Academic literature on the topic 'Single-Phase Forced Convection Cooling'
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Journal articles on the topic "Single-Phase Forced Convection Cooling"
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Bejan, Adrian. "Optimal Internal Structure of Volumes Cooled by Single-Phase Forced and Natural Convection." Journal of Electronic Packaging 125, no. 2 (June 1, 2003): 200–207. http://dx.doi.org/10.1115/1.1566970.
Full textAbstract:
This article is a principle-based review of a growing body of fundamental research that documents the opportunity for optimizing geometrically the cooling of spaces (e.g., electronics packages) that generate heat volumetrically. The chief result of geometric optimization is the identification of an optimal internal structure—optimal spacings between components (e.g., plates and fins), optimal sizes and aspect ratios for cooling channels, and optimal frequencies for pulsating flows. The origin of these optimal geometric features—the construction of the system—lies in the global effort to use every infinitesimal volume to the maximum, i.e., to pack the volume not only with the most heat generating components, but also with the ‘most’ coolant, in such a way that every fluid packet is engaged effectively in cooling. The optimal aspect ratio for ducts with forced and natural convection corresponds to the special geometry and flow conditions where boundary layers meet just as the coolant exits the channel. This “constructal” design principle is illustrated by several classes of examples: laminar forced and natural convection, and various internal arrangements (parallel plates, staggered plates, cylinders in cross flow, square pins with impinging flow). General trends (scaling laws) of optimal geometric form are revealed by the optimal-structure results, this, in spite of the diversity of the optimized configurations.
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Dietz, C. R., and Y. K. Joshi. "Single-Phase Forced Convection in Microchannels with Carbon Nanotubes for Electronics Cooling Applications." Nanoscale and Microscale Thermophysical Engineering 12, no. 3 (September 5, 2008): 251–71. http://dx.doi.org/10.1080/15567260802171937.
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Maddox, D. E., and I. Mudawar. "Single- and Two-Phase Convective Heat Transfer From Smooth and Enhanced Microelectronic Heat Sources in a Rectangular Channel." Journal of Heat Transfer 111, no. 4 (November 1, 1989): 1045–52. http://dx.doi.org/10.1115/1.3250766.
Full textAbstract:
Experiments have been performed to assess the feasibility of cooling microelectronic components by means of single-phase and two-phase forced convection. Tests were conducted using a single heat source flush mounted to one wall of a vertical rectangular channel. An inert fluorocarbon liquid (FC-72) was circulated upward through the channel at velocities up to 4.1 m/s and with subcooling up to 46°C. The simulated microelectronic heat sources tested in this study include a smooth surface and three low-profile microstud surfaces of varying stud height, each having a base area of 12.7×12.7 mm2. Correlations were developed for the single-phase convective heat transfer coefficient over the Reynolds number range from 2800 to 1.5 × 105, where Reynolds number is based on the length of the heater. The results demonstrate that the low thermal resistances required for cooling of microelectronic heat sources may be achieved with single-phase forced convection by using high fluid velocity coupled with surface enhancement. Experiments were also performed to understand better the parametric trends of boiling heat transfer from the simulated microelectronic heat source. It was found that increased velocity and subcooling and the use of microstud surfaces enhance nucleate boiling, increase the critical heat flux, and reduce the magnitude of temperature overshoot upon the inception of nucleation.
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Tou, K. W., G. P. Xu, and C. P. Tso. "DIRECT LIQUID COOLING OF ELECTRONIC CHIPS BY SINGLE-PHASE FORCED CONVECTION OF FC-72." Experimental Heat Transfer 11, no. 2 (April 1998): 121–34. http://dx.doi.org/10.1080/08916159808946557.
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Heindel, T. J., F. P. Incropera, and S. Ramadhyani. "Liquid Immersion Cooling of a Longitudinal Array of Discrete Heat Sources in Protruding Substrates: I—Single-Phase Convection." Journal of Electronic Packaging 114, no. 1 (March 1, 1992): 55–62. http://dx.doi.org/10.1115/1.2905442.
Full textAbstract:
Experiments have been performed using water and FC-77 to investigate heat transfer from an in-line 1 x 10 array of discrete heat sources, flush mounted to protruding substrates located on the bottom wall of a horizontal flow channel. The data encompass flow regimes ranging from mixed convection to laminar and turbulent forced convection. Buoyancy-induced secondary flows enhanced heat transfer at downstream heater locations and provided heat transfer coefficients comparable to upstream values. Upstream heating extended enhancement on the downstream heaters to larger Reynolds numbers. Higher Prandtl number fluids also extended heat transfer enhancement to larger Reynolds numbers, while a reduction in channel height suppressed buoyancy driven flows, thereby reducing enhancement. The protrusions enhanced the transition to turbulent forced convection, causing the critical Reynolds number to decrease with increasing row number. The transition region was characterized by large heater-to-heater variations in the average Nusselt number.
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Bar-Cohen, Avram, and Karl J. L. Geisler. "Cooling the Electronic Brain." Mechanical Engineering 133, no. 04 (April 1, 2011): 38–41. http://dx.doi.org/10.1115/1.2011-apr-3.
Full textAbstract:
This article discusses findings of some immersion cooling studies carried out to define the potential of direct liquid cooling of three-dimensional chip stacks. Four possible immersion cooling strategies were assessed. These included two active cooling strategies and two passive cooling strategies. The cooling densities for all four immersion cooling techniques were determined assuming the use of Fluorinert FC-72, a commonly used perfluorinated dielectric liquid. For passive systems, the cooling densities ranged from 25 W/cm3 for natural convection to 200–400 W/cm3 for pool boiling. For active technologies, the densities were 100–300 W/cm3 for forced convection and more than 2000 W/cm3 for flow boiling. It was found that the optimum die spacings for both single- and two-phase direct cooling was in the range of 0.2–0.6 mm for typical microelectronics geometries, though substantial cooling densities could be achieved at less-than-optimum spacings.
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Tulich, Stefan N., and Brian E. Mapes. "Multiscale Convective Wave Disturbances in the Tropics: Insights from a Two-Dimensional Cloud-Resolving Model." Journal of the Atmospheric Sciences 65, no. 1 (January 1, 2008): 140–55. http://dx.doi.org/10.1175/2007jas2353.1.
Full textAbstract:
Abstract Multiscale convective wave disturbances with structures broadly resembling observed tropical waves are found to emerge spontaneously in a nonrotating, two-dimensional cloud model forced by uniform cooling. To articulate the dynamics of these waves, model outputs are objectively analyzed in a discrete truncated space consisting of three cloud types (shallow convective, deep convective, and stratiform) and three dynamical vertical wavelength bands. Model experiments confirm that diabatic processes in deep convective and stratiform regions are essential to the formation of multiscale convective wave patterns. Specifically, upper-level heating (together with low-level cooling) serves to preferentially excite discrete horizontally propagating wave packets with roughly a full-wavelength structure in troposphere and “dry” phase speeds cn in the range 16–18 m s−1. These wave packets enhance the triggering of new deep convective cloud systems, via low-level destabilization. The new convection in turn causes additional heating over cooling, through delayed development of high-based deep convective cells with persistent stratiform anvils. This delayed forcing leads to an intensification and then widening of the low-level cold phases of wave packets as they move through convecting regions. Additional widening occurs when slower-moving (∼8 m s−1) “gust front” wave packets excited by cooling just above the boundary layer trigger additional deep convection in the vicinity of earlier convection. Shallow convection, meanwhile, provides positive forcing that reduces convective wave speeds and destroys relatively small-amplitude-sized waves. Experiments with prescribed modal wind damping establish the critical role of short vertical wavelengths in setting the equivalent depth of the waves. However, damping of deep vertical wavelengths prevents the clustering of mesoscale convective wave disturbances into larger-scale envelopes, so these circulations are important as well.
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López-Cornejo, Monserrat Sofía, Héctor Javier Vergara-Hernández, Sixtos Antonio Arreola-Villa, Octavio Vázquez-Gómez, and Martín Herrejón-Escutia. "Numerical Simulation of Wire Rod Cooling in Eutectoid Steel under Forced-Convection." Metals 11, no. 2 (January 28, 2021): 224. http://dx.doi.org/10.3390/met11020224.
Full textAbstract:
A coupled thermal-microstructural simulation model was developed to estimate the thermal history in a eutectoid steel wire rod under continuous cooling and forced-convection. The model coupled the phenomena of heat transfer, phase transformation and estimation of the cooling boundary condition. The thermal histories were analyzed at different cooling rates to emulate the forced-convection conditions by air-jet as in the controlled cooling conveyor. The thermal histories were acquired and used to calculate the forced-convection heat transfer coefficients through the solution of the Inverse Heat Conduction Problem, while the phase transformation was approximated with the Johnson–Mehl–Avrami–Kolmogorov (JMAK) kinetic model. From the heat transfer coefficients and the kinetic parameters, a user-defined function (UDF) was coded and employed in the ANSYS Fluent® software. The model results were compared and validated with the experimental histories, obtaining a good agreement between both responses, while the microstructural evolution of the pearlite was validated using Scanning Electron Microscopy (SEM) and Vickers microhardness. It was found that specimen diameter and air velocity are the main variables to modify the undercooling and therefore the pearlite interlamellar spacing.
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Gersey, Christopher O., Thomas C. Willingham, and Issam Mudawar. "Design Parameters and Practical Considerations in the Two-Phase Forced-Convection Cooling of Multi-Chip Modules." Journal of Electronic Packaging 114, no. 3 (September 1, 1992): 280–89. http://dx.doi.org/10.1115/1.2905452.
Full textAbstract:
Forced-convection boiling was investigated with a dielectric coolant (FC-72) in order to address some of the practical issues related to the two-phase cooling of multi-chip modules. The module used in the present study featured a linear array of nine, 10 × 10 mm2, simulated microelectronic chips which were flush-mounted along a 20-mm wide side of a rectangular channel. Experiments were performed with a 5-mm channel gap (distance between the chip surface and the opposing channel wall) at eight orientations spaced 45 degrees apart. Two other channel gaps, 2 and 10 mm, were tested in the vertical up flow configuration. For all these configurations, the velocity and subcooling of the liquid were varied from 13 to 400 cm/s and 3 to 36°C, respectively. Changes in orientation did not affect single-phase or nucleate boiling characteristics, but did have a major impact on CHF. Upflow conditions were found to be the best configuration for the design of two-phase cooling modules because of its inherently stable flow and relatively high CHF values. The CHF value for the most upstream chip in vertical upflow agreed well with a previous correlation for an isolated chip. Combined with the relatively small spread in CHF values for all chips in the array, this correlation was found to be attractive for design purposes in predicting CHF for a multi-chip array. To achieve a given CHF value, it is shown how the strong CHF dependence on velocity rather than flow area allows for a reduction in the required flow rate with the 2-mm, as compared to the 5-mm gap, which also required a smaller flow rate than the 10-mm gap. This reduction inflow rate was significant only with subcooled conditions corresponding to high CHF values.
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Panse, Sanskar S., and Srinath V. Ekkad. "Forced convection cooling of additively manufactured single and double layer enhanced microchannels." International Journal of Heat and Mass Transfer 168 (April 2021): 120881. http://dx.doi.org/10.1016/j.ijheatmasstransfer.2020.120881.
Full textDissertations / Theses on the topic "Single-Phase Forced Convection Cooling"
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Dietz, Carter Reynolds. "Single-phase forced convection in a microchannel with carbon nanotubes for electronic cooling applications." Thesis, Available online, Georgia Institute of Technology, 2007, 2007. http://etd.gatech.edu/theses/available/etd-07052007-155623/.
Full textAbstract:
Thesis (M. S.)--Mechanical Engineering, Georgia Institute of Technology, 2008.Dr. David Gerlach, Committee Member ; Dr. Samuel Graham, Committee Member ; Dr. Minami Yoda, Committee Member ; Dr. Yogendra Joshi, Committee Chair.
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Gupta, Abhishek. "Experimental and theoretical analysis of single-phase convective heat transfer in channel with resistive heater and thermoelectric modules for hydronic cooling and heating device." Cincinnati, Ohio : University of Cincinnati, 2009. http://www.ohiolink.edu/etd/view.cgi?acc_num=ucin1236202446.
Full textAbstract:
Thesis (M.S.)--University of Cincinnati, 2009.Advisors: Dr. Michael Kazmierczak PhD (Committee Chair), Dr. Milind A. Jog PhD (Committee Member), Dr. Sang Y. Son PhD (Committee Member). Title from electronic thesis title page (viewed April 26, 2009). Includes abstract. Keywords: Peltier cooling; developing internal turbulent forced convection; heat pump and coefficient-of-performance. Includes bibliographical references.
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Ates, Ahmet Muaz. "Experimental Comparison Of Fluid And Thermal Characteristics Of Microchannel And Metal Foam Heat Sinks." Master's thesis, METU, 2011. http://etd.lib.metu.edu.tr/upload/12613577/index.pdf.
Full textAbstract:
Doubling transistor count for every two years in a computer chip, transmitter and receiver (T/R) module of a phased-array antenna that demands higher power with smaller dimensions are all results of miniaturization in electronics packaging. These technologies nowadays depend on improvement of reliable high performance heat sink to perform in narrower volumes. Employing microchannels or open cell metal foam heat sinks are two recently developing promising methods of cooling high heat fluxes. Although recent studies especially on microchannels can give a rough estimate on performances of these two methods, since using metal foams as heat sinks is still needed further studies, a direct experimental comparison of heat exchanger performances of these two techniques is still needed especially for thermal design engineers to decide the method of cooling.
For this study, microchannels with channel widths of 300 µm, 420 µ
m, 500 µ
m and 900 µ
m were produced. Also, 92% porous 10, 20 and 40 ppi 6101-T6 open cell aluminum metal foams with compression factors 1,2, and 3 that have the same finned volume of microchannels with exactly same dimensions were used to manufacture heat sinks with method of vacuum brazing. They all have tested under same conditions with volumetric flow rate ranging from 0,167 l/min to 1,33 l/min and 60 W of heat power. Channel height was 4 mm for all heat sinks and distilled water used as cooling fluid. After experiments, pressure drops and thermal resistances were compared with tabulated and graphical forms. Also, the use of metal foam and microchannel heat sinks were highlighted with their advantages and disadvantages for future projects.
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Novak, Vladimir. "Experimental and Numerical Studies of Mist Cooling with Thin Evaporating Subcooled Liquid Films." Diss., Georgia Institute of Technology, 2006. http://hdl.handle.net/1853/10528.
Full textAbstract:
An experimental and numerical investigation has been conducted to examine steady, internal, nozzle-generated, gas/liquid mist cooling in vertical channels with ultra-thin, evaporating subcooled liquid films. Interest in this research has been motivated by the need for a highly efficient cooling mechanism in high-power lasers for inertial fusion reactor applications. The aim is to quantify the effects of various operating and design parameters, viz. liquid atomization nozzle design (i.e. spray geometry, droplet size distribution, etc.), heat flux, liquid mass fraction, film thickness, carrier gas velocity, temperature, and humidity, injected liquid temperature, gas/liquid combinations, channel geometry, length, and wettability, and flow direction, on mist cooling effectiveness.
A fully-instrumented experimental test facility has been designed and constructed. The facility includes three cylindrical and two rectangular electrically-heated test sections with different unheated entry lengths. Water is used as the mist liquid with air, or helium, as the carrier gas. Three types of mist generating nozzles with significantly different spray characteristics are used. Numerous experiments have been conducted; local heat transfer coefficients along the channels are obtained for a wide range of operating conditions. The data indicate that mist cooling can increase the heat transfer coefficient by more than an order of magnitude compared to forced convection using only the carrier gas. The data obtained in this investigation will allow designers of mist-cooled high heat flux engineering systems to predict their performance over a wide range of design and operating parameters.
Comparison has been made between the data and predictions of a modified version of the KIVA-3V code, a mechanistic, three-dimensional computer program for internal, transient, dispersed two-phase flow applications. Good agreement has been obtained for downward mist flow at moderate heat fluxes; at high heat fluxes, the code underpredicts the local heat transfer coefficients and does not predict the onset of film rupture. For upward mist flow, the code underpredicts the local heat transfer coefficients and, contrary to experimental observations, predicts early dryout at the test section exit.
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Ahn, Hee Seok. "Heat transfer enhancement in single-phase forced convection with blockages and in two-phase pool boiling with nano-structured surfaces." Texas A&M University, 2003. http://hdl.handle.net/1969.1/5869.
Full textAbstract:
The first study researched turbulent forced convective heat (mass) transfer down-
stream of blockages with round and elongated holes in a rectangular channel. The
blockages and the channel had the same cross section, and a distance equal to twice
the channel height separated consecutive blockages. Naphthalene sublimation experiments were conducted with four hole aspect ratios (hole-width-to-height ratios) and
two hole-to-blockage area ratios (ratios of total hole cross-sectional area to blockage
area). The effects of the hole aspect ratio, for each hole-to-blockage area ratio, on the
local heat (mass) transfer distribution on the exposed primary channel wall between
consecutive blockages were examined. Results showed that the blockages with holes
enhanced the average heat (mass) transfer by up to 8.5 and 7.0 times that for fully
developed turbulent flow through a smooth channel at the same mass flow rate, respectively, in the smaller and larger hole-to-blockage area ratio (or smaller and larger
hole diameter) cases. The elongated holes caused a higher average heat (mass) transfer and a larger spanwise variation of the local heat (mass) transfer on the channel
wall than did the round holes.
The second study explored the heat transfer enhancement for pool boiling on
nano-structured surfaces. Experiments were conducted with three horizontal silicon surfaces, two of which were coated with vertically aligned multi-walled carbon nanotubes (MWCNT) with heights of 9 and 25 ùm, respectively, and diameters between
8 and 15 nm. The MWCNT arrays were synthesized on the two silicon wafers using
chemical vapor deposition. Experimental results were obtained over the nucleate boiling and film boiling regimes under saturated and sub-cooled (5ñC and 10ñC) boiling
conditions. PF-5060 was the test fluid. Results showed that the MWCNT array with
a height of 25 ùm enhanced the nucleate and film boiling heat fluxes on the silicon
surface by up to 380% and 60%, respectively, under saturated boiling conditions, and
by up to 300% and 80%, respectively, under 10ñC sub-cooled boiling conditions, over
corresponding heat fluxes on a smooth silicon surface. The MWCNT array with a
height of 9 ùm enhanced the nucleate boiling heat flux as much as the taller array,
but did not significantly enhance the wall heat flux in the film boiling regime.
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Bashir, Abubakar Idris. "Single-phase forced and mixed convection in the laminar and transitional flow regimes of inclined smooth tubes with inlet disturbances." Thesis, University of Pretoria, 2019. http://hdl.handle.net/2263/77852.
Full textAbstract:
Laminar and transitional flow regimes in tubes have been extensively investigated in the literature.
However, there are several gaps in the forced and mixed convection literature, especially for
inclined tubes with different inlet disturbances. The purpose of this study was to experimentally
investigate the effect of tube inclination and inlet contraction ratio on the single-phase heat transfer
and pressure drop characteristics in the laminar and transitional flow regimes for pure forced and
mixed convection conditions.
An experimental set-up was designed, constructed and validated against literature with the test
section in a horizontal and different vertical orientation. The test section was 4.6 m long and was
made from a smooth hard drawn copper tube with measured inner and outer diameters of 5.1 mm
and 6.3 mm, respectively. Experiments were conducted at various inclination angles from vertical
upward flow (+90º) to vertical downward flow (–90º), with horizontal flow (0º) and several other
angles in between. A total of 2 679 mass flow rate measurements, 174 135 temperature
measurements and 2 679 pressure drop measurements were conducted using water (Prandtl
numbers between 3.5 and 8.1) as working fluid. The Reynolds number range covered were from
400 to 6 000 at constant heat fluxes varying from 1 to 8 kW/m2. Four different types of inlets
namely; square-edged and re-entrant inlet with different inlet contraction ratios (5, 11, 14 and 33),
as well as hydrodynamically fully developed and 90º bend inlets were used.
It was found that an increase in the inclination angle from horizontal flow (0º) to vertical (±90º)
flow, decreased the buoyancy effects which led to decreased laminar heat transfer coefficients and
friction factors for both upward and downward flows. The onset of buoyancy effects was
significant near the vertical inclination angles and caused a rapid increase in the laminar heat
transfer coefficients and friction factors when the inclination angles moved from vertical to horizontal orientations. An inclined tube Grashof number which is a function of inclination angle
was defined and used to express the laminar Nusselt numbers as a forced convection part plus an
enhancement component owing to mixed convection. The laminar friction factors were expressed
as a function of a forced convection/isothermal part multiplied by the mixed convection part.
Furthermore, it was found that the critical Reynolds numbers at which transitional flow regime
started increased as the inclination angles increased from horizontal to vertical, while the end of
transitional flow regime were inclination angle independent. This caused the width of the
transitional flow regime to decrease, as well as the transition gradients to increase, with increasing
inclination angles at different heat fluxes. It was also found that the flow directions (upward and
downward) had a negligible effect on the heat transfer coefficients and friction factors in the entire
transition and quasi-turbulent regions.
The fully developed laminar forced convection Nusselt numbers were not constant at 4.36, but
were a function of Reynolds number for Reynolds numbers higher than 1 000. Therefore, a revised
laminar Nusselt number correlation for smooth circular tubes was developed. The fully developed
laminar forced convection friction factors were, as expected, equal to 64/Re. For both the forced
convection heat transfer and pressure drop characteristics, transition occurred at the same mass
flow rates for all the heat fluxes, including isothermal flow, but the critical Reynolds numbers
increased with an increase in heat flux. For forced convection condition, the width of the
transitional flow regime in the fully developed region remained constant for all heat fluxes.
For a square-edged inlet geometry, the transition from the laminar to the turbulent flow regimes
occurred earlier as the inlet contraction ratio increased, while for the re-entrant inlet, transition was
delayed. The transitional flow regime was significantly affected by smaller contraction ratios and
this effect increased with increasing heat flux. However, it was found that the critical Reynolds
numbers were independent of inlet geometry for contraction ratios larger than 33. For the 90º bend
inlet, transition occurred earlier than all the other inlet geometries and contraction ratios.Thesis (PhD)--University of Pretoria, 2019.
Mechanical and Aeronautical Engineering
PhD
Unrestricted
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Gdhaidh, Farouq A. S. "Heat Transfer Characteristics of Natural Convection within an Enclosure Using Liquid Cooling System." Thesis, University of Bradford, 2015. http://hdl.handle.net/10454/7824.
Full textAbstract:
In this investigation, a single phase fluid is used to study the coupling between natural convection heat transfer within an enclosure and forced convection through computer covering case to cool the electronic chip. Two working fluids are used (water and air) within a rectangular enclosure and the air flow through the computer case is created by an exhaust fan installed at the back of the computer case. The optimum enclosure size configuration that keeps a maximum temperature of the heat source at a safe temperature level (85℃) is determined. The cooling system is tested for varying values of applied power in the range of 15−40𝑊.
The study is based on both numerical models and experimental observations. The numerical work was developed using the commercial software (ANSYS-Icepak) to simulate the flow and temperature fields for the desktop computer and the cooling system. The numerical simulation has the same physical geometry as those used in the experimental investigations. The experimental work was aimed to gather the details for temperature field and use them in the validation of the numerical prediction.
The results showed that, the cavity size variations influence both the heat transfer process and the maximum temperature. Furthermore, the experimental results
ii
compared favourably with those obtained numerically, where the maximum deviation in terms of the maximum system temperature, is within 3.5%. Moreover, it is seen that using water as the working fluid within the enclosure is capable of keeping the maximum temperature under 77℃ for a heat source of 40𝑊, which is below the recommended electronic chips temperature of not exceeding 85℃. As a result, the noise and vibration level is reduced. In addition, the proposed cooling system saved about 65% of the CPU fan power.
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Gdhaidh, Farouq Ali S. "Heat transfer characteristics of natural convection within an enclosure using liquid cooling system." Thesis, University of Bradford, 2015. http://hdl.handle.net/10454/7824.
Full textAbstract:
In this investigation, a single phase fluid is used to study the coupling between natural convection heat transfer within an enclosure and forced convection through computer covering case to cool the electronic chip. Two working fluids are used (water and air) within a rectangular enclosure and the air flow through the computer case is created by an exhaust fan installed at the back of the computer case. The optimum enclosure size configuration that keeps a maximum temperature of the heat source at a safe temperature level (85°C) is determined. The cooling system is tested for varying values of applied power in the range of 15-40W. The study is based on both numerical models and experimental observations. The numerical work was developed using the commercial software (ANSYS-Icepak) to simulate the flow and temperature fields for the desktop computer and the cooling system. The numerical simulation has the same physical geometry as those used in the experimental investigations. The experimental work was aimed to gather the details for temperature field and use them in the validation of the numerical prediction. The results showed that, the cavity size variations influence both the heat transfer process and the maximum temperature. Furthermore, the experimental results ii compared favourably with those obtained numerically, where the maximum deviation in terms of the maximum system temperature, is within 3.5%. Moreover, it is seen that using water as the working fluid within the enclosure is capable of keeping the maximum temperature under 77°C for a heat source of 40W, which is below the recommended electronic chips temperature of not exceeding 85°C. As a result, the noise and vibration level is reduced. In addition, the proposed cooling system saved about 65% of the CPU fan power.
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Wilson, Scott E. "Investigation of Copper Foam Coldplates as a High Heat Flux Electronics Cooling Solution." Thesis, Georgia Institute of Technology, 2005. http://hdl.handle.net/1853/6944.
Full textAbstract:
Compact heat exchangers such as porous foam coldplates have great potential as a high heat flux cooling solution for electronics due to their large surface area to volume ratio and tortuous coolant path. The focus of this work was the development of unit cell modeling techniques for predicting the performance of coldplates with porous foam in the coolant path.
Multiple computational fluid dynamics (CFD) models which predict porous foam coldplate pressure drop and heat transfer performance were constructed and compared to gain insight into how to best translate the foam microstructure into unit cell model geometry. Unit cell modeling in this study was realized by applying periodic boundary conditions to the coolant entrance and exit faces of a representative unit cell. A parametric study was also undertaken which evaluated dissimilar geometry translation recommendations from the literature. The use of an effective thermal conductivity for a representative orthogonal lattice of rectangular ligaments was compared to a porosity-matching technique of a similar lattice. Model accuracy was evaluated using experimental test data collected from a porous copper foam coldplate using deionized water as coolant. The compact heat exchanger testing facility which was designed and constructed for this investigation was shown to be capable of performing tests with coolant flow rates up to 300 mL/min and heat fluxes up to 290 W/cm2. The greatest technical challenge of the testing facility design proved to be the method of applying the heat flux across a 1 cm2 contact area. Based on the computational modeling results and experimental test data, porous foam modeling recommendations and porous foam coldplate design suggestions were generated.
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Madhavan, Srivatsan. "Review, Design and Computational Study of Some Compact Heat Exchangers." University of Cincinnati / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1511885027497222.
Full textBooks on the topic "Single-Phase Forced Convection Cooling"
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Incropera, Frank P. Liquid Cooling of Electronic Devices by Single-Phase Convection. Wiley-Interscience, 1999.
Find full textBook chapters on the topic "Single-Phase Forced Convection Cooling"
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Yener, Y., S. Kakaç, M. Avelino, and T. Okutucu. "Single-Phase Forced Convection in Microchannels." In Microscale Heat Transfer Fundamentals and Applications, 1–24. Dordrecht: Springer Netherlands, 2005. http://dx.doi.org/10.1007/1-4020-3361-3_1.
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Cumo, Maurizio, and Antonio Naviglio. "Single-Phase Forced Convection Heat Transfer." In Thermal Hydraulics, 131–45. CRC Press, 2018. http://dx.doi.org/10.1201/9781351077262-8.
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"Empirical Correlations for Single-Phase Forced Convection in Ducts." In Convective Heat Transfer, 349–86. CRC Press, 2013. http://dx.doi.org/10.1201/b16194-12.
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Furbish, David Jon. "Thermally Driven Flows." In Fluid Physics in Geology. Oxford University Press, 1997. http://dx.doi.org/10.1093/oso/9780195077018.003.0020.
Full textAbstract:
Recall that we briefly examined the stability of thermally stratified fluids in Chapter 6. Our essential conclusion was that a condition in which hot, light fluid resides beneath cooler, heavier fluid is a potentially unstable configuration, inasmuch as gravitational forces are no longer balanced by forces associated with the vertical pressure gradient. In this regard we obtained a necessary (but insufficient) condition for instability, which stated that the magnitude of the vertical temperature gradient must exceed the adiabatic lapse rate. Further recall, however, that such a condition does not necessarily lead spontaneously to overturning (convection). It is possible for a fluid to possess a steady temperature gradient over its vertical extent, in excess of the adiabatic rate, such that the fluid remains static and merely acts like a thermally conducting solid, and we concluded that this static conduction state represents an unstable equilibrium. We then characterized the tendency for instability in terms of the Rayleigh number Ra. Let us now extend our treatment to a description of thermally driven convection motions. We will concentrate on Rayleigh-Bénard and Hele-Shaw configurations (Chapter 6), and the buoyancy-driven flows that occur within these configurations due to steady heating and cooling of the boundaries. In such configurations, convective motions typically occupy the full region between the boundaries, and vary from steady two-dimensional rolls at small Rayleigh numbers to complex turbulent motions at large Rayleigh numbers. In addition, we will briefly consider buoyancy driven flows that arise from localized temperature and compositional variations near a single solid boundary. Envision, for example, the roof of a magma chamber. For a sufficient contrast in temperature between the magma and country rock, melting of the magma roof occurs. If the density of the melt that is produced is less than that of the underlying magma, thermally driven convection may begin within the buoyant layer of melt, which in turn advects heat upward from the underlying hot magma to the roof. Alternatively, if the density of the melt is greater than that of the underlying magma, compositionally driven convection may occur, which in turn brings hot magma to the roof.
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"Forced Convection Correlations for the Single-Phase Side of Heat Exchangers." In Heat Exchangers, 97–144. CRC Press, 2012. http://dx.doi.org/10.1201/b11784-5.
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Kakaç, Sadık, Hongtan Liu, and Anchasa Pramuanjaroenkij. "Forced Convection Correlations for the Single-Phase Side of Heat Exchangers." In Heat Exchangers, 69–108. CRC Press, 2020. http://dx.doi.org/10.1201/9780429469862-3.
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Prajapati, Yogesh K. "Comparative Study of Conjugate Heat Transfer in Uniform and Diverging Cross-Section Microchannels." In Advanced Numerical Simulations in Mechanical Engineering, 76–95. IGI Global, 2018. http://dx.doi.org/10.4018/978-1-5225-3722-9.ch005.
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This chapter covers single-phase heat transfer analysis in microchannel heat sink relevant to electronic cooling application. In order to estimate the correct heat transfer performance, it is required to consider both, conduction and convection. Hence, conjugate analysis of heat transfer has been considered where both conduction and convection heat transfer are calculated as a part of solution. Two different configurations of microchannels namely, uniform and diverging cross-section have been considered individually on different copper substrate. A copper substrate of dimension 25×0.9×4 mm has been used to generate microchannel. Inlet cross-section (0.4×0.75 mm) of both channels has been kept equal however; cross-section of diverging channel keeps on increasing as width is continuously increasing along the flow direction. A constant heat flux of 250 kW/m2 has been provided from the bottom. Comparative study has been done to analyse the heat transfer performance of both the configurations of microchannels.
Conference papers on the topic "Single-Phase Forced Convection Cooling"
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Chiang, Hsiao-Wei D., and Hsin-Lung Li. "Jet Impingement and Forced Convection Cooling Experimental Study in Rotating Turbine Blades." In ASME Turbo Expo 2009: Power for Land, Sea, and Air. ASMEDC, 2009. http://dx.doi.org/10.1115/gt2009-59795.
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Both jet impingement and forced convection are attractive cooling mechanisms and have been widely used in cooling of gas turbine blades. Convective heat transfer from impinging jets is known to yield high local and area averaged heat transfer coefficients. Impingement jets are of particular interest in the cooling of gas turbine components where advancement relies on the ability to dissipate extremely large heat loads. The current research is concerned with the measurement and comparison of both jet impingement and forced convection heat transfer in the Reynolds number range of 10,000 to 30,000. The present study is aimed at experimentally testing two different setups with forced convection and jet impingement in rotating turbine blades up to 700 rpm. This research also focused on to observe how Coriolis forces and impingement cooling inside the passage in rotating conditions within a cooling passage. Local heat transfer coefficients are obtained for each test section through thermal-couple technique with slip rings. The cross section of the passage is 10 mm × 10 mm without ribs. The surface heating condition has a uniform heat flux enforced. The forced convection cooling effects were studied using serpentine passages with three corner turns under different rotating speeds and different inlet Reynolds numbers. The impingement cooling study uses a straight passage with a single jet hole under different Reynolds numbers of the impingement flow and the cross flow. In summary, the main purpose is to study the rotation effects on both the jet impingement and the serpentine convection cooling types. Our study shows that rotation effects increase the serpentine cooling and, on the other hand, reduce the jet impingement cooling.
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Hassanipour, Fatemeh, and Jose´ Lage. "Enhanced Mini-Channel Forced Convection With Encapsulated Phase-Change Particles." In ASME 2008 Heat Transfer Summer Conference collocated with the Fluids Engineering, Energy Sustainability, and 3rd Energy Nanotechnology Conferences. ASMEDC, 2008. http://dx.doi.org/10.1115/ht2008-56037.
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In this study we propose a new cooling concept using encapsulated phase-change particles flowing in a parallel-plate mini-channel. This novel concept is inspired by the gas exchange process in alveolar capillaries, where red blood cells (RBCs) flow with blood plasma, yielding very high gas transfer efficiency. Another important characteristic of alveolar capillary blood flow, which is related to the high efficiency of the lungs, is the snug fitting of the RBCs into the capillary. Hence, we conjecture that using particles similar to RBCs, i.e. with diameter similar to the spacing between the parallel plates, is likely to lead to high heat transfer efficiency as well. We report here experimental results of preliminary tests performed with octadecane paraffin (C18H38), a phase-change material, encapsulated in a thin melamine shell, flowing with water through a heated parallel-plate channel test module. We measured the temperature distribution along the heated surface of the channel for various water flow rates, with and without particles, and varying the number of particles. Results are reported in terms of the channel heated surface average temperature and the average Nusselt number.
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Huang, LiDong, and Kevin J. Farrell. "Mixed Convection in Vertical Tubes: High Reynolds Number." In 2010 14th International Heat Transfer Conference. ASMEDC, 2010. http://dx.doi.org/10.1115/ihtc14-23266.
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The complex interaction of forced and natural convection depends on flow regime and flow direction. Aiding flow occurs when both driving forces act in the same direction (heating upflow fluid and cooling downflow fluid); opposing flow occurs when they act in different directions (cooling upflow fluid and heating downflow fluid). This paper discusses the buoyancy effect on forced convection for single-phase flows in vertical tubes. To evaluate mixed convection methods, Heat Transfer Research, Inc. (HTRI) recently collected water and propylene glycol data in two vertical tubes of different tube diameters. The data cover wide ranges of Reynolds, Grashof, and Prandtl numbers and differing ratios of heated tube length to diameter in laminar, transition, and turbulent forced flow regimes. In this paper, we focus on mixed convection with Reynolds numbers higher than 2000. Using HTRI data and experimental data in literature, we demonstrate that natural convection can greatly increase or decrease the convective heat transfer coefficient. In addition, we establish that natural convection should not be neglected if the Richardson number is higher than 0.01 or the mixed turbulent parameter Ra1/3/(Re0.8 Pr0.4) is higher than 0.05 even in forced turbulent flow with Reynolds numbers greater than 10000. High resolution Reynolds-Averaged Navier-Stokes (RANS) simulations of several experimental conditions confirm the importance of the buoyancy effect on the production of turbulence kinetic energy. We also determine that flow regime maps are required to predict the mixed convection heat transfer coefficient accurately.
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Yu, Leyuan, and Dong Liu. "Single-Phase Thermal Transport of Nanofluids in a Minichannel." In ASME 2009 International Mechanical Engineering Congress and Exposition. ASMEDC, 2009. http://dx.doi.org/10.1115/imece2009-13259.
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As a promising candidate for heat transfer fluids in advanced cooling technologies, nanofluids have been studied extensively in the past decade. Despite the tremendous research efforts, it is still unclear if and how the presence of dispersed nanoparticles alters the thermal transport and leads to enhanced thermal performance of nanofluids. An experimental investigation was conducted to explore the single-phase forced convection of Al2O3-water nanofluids in a circular minichannel with 1.09 mm inner diameter. The Reynolds number studied ranges from approximately 600 to 2300. The friction factor and convective heat transfer coefficient were measured for nanofluids with volume concentrations of up to 2%. The effects of nanoparticle concentration and flow rate on the local and average heat transfer coefficient as well as Nusselt number are examined. It was found that, once the thermophysical properties of the nanofluids are properly accounted for, the established pressure drop and heat transfer correlations can offer satisfactory predictions of the single-phase thermal transport of nanofluids under the experimental conditions considered in this study.
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Shrivastava, Saurabh, and Bahgat Sammakia. "Transient Mixed-Convection With Applications to Cooling of Biomaterials." In ASME 2005 Pacific Rim Technical Conference and Exhibition on Integration and Packaging of MEMS, NEMS, and Electronic Systems collocated with the ASME 2005 Heat Transfer Summer Conference. ASMEDC, 2005. http://dx.doi.org/10.1115/ipack2005-73235.
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2-Dimensional transient mixed-convection in a horizontal rectangular enclosed cavity heated from a lower solid block is numerically studied. The enclosure simulates the thermal reservoir for the storage and shipment of biomaterials. The lower solid block containing the thermal biomass that has adiabatic sides and bottom wall, is coupled along the top wall with a hollow cavity of aspect ratio (H/L = 0.5), whose side and top walls are assumed to be surrounded by a phase change material and has been assigned constant temperature of 273K. Initially, the temperature of the biomaterials is raised to 283K; the upper cavity is filled with quiescent air and uniform temperature at time zero. Laminar airflow is assumed with a fan in middle of the cavity. The basic characteristics and flow structures during the transition of natural-convection-dominated flow to forced-convection-dominated flow are determined. The problem is solved for the range of mixed-convection regime and the fluid flow structure and heat transfer is found to be dependent on mixed-convection as determined by the buoyancy parameter Gr/Re2. As anticipated, the forced-convection-dominated flow is found to be more effective in cooling of the thermal biomass than the natural-convection-dominated flow. This study shows that using the assisted forced convection results in an increase in the cooling performance of the biomaterial container in the natural-convection-dominated type mixed-convection flow. Examining the area averaged Surface Nusselt number along the coupled wall with time and the rate of heat transfer from the thermal biomass during the Quasi-steady stage validates the above hypothesis.
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Battaglia, Fabio, Farah Singer, Serguei V. Dessiatoun, and Michael M. Ohadi. "Comparison of near source two-phase flow cooling of power electronics in thermosiphon and forced convection modes." In 2017 16th IEEE Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems (ITherm). IEEE, 2017. http://dx.doi.org/10.1109/itherm.2017.7992561.
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Kondle, Satyanarayana, Jorge L. Alvarado, Charles Marsh, and Gurunarayana Ravi. "Laminar Flow Forced Convection Heat Transfer Behavior of Phase Change Material Fluid in Microchannels With Staggered Pins." In 2010 14th International Heat Transfer Conference. ASMEDC, 2010. http://dx.doi.org/10.1115/ihtc14-22512.
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Microchannels have been extensively studied for electronic cooling applications ever since they were found to be effective in removing high heat flux from small areas. Many configurations of microchannels have been studied and compared for their effectiveness in heat removal. However, there is little data available in the literature on the use of pins in microchannels. Staggered pins in microchannels have higher heat removal characteristics because of the continuous breaking and formation of the boundary layer, but they also exhibit higher pressure drop because pins act as flow obstructions. This paper presents numerical results of two characteristic staggered pins (square and circular) in microchannels. The heat transfer performance of a single phase fluid in microchannels with staggered pins, and the corresponding pressure drop characteristics are also presented. An effective specific heat capacity model was used to account for the phase change process of PCM fluid. Comparison of heat transfer characteristics of single phase fluid and PCM fluid are made for two pins geometries for three different Reynolds numbers. Circular pins were found to be more effective in terms of heat transfer by exhibiting higher Nusselt number. Circular pin microchannels were also found to have lower pressure drop compared to the square pin microchannels.
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Manca, O., S. Nardini, D. Ricci, and S. Tamburrino. "Numerical Analysis on Nanofluid Forced Convection in Ducts With Triangular Cross Sections." In ASME 2011 International Mechanical Engineering Congress and Exposition. ASMEDC, 2011. http://dx.doi.org/10.1115/imece2011-62700.
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Heat transfer of fluids is very important to many industrial heating or cooling equipments. Convective heat transfer can be enhanced passively by changing flow geometry, boundary conditions or by enhancing the thermal conductivity of the working fluids. An innovative way of improving the fluid thermal conductivity is to introduce suspended small solid nanoparticles in the base fluids. In this paper a numerical investigation on laminar forced convection flow of a water–Al2O3 nanofluid in a duct having an equilateral triangular cross section is performed. The hydraulic diameter is set equal to 1.0×10−2 m. A constant and uniform heat flux on the external surfaces has been applied and the single-phase model approach has been employed. The analysis has been run in steady state regime for a nanoparticle size equal to 38 nm, considering different volume particle concentrations. The CFD code Fluent has been employed in order to solve the tri-dimensional numerical model. Results are presented in terms of temperature and velocity distributions, surface shear stress and heat transfer convective coefficient, Nusselt number and required pumping power profiles. Comparison with results related to the fluid dynamic and thermal behaviors in pure water are carried out in order to evaluate the enhancement due to the presence of nanoparticles in terms of volumetric concentration.
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Stromberger, J. H., S. I. Abdel-Khalik, S. M. Ghiaasiaan, and S. M. Jeter. "Effects of Forced Wall Vibration on the Onset of Flow Instability and Critical Heat Flux in Uniformly-Heated Microchannels." In ASME 2003 Heat Transfer Summer Conference. ASMEDC, 2003. http://dx.doi.org/10.1115/ht2003-47309.
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Forced convection using single-phase liquid water is a common cooling mechanism utilized in high power density engineering applications. Typically, design specifications require the coolant to remain subcooled throughout the heat transfer channel to ensure adequate cooling of the heated surfaces. Despite these planned steady state parameters, accident or transient conditions can cause boiling to take place within the channels. For this reason, it is important in the design and operation of heated channels to understand and predict the onset of boiling and two-phase flow instabilities that can lead to channel dryout and potential overheating and/or burnout of the heat transfer system.
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Nicole, C. C. S., R. Dekker, A. Aubry, and R. Pijnenburg. "Integrated Micro-Channel Cooling in Industrial Applications." In ASME 2004 2nd International Conference on Microchannels and Minichannels. ASMEDC, 2004. http://dx.doi.org/10.1115/icmm2004-2397.
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Experiments and simulations have been performed in order to assess the feasibility of integrated single phase forced convection in silicon micro-channels for the cooling of electronics. A silicon micro-channel device has been fabricated with channel size of 100 by 300 μm. Cooling has been achieved with a heater dissipating up to 370 W (750 W/cm2) with a flow rate of 0.1 1/min. In this case the maximum junction temperature was 130°C. This paper presents characteristics of such a cooling device as well as its description and fabrication. Experimental results are shown and compared with simulations. A description of a rough optimization of the channels size is given followed by comments describing the main advantages and drawbacks regarding industrial feasibility.
Reports on the topic "Single-Phase Forced Convection Cooling"
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Hartnett, J. P. Single phase channel flow forced convection heat transfer. Office of Scientific and Technical Information (OSTI), April 1999. http://dx.doi.org/10.2172/335180.
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