Download or read book Design and Fabrication of an Internal Condensation Loop for Effectiveness and Robustness Testing of Nanostructured Superhydrophobic Steam Condenser written by Dhananjai V. Saranadhi and published by . This book was released on 2014 with total page 47 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Rankine cycle is at the heart of steam-electric power stations, which are responsible for generating about 90% of the world's electricity. Improving the efficiency of the cycle thus of great importance, and the greatest possible gain lies in improving the condensation process. Industrial condensers feature once-through water cooling, and the substantial amount of water they consume coupled with the increasing scarcity of freshwater supplies provides further motivation to focus on the condensation process. Condensation in these systems occurs predominantly via the filmwise mechanism, in which a thin film of water forms upon the condensing surface, adversely affecting its heat transfer abilities. However, forming a nanostructure and adding certain hydrophobic coatings on the heat exchanging surface of the condenser can render them superhydrophobic. This causes condensation to instead occur via the jumping droplet mechanism, which promises drastically improved heat exchanging performance. This thesis discusses the design and fabrication of an internal condensation loop which will allow us to test the heat transfer, fluid dynamic performance of the novel jumping droplet internal mode, and the durability and robustness of various hydrophobic coatings at the lab scale.

Download or read book Characterization of the Robustness of Superhydrophobic Surfaces During Condensation written by Emmanuel E. Simpri and published by . This book was released on 2016 with total page 30 pages. Available in PDF, EPUB and Kindle. Book excerpt: Condensation is a process utilized by about 85% of power plants in their power generation cycles. Superhydrophobic surfaces can potentially improve the heat transfer due to condensation when compared to the untreated surfaces typically used in condensers. This can improve the efficiency of power plants by up to 3%. These surfaces are made by combining nanoscale roughness with chemical hydrophobicity, and can promote the mode of condensation that has the least resistance to heat transfer. However, it is unclear how long these surfaces will last under industrial conditions. This thesis is focused on testing the robustness of the surfaces in multiple experiments and analyzing the data gathered from these experiments, along with theorizing the mechanism behind any surface functionality deterioration that may be seen. Hydrophobic and superhydrophobic surface samples that have been prepared previously were subjected to water immersion and continuous condensation tests. For the water immersion tests, samples were submerged in water under neutral (pH = 7) and basic (pH = 10) conditions at room (~25°C) and elevated (~50°C) temperatures. The continuous condensations tests were run at a steam temperature of 27°C as well as 100°C. To understand the change in surface properties over the duration of the tests, the surface contact angle was chosen as the metric to be measured. The contact angles of water droplets on the samples were taken beforehand and throughout the tests using a micro-goniometer in order to quantify the change in surface functionality. The data gathered from these experiments were processed in Matlab to produce plots of the change in contact angle over the duration of each test. These plots showed significant contact angle decreases for the hydrophobic surfaces but little change in the contact angle for the superhydrophobic surfaces. This suggests that the addition of nanostructures on the surface, and thus the promotion of super- hydrophobicity, inhibits the surface functionality deterioration mechanism that is seen with the hydrophobic surfaces.

Download or read book The Steam and Condensate Loop written by and published by . This book was released on 2008 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Condensation and Condenser Design written by J. Taborek and published by American Society of Mechanical Engineers. This book was released on 1993 with total page 624 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Steam and Condensate Loop written by Spirax-Sarco Limited and published by . This book was released on 2007 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Steam and Condensate Loop written by Spirax-Sarco (Gloucestershire). and published by . This book was released on 2008 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Theoretical and Experimental Investigation of Condensation on Amphiphilic Nanostructured Surfaces written by David Milton Anderson and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Condensation of water vapor is an everyday phenomenon which plays an important role in power generation schemes, desalination applications and high-heat flux cooling of power electronic devices. Continuous dropwise condensation is a desirable mode of condensation in which small, highly-spherical droplets regularly form and shed off the surface before a thick liquid is formed, thereby minimizing the thermal resistance to heat transfer across the condensate layer. While difficult to induce and sustain, dropwise condensation has been shown to achieve heat and mass transfer coefficients over an order of magnitude higher than its filmwise counterpart. Superhydrophobic surfaces have been extensively studied to promote dropwise condensation with mixed results; often surfaces that are superhydrophobic to deposited droplets formed in the gas phase above the surface do not retain this behavior with condensed droplets nucleated and grown on the surface. Recently, nanostructured superhydrophobic surfaces have been developed that are robust to vapor condensation; however, these surfaces still are not ideal for condensation heat transfer due to the high thermal resistance of the vapor layer trapped underneath the droplets and the reduced footprint of direct contact between the highly-spherical droplets and the underlying substrate. This work has two main objectives. First, a comprehensive free energy based thermodynamic model is developed to better understand why traditional superhydrophobic surfaces often lose their properties when exposed to condensed droplets. The model is first validated using data from the existing literature and then extended to analyze the suitability of amphiphilic (e.g. part hydrophobic and part hydrophilic) nanostructured surfaces for condensation applications. Secondly, one of the promising amphiphilic surfaces identified by the thermodynamic model is fabricated and tested to observe condensation dynamic behavior. Two complementary visualization techniques, environmental scanning electron microscopy (ESEM) and optical (light) microscopy, are used to probe the condensation behavior and compare the performance to that of a traditional superhydrophobic surface. Observations from the condensation experiments are used to propose a new mechanism of coalescence that governs the temporal droplet size distribution on the amphiphilic nanostructured surface and continually generates fresh sites for the droplet nucleation and growth cycle that is most efficient at heat transfer.

Download or read book Condensation Heat Transfer on Nanoengineered Surfaces written by Adam Taylor Paxson and published by . This book was released on 2011 with total page 74 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis presents a series of three related studies with the aim of developing a surface that promotes robust dropwise condensation. Due to their remarkably low droplet adhesion, superhydrophobic surfaces were investigated for application to dropwise condensation. Although precise model superhydrophobic surfaces were necessary to gain insight into these phenomena, it was recognized that wide-scale implementation necessitates a surface that can be mass-produced at an industrial scale. To this end, anodized metal oxide surfaces were pursued as candidate condenser materials. First, a study was performed to determine the precise conditions leading to the transition between wetting and non-wetting states. By depositing pendant drops of various sizes on a superhydrophobic surface and observing their wetting behavior, a hitherto unknown mechanism for wetting transition is reported. A new phase diagram was developed which shows that both large and small droplet can transition to wetted states due to the new deceleration-driven and the previously-known Laplace mechanisms. It is shown that the attainment of a non-wetted superhydrophobic state is more restrictive than previously thought. Second, we investigate the large-scale fabrication of superhydrophobic surfaces via two different methods: solvent-induced crystallization of a thermoplastic polymer, and anodic oxidation of aluminum. Although the polymer surface as not able to withstand the high temperatures seen during condensation, the applicability of the anodized metal surface to dropwise condensation was further investigated. Third, to replicate the conditions of a typical power plant or desalination plant, an apparatus was constructed that condenses steam at pressures below 1 atm. It employs a vacuum chamber in which a surface is exposed to saturated steam at various pressures. The rig design and operating principles are explained, and the results of condensation tests on superhydrophobic anodized metal oxide surfaces are presented. It was found that although the metal oxide surfaces were able to resist wetting of macroscale droplets, they suffered from non-preferential nucleation and droplet growth. This led to the eventual growth of a macroscale Wenzel droplet, which proved to be difficult to shed from the surface.

Download or read book Design and Testing of Equipment to Study the Condensation of Steam on a Horizontal Rotating Cylinder written by Anthony F. Szwarc and published by . This book was released on 1964 with total page 144 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Proceedings of the 6th International Conference and Exhibition on Sustainable Energy and Advanced Materials written by Ubaidillah Sabino and published by Springer Nature. This book was released on 2020-06-01 with total page 813 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book gathers the proceedings of the 6th International Conference and Exhibition on Sustainable Energy and Advanced Materials (ICE-SEAM 2019), held on 16–17 October 2019 in Surakarta, Indonesia. It focuses on two relatively broad areas – advanced materials and sustainable energy – and a diverse range of subtopics: Advanced Materials and Related Technologies: Liquid Crystals, Semiconductors, Superconductors, Optics, Lasers, Sensors, Mesoporous Materials, Nanomaterials, Smart Ferrous Materials, Amorphous Materials, Crystalline Materials, Biomaterials, Metamaterials, Composites, Polymers, Design, Analysis, Development, Manufacturing, Processing and Testing for Advanced Materials. Sustainable Energy and Related Technologies: Energy Management, Storage, Conservation, Industrial Energy Efficiency, Energy-Efficient Buildings, Energy-Efficient Traffic Systems, Energy Distribution, Energy Modeling, Hybrid and Integrated Energy Systems, Fossil Energy, Nuclear Energy, Bioenergy, Biogas, Biomass Geothermal Power, Non-Fossil Energies, Wind Energy, Hydropower, Solar Photovoltaic, Fuel Cells, Electrification, and Electrical Power Systems and Controls.

Download or read book Heat and Mass Transfer written by Hans Dieter Baehr and published by Springer Science & Business Media. This book was released on 2006-08-02 with total page 706 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides a solid foundation in the principles of heat and mass transfer and shows how to solve problems by applying modern methods. The basic theory is developed systematically, exploring in detail the solution methods to all important problems. The revised second edition incorporates state-of-the-art findings on heat and mass transfer correlations. The book will be useful not only to upper- and graduate-level students, but also to practicing scientists and engineers. Many worked-out examples and numerous exercises with their solutions will facilitate learning and understanding, and an appendix includes data on key properties of important substances.

Download or read book Fundamentals of Heat and Mass Transfer written by T. L. Bergman and published by John Wiley & Sons. This book was released on 2011-04-12 with total page 2249 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fundamentals of Heat and Mass Transfer, 7th Edition is the gold standard of heat transfer pedagogy for more than 30 years, with a commitment to continuous improvement by four authors having more than 150 years of combined experience in heat transfer education, research and practice. Using a rigorous and systematic problem-solving methodology pioneered by this text, it is abundantly filled with examples and problems that reveal the richness and beauty of the discipline. This edition maintains its foundation in the four central learning objectives for students and also makes heat and mass transfer more approachable with an additional emphasis on the fundamental concepts, as well as highlighting the relevance of those ideas with exciting applications to the most critical issues of today and the coming decades: energy and the environment. An updated version of Interactive Heat Transfer (IHT) software makes it even easier to efficiently and accurately solve problems.

Download or read book Oscillating Heat Pipes written by Hongbin Ma and published by Springer. This book was released on 2015-05-22 with total page 441 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents the fundamental fluid flow and heat transfer principles occurring in oscillating heat pipes and also provides updated developments and recent innovations in research and applications of heat pipes. Starting with fundamental presentation of heat pipes, the focus is on oscillating motions and its heat transfer enhancement in a two-phase heat transfer system. The book covers thermodynamic analysis, interfacial phenomenon, thin film evaporation, theoretical models of oscillating motion and heat transfer of single phase and two-phase flows, primary factors affecting oscillating motions and heat transfer, neutron imaging study of oscillating motions in an oscillating heat pipes, and nanofluid’s effect on the heat transfer performance in oscillating heat pipes. The importance of thermally-excited oscillating motion combined with phase change heat transfer to a wide variety of applications is emphasized. This book is an essential resource and learning tool for senior undergraduate, graduate students, practicing engineers, researchers, and scientists working in the area of heat pipes. This book also · Includes detailed descriptions on how an oscillating heat pipe is fabricated, tested, and utilized · Covers fundamentals of oscillating flow and heat transfer in an oscillating heat pipe · Provides general presentation of conventional heat pipes

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 Biological Activities and Application of Marine Polysaccharides written by Emad Shalaby and published by BoD – Books on Demand. This book was released on 2017-01-11 with total page 330 pages. Available in PDF, EPUB and Kindle. Book excerpt: Marine organisms have been under research for the last decades as a source for different active compounds with various biological activities and application in agriculture, pharmacy, medicine, environment, and industries. Marine polysaccharides from these active compounds are used as antibacterial, antiviral, antioxidant, anti-inflammation, bioremediations, etc. During the last three decades, several important factors that control the production of phytoplankton polysaccharides have been identified such as chemical concentrations, temperature, light, etc. The current book includes 14 chapters contributed by experts around the world; the chapters are categorized into three sections: Marine Polysaccharides and Agriculture, Marine Polysaccharides and Biological Activities, and Marine Polysaccharides and Industries.

Download or read book Innovative Heat Exchangers written by Hans-Jörg Bart and published by Springer. This book was released on 2017-12-30 with total page 398 pages. Available in PDF, EPUB and Kindle. Book excerpt: This accessible book presents unconventional technologies in heat exchanger design that have the capacity to provide solutions to major concerns within the process and power-generating industries. Demonstrating the advantages and limits of these innovative heat exchangers, it also discusses micro- and nanostructure surfaces and micro-scale equipment, and introduces pillow-plate, helical and expanded metal baffle concepts. It offers step-by-step worked examples, which provide instructions for developing an initial configuration and are supported by clear, detailed drawings and pictures. Various types of heat exchangers are available, and they are widely used in all fields of industry for cooling or heating purposes, including in combustion engines. The market in 2012 was estimated to be U$ 42.7 billion and the global demand for heat exchangers is experiencing an annual growth of about 7.8 %. The market value is expected to reach U$ 57.9 billion in 2016, and approach U$ 78.16 billion in 2020. Providing a valuable introduction to students and researchers, this book offers clear and concise information to thermal engineers, mechanical engineers, process engineers and heat exchanger specialists.

Download or read book Introduction to Nanoscience written by Stuart Lindsay and published by OUP Oxford. This book was released on 2009-10-22 with total page 480 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nanoscience is not physics, chemistry, engineering or biology. It is all of them, and it is time for a text that integrates the disciplines. This is such a text, aimed at advanced undergraduates and beginning graduate students in the sciences. The consequences of smallness and quantum behaviour are well known and described Richard Feynman's visionary essay 'There's Plenty of Room at the Bottom' (which is reproduced in this book). Another, critical, but thus far neglected, aspect of nanoscience is the complexity of nanostructures. Hundreds, thousands or hundreds of thousands of atoms make up systems that are complex enough to show what is fashionably called 'emergent behaviour'. Quite new phenomena arise from rare configurations of the system. Examples are the Kramer's theory of reactions (Chapter 3), the Marcus theory of electron transfer (Chapter 8), and enzyme catalysis, molecular motors, and fluctuations in gene expression and splicing, all covered in the final Chapter on Nanobiology. The book is divided into three parts. Part I (The Basics) is a self-contained introduction to quantum mechanics, statistical mechanics and chemical kinetics, calling on no more than basic college calculus. A conceptual approach and an array of examples and conceptual problems will allow even those without the mathematical tools to grasp much of what is important. Part II (The Tools) covers microscopy, single molecule manipulation and measurement, nanofabrication and self-assembly. Part III (Applications) covers electrons in nanostructures, molecular electronics, nano-materials and nanobiology. Each chapter starts with a survey of the required basics, but ends by making contact with current research literature.