Download or read book Heat Transfer and Pressure Drop Augmentation in Micro Channels with Pin Fins written by Stephen Weaver and published by . This book was released on 2010 with total page 89 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Experimental Study of Heat Transfer and Pressure Drop Over an Array of Short Micro Pin Fins written by Aditya Bhat and published by . This book was released on 2015 with total page 106 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Studies on thermal enhancement for electronic chips has been gaining prominence as increased transistor density in the chips calls for larger heat dissipation. Various enhancement techniques have been proposed ever since 1981, to enhance the heat dissipation from the chip surface. Micro pin fins have been gaining recognition as a highly favorable surface enhancement due to the design versatility it provides in the form of myriad geometric shapes and fin arrangements as opposed to convention microchannels. The micro pin fins however, present a larger pressure drop over the surface as compared to other conventional methods which reduces the thermal efficiency of the chip surface. To reduce the pressure drop associated with micro pin fins, short micro pin fins were proposed. A short micro pin fin arrangement is similar to micro pin fin arrays, with one change, in that short micro pin fins have a clearance between the fins and the top of the channel. The current study focusses on heat transfer and pressure drop over short micro pin fin arrays. Experimental studies were conducted over 10 mm × 10 mm with fin heights varying from 200 to 500 [microns] and clearance over the fins varying from 265 to 900 μm. Distilled water was used as the cooling medium. The heat transfer coefficient and pressure drop characteristics were evaluated at varying fin heights and varying clearance of the surfaces with an aim to identify optimum fin height and clearance parameters. The heat transfer coefficient and pressure drop data obtained from experiments were also evaluated with the correlation proposed by Tullius et al. Data showed that the highest heat transfer coefficient was observed for fins with the largest fin height. When fin clearance was evaluated for its effect on heat transfer coefficient, a hint of mixing phenomenon leading to enhancement in heat transfer coefficient was observed at higher clearance values. A higher pressure drop was observed at longer fins owing to the increased friction factor at the fin walls. The highest pressure drop of over 100 kPa was observed for a chip gasket combination which consisted of the longest fins with the least amount of clearance. It was also observed that the Nusselt number and Pressure drop correlations proposed by Tullius et al was not able to accurately predict the experimental data. However, the correlation did show the same trend as the experimental data, hence, the present correlation could be modified or used as a basis for new correlations of Nusselt number and friction factor."--Abstract.
Download or read book Advances in Heat Transfer Enhancement written by Sujoy Kumar Saha and published by Springer. This book was released on 2016-04-23 with total page 128 pages. Available in PDF, EPUB and Kindle. Book excerpt: This Brief addresses the phenomena of heat transfer enhancement. A companion edition in the SpringerBrief Subseries on Thermal Engineering and Applied Science to three other monographs including “Critical Heat Flux in Flow Boiling in Microchannels,” this volume is idea for professionals, researchers, and graduate students concerned with electronic cooling.
Download or read book Heat Transfer and Pressure Drop in Flow Boiling in Microchannels written by Sujoy Kumar Saha and published by Springer. This book was released on 2015-07-08 with total page 63 pages. Available in PDF, EPUB and Kindle. Book excerpt: This Brief addresses the phenomena of heat transfer and pressure drop in flow boiling in micro channels occurring in high heat flux electronic cooling. A companion edition in the Springer Brief Subseries on Thermal Engineering and Applied Science to “Critical Heat Flux in Flow Boiling in Micro channels,” by the same author team, this volume is idea for professionals, researchers and graduate students concerned with electronic cooling.
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 Next Generation Microchannel Heat Exchangers written by Michael Ohadi and published by Springer Science & Business Media. This book was released on 2012-10-16 with total page 124 pages. Available in PDF, EPUB and Kindle. Book excerpt: In Next Generation Microchannel Heat Exchangers, the authors’ focus on the new generation highly efficient heat exchangers and presentation of novel data and technical expertise not available in the open literature. Next generation micro channels offer record high heat transfer coefficients with pressure drops much less than conventional micro channel heat exchangers. These inherent features promise fast penetration into many mew markets, including high heat flux cooling of electronics, waste heat recovery and energy efficiency enhancement applications, alternative energy systems, as well as applications in mass exchangers and chemical reactor systems. The combination of up to the minute research findings and technical know-how make this book very timely as the search for high performance heat and mass exchangers that can cut costs in materials consumption intensifies.
