Theoretical Study for Boiling Heat Transfer in a Confined Space

Theoretical Study for Boiling Heat Transfer in a Confined Space PDF Author: Aboubakr A. Khalil
Publisher:
ISBN:
Category : Heat
Languages : en
Pages : 102

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Theoretical Study for Boiling Heat Transfer in a Confined Space

Theoretical Study for Boiling Heat Transfer in a Confined Space PDF Author: Aboubakr A. Khalil
Publisher:
ISBN:
Category : Heat
Languages : en
Pages : 102

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Enhancement of Pool Boiling Heat Transfer in Confined Space

Enhancement of Pool Boiling Heat Transfer in Confined Space PDF Author: Chia-Hsiang Hsu
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Pool boiling is an effective method used in many technical applications for a long time. Its highly efficient heat transfer performance results from not only the convection effect but also the phase change process in pool boiling. Pool boiling enhancement has been studied in the past decade. However, the mechanisms of pool boiling has not yet been fully understood because of the many parameters that affect its behavior including the latent heat of vaporization, nucleation density, bubble and fluid motion, interaction at the interface, and the physical properties of surface. Among the current studies, bubble departure rate is viewed as one of the dominant factors that affect heat transfer. This research considers the effect of bubble confinement on pool boiling. In the study, confinement was achieved by placing a flat plate over heated surface. The flat plate has a hole in the middle, and there is a gap between the flat plate and the heater. The diameters of hole are 2 mm, 3 mm, and 4 mm; the gap distances are 2.3 mm, 3.6 mm, and 5 mm. The heater consists of an indium-tin-oxide layer deposited on a silicon wafer. An IR camera and high speed cameras are used to acquire the surface temperature distribution and bubble image. By controlling the plate hole size and the gap distance, the effect of confinement on heat transfer performance can be evaluated. Moreover, heat transfer performance of pool boiling with three-2mm-holes plate was investigated and compared with that of single-2mm-hole plate with the smallest gap size. At the lower heat flux values, heat transfer enhancement in confined space was experimentally observed. Surface temperature can be reduced by 4 °C at most. Results indicate that higher bubble departure rate and coalescence effect might be the dominant factor for improving heat transfer performance in a confined space caused by induced shear flow. The electronic version of this dissertation is accessible from http://hdl.handle.net/1969.1/152843

Boiling Heat Transfer in Confined Space

Boiling Heat Transfer in Confined Space PDF Author: Shi-Chune Yao
Publisher:
ISBN:
Category :
Languages : en
Pages : 42

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Book Description
In many equipments, boiling occurs in confined space such as the clearance between the tube and the support plate of steam generators. Corrosive concentration builds up at the boundary of dryout zone and induces severe damage. The knowledge on this kind of boiling phenomena is very limited. It is the objective of this research to understand this fundamental heat transfer of this problem through systematical analysis and experimental studies. This report covers the following aspects of the boiling in confined space: (1) Analysis of single phase forced convection in support plate crevices; (2) Analysis of convective boiling and dryout in support plate crevices; (3) Experiments of boiling and dryout in annular crevices with closed bottom; and (4) Experiments of convective boiling and dryout in annular crevices. (Author).

Hydrodynamic Aspects of Boiling Heat Transfer

Hydrodynamic Aspects of Boiling Heat Transfer PDF Author: N. Zuber
Publisher:
ISBN:
Category : Heat
Languages : en
Pages : 216

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Advances in Heat Transfer

Advances in Heat Transfer PDF Author:
Publisher: Academic Press
ISBN: 0080575749
Category : Science
Languages : en
Pages : 411

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Advances in Heat Transfer

Subcooled Boiling Heat Transfer Under Forced Convection in a Heated Tube

Subcooled Boiling Heat Transfer Under Forced Convection in a Heated Tube PDF Author: S. Stephen Papell
Publisher:
ISBN:
Category : Heat
Languages : en
Pages : 28

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Thermal Transport Characteristics of Phase Change Materials and Nanofluids

Thermal Transport Characteristics of Phase Change Materials and Nanofluids PDF Author: S. Harikrishnan
Publisher: CRC Press
ISBN: 1000787656
Category : Science
Languages : en
Pages : 221

