Download or read book Experimental Study of Two phase Flow and Heat Transfer During Vaporization Filmwise and Dropwise Condensation of Refrigerants and Steam Inside Small Diameter Channels written by Daniele Torresin and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Handbook of Thermal Science and Engineering written by and published by Springer. This book was released on 2018-07-31 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This Handbook provides researchers, faculty, design engineers in industrial R&D, and practicing engineers in the field concise treatments of advanced and more-recently established topics in thermal science and engineering, with an important emphasis on micro- and nanosystems, not covered in earlier references on applied thermal science, heat transfer or relevant aspects of mechanical/chemical engineering. Major sections address new developments in heat transfer, transport phenomena, single- and multiphase flows with energy transfer, thermal-bioengineering, thermal radiation, combined mode heat transfer, coupled heat and mass transfer, and energy systems. Energy transport at the macro-scale and micro/nano-scales is also included. The internationally recognized team of authors adopt a consistent and systematic approach and writing style, including ample cross reference among topics, offering readers a user-friendly knowledgebase greater than the sum of its parts, perfect for frequent consultation. The Handbook of Thermal Science and Engineering is ideal for academic and professional readers in the traditional and emerging areas of mechanical engineering, chemical engineering, aerospace engineering, bioengineering, electronics fabrication, energy, and manufacturing concerned with the influence thermal phenomena.
Download or read book Two Phase Heat Transfer written by Mirza Mohammed Shah and published by John Wiley & Sons. This book was released on 2021-03-04 with total page 388 pages. Available in PDF, EPUB and Kindle. Book excerpt: A guide to two-phase heat transfer theory, practice, and applications Designed primarily as a practical resource for design and development engineers, Two-Phase Heat Transfer contains the theories and methods of two-phase heat transfer that are solution oriented. Written in a clear and concise manner, the book includes information on physical phenomena, experimental data, theoretical solutions, and empirical correlations. A very wide range of real-world applications and formulas/correlations for them are presented. The two-phase heat transfer systems covered in the book include boiling, condensation, gas-liquid mixtures, and gas-solid mixtures. The authora noted expert in this fieldalso reviews the numerous applications of two-phase heat transfer such as heat exchangers in refrigeration and air conditioning, conventional and nuclear power generation, solar power plants, aeronautics, chemical processes, petroleum industry, and more. Special attention is given to heat exchangers using mini-channels which are being increasingly used in a variety of applications. This important book: Offers a practical guide to two-phase heat transfer Includes clear guidance for design professionals by identifying the best available predictive techniques Reviews the extensive literature on heat transfer in two-phase systems Presents information to aid in the design and analysis of heat exchangers. Written for students and research, design, and development engineers, Two-Phase Heat Transfer is a comprehensive volume that covers the theory, methods, and applications of two-phase heat transfer.
Download or read book Applied mechanics reviews written by and published by . This book was released on 1948 with total page 400 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Droplet Dynamics in Mini channel Steam Flow Condensation written by Chen, Xi and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Power plants are significant water users, accounting for 15% of water withdrawals worldwide. To reduce water usage, compact condensers are required to enable air-cooled condensers and reduce infrastructure costs. Steam flow condensation was studied in 0.952-mm and 1.82-mm hydraulic diameter mini-gaps in an open loop experimental apparatus. The apparatus was validated with single-phase flow. Flow condensation experiments were conducted for a wide range of steam mass fluxes (i.e., 35-100 kg/m2s) and qualities (i.e., 0.2-0.9) in hydrophilic copper and hydrophobic Teflon-coated channels. Water contact angles were 70° and 110° on copper and Teflon, respectively, and in general, filmwise condensation was the primary condensation mode in the hydrophilic channel and dropwise condensation was the primary mode observed in the hydrophobic channel. Pressure drops were reduced by 500́380% in the hydrophobic channels. Condensation heat transfer was enhanced by 200-350% in hydrophobic mini-gaps over hydrophilic mini-gap due to dropwise condensation. Droplet dynamics (e.g., nucleation, coalescence and departure) were quantified during dropwise condensation. A model was created which includes droplet adhesion and drag forces for droplet departure diameters which were then correlated to heat transfer coefficients. An overall mean absolute error of 9.6% was achieved without curve fitting. Noncondensable gases can reduce heat transfer in industrial systems, such as power plants due to the additional layer of thermal resistance from the gas. Condensing steam-nitrogen experiments were conducted for nitrogen mass fractions of 0-30%; the addition of nitrogen reduced heat transfer coefficients by up to 59% and 30% in hydrophilic and hydrophobic mini-gaps, respectively. It was found that during dropwise condensation, the noncondensable layer was perturbed by cyclical droplet motion, and therefore heat transfer coefficients were increased by 2-5 times compared with filmwise condensation of the same mass fraction of nitrogen.
