Heat Transfer and Film Thickness Characteristics of Spray Cooling with Phase Change PDF Download

Author: Adam G. Pautsch
Publisher:
ISBN:
Category :
Languages : en
Pages : 130

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Author: Peter Joseph Halvorson
Publisher: Ann Arbor, Mich. : University Microfilms International
ISBN:
Category : Cooling
Languages : en
Pages : 592

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Book Description

Author: S. M. Sohel Murshed
Publisher: BoD – Books on Demand
ISBN: 1789848385
Category : Science
Languages : en
Pages : 154

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Book Description
Since conventional cooling techniques are increasing falling short of meeting the ever-growing cooling demands of high heat generating devices, thermal systems, and processes, advanced and innovative cooling technologies are of immense importance to deal with such high thermal management. Hence, this book covers a number of key topics related to advanced cooling approaches, their performance, and applications, including: Evaporative air cooling; Spray impingement cooling; Heat pump-based cooling; Modular cooling for photovoltaic plant; Nucleate pool boiling of refrigerants; Transient flashing spray cooling and application; Compressor cooling systems for industry. The book is aimed at a wide variety of people from graduate students and researchers to manufacturers who are involved or interested in the areas of thermal management systems, cooling technologies, and their applications.

Author: Amimul Ahsan
Publisher: IntechOpen
ISBN: 9789533075846
Category : Computers
Languages : en
Pages : 598

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Book Description
The heat transfer and analysis on laser beam, evaporator coils, shell-and-tube condenser, two phase flow, nanofluids, complex fluids, and on phase change are significant issues in a design of wide range of industrial processes and devices. This book includes 25 advanced and revised contributions, and it covers mainly (1) numerical modeling of heat transfer, (2) two phase flow, (3) nanofluids, and (4) phase change. The first section introduces numerical modeling of heat transfer on particles in binary gas-solid fluidization bed, solidification phenomena, thermal approaches to laser damage, and temperature and velocity distribution. The second section covers density wave instability phenomena, gas and spray-water quenching, spray cooling, wettability effect, liquid film thickness, and thermosyphon loop. The third section includes nanofluids for heat transfer, nanofluids in minichannels, potential and engineering strategies on nanofluids, and heat transfer at nanoscale. The forth section presents time-dependent melting and deformation processes of phase change material (PCM), thermal energy storage tanks using PCM, phase change in deep CO2 injector, and thermal storage device of solar hot water system. The advanced idea and information described here will be fruitful for the readers to find a sustainable solution in an industrialized society.

Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 141

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In the spray cooling of a heat surface, variations in the surface contact angle cause a change in nucleation characteristics and thereby influence the heat transfer process. The surface roughness variations affect the thickness of the liquid film formed by the spray; this has a profound effect on the heat transfer from the surface. The effect of these two parameters is studied experimentally under different spray conditions involving an air atomizing nozzle.

Author: Andrea C. Ashwood
Publisher:
ISBN:
Category :
Languages : en
Pages : 144

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Book Description

Author: S.G. Kandlikar
Publisher: Routledge
ISBN: 1351442198
Category : Science
Languages : en
Pages : 786

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Book Description
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

Author: Sai Sujith Obuladinne
Publisher:
ISBN:
Category : Fluids
Languages : en
Pages : 73

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Book Description
Two-phase spray cooling has been an emerging thermal management technique offering high heat transfer coefficients and critical heat flux levels, near-uniform surface temperatures, and efficient coolant usage that enables to design of compact and lightweight systems. Due to these capabilities, spray cooling is a promising approach for high heat flux applications in computing, power electronics, and optics. Two-phase spray cooling inherently depends on saturation temperature-pressure relationships of the working fluid to take advantage of high heat transfer rates associated with liquid-vapor phase change. When a certain application requires strict temperature and/or pressure conditions, thermo-physical properties of the working fluid play a critical role in attaining proper efficiency, reliability, or packaging structure. However, some of the commonly used single-component working fluids have relatively poor properties and heat transfer performance. For example, water is the best coolant in terms of properties, yet in certain applications where the system operates at low temperature ambient, it cannot be implemented due to freezing risk. The common solution for this problem is to use the antifreeze mixtures (binary mixtures of water and alcohol) to reduce the freezing point. In such cases, utilizing binary mixtures to tune working fluid properties becomes an alternative approach. This study has two main objectives; (1) to experimentally investigate the two-phase spray cooling performance of water/2-propanol binary mixture, and (2) to numerically investigate the performance of an advanced heat spreader featuring high and directional thermal conductivity materials for high heat flux focal sources. The first part of the study involves experimental characterization of heat transfer performance. Tests are conducted on a small-scale, closed loop spray cooling system featuring a pressure atomized spray nozzle. The test section, made of copper, measures 10 mm x 10 mm x 2 mm with a plain, smooth surface. A cylindrical copper block, with a matching size square protrusion attached onto the back side of the test section, generates heat using cartridge heaters and simulates high heat flux source. Embedded thermocouples are used to determine the spray surface temperature. The working fluid, water/alcohol mixture, has various concentration levels of 2-propanol by mass fraction 0.0 (pure water), 0.25, 0.50, 0.879 (azeotrope) and 1.0 (pure alcohol)), representing both non-azeotropic and azeotropic cases. Spray cooling tests are performed with a constant flow rate of 5.6 ml/cm2.s at subcooled temperatures (̃20oC) and atmospheric pressure. Experimental procedure involves controlling the heat flux in increasing steps, and recording the corresponding steady-state temperatures to obtain cooling curves in the form of surface superheat vs. heat flux. The second part of the study investigates an advanced heat spreader design for thermal management of a high heat flux focal source. The heat spreader comprises of three layers: a copper layer that interfaces with the heat source, a high and directional thermal conductivity material (such as CVD diamond and Pyrolytic graphite) layer, and another copper layer that is exposed to two-phase spray cooling. The analysis applies various heat fluxes on the heat source side and the experimentally obtained heat transfer coefficients on the spray side of the spreader design to determine the temperature and heat flux distributions, and examine the potential capabilities of this configuration.

Author: Amimul Ahsan
Publisher: IntechOpen
ISBN: 9789533075846
Category : Computers
Languages : en
Pages : 598

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Book Description
The heat transfer and analysis on laser beam, evaporator coils, shell-and-tube condenser, two phase flow, nanofluids, complex fluids, and on phase change are significant issues in a design of wide range of industrial processes and devices. This book includes 25 advanced and revised contributions, and it covers mainly (1) numerical modeling of heat transfer, (2) two phase flow, (3) nanofluids, and (4) phase change. The first section introduces numerical modeling of heat transfer on particles in binary gas-solid fluidization bed, solidification phenomena, thermal approaches to laser damage, and temperature and velocity distribution. The second section covers density wave instability phenomena, gas and spray-water quenching, spray cooling, wettability effect, liquid film thickness, and thermosyphon loop. The third section includes nanofluids for heat transfer, nanofluids in minichannels, potential and engineering strategies on nanofluids, and heat transfer at nanoscale. The forth section presents time-dependent melting and deformation processes of phase change material (PCM), thermal energy storage tanks using PCM, phase change in deep CO2 injector, and thermal storage device of solar hot water system. The advanced idea and information described here will be fruitful for the readers to find a sustainable solution in an industrialized society.

Author: Frank Kreith
Publisher: Springer Science & Business Media
ISBN: 3662301822
Category : Science
Languages : en
Pages : 400

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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.