Download or read book A Systematic Investigation of Condensation Heat Transfer Using Asymmetric Micro scale Surfaces written by Emily Elizabeth Brown and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Study of the Effects of Surface Morphology and Droplet Growth Dynamics on Condensation Heat Transfer written by Chun-Wei Yao and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Condensation heat transfer has recently received a lot of renewed attention due to the development and use of surfaces with micro- and nano-scale features. Most of the new surfaces tend to promote dropwise condensation, which leads to higher rates of heat transfer when compared with filmwise condensation. In the current study, the effects of surface morphology and surface chemistry on the condensation mechanisms have been investigated using engineered surfaces. Firstly, hybrid surfaces consisting of an array of micropillars with hydrophobic and hydrophilic sites have been designed to exhibit a distinct Cassie-Baxter wetting behavior at different temperatures. Characterization experiments have revealed that hybrid surfaces depict a unique wetting behavior. Furthermore, more types of engineered surfaces were fabricated including nanoparticle-based hydrophobic surface, polytetrafluoroethylene (PTFE) surface, and self-assembled monolayers (SAMs) surface. Experiments have been conducted to determine the heat transfer performance of all engineered surfaces under a constant humidity level, surface-to-ambient temperature difference, and laminar flow conditions. Experimental results reveal that droplet sliding can have an important effect on heat transfer performance. Also, empirical heat transfer correlations have been postulated and fitted using experimental data using condensing and air temperature difference and Reynolds number as independent variables. Results indicate that the postulated correlations are in excellent agreement with experimental data. In addition, surface temperature data obtained using an advanced IR imaging system have been analyzed to determine the effects of the surface features on droplet growth dynamics. The non-invasive IR measurement technique has been helpful in understanding the droplet growth dynamics such as droplet coalescence. Results to date show that the static contact angles and sliding angles have marked effects on droplet growth and coalescence on the surfaces in the early stages of condensation. Furthermore, results also reveal that droplet sliding angles can have an important effect on droplet sliding motion and condensed droplet dynamics play an important role during the overall condensation process. In summary, the effect of surface morphology and droplet growth dynamics on heat transfer during condensation were investigated and elucidated. The electronic version of this dissertation is accessible from http://hdl.handle.net/1969.1/152590

Download or read book Experimental Investigation of Condensation Heat Transfer in Microchannels written by 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 Analytical and Numerical Study of Filmwise Condensation on Periodic Asymmetrically Textured Surfaces written by Shashank Natesh and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Filmwise condensation on a horizontal surface with asymmetric millimeter-sized ratchets and periodically located film drainage pathways in the span-wise direction is analytically and numerically characterized in this research work. The central hypothesis of the proposed research work is that the asymmetry in the surface texture can induce a self-generated directional motion of the condensed vapor. Within the framework of this research work, the hypothesis is tested in three stages. The first stage includes the numerical characterization of the initial transient growth of the condensate film inside a single periodic asymmetric ratchet. The second stage includes testing the validity of a net steady-state preferential drainage of the condensate on a small drainage-pathway-density surface through experimental visualization of the steady-state condensate film and development of a two-dimensional adiabatic analytical model describing the asymmetric steady-state characteristics of condensate film. The third stage comprises of analytical modeling of the condensate film drainage on arbitrarily-shaped smooth periodic surfaces based on orthogonal curvilinear coordinates. The model is utilized to quantify the impact of structural asymmetry introduced to periodic surface profiles on the condensate drainage and surface heat transfer. An optimization of the surface heat transfer rate under the constraints of various surface and fluid parameters is carried out to engender best possible asymmetric surface topologies. Parametric studies are conducted at all stages of the research to evaluate the effects of ratchet pitch, ratchet angles, drainage-pathway-density, orientation of gravity, and Bond number on the condensate film profile. The results from the analysis of experimental visualization, analytical modeling, numerical simulations, and optimization studies in this research work have the potential to enable design of condenser surfaces with novel asymmetric textures, which can be employed in a passive (pump-less) closed-loop microgravity phase-change thermal management system.