Download or read book Handbook of Phase Change written by S.G. Kandlikar and published by Routledge. This book was released on 2019-01-22 with total page 786 pages. Available in PDF, EPUB and Kindle. Book excerpt: Provides a comprehensive coverage of the basic phenomena. It contains twenty-five chapters which cover different aspects of boiling and condensation. First the specific topic or phenomenon is described, followed by a brief survey of previous work, a phenomenological model based on current understanding, and finally a set of recommended design equa
Download or read book Heat Transfer Studies of Vapor Condensing at High Velocities in Small Straight Tubes written by Winthrop E. Hilding and published by . This book was released on 1964 with total page 148 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book An Analytical and Experimental Study of the Two phase Flow of a High Velocity Vapor Condensing in a Tube written by United States. National Aeronautics and Space Administration and published by . This book was released on 1967 with total page 364 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book An Analytical and Experimental Study of the Two phase Flow of a High Velocity Vapor Condensing in a Tube written by Winthrop Edward Hilding and published by . This book was released on 1968 with total page 364 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Annular Two Phase Flow written by Geoffrey Hewitt and published by Elsevier. This book was released on 2013-10-22 with total page 327 pages. Available in PDF, EPUB and Kindle. Book excerpt: Annular Two-Phase Flow presents the wide range of industrial applications of annular two-phase flow regimes. This book discusses the fluid dynamics and heat transfer aspects of the flow pattern. Organized into 12 chapters, this book begins with an overview of the classification of the various types of interface distribution observed in practice. This text then examines the various regimes of two-phase flow with emphasis on the regions of occurrence of the annular flow regime. Other chapters consider the single momentum and energy balances, which illustrate the differences and analogies between single- and two-phase flows. This book discusses as well the simple modes for annular flow with consideration to the calculation of the profile of shear stress in the liquid film. The final chapter deals with the techniques that are developed for the measurement of flow pattern, entrainment, and film thickness. This book is a valuable resource for chemical engineers.
Download or read book Encyclopedia of Two phase Heat Transfer and Flow Special topics in condensation written by John R. Thome and published by . This book was released on 2016 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Flow Regime Transitions During Condensation in Microchannels written by Gaurav Nema and published by . This book was released on 2008 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Microchannel heat exchangers are widely used in air-conditioning and refrigeration systems, high heat flux electronics cooling, and are also being considered for biological devices. Heat transfer and pressure drop in microchannels with single-phase flow have been studied in greater detail compared to two-phase flow. Heat transfer and pressure drop in two-phase flow inside tubes are closely related to the structure of the flow. In convective condensation, the fluid flows in a variety of flow regimes as it changes from vapor to liquid. The flow patterns formed in microchannels differ in type and extent from those seen in conventional tubes. Wavy and stratified flows are virtually absent at microchannel dimension, while intermittent and annular flows predominate. The subject research focuses on understanding the flow physics in microchannels during condensation. The extensive condensation flow-regime database of a previous study is employed for this purpose. This database comprises the flow-regime observations in tubes of hydraulic diameter ranging from 1-4.91 mm during condensation of refrigerant R-134a. The mass flux ranges from 150-750 kg/m2-s over a vapor quality range of 0 to 1. The results from this previous experimental study are used to understand the physical mechanisms and the governing influences for each of the identified flow regimes. Using this understanding and data, criteria for transitions between the different regimes have been developed. These criteria developed in non-dimensional form can be utilized to identify the flow regimes and transitions for various fluids, operating conditions and channel sizes, thereby generalizing the applicability of these results. This mechanistic determination of condensation flow regimes in different operating conditions and geometries will assist in the choice of the appropriate models for the evaluation of heat transfer and pressure drop, and therefore enable the development of optimum microchannel heat exchangers.
Download or read book The Engineering Index Annual written by and published by . This book was released on 1992 with total page 2264 pages. Available in PDF, EPUB and Kindle. Book excerpt: Since its creation in 1884, Engineering Index has covered virtually every major engineering innovation from around the world. It serves as the historical record of virtually every major engineering innovation of the 20th century. Recent content is a vital resource for current awareness, new production information, technological forecasting and competitive intelligence. The world?s most comprehensive interdisciplinary engineering database, Engineering Index contains over 10.7 million records. Each year, over 500,000 new abstracts are added from over 5,000 scholarly journals, trade magazines, and conference proceedings. Coverage spans over 175 engineering disciplines from over 80 countries. Updated weekly.
Download or read book Pressure Drop and Heat Transfer Study of Two phase Flow in Small Channels written by Thanh Nhon Tran and published by . This book was released on 1998 with total page 452 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Void Fraction Pressure Drop and Heat Transfer in High Pressure Condensing Flows Through Microchannels written by Brendon Louis Keinath and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Flow mechanisms affect transport processes during condensation. Most studies on two-phase flow regimes are qualitative in nature, typically providing only information to guide the identification of the respective regimes and the transitions between them. These studies have, however, not yielded quantitative information to assist the development of pressure drop and heat transfer models. Such qualitative studies have also yielded results with considerable variability between investigators. A comprehensive investigation of flow mechanisms, void fraction, pressure drop and heat transfer during condensation of R404A in microchannels was conducted. In contrast to all prior investigations, high-speed video recordings and image analyses were used to directly measure void fraction, slug frequencies, vapor bubble velocity, vapor bubble dimensions and liquid film thicknesses in tube diameters ranging from 0.508 to 3.00 mm. Experiments were conducted at reduced pressures and mass fluxes ranging from 0.38 to 0.77 and 200 to 800 kg m-2 s-1, respectively, to document their influences on the condensation process at local vapor qualities ranging from 0 to 1. This information was used to develop a model for the void fraction in condensing flows. A complementing set of heat transfer and pressure drop measurements were conducted on the same geometries at similar conditions, and the void fraction model was used in conjunction with these measurements to develop improved heat transfer and pressure drop models. This comprehensive set of experiments and analyses yields a self-consistent and accurate treatment of high-pressure condensation in small hydraulic diameter geometries. Furthermore, the heat transfer model was found to agree well with condensing ammonia and carbon dioxide data that were obtained at significantly different conditions in different tube diameters. The added physical understanding of the condensation process and the models developed will serve as important building blocks for the design of microscale condensers and thermal systems.
Download or read book Fluid Mechanics Heat Transfer and Mass Transfer written by K. S. Raju and published by John Wiley & Sons. This book was released on 2011-04-20 with total page 1422 pages. Available in PDF, EPUB and Kindle. Book excerpt: This broad-based book covers the three major areas of Chemical Engineering. Most of the books in the market involve one of the individual areas, namely, Fluid Mechanics, Heat Transfer or Mass Transfer, rather than all the three. This book presents this material in a single source. This avoids the user having to refer to a number of books to obtain information. Most published books covering all the three areas in a single source emphasize theory rather than practical issues. This book is written with emphasis on practice with brief theoretical concepts in the form of questions and answers, not adopting stereo-typed question-answer approach practiced in certain books in the market, bridging the two areas of theory and practice with respect to the core areas of chemical engineering. Most parts of the book are easily understandable by those who are not experts in the field. Fluid Mechanics chapters include basics on non-Newtonian systems which, for instance find importance in polymer and food processing, flow through piping, flow measurement, pumps, mixing technology and fluidization and two phase flow. For example it covers types of pumps and valves, membranes and areas of their use, different equipment commonly used in chemical industry and their merits and drawbacks. Heat Transfer chapters cover the basics involved in conduction, convection and radiation, with emphasis on insulation, heat exchangers, evaporators, condensers, reboilers and fired heaters. Design methods, performance, operational issues and maintenance problems are highlighted. Topics such as heat pipes, heat pumps, heat tracing, steam traps, refrigeration, cooling of electronic devices, NOx control find place in the book. Mass transfer chapters cover basics such as diffusion, theories, analogies, mass transfer coefficients and mass transfer with chemical reaction, equipment such as tray and packed columns, column internals including structural packings, design, operational and installation issues, drums and separators are discussed in good detail. Absorption, distillation, extraction and leaching with applications and design methods, including emerging practices involving Divided Wall and Petluk column arrangements, multicomponent separations, supercritical solvent extraction find place in the book.
Download or read book A Study on Heat Transfer in Dropwise Condensation written by Sanjay Adhikari and published by . This book was released on 2020 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Dropwise condensation (DWC) is a high intensity heat transfer phenomenon, with heat fluxes up to an order of magnitude higher than in filmwise condensation. Many industrial applications like desalination, thermal management, power generation and fog water harvesting may benefit from employing DWC. Considerable work has been done in this field and yet there are some challenges which remain open for research and further investigation. High resolution numerical studies that capture the complex hydrodynamics of larger droplets as they coalesce and move on the surface, effectively refreshing it for renucleation, have still not been realized as the drop size distribution spans six orders of magnitude. A new Volume of Fluid (VOF) based multi-scale approach, which resolves the grid scale larger droplets O(50 [mu]m) and models the heat transfer for the subgrid scale smaller droplets, is proposed in this dissertation. To supplement this approach, heat transfer models for individual droplets (Chapter 1) and droplet interaction (Chapter 2) are presented. Modeling work described in chapter 2 also solves many challenges associated with resolving grid scale droplets in VOF simulations. The proposed multi-scale approach also requires a transient heat transfer closure model for the subgrid scale droplets. Experimental studies have so far focused only on the steady state behavior of DWC. The startup period is still not well understood. Transient phenomena in DWC startup may significantly affect the performance of proposed applications like vapor chambers subjected to pulsed heat fluxes, or refrigeration cycles operating intermittently. This dissertation provides first characterization of fast transients during startup (chapter 4). A unique experimental facility and instrumentation are developed for measurements. Inverse numerical methods are employed to extract data (q" and HTC) from these measurements. Three distinct phases during DWC startup have been identified, which further highlight the importance of characterizing this period. The experimental data can be coupled with the numerical work described in this dissertation to formulate a robust, widely applicable simulation framework.
