Development of an Experimental Technique to Investigate Droplet Cooling Phenomena on Accident Tolerant Fuel Materials PDF Download
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Author: Warner A. McGhee Publisher: ISBN: Category : Languages : en Pages : 51
Book Description
Droplet cooling is used in many heat removal applications, including core spray coolers in boiling water reactors. As new accident tolerant fuels are developed, understanding how they respond to droplet cooling is important to ensuring safe operations. Recent studies have indicated that surfaces engineered with micro- and nanostructures may affect the Leidenfrost point temperature of water and thus the efficiency of droplet cooling by altering the wettability of the surfaces. In this project, smooth and rough chromium surfaces were subjected to droplet cooling at temperatures ranging from 100 to 400°C, and the surface temperature was measured with a high speed infrared camera while a video camera observed the droplet shape and behavior during boiling. While the rough and smooth surfaces performed similarly at temperatures below 200°C, the data indicates that at higher temperatures the smooth surface allows for greater heat flux, longer droplet contact time, and more total heat removed. The sparsity of data makes this result very uncertain, especially since it seems to oppose most literature on the topic. The techniques developed for this study are promising for future illumination how surface structure affects droplet cooling.
Author: Warner A. McGhee Publisher: ISBN: Category : Languages : en Pages : 51
Book Description
Droplet cooling is used in many heat removal applications, including core spray coolers in boiling water reactors. As new accident tolerant fuels are developed, understanding how they respond to droplet cooling is important to ensuring safe operations. Recent studies have indicated that surfaces engineered with micro- and nanostructures may affect the Leidenfrost point temperature of water and thus the efficiency of droplet cooling by altering the wettability of the surfaces. In this project, smooth and rough chromium surfaces were subjected to droplet cooling at temperatures ranging from 100 to 400°C, and the surface temperature was measured with a high speed infrared camera while a video camera observed the droplet shape and behavior during boiling. While the rough and smooth surfaces performed similarly at temperatures below 200°C, the data indicates that at higher temperatures the smooth surface allows for greater heat flux, longer droplet contact time, and more total heat removed. The sparsity of data makes this result very uncertain, especially since it seems to oppose most literature on the topic. The techniques developed for this study are promising for future illumination how surface structure affects droplet cooling.
Author: H. Dawson Publisher: ISBN: Category : Cooling Languages : en Pages : 208
Book Description
Techniques of infrared thermography were used to conduct an experimental study of the evaporative cooling of a hot, low thermal conductivity, non-metallic surface heated by radiation and subject to a random array of impinging water droplets. A droplet generating and distributing apparatus and a data acquisition system employing digital image analysis devices were also developed and implemented. Real time infrared images of the heated surface were recorded and digitized using computer resident frame grabbing hardware and analyzed on a pixel by pixel basis, giving a high degree of thermal and spatial resolution. From these analyses, the instantaneous surface temperature distribution and transient surface temperature profile were obtained for a range of initial temperatures and impinging mass fluxes. The surface temperature was found to decay exponentially with time to a steady state value for the fluxes used. Three dimensional plots of the temperature distribution on the surface also showed the significant lowering of the average surface temperature, and provided a qualitative description of the cooling phenomena at various stages during the transient. Results obtained will be used in the future validation of a computer model of the phenomena.
Author: Martin Rein Publisher: Springer Science & Business Media ISBN: 9783211836927 Category : Computers Languages : en Pages : 328
Book Description
This book presents a comprehensive overview of fluid mechanical, thermal and physico-chemical aspects of drop-surface interactions. Basic physical mechanisms pertaining to free-surface flow phenomena characteristic of drop impact on solid and liquid surfaces are explained emphasizing the importance of scaling. Moreover, physico-chemical fundamentals relating to a forced spreading of complex solutions, analytical tools for calculating compressibility effects, and heat transfer and phase change phenomena occurring during solidification and evaporation processes, respectively, are introduced in detail. Finally, numerical approaches particularly suited for modeling drop-surface interactions are consisely surveyed with a particular emphasis on boundary integral methods and Navier-Stokes algorithms (volume of fluid, level set and front tracking algorithms). The book is closed by contributions to a workshop on Drop-Surface Interactions held at the International Centre of Mechanical Sciences.
Author: Publisher: ISBN: Category : Languages : en Pages :
Book Description
Abstract : The fuel spray wall interaction phenomenon plays an essential role in determining the emissions and performance of an internal combustion engine. The investigation of single droplet wall interaction is crucial to understanding of a spray wall impingement process. This report is a compilation of the experimental work done to understand the droplet impingement characteristics, through optical diagnostics and temperature measurement. Different fuels and different surface under ambient and elevated temperature conditions are used for these tests, with two objectives: Development of a common depositionsplashing criteria; and Understanding droplet post impingement dynamics variation with factors like: Weber number (ratio of inertia and surface tension forces), and with temperature. The droplet post impinging characteristics include spread factor, height ratio, contact line velocity and dynamic contact angle. The effect of Weber no on droplet impingement characteristics is investigated using water and diesel. The effect of temperature is divided into two subsections: Isothermal (cold wall-cold droplet and hot wall-hot droplet) and non-isothermal conditions (hot wall-cold droplet and hot droplet and cold wall), to understand the influence of both variation in thermophysical properties and heat transfer between droplet and surface. Using the experimental results, a comprehensive review of splashing criteria is done, along with a proposed new correlation for same and concept of splashing probability is introduced. The observation presented for variation in post-impingement characteristics with the mentioned factors are useful for future development of numerical codes.
Author: International Atomic Energy Agency Publisher: International Atomic Energy Agency ISBN: 9789201019196 Category : Technology & Engineering Languages : en Pages : 74
Book Description
There is considerable interest in both developing and developed countries in the design of innovative water cooled reactors (WCRs) and, owing to the higher thermal efficiency and significant system simplifications, supercritical water cooled reactors (SWCRs). Compared to conventional WCRs the SCWR concept requires extensive, comprehensive research and development (R&D). Fundamental research in understanding important phenomena has been completed successfully in providing information required for the next step of development. Currently, a few concepts have been assessed as being technical feasible, and several other concepts are under development. These concepts are described in this publication, together with detailed analysis of remaining gaps requiring future R&D.
Author: International Atomic Energy Agency Publisher: ISBN: 9789201253101 Category : Business & Economics Languages : en Pages : 639
Book Description
This publication reports on the results of a coordinated research project on advances in high temperature gas cooled reactor (HTGR) fuel technology and describes the findings of research activities on coated particle developments. These comprise two specific benchmark exercises with the application of HTGR fuel performance and fission product release codes, which helped compare the quality and validity of the computer models against experimental data. The project participants also examined techniques for fuel characterization and advanced quality assessment/quality control. The key exercise included a round-robin experimental study on the measurements of fuel kernel and particle coating properties of recent Korean, South African and US coated particle productions applying the respective qualification measures of each participating Member State. The summary report documents the results and conclusions achieved by the project and underlines the added value to contemporary knowledge on HTGR fuel.
Author: Publisher: ISBN: Category : Languages : en Pages : 116
Book Description
The Bulletin of the Atomic Scientists is the premier public resource on scientific and technological developments that impact global security. Founded by Manhattan Project Scientists, the Bulletin's iconic "Doomsday Clock" stimulates solutions for a safer world.
Author: Warner A. McGhee
Author: Warner A. McGhee
Author: H. Dawson
Author: Songbai Cheng
Author: Martin Rein
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Author: 
Author: International Atomic Energy Agency
Author: 
Author: International Atomic Energy Agency
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