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Book Description
This book provides detailed information related to nanofluids, synthesis and preparation, morphologies of nanoparticles, selection of base fluids and thermophysical properties of nanofluids. The advantage of various conduits, the improvement of the heat transfer performance of phase change materials (PCMs), and the base PCMs for diverse applications are also discussed. Crucial difficulties like stability, aggregation, and clogging of nanoparticles are detailed including factors like the size, shape, and motion of nanoparticles that influence the heat transfer performance of nanofluids. Challenges, applications, and scope of the future works in the subject area are included. Features: Covers heat transfer techniques in utilization of base fluids application of phase change materials (PCMs) Describes preparation and characterization of nanofluids and nano-based PCMs Explains how nanoscience can be utilized in heat transfer studies Reviews conventional heat transfer fluids This volume is aimed at graduate students and researchers in thermal engineering, heat transfer, material science and engineering, and heat transfer enhancement.

Microscale Heat Transfer - Fundamentals and Applications

Microscale Heat Transfer - Fundamentals and Applications PDF Author: S. Kakaç
Publisher: Springer Science & Business Media
ISBN: 1402033613
Category : Technology & Engineering
Languages : en
Pages : 517

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Book Description
This volume contains an archival record of the NATO Advanced Institute on Microscale Heat Transfer – Fundamental and Applications in Biological and Microelectromechanical Systems held in Çesme – Izmir, Turkey, July 18–30, 2004. The ASIs are intended to be high-level teaching activity in scientific and technical areas of current concern. In this volume, the reader may find interesting chapters and various Microscale Heat Transfer Fundamental and Applications. The growing use of electronics, in both military and civilian applications has led to the widespread recognition for need of thermal packaging and management. The use of higher densities and frequencies in microelectronic circuits for computers are increasing day by day. They require effective cooling due to heat generated that is to be dissipated from a relatively low surface area. Hence, the development of efficient cooling techniques for integrated circuit chips is one of the important contemporary applications of Microscale Heat Transfer which has received much attention for cooling of high power electronics and applications in biomechanical and aerospace industries. Microelectromechanical systems are subject of increasing active research in a widening field of discipline. These topics and others are the main themeof this Institute.

Flow Boiling of a Dilute Emulsion In Smooth and Rough Microgaps

Flow Boiling of a Dilute Emulsion In Smooth and Rough Microgaps PDF Author: Brandon M. Shadakofsky
Publisher: Springer Nature
ISBN: 3031277732
Category : Science
Languages : en
Pages : 151

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Book Description
This book elucidates heat transfer behavior for boiling of dilute emulsions- mixtures of two immiscible fluids- which has received little attention to date. Of the work completed in this area, the majority has been focused on pool boiling where no mean flow is present, and this book is the first major work to be published regarding flow boiling of emulsions. The book includes a comprehensive review and assessment of research on emulsion-based heat transfer. Recent experiments are reported and analyzed to characterize heat transfer in microgap flow boiling via a systematic investigation into the effects of gap size, mass flux, and volume fraction on the heat transfer coefficient and pressure drop. The emulsion used in all experiments comprises droplets of an immiscible electronics cooling fluid suspended in water. The volume provides a complete baseline for flow boiling of water in the microgaps, enabling a determination of the enhancement of the heat transfer coefficient when the disperse component is present. Moreover, a subset of the data set pertains to flow boiling of dilute emulsions over microporous surfaces. The flow conditions for which the microporous surfaces enhance or degrade heat transfer are presented. Finally, this book provides a discussion of the physical phenomena which affect boiling and a set of nondimensional numbers that can be used for correlation.

Advances in Heat Transfer

Advances in Heat Transfer PDF Author: Ephraim M. Sparrow
Publisher: Academic Press
ISBN: 0124079326
Category : Science
Languages : en
Pages : 360

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Book Description
Advances in Heat Transfer fills the information gap between regularly scheduled journals and university-level textbooks by providing in-depth review articles over a broader scope than in journals or texts. The articles, which serve as a broad review for experts in the field, will also be of great interest to non-specialists who need to keep up-to-date with the results of the latest research. This serial is essential reading for all mechanical, chemical and industrial engineers working in the field of heat transfer, graduate schools or industry. - This serial is essential reading for all mechanical, chemical and industrial engineers working in the field of heat transfer, graduate schools or industry