Download or read book Experimental and Numerical Study on Flow Boiling with an Advanced Structure in Microchannel written by Xiangfei Yu and published by . This book was released on 2017 with total page 252 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Flow Boiling in Microgap Channels written by Tamanna Alam and published by Springer Science & Business Media. This book was released on 2013-08-26 with total page 88 pages. Available in PDF, EPUB and Kindle. Book excerpt: Flow Boiling in Microgap Channels: Experiment, Visualization and Analysis presents an up-to-date summary of the details of the confined to unconfined flow boiling transition criteria, flow boiling heat transfer and pressure drop characteristics, instability characteristics, two phase flow pattern and flow regime map and the parametric study of microgap dimension. Advantages of flow boiling in microgaps over microchannels are also highlighted. The objective of this Brief is to obtain a better fundamental understanding of the flow boiling processes, compare the performance between microgap and conventional microchannel heat sinks, and evaluate the microgap heat sink for instabilities and hotspot mitigation.

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 Flow Boiling in Microgap Channels written by Tamanna Alam and published by Springer. This book was released on 2013-08-26 with total page 84 pages. Available in PDF, EPUB and Kindle. Book excerpt: Flow Boiling in Microgap Channels: Experiment, Visualization and Analysis presents an up-to-date summary of the details of the confined to unconfined flow boiling transition criteria, flow boiling heat transfer and pressure drop characteristics, instability characteristics, two phase flow pattern and flow regime map and the parametric study of microgap dimension. Advantages of flow boiling in microgaps over microchannels are also highlighted. The objective of this Brief is to obtain a better fundamental understanding of the flow boiling processes, compare the performance between microgap and conventional microchannel heat sinks, and evaluate the microgap heat sink for instabilities and hotspot mitigation.

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 Numerical Investigation on the Effect of Gravitational Orientation on Bubble Growth During Flow Boiling in a High Aspect Ratio Microchannel written by Jarryd Potgieter and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Recent technological developments, mostly in the fields of concentrated solar power and microelectronics, have driven heat transfer requirements higher than current heat exchangers are capable of producing. Processing power is increasing, while processor size simultaneously decreases and the heat flux requirements of concentrating solar power plants are being driven up by the high temperatures that produce the best thermal efficiency. Heat transfer in microchannels, specifically when utilising flow boiling, has been shown to produce significantly higher heat fluxes than their macro-scale counterparts and could have a large impact on many industrial fields. This high heat transfer characteristic is caused by a number of factors, including the large difference between the sensible and latent heat of the working fluid and the evaporation of a thin liquid film that forms between the microchannel walls and the vapour bubbles. These phenomena occur at incredibly small scales. Flow visualisations, temperature and pressure measurements are therefore difficult to obtain. Many experiments that cover a wide range of microchannel sizes, shapes and orientations, and utilise different working fluids and heat fluxes have been reported. However, the correlations between confined boiling, heat flux and pressure drop have mostly been produced for macro-scale flow. Many different criteria have been developed to distinguish the macro scale from the micro scale, but the general consensus is that macro-scale heat transfer correlations do not perform well when used in the micro scale. Heat transfer correlations are typically created by performing physical experiments over a wide range of parameters and then quantifying the effect that varying these parameters has on the performance of the system. The small scale and high complexity of microchannel-based heat exchangers make visualising the flow within them difficult and inaccurate because both the working fluid and the microchannel walls distort light. The use of numerical modelling via computational fluid dynamics software allows phenomena that occur within the channel to be simulated, which provides valuable insight into how rapid bubble growth affects the surrounding fluid, which can lead to the design of better heat exchangers. This study focused on numerically modelling the growth of a single bubble during the flow boiling of FC-72 in a microchannel with a hydraulic diameter of 0.9 mm and an aspect ratio of 10. The numerical domain was limited to a 10 mm section of the microchannel where bubble nucleation and detachment were observed in an experimental study on a similar microchannel setup. The high cost of 3D simulations was offset by an interface-tracking mesh refinement method, which refined cells not only at the interface, but also a set distance on either side of the interface. To focus on the effects of gravity, a simplified approach is used, which isolates certain phenomena. Density gradients, material roughness and multiple bubble interaction are ignored so that the effects of buoyancy and bubble detachment can be analysed. Simulations are first performed in a 2D section through the centre of the microchannel, and then in the full 3D domain. In both the 3D numerical and experimental cases (Meyer et al., 2020), the bottom heated case had the lowest maximum temperature and the highest heat transfer characteristics, which were influenced by the detachment of the bubble from the heated surface. This observation indicates that the gravitational orientation of the channel can have a significant effect on the heat transfer characteristics of microchannel-based heat exchangers, and that more investigation is required to characterise the extent of this effect.

Download or read book Heat Transfer in Boiling written by Erich Hahne and published by . This book was released on 1977 with total page 508 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Flow boiling and condensation in microscale channels written by Fabio Toshio Kanizawa and published by Springer Nature. This book was released on 2021-04-30 with total page 290 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book covers aspects of multiphase flow and heat transfer during phase change processes, focusing on boiling and condensation in microscale channels. The authors present up-to-date predictive methods for flow pattern, void fraction, pressure drop, heat transfer coefficient and critical heat flux, pointing out the range of operational conditions that each method is valid. The first four chapters are dedicated on the motivation to study multiphase flow and heat transfer during phase change process, and the three last chapters are focused on the analysis of heat transfer process during boiling and condensation. During the description of the models and predictive methods, the trends are discussed and compared with experimental findings.

Download or read book Experimental Investigation and Analytical Modeling of Flow Boiling Characteristics in Silicon Microchannel Arrays written by Ayman Megahed and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Emerging Topics in Heat Transfer written by Qiuwang Wang and published by WIT Press. This book was released on 2013-11-06 with total page 417 pages. Available in PDF, EPUB and Kindle. Book excerpt: Presented in ten edited chapters this book encompasses important emerging topics in heat transfer equipment, particularly heat exchangers. The chapters have all been selected by invitation only. Advances in high temperature equipment and small scale devices continue to be important as the involved heat transfer and related phenomena are often complex in nature and different mechanisms like heat conduction, convection, turbulence, thermal radiation and phase change as well as chemical reactions may occur simultaneously. The book treats various operating problems, like fouling, and highlights applications in heat exchangers and gas turbine cooling. In engineering design and development, reliable and accurate computational methods are required to replace or complement expensive and time consuming experimental trial and error work. Tremendous advancements in knowledge and competence have been achieved during recent years due to improved computational solution methods for non-linear partial differential equations, turbulence modelling advancement and developments of computers and computing algorithms to achieve efficient and rapid simulations. The chapters of the book thoroughly present such advancement in a variety of applications.

Download or read book Compact Heat Exchangers written by Alexander Louis London and published by CRC Press. This book was released on 1990 with total page 798 pages. Available in PDF, EPUB and Kindle. Book excerpt: Heat exchangers are a crucial part of aerospace, marine, cryogenic and refrigeration technology. These essays cover such topics as complicated flow arrangements, complex extended surfaces, two-phase flow and irreversibility in heat exchangers, and single-phase heat transfer.

Download or read book Experimental Study of Flow Boiling Heat Transfer and Critical Heat Flux in Microchannels written by Wai Keat Kuan and published by . This book was released on 2006 with total page 584 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Advancements in microprocessors and other high power electronics have resulted in increased heat dissipation from those devices. In addition, to reduce cost, the functionality of microprocessor per unit area has been increasing. The increase in functionality accompanied by reduction in chip size has caused its thermal management to be challenging. In order to dissipate the increase in heat generation, the size of conventional fin-type heat sinks has to be increased. As a result, the performance of these high heat flux generating electronics is often limited by the available cooling technology and space to accommodate the larger conventional air-cooled heat sinks. One way to enhance heat transfer from electronics without sacrificing their performance is the use of heat sink with many microchannels and liquid passing through it. The present work is aimed toward understanding the flow boiling stability and critical heat flux (CHF) with water and R-123 in microchannel passages. Experimental data and theoretical model to predict the heat transfer and CHF are the focus of this work. The experimental test section has six parallel microchannels with each having a cross sectional area of 1054 x 157 um2 or 1054 x 197 um2. The effect of flow instabilities in microchannels is investigated using flow restrictors at the inlet of each microchannel to stabilize the flow boiling process and avoid the backflow phenomena. This technique resulted in successfully stabilizing the flow boiling process as seen through a high-speed camera. The present CHF result is found to correlate to mean absolute error (MAE) of 24.1% with a macro-scale empirical equation by Katto et al. A theoretical analysis of flow boiling phenomena revealed that the ratio of evaporation momentum to surface tension forces is an important parameter. For the first time, a theoretical CHF model is proposed using these underlying forces to represent CHF mechanism in microchannels, and its correlation agrees with the experiemental data with overall MAE of 12.3%. CHF is found to increase with increasing mass flux, and it leads to a change in the flow pattern from a wetted film flow to liquid streams that flow in the core of the flow"--Abstract.

Download or read book Microscale and Nanoscale Heat Transfer written by C.B. Sobhan and published by CRC Press. This book was released on 2008-06-12 with total page 317 pages. Available in PDF, EPUB and Kindle. Book excerpt: Through analyses, experimental results, and worked-out numerical examples, Microscale and Nanoscale Heat Transfer: Fundamentals and Engineering Applications explores the methods and observations of thermophysical phenomena in size-affected domains. Compiling the most relevant findings from the literature, along with results from their own re

Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1995 with total page 702 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Translational Research in Cardio Oncology An Issue of Heart Failure Clinics written by Ragavendra R. Baliga and published by Elsevier Health Sciences. This book was released on 2022-06-23 with total page 217 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this issue of Heart Failure Clinics, guest editors Drs. Ragavendra R Baliga and George A. Mensah bring their considerable expertise to the topic of Translational Research in Cardio-Oncology. Top experts in the field cover key topics such as radiation-induced cardiac dysfunction; training and career development; cardiovascular imaging; CAR-T cell therapy and cardiovascular disease; and more. Contains 12 relevant, practice-oriented topics including cardio-protection of high-risk individuals; myocardial metabolism; amyloidosis; arrhythmic complications associated with cancer therapies; and more. Provides in-depth clinical reviews on translational research in cardio-oncology, offering actionable insights for clinical practice. Presents the latest information on this timely, focused topic under the leadership of experienced editors in the field. Authors synthesize and distill the latest research and practice guidelines to create clinically significant, topic-based reviews.

Download or read book Experimental and Numerical Study of Fluid Mixing in a Lid driven Cavity Flow Model and Its Application to Micro channels written by Kai Kang and published by . This book was released on 2004 with total page 352 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Experimental Investigation and Numerical Simulation of Fluid Flow and Heat Transfer in Microchannels written by Toru Yamada and published by . This book was released on 2011 with total page 240 pages. Available in PDF, EPUB and Kindle. Book excerpt: