Spatio - Temporal Temperature Variations During Droplet Impingement Evaporation PDF Download
Are you looking for read ebook online? Search for your book and save it on your Kindle device, PC, phones or tablets. Download Spatio - Temporal Temperature Variations During Droplet Impingement Evaporation PDF full book. Access full book title Spatio - Temporal Temperature Variations During Droplet Impingement Evaporation by Christof Graber. Download full books in PDF and EPUB format.
Author: Christof Graber
Publisher:
ISBN:
Category : Evaporative cooling
Languages : en
Pages : 316
Get Book Here
Book Description
Droplet and spray impingement cooling are typically used in high heat flux thermal management. In this thesis, droplet impingement and evaporation heat transfer characteristics are determined from measured spatially- and temporally- varying fluid and surface temperatures. Unique to this study is the documentation of the effects of using a nanofluid and a nano-structured surface for dropwise cooling by comparison of heat transfer characteristics with that of water droplet impingement on a polished surface. Temperatures were determined using radiation intensities recorded using an Infrared (IR) camera. The impingement surface is either comprised of IR transparent silicon, which permits near-surface fluid temperature measurements, or an IR opaque gold coated surface, which permits surface temperature measurements. A range of surface heat fluxes, resulting in both single-phase and boiling conditions are studied. Three different impingement surfaces have been tested, including polished silicon, nano-structured porous silicon, and gold coated polished silicon. The nanofluid is a water-based carbon nanotube suspension. Five major droplet impingement and evaporation stages have been identified: initial impact, boiling (if the surface temperature was sufficiently high), approximately constant diameter evaporation, stepwise fast receding contact line evaporation, and simultaneously decaying diameter and contact angle final dryout period. The surface temperature spatial distribution shows the lowest temperature values within the contact area bulk region and increasing temperature values toward the contact line region and beyond. The basic temperature trends and evaporation behavior are similar for the polished and nano-structured surface while the nanofluid exhibits some distinction. Evaporation times are reduced up to 20% and 37% using the nanostructured surface and nanofluid, respectively. Considering the evaporation time reduction as a measure of droplet cooling performance, the nano-enhanced surface and nanofluid may improve heat transfer in droplet impingement and spray cooling applications.
Author: Christof Graber
Publisher:
ISBN:
Category : Evaporative cooling
Languages : en
Pages : 316
Get Book Here
Book Description
Droplet and spray impingement cooling are typically used in high heat flux thermal management. In this thesis, droplet impingement and evaporation heat transfer characteristics are determined from measured spatially- and temporally- varying fluid and surface temperatures. Unique to this study is the documentation of the effects of using a nanofluid and a nano-structured surface for dropwise cooling by comparison of heat transfer characteristics with that of water droplet impingement on a polished surface. Temperatures were determined using radiation intensities recorded using an Infrared (IR) camera. The impingement surface is either comprised of IR transparent silicon, which permits near-surface fluid temperature measurements, or an IR opaque gold coated surface, which permits surface temperature measurements. A range of surface heat fluxes, resulting in both single-phase and boiling conditions are studied. Three different impingement surfaces have been tested, including polished silicon, nano-structured porous silicon, and gold coated polished silicon. The nanofluid is a water-based carbon nanotube suspension. Five major droplet impingement and evaporation stages have been identified: initial impact, boiling (if the surface temperature was sufficiently high), approximately constant diameter evaporation, stepwise fast receding contact line evaporation, and simultaneously decaying diameter and contact angle final dryout period. The surface temperature spatial distribution shows the lowest temperature values within the contact area bulk region and increasing temperature values toward the contact line region and beyond. The basic temperature trends and evaporation behavior are similar for the polished and nano-structured surface while the nanofluid exhibits some distinction. Evaporation times are reduced up to 20% and 37% using the nanostructured surface and nanofluid, respectively. Considering the evaporation time reduction as a measure of droplet cooling performance, the nano-enhanced surface and nanofluid may improve heat transfer in droplet impingement and spray cooling applications.
Author: N.A. Fuchs
Publisher: Elsevier
ISBN: 1483225631
Category : Science
Languages : en
Pages : 81
Get Book Here
Book Description
Evaporation and Droplet Growth in Gaseous Media deals with the evaporation of droplets of liquid in gaseous media and the reverse process of droplet growth in a medium supersaturated with the vapor of the liquid. Thediscussion is restricted to the kinetics of evaporation and growth of droplets of pure liquids (and heat transfer to the same). Comprised of three chapters, this book first examines the quasi-stationary evaporation and growth of droplets that are motionless relative to the medium and the hydrodynamic factor is absent. The Maxwell equation, the basis of the theory of evaporation of droplets in a gaseous medium, is taken into account. The influence of the Stefan flow and the concentration change at the surface on the rate of evaporation are considered, along with the evaporation of droplets in a vessel with absorbing walls and the fall in temperature of both free evaporating droplets and supported evaporating droplets. The second chapter is devoted to the quasi-stationary evaporation of droplets in a stream of gas, that is, droplets moving relative to the medium. The last chapter focuses on non-stationary evaporation and growth of droplets that either motionless or moving relative to the medium. This monograph will be of interest to students, practitioners, and researchers in inorganic and structural chemistry.
