Heat Transfer Enhancement in the Heat Sinks for Electronic Cooling Applications

2005 ◽  
Author(s):  
Evan Small ◽  
Sadegh M. Sadeghipour ◽  
Mehdi Asheghi
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Heat Transfer Enhancement ◽  
Heat Sink ◽  
Engineering Students ◽  
Electronic Cooling ◽  
Heat Sinks ◽  
Optimum Number ◽  
Transfer Enhancement

In a design competition by the mechanical engineering students at Carnegie Mellon University, which was the design of heat sinks for electronic cooling applications, twenty seven heat sinks were designed and tested for thermal performance. A heat sink with three rows of 9, 8, and 9 dimpled rectangular fins (staggered configuration) demonstrated the best performance in the test. This heat sink even had the least total volume (about 25% less than the set value). This paper reports on an effort made to verify and quantify the role of dimples on heat transfer enhancement of the heat sinks. This includes measurements and simulations of the thermal fluid properties of the heat sinks with and without dimples. Results of both the measurements and simulations indicate that dimples do in fact improve heat transfer capability of the heat sinks. Albeit, dimpled fins cause more pressure drop in air along the heat sink. Keeping the total volume of the heat sink and the height of the fins constant and changing the number of the fins and their arrangement show that there exist an optimum number of fins for the best performance of the heat sink. However, this number of fins is different for inline and staggered arrangements. To check the role of the roughness type on the heat transfer behavior of the fins, a heat sink with twenty-seven bumped fins with inline arrangement was also simulated. Results indicated that bumps increase both thermal resistance and pressure drop relative to that of the heat sinks with plain fins.

Cooling Performance Comparisons of Five Different Plate-Pin Compound Heat Sinks Based on Two Different Length Scale

2011 ◽  
Author(s):  
Feng Zhou ◽  
David Geb ◽  
Ivan Catton
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Heat Transfer Enhancement ◽  
Cross Section ◽  
Heat Sink ◽  
Heat Sinks ◽  
Length Scale ◽  
Transfer Enhancement ◽  
Pin Fin ◽  
New Type

Plate fin heat sinks (PFHS) are widely used to remove heat from the microelectronic devices. In the present study, a new type of compound heat sink, named as plate-pin fin heat sink (PPFHS), is employed to improve the air cooling performance. With CFD numerical method, PPFHSs with five forms of pin cross-section profiles (square, circular, elliptic, NACA 0050, and dropform) and PFHS were simulated. Two different length scales were adopted to evaluate the performance of six types of heat sinks, including PFHS. One of the length scales is commonly used by many investigators, which is two times of the channel spacing. The other length scale is suggested by volume averaging theory (VAT), which is four times of average porosity divided by specific interface. The influence of pin fin cross-section profile on the flow and heat transfer characteristics was presented by means of Nusselt number, pressure drop and overall efficiency. It is found that the Nu number of a PPFHS is at least 35% higher than that of a PFHS used to construct the PPFHS at the same Reynolds number no matter which length scale was used. It is also revealed that the heat transfer enhancement of square PPFHS is offset by its excessively high pressure drop, which makes it not as efficient as the other types of PPFHS. Circular PPFHS performs similar to the streamline shaped PPFHS when the Reynolds number is not too high. However, with the increase in Re the advantage of the circular cross-section diminishes. Using the streamline shaped pins, not only the pressure drop of the compound heat sinks could be decreased considerably, the heat transfer enhancement also makes a step forward. However, evaluating the performance of heat sinks by using the commonly used length scale, the benefit of streamline shaped types of PPFHSs is a little bit overstated. The VAT suggested length scale is more reasonable to do the performance comparison of different heat sinks, especially when it is difficult to provide a fair and physically meaningful basis for the comparison. In short, the present numerical simulation provides original information of the influence of different pin-fin cross-section profiles on the thermal and hydraulic performance of the new type compound heat sink and emphasizes the importance of choosing a proper length scale when evaluating heat transfer enhancement, which is helpful in the design of heat sinks.

Heat Sinks With Enhanced Heat Transfer Capability for Electronic Cooling Applications

2005 ◽  
Vol 128 (3) ◽  
pp. 285-290 ◽  
Author(s):  
Evan Small ◽  
Sadegh M. Sadeghipour ◽  
Mehdi Asheghi
Keyword(s):  
Heat Transfer ◽  
Thermal Performance ◽  
Heat Sink ◽  
Engineering Students ◽  
Electronic Cooling ◽  
Heat Sinks ◽  
Optimum Number ◽  
Transfer Capability ◽  
Improve Heat Transfer ◽  
Heat Transfer Capability

In a competition at Carnegie Mellon University, the mechanical engineering students designed and manufactured 27 heat sinks. The heat sinks were then tested for thermal performance in cooling a mock processor. A heat sink with three rows of 9, 8, and 9 dimpled rectangular fins in staggered configuration performed the best, while having the least total volume (about 25% less than the set value). Validation of the observed thermal performance of this heat sink by experimentation and numerical simulations has motivated the present investigation. Thermal performance of the heat sinks with and without dimples have been evaluated and compared. Results of both the measurements and simulations indicate that dimples do in fact improve heat transfer capability of the heat sinks. However, dimples cause more pressure drop in the air flow. Keeping the total volume of the heat sink and the height of the fins constant and changing the number of the fins and their arrangement show that there is an optimum number of fins for the best performance of the heat sink. The optimum fin numbers are different for inline and staggered arrangements.

Enhanced Thermal Transport in Microchannel Using Oblique Fins

2012 ◽  
Vol 134 (10) ◽  
Author(s):  
Y. J. Lee ◽  
P. S. Lee ◽  
S. K. Chou
Keyword(s):  
Heat Transfer ◽  
Boundary Layer ◽  
Heat Transfer Enhancement ◽  
Heat Sink ◽  
Heat Sinks ◽  
Maximum Temperature ◽  
Working Fluid ◽  
Microchannel Heat Sink ◽  
Transfer Enhancement ◽  
Microchannel Heat Sinks

Sectional oblique fins are employed, in contrast to continuous fins in order to modulate the flow in microchannel heat sinks. The breakage of a continuous fin into oblique sections leads to the reinitialization of the thermal boundary layer at the leading edge of each oblique fin, effectively reducing the boundary layer thickness. This regeneration of entrance effects causes the flow to always be in a developing state, thus resulting in better heat transfer. In addition, the presence of smaller oblique channels diverts a small fraction of the flow into adjacent main channels. The secondary flows created improve fluid mixing, which serves to further enhance heat transfer. Both numerical simulations and experimental investigations of copper-based oblique finned microchannel heat sinks demonstrated that a highly augmented and uniform heat transfer performance, relative to the conventional microchannel, is achievable with such a passive technique. The average Nusselt number, Nuave, for the copper microchannel heat sink which uses water as the working fluid can increase as much as 103%, from 11.3 to 22.9. Besides, the augmented convective heat transfer leads to a reduction in maximum temperature rise by 12.6 °C. The associated pressure drop penalty is much smaller than the achieved heat transfer enhancement, rendering it as an effective heat transfer enhancement scheme for a single-phase microchannel heat sink.

Analysis of Heat Transfer Enhancement in Minichannel Heat Sinks With Turbulent Flow Using H2O–Al2O3 Nanofluids

2009 ◽  
Vol 131 (2) ◽  
Author(s):  
T. L. Bergman
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Turbulent Flow ◽  
Heat Transfer Enhancement ◽  
Thermophysical Properties ◽  
Heat Sink ◽  
Heat Sinks ◽  
Transfer Enhancement ◽  
Electronic Heat ◽  
Limited Usefulness

Heat transfer enhancement associated with use of a nanofluid coolant is analyzed for small electronic heat sinks. The analysis is based on the ε-NTU heat exchanger methodology, and is used to examine enhancement associated with use of H2O–Al2O3 nanofluids in a heat sink experiencing turbulent flow. Predictive correlations are generated to ascertain the degree of enhancement based on the fluid’s thermophysical properties. The enhancement is quite small, suggesting the limited usefulness of nanofluids in this particular application.

Enhancing Heat Transfer of Air-Cooled Heat Sinks Using Piezoelectrically-Driven Agitators and Synthetic Jets

2011 ◽  
Author(s):  
Youmin Yu ◽  
Terrence Simon ◽  
Min Zhang ◽  
Taiho Yeom ◽  
Mark North ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Enhancement ◽  
Heat Sink ◽  
Heat Transfer Performance ◽  
Single Channel ◽  
Synthetic Jets ◽  
Heat Sinks ◽  
Transfer Performance ◽  
Transfer Enhancement ◽  
Enhancing Heat Transfer

Air-cooled heat sinks prevail in microelectronics cooling due to their high reliability, low cost, and simplicity. But, their heat transfer performance must be enhanced if they are to compete for high-flux applications with liquid or phase-change cooling. Piezoelectrically-driven agitators and synthetic jets have been reported as good options in enhancing heat transfer of surfaces close to them. This study proposes that agitators and synthetic jets be integrated within air-cooled heat sinks to significantly raise heat transfer performance. A proposed integrated heat sink has been investigated experimentally and with CFD simulations in a single channel heat sink geometry with an agitator and two arrays of synthetic jets. The single channel unit is a precursor to a full scale, multichannel array. The agitator and the jet arrays are separately driven by three piezoelectric stacks at their individual resonant frequencies. The experiments show that the combination of the agitator and synthetic jets raises the heat transfer coefficient of the heat sink by 80%, compared with channel flow only. The 3D computations show similar enhancement and agree well with the experiments. The numerical simulations attribute the heat transfer enhancement to the additional air movement generated by the oscillatory motion of the agitator and the pulsating flow from the synthetic jets. The component studies reveal that the heat transfer enhancement by the agitator is significant on the fin side and base surfaces and the synthetic jets are most effective on the fin tips.

scholarly journals Recent Advancements in Thermal Performance Enhancement in Microchannel Heatsinks for Electronic Cooling Application

2021 ◽  
Author(s):  
Naga Ramesh Korasikha ◽  
Thopudurthi Karthikeya Sharma ◽  
Gadale Amba Prasad Rao ◽  
Kotha Madhu Murthy
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Enhancement ◽  
Power Density ◽  
High Power ◽  
Performance Enhancement ◽  
Electronic Cooling ◽  
Heat Sinks ◽  
High Power Density ◽  
Transfer Enhancement ◽  
Microchannel Heat Sinks

Thermal management of electronic equipment is the primary concern in the electronic industry. Miniaturization and high power density of modern electronic components in the energy systems and electronic devices with high power density demanded compact heat exchangers with large heat dissipating capacity. Microchannel heat sinks (MCHS) are the most suitable heat exchanging devices for electronic cooling applications with high compactness. The heat transfer enhancement of the microchannel heat sinks (MCHS) is the most focused research area. Huge research has been done on the thermal and hydraulic performance enhancement of the microchannel heat sinks. This chapter’s focus is on advanced heat transfer enhancement methods used in the recent studies for the MCHS. The present chapter gives information about the performance enhancement MCHS with geometry modifications, Jet impingement, Phase changing materials (PCM), Nanofluids as a working fluid, Flow boiling, slug flow, and magneto-hydrodynamics (MHD).

A novel heat sink design for simultaneous heat transfer enhancement and pressure drop reduction utilizing porous fins and magnetite ferrofluid

2019 ◽  
Vol 29 (9) ◽  
pp. 3128-3147 ◽  
Author(s):  
Mojtaba Bezaatpour ◽  
Mohammad Goharkhah
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Convective Heat Transfer ◽  
Heat Transfer Enhancement ◽  
Heat Sink ◽  
Reynolds Numbers ◽  
Transfer Enhancement ◽  
Content Type ◽  
Porous Fins ◽  
Simultaneous Heat

Purpose With development of the modern electronic and mechanical devices, cooling requirement has become a serious challenge. Innovative heat transfer enhancement methods are generally accompanied by undesirable increase of pressure drop and consequently a pumping power penalty. The current study aims to present a novel and easy method to manufacture a mini heat sink using porous fins and magnetite nanofluid (Fe3O4/water) as the coolant for simultaneous heat transfer enhancement and pressure drop reduction. Design/methodology/approach A three-dimensional numerical study is carried out to evaluate the thermal and hydrodynamic performance of the mini heat sink at different volume fractions, porosities and Reynolds numbers, using finite volume method. The solver specifications for discretization of the domain involve the SIMPLE, second-order upwind and second order for pressure, momentum and energy, respectively. Findings Results show that porous fins have a favorable effect on both heat transfer and pressure drop compared to solid fins. Creation of a virtual velocity slip on the channel-fin interfaces similar to the micro scale conditions and the flow permeation into the porous fins are the main mechanisms of pressure drop reduction. On the other hand, the heat transfer enhancement is attributed to the increase of the solid-fluid contact area and the improvement of the flow mixing because of the flow permeation into the porous fins. An optimal porosity for maximum convective heat transfer enhancement is obtained as a function of Reynolds number. However, taking both pressure drop and heat transfer effects into account, the overall heat sink performance is shown to be improved at high of Reynolds numbers, volume fractions and fin porosities. Research limitations/implications Thermal radiation and gravity effects are ignored, and thermal equilibrium is assumed between solid and fluid phases. Originality/value A maximum of 32 per cent increase of convective heat transfer is achieved along with a maximum of 33 per cent reduction in the pressure drop using porous fins and ferrofluid in heat sink.

Modeling Forced Convection in Finned Metal Foam Heat Sinks

2009 ◽  
Vol 131 (2) ◽  
Author(s):  
Christopher T. DeGroot ◽  
Anthony G. Straatman ◽  
Lee J. Betchen
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Enhancement ◽  
Forced Convection ◽  
Heat Sink ◽  
Aluminum Foam ◽  
Heat Sinks ◽  
Moderate Pressure ◽  
Transfer Enhancement ◽  
Equivalent Conductivity ◽  
Porous Aluminum

A numerical study has been undertaken to explore the details of forced convection heat transfer in finned aluminum foam heat sinks. Calculations are made using a finite-volume computational fluid dynamics (CFD) code that solves for the flow and heat transfer in conjugate fluid/porous/solid domains. The results indicate that using unfinned blocks of porous aluminum results in low convective heat transfer due to the relatively low effective thermal conductivity of the porous aluminum. The addition of aluminum fins to the heat sink significantly enhances the heat transfer with only a moderate pressure drop penalty. The convective enhancement is maximized when thermal boundary layers between adjacent fins merge together and become nearly developed for much of the length of the heat sink. It is found that the heat transfer enhancement is due to increased heat entrainment into the aluminum foam by conduction. A model for the equivalent conductivity of the finned/foam heat sinks is developed using extended surface theory. This model is used to explain the heat transfer enhancement as an increase in equivalent conductivity of the device. The model is also shown to predict the heat transfer for various heat sink geometries based on a single CFD calculation to find the equivalent conductivity of the device. This model will find utility in characterizing heat sinks and in allowing for quick assessments of the effect of varying heat sink properties.

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