Download or read book Bubble Dynamics in Microchannel Flow Boiling written by David W. Fogg and published by . This book was released on 2007 with total page 192 pages. Available in PDF, EPUB and Kindle. Book excerpt: Microchannel flow boiling is a very promising solution to the thermal management problem facing the microprocessor industry. In macroscale systems, such as nuclear reactors, flow boiling has been successful in removing large amounts of power. Unfortunately, microscale flows deviate from conventional theory. Large fluctuations in pressure, temperature, and flow distribution are generated by single bubbles due to channel confinement.

Download or read book Bubble Dynamics on Structured Surface in Microchannel written by Siyu Chen (S.M.) and published by . This book was released on 2013 with total page 72 pages. Available in PDF, EPUB and Kindle. Book excerpt: Surface enhancement is a potential way to improve the performance of flow boiling in microchannels, which is considered to be one of the most promising cooling methods to solve thermal management challenges faced by future semiconductor products. Considerable research has been done on examining the functions of engineered surfaces. However, the mechanism of how these surfaces improve the flow boiling performance is still unclear. In this thesis, bubble dynamics on micropillar array surfaces were studied. A surface energy based model is presented to predict the bubble morphology on pillar array surfaces. The results showed that bubbles tend to stay on top surfaces of pillars at solid fractions greater than 0.162, keeping liquid films underneath the bubbles. On the other hand, on surfaces at solid fraction less than 0.162, bubbles tend to propagate within the pillar unit cells. A flow loop with good degassing and a fluid temperature control system was designed and built for various flow boiling experiments. Five different types of silicon micropillar array surfaces were fabricated. Moreover a setup for observing bubble dynamics in microchannels under flow boiling conditions was developed. Experiments were performed to investigate the bubble dynamics on silicon micropillar array surfaces. Bubble departure modes were observed. The bubble departure size of direct departing mode was found to be independent with flow rate while departure size of sliding mode decreased with increasing of the flow rate. Three potential methods to create single nucleation sites for improved studies of bubble dynamics were also presented in this thesis. An experimental setup to investigate behavior of a single bubbles created by air injection on micropillar array was presented. Single 10-30 [mu]m injection holes were fabricated on micropillar array surfaces by laser cutter. The experimental results show that structured surfaces have higher bubble departure sizes than that for a plain surface. The surfaces with solid fractions greater than 0.162 had larger departure sizes than that of surfaces with solid fractions smaller than 0.162 at mass flow rates above 250 kg/m2s while departure sizes of the higher solid fraction surfaces become smaller than that of lower solid fraction surfaces when flow rates decreased below 200 kg/m2s. The similarity between the departure sizes obtained by air injection experiments and flow boiling experiments suggest that air injection experiments could provide useful information on understanding the vapor bubble departure behavior on micropillar array surfaces. Silicon micropillar array surfaces may have larger bubble departure sizes than plain surfaces, however, the surfaces with solid fractions greater than 0.162 are suggested for boiling due the a large amount of liquid thin films may create for higher heat transfer rates.

Download or read book Numerical Modeling of Bubble Dynamics and Heat Transfer on Flow Boiling Within Microchannels written by Konstantinos Vontas and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Convective Boiling and Condensation written by John G. Collier and published by Clarendon Press. This book was released on 1994-05-19 with total page 646 pages. Available in PDF, EPUB and Kindle. Book excerpt: * Third edition of a well-known and well established text both in industry and for teaching * Fully up-to-date and includes extra problems This book is an aid to heat exchanger design written primarily for design and development engineers in the chemical process, power generation, and refrigeration industries. It provides a comprehensive reference on two-phase flows, boiling, and condensation. The text covers all the latest advances like flows over tube bundles and two-phase heat transfer regarding refrigerants and petrochemicals. Another feature of this third edition is many new problems at chapter ends to enhance its use as a teaching text for graduate and post-graduate courses on two-phase flow and heat transfer. - ;This book is written for practising engineers as a comprehensive reference on two-phase flows, boiling, and condensation. It deals with methods for estimating two-phase flow pressure drops and heat transfer rates. It is a well-known reference book in its third edition and is also used as a text for advanced university courses. Both authors write from practical experience as both are professional engineers. -

Download or read book Heat Transfer and Fluid Flow in Minichannels and Microchannels written by Satish Kandlikar and published by Elsevier. This book was released on 2006 with total page 492 pages. Available in PDF, EPUB and Kindle. Book excerpt: &Quot;This book explores flow through passages with hydraulic diameters from about 1 [mu]m to 3 mm, covering the range of minichannels and microchannels. Design equations along with solved examples and practice problems are also included to serve the needs of practicing engineers and students in a graduate course."--BOOK JACKET.