Author:
Publisher:
ISBN:
Category : Aeronautics
Languages : en
Pages : 1124
Get Book Here
Book Description
Author: Guang-Jyh Hwang
Publisher: CRC Press
ISBN: 9780891168881
Category : Science
Languages : en
Pages : 822
Get Book Here
Book Description
A collection of research papers into transport phenomena in thermal control, closely related to several important aspects of cooling technology. Articles provide overviews of current advances and details of individual technologies including electronic and turbine cooling and Marangoni convection.
Author:
Publisher:
ISBN:
Category : Mechanics, Applied
Languages : en
Pages : 348
Get Book Here
Book Description
Author: Frank Kreith
Publisher: Springer Science & Business Media
ISBN: 3662301822
Category : Science
Languages : en
Pages : 400
Get Book Here
Book Description
to increase the use of direct contact processes, the National Science Foundation sup ported a workshop on direct contact heat transfer at the Solar Energy Research Insti tute in the summer of 1985. We served as organizers for this workshop, which em phasized an area of thermal engineering that, in our opinion, has great promise for the future, but has not yet reached the point of wide-spread commercial application. Hence, a summary of the state of knowledge at this point is timely. The workshop had a dual objective: 1. To summarize the current state of knowledge in such a form that industrial practi tioners can make use of the available information. 2. To indicate the research and development needed to advance the state-of-the-art, indicating not only what kind of research is needed, but also the industrial poten tial that could be realized if the information to be obtained through the proposed research activities were available.
Author:
Publisher:
ISBN:
Category : Space vehicles
Languages : en
Pages : 668
Get Book Here
Book Description
Author: Russell A. Ogle
Publisher: Butterworth-Heinemann
ISBN: 0128038292
Category : Technology & Engineering
Languages : en
Pages : 687
Get Book Here
Book Description
Dust Explosion Dynamics focuses on the combustion science that governs the behavior of the three primary hazards of combustible dust: dust explosions, flash fires, and smoldering. It explores the use of fundamental principles to evaluate the magnitude of combustible dust hazards in a variety of settings. Models are developed to describe dust combustion phenomena using the principles of thermodynamics, transport phenomena, and chemical kinetics. Simple, tractable models are described first and compared with experimental data, followed by more sophisticated models to help with future challenges. Dr. Ogle introduces the reader to just enough combustion science so that they may read, interpret, and use the scientific literature published on combustible dusts. This introductory text is intended to be a practical guide to the application of combustible dust models, suitable for both students and experienced engineers. It will help you to describe the dynamics of explosions and fires involving dust and evaluate their consequences which in turn will help you prevent damage to property, injury and loss of life from combustible dust accidents. - Demonstrates how the fundamental principles of combustion science can be applied to understand the ignition, propagation, and extinction of dust explosions - Explores fundamental concepts through model-building and comparisons with empirical data - Provides detailed examples to give a thorough insight into the hazards of combustible dust as well as an introduction to relevant scientific literature
Author: David T. Harrje
Publisher:
ISBN:
Category : Liquid propellant rockets
Languages : en
Pages : 668
Get Book Here
Book Description
The solution of problems of combustion instability for more effective communication between the various workers in this field is considered. The extent of combustion instability problems in liquid propellant rocket engines and recommendations for their solution are discussed. The most significant developments, both theoretical and experimental, are presented, with emphasis on fundamental principles and relationships between alternative approaches.
Author: David Brutin
Publisher: Academic Press
ISBN: 0128008083
Category : Science
Languages : en
Pages : 464
Get Book Here
Book Description
Droplet Wetting and Evaporation provides engineers, students, and researchers with the first comprehensive guide to the theory and applications of droplet wetting and evaporation. Beginning with a relevant theoretical background, the book moves on to consider specific aspects, including heat transfer, flow instabilities, and the drying of complex fluid droplets. Each chapter covers the principles of the subject, addressing corresponding practical issues and problems. The text is ideal for a broad range of domains, from aerospace and materials, to biomedical applications, comprehensively relaying the challenges and approaches from the different communities leading the way in droplet research and development. - Provides a broad, cross-subject coverage of theory and application that is ideal for engineers, students and researchers who need to follow all major developments in this interdisciplinary field - Includes comprehensive discussions of heat transfer, flow instabilities, and the drying of complex fluid droplets - Begins with an accessible summary of fundamental theory before moving on to specific areas such as heat transfer, flow instabilities, and the drying of complex fluid droplets
