using the operating requirements for a fullscale heat exchanger, (2) experimental verification of the structural, manufacturing, and performance features of this design, and (3) design, fabrication, and testing of a small-scale heat exchanger that incorporates the characteristic features of the reference design. This report represents the work accomplished in (1) fabrication of the test heat exchanger components, (2) test heat exchanger design, and (3) test planning. The coolant header insert design and coolant pressure drop summary are included. Included is the performance of the test heat exchanger with air substituted for hydrogen as the coolant. The fabrication of the test heat exchanger components is discussed. (Author).
Fundamentals Of Heat Exchanger Design
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Author : Dusan P. Sekulic
language : en
Publisher: John Wiley & Sons
Release Date : 2023-12-07
Fundamentals Of Heat Exchanger Design written by Dusan P. Sekulic and has been published by John Wiley & Sons this book supported file pdf, txt, epub, kindle and other format this book has been release on 2023-12-07 with Technology & Engineering categories.
Fundamentals of Heat Exchanger Design, Second Edition builds upon the widely-used First Edition, a text often considered to be the most prominent single-volume heat exchanger text on the market. The new and improved Second Edition serves as an equally comprehensive resource, updated to suit the latest technologies and design methods being used in the Heat Exchanger field. Written by First-Edition author Dusan P. Sekulic, this text addresses the latest developments in the industry, including a brand-new chapter on the manufacturing of compact heat exchangers. After opening with a basic introduction to heat exchanger types and design methods, the book goes on to cover more specialized topics such as such as the design of recuperators and regenerators, pressure drop analysis, geometric properties, flow friction, fouling and corrosion, and more. With many significant revisions throughout, this new edition offers more streamlined content while maintaining the consistent, detailed coverage of the fundamentals of the topic that readers appreciated in the First Edition. These unique features position the Second Edition of Fundamentals of Heat Exchanger Design as the ideal text for both engineering professionals and advanced students alike.