Download or read book Experimental Investigation of Condensation Heat Transfer on Corrugated Surfaces written by George Stuart Harrison and published by . This book was released on 1970 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Experimental Investigation Into Condensation on Heterogeneous Surface written by Ramana Saketh Vanga and published by . This book was released on 2014 with total page 100 pages. Available in PDF, EPUB and Kindle. Book excerpt: Renewable energy systems operated by a thermal energy resource such as geothermal power plants and solar thermal power systems are demanding improvement in their condensation performance. While their energy resources are naturally obtained at almost no cost, heat rejecting components are relatively expensive to maintain and operate. In this research, a heterogeneous condensing surface is proposed to enhance the condensation heat transfer coefficient in vapor-to-liquid heat exchangers. Parallel stripes with hydrophobic feature and ones without it alternate on its surface. The effect of surface wettability variation that is generated by the heterogeneous surface on the dropwise condensation heat transfer of saturated steam on the flat plate copper surface is experimentally investigated. A vertical flat plate condenser is constructed to evaluate the performance of the heterogeneous condensing surface in comparison with a plain copper sample and a homogeneous hydrophobic-treated copper sample. Experimental results show that condensation heat transfer of steam on the homogeneous hydrophobic-treated sample is superior to that of the plain copper surface despite the fact that both the surfaces stably promote dropwise condensation. At the subcooling temperature of 3°C, the difference in the heat transfer coefficients between the plain copper sample and the hydrophobic-treated copper sample is almost twofold. The heat transfer coefficients for the heterogeneous surface at smaller subcooling temperatures, when its stripes situate horizontally, are as high as the heat transfer coefficients for the homogeneous hydrophobic-treated surface. The enhancement for the horizontal heterogeneous sample over the plain copper sample is approximately 100%. The heat transfer coefficient for the heterogeneous sample with its stripes being vertical at 4°C subcooling is 25% greater than that of the plain copper sample. Higher heat transfer coefficients are observed at smaller subcooling temperatures for all the samples. The results and observations of this project suggest that the heterogeneous surface has the potential to enhance the heat transfer coefficients.

Download or read book Applied Mechanics Reviews written by and published by . This book was released on 1974 with total page 620 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Journal of Thermophysics and Heat Transfer written by and published by . This book was released on 2004 with total page 1238 pages. Available in PDF, EPUB and Kindle. Book excerpt: This journal is devoted to the advancement of the science and technology of thermophysics and heat transfer through the dissemination of original research papers disclosing new technical knowledge and exploratory developments and applications based on new knowledge. It publishes papers that deal with the properties and mechanisms involved in thermal energy transfer and storage in gases, liquids, and solids or combinations thereof. These studies include conductive, convective, and radiative modes alone or in combination and the effects of the environment.

Download or read book Handbook of Clean Energy Systems 6 Volume Set written by Jinyue Yan and published by John Wiley & Sons. This book was released on 2015-06-22 with total page 4038 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Handbook of Clean Energy Systems brings together an international team of experts to present a comprehensive overview of the latest research, developments and practical applications throughout all areas of clean energy systems. Consolidating information which is currently scattered across a wide variety of literature sources, the handbook covers a broad range of topics in this interdisciplinary research field including both fossil and renewable energy systems. The development of intelligent energy systems for efficient energy processes and mitigation technologies for the reduction of environmental pollutants is explored in depth, and environmental, social and economic impacts are also addressed. Topics covered include: Volume 1 - Renewable Energy: Biomass resources and biofuel production; Bioenergy Utilization; Solar Energy; Wind Energy; Geothermal Energy; Tidal Energy. Volume 2 - Clean Energy Conversion Technologies: Steam/Vapor Power Generation; Gas Turbines Power Generation; Reciprocating Engines; Fuel Cells; Cogeneration and Polygeneration. Volume 3 - Mitigation Technologies: Carbon Capture; Negative Emissions System; Carbon Transportation; Carbon Storage; Emission Mitigation Technologies; Efficiency Improvements and Waste Management; Waste to Energy. Volume 4 - Intelligent Energy Systems: Future Electricity Markets; Diagnostic and Control of Energy Systems; New Electric Transmission Systems; Smart Grid and Modern Electrical Systems; Energy Efficiency of Municipal Energy Systems; Energy Efficiency of Industrial Energy Systems; Consumer Behaviors; Load Control and Management; Electric Car and Hybrid Car; Energy Efficiency Improvement. Volume 5 - Energy Storage: Thermal Energy Storage; Chemical Storage; Mechanical Storage; Electrochemical Storage; Integrated Storage Systems. Volume 6 - Sustainability of Energy Systems: Sustainability Indicators, Evaluation Criteria, and Reporting; Regulation and Policy; Finance and Investment; Emission Trading; Modeling and Analysis of Energy Systems; Energy vs. Development; Low Carbon Economy; Energy Efficiencies and Emission Reduction. Key features: Comprising over 3,500 pages in 6 volumes, HCES presents a comprehensive overview of the latest research, developments and practical applications throughout all areas of clean energy systems, consolidating a wealth of information which is currently scattered across a wide variety of literature sources. In addition to renewable energy systems, HCES also covers processes for the efficient and clean conversion of traditional fuels such as coal, oil and gas, energy storage systems, mitigation technologies for the reduction of environmental pollutants, and the development of intelligent energy systems. Environmental, social and economic impacts of energy systems are also addressed in depth. Published in full colour throughout. Fully indexed with cross referencing within and between all six volumes. Edited by leading researchers from academia and industry who are internationally renowned and active in their respective fields. Published in print and online. The online version is a single publication (i.e. no updates), available for one-time purchase or through annual subscription.