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 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 Thermal Transport in Oblique Finned Micro Minichannels written by Yan Fan and published by Springer. This book was released on 2014-10-15 with total page 143 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 Analysis of Conjugate Heat Transfer and Pressure Drop in Microchannels for Different Aspects Ratios written by Marc Robert Greenland and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: In this study the heat transfer and hydrodynamic parameters were experimentally investigated for a single microchannel housed in a stainless steel solid base material for different aspect ratios in the laminar regime with water as the working fluid. The stainless steel base material had a low thermal conductivity (15.1 W / mK) which magnified the conjugative effects in order to better understand the heat transfer. Rectangular microchannels with a height and width of 0.64 mm x 0.41 mm for Test Section 1, 0.5 mm x 0.5 mm for Test Section 2 and 0.43 mm x 0.58 mm for Test Section 3 were considered. The overall width of the solid substrate was 1.5 mm and the length was 50 mm for all of the test sections. The aspect ratio of the channel and the solid substrate was kept equal. A constant heat flux of 10 W / cm2 was applied to the bottom outer wall of the test section. A sudden contraction inlet and a sudden expansion outlet manifold contained pressure ports, to measure the pressure drop across the test sections, and thermocouples measured the mean inlet and outlet fluid temperatures. Thermocouples were used to measure the outer top and side wall temperatures at four equally spaced positions along the axial direction. The amount of axial heat conduction was below 0.6 % for all of the test sections and therefore warranted the use of a two-dimensional conduction model to determine the heat transfer parameters at the fluid to solid interface based on the outer measured wall temperatures. The local Nusselt number decreased, along the axial direction but increased towards the exit for all of the test sections. The average Nusselt number increased with the flow rate and the critical Reynolds number for fully turbulent flow Test Section 1 was 1950, for Test Section 2 was 2250 and for Test Section 3 was 1650. The average Nusselt number was directly related to the perimeter of the microchannels two side walls and the bottom wall (not the top wall), and thus decreased as the aspect ratio of the channel increased. The experimentally determined Nusselt numbers were larger for all three test sections when compared to common acceptable correlations. The friction factor decreased with the flow rate and was smaller in magnitude when compared to conventional theories. The diabatic friction factor magnitudes were smaller than the adiabatic friction factors. The friction factor decreased as the aspect ratio decreased, where the aspect ratio was calculated by taking the maximum of the microchannels width or height, divided by the minimum of the two. The possibility of a relationship could exist between the Colburn j-factor and the friction factor when considering the results for Test Section 1 and Test Section 2 but the results for Test Section 3 were significantly different.
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 Pressure Drop in a Compact Pin Fin Heat Exchanger with Pin Orientation at 18 Deg to the Flow Direction written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-07-08 with total page 86 pages. Available in PDF, EPUB and Kindle. Book excerpt: The heat transfer and pressure drop characteristics of a novel, compact heat exchanger in helium gas were measured at 3.5 MPa and Reynolds numbers of 450 to 12,000. The pin-fin specimen consisted of pins, 0.51 mm high and spaced 2.03 mm on centers, spanning a channel through which the helium flows; the angle of the row of pins to the flow direction was 18 deg. The specimen was radiatively heated on the top side at heat fluxes up to 74 W/sq cm and insulated on the back side. Correlations were developed for the friction factor and Nusselt number. The Nusselt number compares favorably to those of past studies of staggered pin-fins, when the measured temperatures are extrapolated to the temperature of the wall-fluid interface. Olson, D. A. Unspecified Center...
Download or read book Single phase Liquid Flow and Heat Transfer in Plain and Enhanced Silicon Microchannels written by Mark E. Steinke and published by . This book was released on 2005 with total page 520 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Microscale heat transfer and microfluidics have become increasingly important to overcome some very complex engineering challenges. The use of very small passages to gain heat transfer enhancement is a well documented method for achieving high heat flux dissipation. However, some interesting experimental results have caused researchers to question if the conventional theories for fluid flow and heat transfer are valid in the microscale passages. However, there is no significant physical basis for the discrepancies with single-phase liquid flows when the passage is scaled to the microscale. The present work identifies the sources of the discrepancies reported in literature and provides a method to correct for them. In the course of this pursuit, a new experimental facility is developed to generate highly accurate experimental data for single-phase flow of water. The new experimental data are used to highlight the sources of discrepancies and illustrate a course of action to correct for them. Finally, a novel method for creating even greater heat transfer enhancement has been realized. Small offset fins have been fabricated in silicon microchannels in order to create a constantly developing flow in the microchannel heat exchanger and thus heat transfer enhancement. A new parameter based upon the heat flux dissipated and the pressure drop required is developed to aid in the comparison between these enhanced silicon microchannels and plain geometry silicon microchannels. The result is an order of magnitude increase in thermal performance with a marginal increase in overall pressure drop"--Abstract.
Download or read book Laminar Flow Forced Convection in Ducts written by R. K. Shah and published by Academic Press. This book was released on 2014-06-28 with total page 492 pages. Available in PDF, EPUB and Kindle. Book excerpt: Laminar Flow Forced Convection in Ducts is a sourcebook for compact heat exchanger analytical data. This book describes the analytical solutions for laminar fluid flow and forced convection heat transfer in circular and noncircular pipes, including applicable differential equations and boundary conditions involving velocity and temperature problems of fluid flow. The book also discusses fluid flow—how much power is required to pump fluids through the heat exchanger, as well as the heat transfer—the determination of q" distribution, and the temperature of fluid and walls. The text also analyzes the coolant or heat transfer fluid flows in a nuclear power reactor composed of a bundle of circular section fuel rods located inside a round tube. R.A. Axford addresses fluid flow and heat transfers results for the rod bundle geometry in "Heat Transfer in Rod Bundles." The book also provides an overview and guidelines that can be used for the designer and the applied mathematician. This book is suitable for engineers working in electronics, aerospace, instrumentation, and biomechanics that use cooling or heating exchanges or solar collection systems.
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 Measurement of Pressure Drop and Heat Transfer Analysis of Microchannels written by Cormac James Eason and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Microchannels Enhanced by Porous Materials Heat Transfer Enhancement Or Pressure Drop Increment written by and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