Download or read book Numerical Simulation and Parametric Study of Bubble Growth During Water and Nanofluid Flow Boiling in a Microchannel written by Arman Khalighi and published by . This book was released on 2015 with total page 48 pages. Available in PDF, EPUB and Kindle. Book excerpt: In recent years, heat dissipation in micro-electronic devices has become a significant limitation for electronics manufacturers. The amount of heat generation per unit area increases as electronic devices become smaller. Micro heat exchangers have become one of the most effective cooling solutions due to their ability to remove a significant amount of heat from small electronic devices. Utilization of two phase flow in these heat exchangers provides an advantage of removing more heat than single phase flow. Microchannel is the most important part of the micro heat exchangers but it is also the most challenging part due to complications of boiling phenomenon in microchannels. Investigating the bubble dynamics inside these channels helps to better understand the bubble behavior to improve current designs of micro heat exchangers. In this study, a numerical model has been used to perform a parametric study of the bubble dynamics inside a microchannel. Effect of Reynolds number, wall superheat, and bubble contact angles has been studied. Effect of using nanofluids as a homogenous mixture to improve heat transfer has been studied, too. The results show a significant change in bubble dynamics by changing the wall superheat and bubble contact angles. On the other hand, changing the Reynolds number and nanofluid concentration were found to be less effective in altering the bubble dynamics.

Download or read book Thermal Transport in Oblique Finned Micro Minichannels written by Yan Fan and published by Springer. This book was released on 2014-11-05 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The main aim of this book is to introduce and give an overview of a novel, easy, and highly effective heat transfer augmentation technique for single-phase micro/minichannel heat sink. The specific objectives of the volume are to: Introduce a novel planar oblique fin microchannel and cylindrical oblique fin minichannel heat sink design using passive heat transfer enhancement techniques Investigate the thermal transport in both planar and cylindrical oblique fin structures through numerical simulation and systematic experimental studies. Evaluate the feasibility of employing the proposed solution in cooling non-uniform heat fluxes and hotspot suppression Conduct the similarity analysis and parametric study to obtain empirical correlations to evaluate the total heat transfer rate of the oblique fin heat sink Investigate the flow mechanism and optimize the dimensions of cylindrical oblique fin heat sink Investigate the influence of edge effect on flow and temperature uniformity in these oblique fin channels.

Download or read book Encyclopedia of Two Phase Heat Transfer and Flow IV written by John R Thome and published by World Scientific Publishing. This book was released on 2018-05-18 with total page 1372 pages. Available in PDF, EPUB and Kindle. Book excerpt: Set IV is a new addition to the previous Sets I, II and III. It contains 23 invited chapters from international specialists on the topics of numerical modeling of pulsating heat pipes and of slug flows with evaporation; lattice Boltzmann modeling of pool boiling; fundamentals of boiling in microchannels and microfin tubes, CO2 and nanofluids; testing and modeling of micro-two-phase cooling systems for electronics; and various special topics (flow separation in microfluidics, two-phase sensors, wetting of anisotropic surfaces, ultra-compact heat exchangers, etc.). The invited authors are leading university researchers and well-known engineers from leading corporate research laboratories (ABB, IBM, Nokia Bell Labs). Numerous 'must read' chapters are also included here for the two-phase community. Set IV constitutes a 'must have' engineering and research reference together with previous Sets I, II and III for thermal engineering researchers and practitioners.