Download or read book Microscale and Nanoscale Heat Transfer written by C.B. Sobhan and published by CRC Press. This book was released on 2008-06-12 with total page 440 pages. Available in PDF, EPUB and Kindle. Book excerpt: Through analyses, experimental results, and worked-out numerical examples, Microscale and Nanoscale Heat Transfer: Fundamentals and Engineering Applications explores the methods and observations of thermophysical phenomena in size-affected domains. Compiling the most relevant findings from the literature, along with results from their own re

Download or read book 21st Century Surface Science written by Phuong Pham and published by BoD – Books on Demand. This book was released on 2020-11-26 with total page 295 pages. Available in PDF, EPUB and Kindle. Book excerpt: Surface sciences elucidate the physical and chemical aspects of the surfaces and interfaces of materials. Of great interest in this field are nanomaterials, which have recently experienced breakthroughs in synthesis and application. As such, this book presents some recent representative achievements in the field of surface science, including synthesis techniques, surface modifications, nanoparticle-based smart coatings, wettability of different surfaces, physics/chemistry characterizations, and growth kinetics of thin films. In addition, the book illustrates some of the important applications related to silicon, CVD graphene, graphene oxide, transition metal dichalcogenides, carbon nanotubes, carbon nanoparticles, transparent conducting oxide, and metal oxides.

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 Bioinspired Design of Materials Surfaces written by Yongmei Zheng and published by Elsevier. This book was released on 2019-08-23 with total page 340 pages. Available in PDF, EPUB and Kindle. Book excerpt: Bioinspired Design of Materials Surfaces reviews novel methods and technologies used to design surfaces and materials for smart material and device applications. The author discusses how materials wettability can be impacted by the fabrication of micro- and nanostructures, anisotropic structures, gradient structures, and heterogeneous patterned structures on the surfaces of materials. The design of these structures was inspired by nature, including lotus, cactus, beetle back and butterfly wings, spider silk, and shells. The author reviews the various wettability functions that can result from these designs, such as self-cleaning, directional adhesion, droplet driving, anti-adhesion, non-wetting, liquid repellent properties, liquid separation, liquid splitting, and more. This book presents a key reference on how to fabricate bioinspired structures on materials for desired functions of materials wettability. It also discusses challenges, opportunities and many potential applications, such as oil-water separation devices, water harvesting devices and photonic device applications. Introduces the fundamentals of both bioinspired materials design and the theory behind dynamic materials wettability Reviews the latest methods and technologies used to create functional surfaces and structured materials that impact and potentially control wettability Provides a snapshot of potential device applications, such as oil-water separation, water harvesting, fluid transport, photonic applications, and much more

Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1994 with total page 728 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Japanese Science and Technology 1983 1984 written by United States. National Aeronautics and Space Administration. Scientific and Technical Information Branch and published by . This book was released on 1985 with total page 1080 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Selected Water Resources Abstracts written by and published by . This book was released on 1976 with total page 790 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Physics Briefs written by and published by . This book was released on 1993 with total page 1212 pages. Available in PDF, EPUB and Kindle. Book excerpt: