Thermal Analysis of Heat Dissipating Electronic Devices (original) (raw)
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Thermal analyses of minichannels and use of mathematical and numerical models
Numerical Heat Transfer, Part A: Applications, 2020
Growth in electronic devices comes with a challenge to engineers to provide proficient cooling mechanism in order to evade performance decline. Minichannel heat sinks are one among type of cooling devices to absorb heat formed in the electronic devices. Air is largely employed as cooling fluid in minichannels, but innovative methods are also adopted to enhance the heat transfer during the process. These days with modifications in the fluid flow passage and using liquid coolants such as nanofluids the Nusselt number is enhanced. These structural modifications adopted and different nanofluids employed with various volume concentrations and flow rates passed through minichannels to obtain enhancement in heat transfer rate are compiled in this article. The approach for these investigations is majorly categorized into numerical and experimental works. Numerical studies consisting of wide spread modeling methods like single phase/two phase flow modeling, laminar, transition/turbulent modeling etc. are reviewed. The related in-depth numerical and mathematical models used for computational analyses are detailed out exclusively. Experimental methods consisting of unusual passive techniques such as dimples/protrusions, pin fins, and corrugated channels. to achieve betterment in minichannel thermal performance are also provided. Another prime highlight of this article is compilation (in tabular form) of all the correlations and mathematical models used and developed to analyze different factors/properties during the thermal analyses. This article is concluded by providing an overall idea of different mathematical models and methods adopted in minichannels heat transfer analyses and future aspects to be addressed. Several important areas in minichannels heat transfer analyses exist which demand the optimization of heat and fluid flow processes and the use of machine learning concepts for analysis.
Heat Transfer Analysis of Microchannel using Fluids
2020
In recent time due to high performance of electronic component the heat generation is increasing drastically. Due to this scenario heat dissipation becomes a major issue in efficiency promation and stable operation. Silicon based microchannel heat sink fabricated using semiconductor production technique plays important role in cooling devices. The effect of the thermophysical properties of working fluids on the performance of microchannel is tested or we can say investigated. For this purpose the different working fluids are selected. water, hepthane, ammonia, methanol, and ethanol. KeywordsHeat transfer, Micro channel, different coolents, natural convection, heat transfer, heat sink, , cooling, micro heat sinks. I.INTRODUCTION Now a days the electronic devices become compact. Due to compactness of this devices there is huge heat generation in this devices. Hence for the safety purpose heat should be remove from this devices continuosly.so the purpose of cooling system is to maintai...
IJERT-Heat Transfer Analysis of Microchannel using Fluids
International Journal of Engineering Research and Technology (IJERT), 2020
https://www.ijert.org/heat-transfer-analysis-of-microchannel-using-fluids https://www.ijert.org/research/heat-transfer-analysis-of-microchannel-using-fluids-IJERTV9IS070503.pdf In recent time due to high performance of electronic component the heat generation is increasing drastically. Due to this scenario heat dissipation becomes a major issue in efficiency promation and stable operation. Silicon based microchannel heat sink fabricated using semiconductor production technique plays important role in cooling devices. The effect of the thermophysical properties of working fluids on the performance of microchannel is tested or we can say investigated. For this purpose the different working fluids are selected. water, hepthane, ammonia, methanol, and ethanol.
Applied Thermal Engineering, 2009
With the rapid development of the information technology (IT) industry, the heat flux in integrated circuit (IC) chips cooled by air has almost reached its limit about 100 W/cm 2. Some applications in high technologies require heat fluxes well beyond such a limitation. Therefore the search of a more efficient cooling technology becomes one of the bottleneck problems of the further development of IT industry. The microchannel flow geometry offers large surface area of heat transfer and a high convective heat transfer coefficient. However, it has been hard to implement because of its very high pressure head required to pump the coolant fluid though the channels. A normal channel could not give high heat flux although the pressure drop is very small. A minichannel can be used in heat sink with a quite high heat flux and a mild pressure loss. A minichannel heat sink with bottom size of 20 mm  20 mm is analyzed numerically for the single-phase laminar flow of water as coolant through small hydraulic diameters and a constant heat flux boundary condition is assumed. The effects of channel dimensions, channel wall thickness, bottom thickness and inlet velocity on the pressure drop, thermal resistance and the maximum allowable heat flux are presented. The results indicate that a narrow and deep channel with thin bottom thickness and relatively thin channel wall thickness results in improved heat transfer performance with a relatively high but acceptable pressure drop. A nearly-optimized configuration of heat sink is found which can cool a chip with heat flux of 256 W/cm 2 at the pumping power of 0.205 W. The nearly-optimized configuration is verified by an orthogonal design. The simulated thermal resistance agrees quite well with the result of conventional correlations method with the maximum difference of 12%.
Iranian Journal of Chemistry & Chemical Engineering-international English Edition, 2018
In this paper, the cooling performance of water-cooled heat sinks for heat dissipation from electronic components is investigated numerically. Computational Fluid Dynamics (CFD) simulations are carried out to study the rectangular and circular cross-sectional shaped heat sinks.The sectional geometry of channels affects the flow and heat transfer characteristics of minichannel heat sinks. The three-dimensional governing equations in steady state and laminar flow are solved using Finite Volume Method (FVM) with the SIMPLE algorithm. The results show that the numerical simulation is in good agreement with the experimental data. The thermal and hydrodynamic characteristics of the heat sinks including Nusselt number, friction factor, thermal resistance and pumping power for various geometries of heat sinks are discussed in details. The results indicate that the heat sink with rectangular cross-section has a better heat transfer rate and the circular channel heat sink has the lower pumping power.
Nihon Kikai Gakkai Ryutai …, 2006
The authors have reported that minichannel flow system had high heat transfer coefficient. We investigated experimentally and numerically the heat transfer and flow structure of single and array minichannel combined with impingement flow system. The diameter D of the channel was 1.27 mm and length to diameter ratio L/D was 5. The minichannel array was so called shower head which was constructed by 19 minichannels located at the apex of equilateral triangle, the side length S of which was 4 mm. The mechanism of high heat transfer was studied numerically by the Reynolds averaged Navier-Stokes equation and k-.OMEGA. turbulence model. The limiting streamline pattern was correlated well to the surface heat flux distribution. The high heat transfer in the single minichannel was achieved by suppressing the development of boundary layer under strong pressure gradient near the channel inlet and by the formation of large recirculating flow system in the downstream plenum of the minichannel exit. These heat transfer mechanisms became dominant when the channel size fallen into the regime of minichannel. The heat transfer performance of minichannel array was equivalent to that of impingement jet.
Study on the convective heat transfer and pressure drop in the micro-channel heat sink
International Communications in Heat and Mass Transfer, 2009
In recent times, the use of multi-walled carbon nanotubes (MWCNTs)/water nanofluids as a coolant has garnered immense interest due to their high thermal conductivity. Thus, this study investigates the effect of different mass fractions (u w) of MWCNTs (0.075, 0.125 and 0.25 mass%) on forced convection heat transfer. Uniform and stable nanofluids were prepared using the two-step method coupled with the addition of water-soluble polymer polyvinyl pyrrolidone (PVP) and using high-power probe sonicator. The test was carried out in a circular mini-tube (D in = 1.1 mm), which was heated uniformly to study the developing and fully developed laminar flow. The Reynolds number (Re) varied from 200 to 500. The heat transfer coefficient was found to be significantly enhanced with increase in mass fraction of MWCNTs in the prepared nanofluid. The maximum enhancement of heat transfer coefficient was 23.9% for the nanofluid prepared with 0.25 mass% of MWCNTs. The experimental result revealed an increase in friction factor using the MWCNTs/water nanofluid. A maximum pressure drop of 9.9% was achieved for the highest mass fraction of MWCNTs.
Experimental investigations on heat transfer in a new minichannel heat sink
International Journal of Thermal Sciences, 2019
Highlights •The effect of variable baffle configurations on HX performance was investigated. •The influence of water mass flow and heat flux on the HTC was presented. •Experimental correlation for investigated configurations was developed. •Recognized the secondary fluid motion influence on heat transfer was investigated •Compared the efficiency of the proposed shell-coil design with baffles with typical heat exchanger designs was presented
IJSRD, 2014
Convective heat transfer coefficient and friction factor of water in circular minichannels were measured. An integrated system consisting of a single minichannel on one side, and one heater and four thermocouple temperature sensors along the channel on the other side were fabricated. Distilled water was used in experiments to investigate the effect of the Reynolds number to the convective heat transfer and fluid flow in minichannels. The convective heat transfer coefficient of the water in turbulent flow regime was measured to be increased by increasing the Reynolds number. The Nusselt number measured increases with increasing the Reynolds number in turbulent flow regime. We have measured the pressure drop and convective heat transfer coefficient of water flowing through a uniformly heated circular minichannel in the turbulent flow regime. The experimental results show that the data for water friction factor show a good agreement with analytical predictions from the Darcy's equation for single-phase flow.
Study of thermal and hydraulic performance of air cooled minichannel heatsink with novel geometries
International Communications in Heat and Mass Transfer, 2019
Numerical and experimental study of minichannel heat sinks (MCHS), with air as a cooling medium, has been performed for straight channel heatsink (SC HS), wavy channel heatsink (WC HS) and branch wavy channel heatsink (BWC HS) to investigate thermal and hydraulic performances. After considering both the conduction and the convection as a mode of heat transfer, numerical computation of three-dimensional conjugated heat transfer between the heat sink and air flow has been performed by using full domain simulation in ANSYS Fluent. Laminar model is selected for the study of air flow and heat transfer as the Reynolds number varied from 300 to 1900 for a different range of air flow rates. Heating powers of 20 watt and 30 watt are applied at the base of the heat sink. Followed by detailed experimentation, the numerical results are also examined to get acquainted with the flow fields and their roles in the thermal performance of individual heat sinks. It has been found that the thermal-hydraulic performance factor of BWC HS exhibited superiority over SC HS and WC HS. It is also noticed that significant improvements in the junction temperature of BWC HS have been achieved. Experimental results have been validated with numerical results.