Download or read book Bubble Systems written by Alexander A. Avdeev and published by Springer. This book was released on 2016-04-29 with total page 481 pages. Available in PDF, EPUB and Kindle. Book excerpt: This monograph presents a systematic analysis of bubble system mathematics, using the mechanics of two-phase systems in non-equilibrium as the scope of analysis. The author introduces the thermodynamic foundations of bubble systems, ranging from the fundamental starting points to current research challenges. This book addresses a range of topics, including description methods of multi-phase systems, boundary and initial conditions as well as coupling requirements at the phase boundary. Moreover, it presents a detailed study of the basic problems of bubble dynamics in a liquid mass: growth (dynamically and thermally controlled), collapse, bubble pulsations, bubble rise and breakup. Special emphasis is placed on bubble dynamics in turbulent flows. The analysis results are used to write integral equations governing the rate of vapor generation (condensation) in non-equilibrium flows, thus creating a basis for solving a number of practical problems. This book is the first to present a comprehensive theory of boiling shock with applications to problems of critical discharge and flashing under the fast decompression conditions. Reynolds’ analogy was the key to solving a number of problems in subcooled forced-flow boiling, the theoretical results of which led to easy-to-use design formulas. This book is primarily aimed at graduate and post-graduate students specializing in hydrodynamics or heat and mass transfer, as well as research expert focused on two-phase flow. It will also serve as a comprehensive reference book for designers working in the field of power and aerospace technology.

Download or read book Handbook of Phase Change written by S.G. Kandlikar and published by Routledge. This book was released on 2019-01-22 with total page 786 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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

Download or read book Flow Boiling in Expanding Microchannels written by Tamanna Alam and published by Springer. This book was released on 2017-05-24 with total page 89 pages. Available in PDF, EPUB and Kindle. Book excerpt: This Brief presents an up to date summary of details of the flow boiling heat transfer, pressure drop and instability characteristics; two phase flow patterns of expanding microchannels. Results obtained from the different expanding microscale geometries are presented for comparison and addition to that, comparison with literatures is also performed. Finally, parametric studies are performed and presented in the brief. The findings from this study could help in understanding the complex microscale flow boiling behavior and aid in the design and implementation of reliable compact heat sinks for practical applications.

Download or read book Experimental Investigation of Nucleate Boiling Bubble Dynamics in Normal and Zero Gravities written by Thomas H. Cochran and published by . This book was released on 1968 with total page 26 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Bubble Dynamics During Boiling in Enhanced Surface Microchannels written by Chih-Jung Kuo and published by . This book was released on 2005 with total page 54 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Critical Heat Flux in Flow Boiling in Microchannels written by Sujoy Kumar Saha and published by Springer. This book was released on 2015-06-04 with total page 62 pages. Available in PDF, EPUB and Kindle. Book excerpt: This Brief concerns the important problem of critical heat flux in flow boiling in microchannels. A companion edition in the SpringerBrief Subseries on Thermal Engineering and Applied Science to “Heat Transfer and Pressure Drop in Flow Boiling in Microchannels,” by the same author team, this volume is idea for professionals, researchers, and graduate students concerned with electronic cooling.

Download or read book Two Phase Flow Boiling and Condensation written by S. Mostafa Ghiaasiaan and published by Cambridge University Press. This book was released on 2014-08-07 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This text is an introduction to gas-liquid two-phase flow, boiling and condensation for graduate students, professionals, and researchers in mechanical, nuclear, and chemical engineering. The book provides a balanced coverage of two-phase flow and phase change fundamentals, well-established art and science dealing with conventional systems, and the rapidly developing areas of microchannel flow and heat transfer. It is based on the author's more than 15 years of teaching experience. Instructors teaching multiphase flow have had to rely on a multitude of books and reference materials. This book remedies that problem by covering all the topics that are essential for a graduate first course. Among the important areas that are discussed in the book, and are not adequately covered by virtually all the available textbooks, are: two-phase flow model conservation equations and their numerical solution; condensation with and without noncondensables; and two-phase flow, boiling, and condensation in mini and microchannels.

Download or read book Numerical Study of Single Bubble Dynamics During Flow Boiling written by Ding Li and published by . This book was released on 2005 with total page 712 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Forced Convection Flow Boiling and Two phase Flow Phenomena in a Microchannel written by Yun Whan Na and published by . This book was released on 2008 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: ABSTRACT: The present study was performed to numerically analyze the evaporation phenomena through the liquid-vapor interface and to investigate bubble dynamics and heat transfer behavior during forced convective flow boiling in a microchannel. Flow instabilities of two-phase flow boiling in a microchannel were studied as well. The main objective of this research is to investigate the fundamental mechanisms of two-phase flow boiling in a microchannel and provide predictive tools to design thermal management systems, for example, microchannel heat sinks. The numerical results obtained from this study were qualitatively and quantitatively compared with experimental results in the open literature.