The Influence of the Thermal Conductivity on the Heat Transfer Performance in a Heat Sink

2002 ◽  
Vol 124 (3) ◽  
pp. 164-169 ◽  
Author(s):  
H. B. Ma ◽  
G. P. Peterson
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Fluid Flow ◽  
Temperature Distribution ◽  
Heat Sink ◽  
Heat Transfer Performance ◽  
Solid Material ◽  
Heat Sinks ◽  
Transfer Performance ◽  
Desktop Computers

An extensive numerical analysis of the temperature distribution and fluid flow in a heat sink currently being used for cooling desktop computers was conducted, and demonstrated that if the base of a heat sink was fabricated as a heat pipe instead of a solid material, the heat transfer performance could be significantly increased. It was shown that as the heat sink length increases, the effect of the thermal conductivity of the base on the heat transfer performance increases to be a predictable limit. As the thermal conductivity is increased, the heat transfer performance of heat sinks is enhanced, but cannot exceed this limit. When the thermal conductivity increases to 2,370 W/m-K, the heat transfer performance of the heat sinks will be very close to the heat transfer performance obtained assuming a base with infinite thermal conductivity. Further increases in the thermal conductivity would not significantly improve the heat transfer performance of the heat sinks.

Thermal Fluid Flow Transport Phenomenon Over Vertical Slot-Perforated Flat Fins With Heat Sink in Natural Convection Environment

2005 ◽  
Author(s):  
Shuichi Torii ◽  
Wen-Jei Yang ◽  
Naoko Iino
Keyword(s):  
Heat Transfer ◽  
Fluid Flow ◽  
Natural Convection ◽  
Rayleigh Number ◽  
Heat Sink ◽  
Heat Transfer Performance ◽  
Transfer Performance ◽  
Vertical Slot ◽  
Flow Transport ◽  
Thermal Fluid Flow

A theoretical study is performed to investigate unsteady thermal and fluid flow transport phenomena over vertical slot-perforated flat fins with heat sink, which are placed in a natural convection environment. Emphasis is placed on the effects of Rayleigh number and fin pitch on heat transfer performance and velocity and thermal fields. It is found from the study that (i) in the high Rayleigh number region, the alternating changes in the fluid flow take place for larger fin pitch, (ii) the alternating flow in the space area between two fins is mutually interacted by the corresponding one from the adjacent in-line plate fines, resulting in an amplification of heat transfer performance, and (iii) heat-transfer performance is intensified with an increase in the fin pitch, whose trend becomes larger in the higher Rayleigh number region considered here.

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.

Thermal Transport Phenomena Over Slot-Perforated Flat Fins With Heat Sink in Forced Convection Environment

2004 ◽  
Author(s):  
Shuichi Torii ◽  
Wen-Jei Yang
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Fluid Flow ◽  
Forced Convection ◽  
Heat Sink ◽  
Heat Transfer Performance ◽  
Transport Phenomena ◽  
Transfer Performance ◽  
Thermal Fields ◽  
High Reynolds

A theoretical study is performed to investigate unsteady thermal and fluid flow transport phenomena over flat fins with heat sink, which are placed in a forced convection environment. Emphasis is placed on the effects of Reynolds number and fin pitch on heat transfer performance and velocity and thermal fields. It is found from the study that (i) in the high Reynolds number region, the alternating changes in the fluid flow take place for larger fin pitch, (ii) the alternating flow in the space area between two fins is mutually interacted by the corresponding one from the adjacent in-line plate fines, resulting in an amplification of heat transfer performance, and (iii) heat-transfer performance is intensified with a decrease in the fin pitch, whose trend becomes larger in the higher Reynolds number region considered here.

Numerical Study on Mitigation of Flow Maldistribution in Parallel Microchannel Heat Sink: Channels Variable Width Versus Variable Height Approach

2019 ◽  
Vol 141 (2) ◽  
Author(s):  
Ritunesh Kumar ◽  
Gurjeet Singh ◽  
Dariusz Mikielewicz
Keyword(s):  
Heat Transfer ◽  
Heat Sink ◽  
Heat Transfer Performance ◽  
Numerical Study ◽  
Heat Sinks ◽  
Computational Time ◽  
Microchannel Heat Sink ◽  
Transfer Performance ◽  
Parallel Microchannels ◽  
Flow Maldistribution

Microchannel heat sink on one hand enjoys benefits of intensified several folds heat transfer performance but on the other hand has to suffer aggravated form of trifling limitations associated with imperfect hydrodynamics and heat transfer behavior. Flow maldistribution is one of such limitation that exaggerates temperature nonuniformity across parallel microchannels leading to increase in maximum base temperature. Recently, variable width channels approach had been proposed by the current authors to mitigate the flow maldistribution in parallel microchannels heat sinks (MCHS), and in the current numerical study, variable height approach is opted for flow maldistribution mitigation. It is found that variable height microchannels heat sinks (VHMCHS) approach mitigates flow maldistribution rapidly in comparison to variable width microchannels heat sinks (VWMCHS) approach, almost 50% computational time can be saved by VHMCHS approach. Average fluid–solid interface temperature fluctuation across parallel microchannels reduces 3.3 °C by VHMCHS in comparison to VWMCHS approach. The maximum and average temperatures of the base of the heat sink are further reduced by 5.1 °C and 2.7 °C, respectively, for the VHMCHS. It is found that overall heat transfer performance of the heat sink improves further by 3.8% and 5.1% for the VWMCHS and VHMCHS, respectively. The pressure drop penalty of the VHMCHS is found to be 7.2% higher than VWMCHS.

Proposal of a Micro/Mini Cooling Device Using Fins-Installed Porous Media for High Heat Flux Removal Exceeding 1000W/cm2

2009 ◽  
Author(s):  
Kazuhisa Yuki ◽  
Akira Matsui ◽  
Hidetoshi Hashizume ◽  
Koichi Suzuki
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Heat Sink ◽  
Heat Transfer Performance ◽  
High Heat ◽  
Heat Sinks ◽  
High Heat Flux ◽  
Transfer Performance ◽  
Cooling Device ◽  
Fin Thickness

Heat transfer characteristics of micro-sized bronze particle-sintered porous heat sinks and copper minichannel-fins heat sinks are experimentally investigated in order to clarify the feasibility of a newly proposed micro/mini cooling device using fins-installed porous media. Regarding the porous heat sinks, fin effect toward more inside of the porous medium is promoted by sintering the porous heat sink on the heat transfer surface, which results in increasing the heat transfer performance up to 0.8MW/m2K at heat flux of 8.2MW/m2 though there still remains a large pressure loss issue. In addition, the results clarify that the heat exchanging area exists only in the vicinity of the heat transfer surface. As to the minichannel-fins heat sinks, the influence of the channel width and the fin thickness are evaluated in detail. As a result, the minichannel-fins heat sink having the narrower channel width (i.e. scale effect) and lower porosity (i.e. thicker fin thickness with larger heat capacity) achieves higher heat transfer performance up to 0.10MW/m2K at 8.3MW/m2. However, rapid increase of pressure loss, which is occasionally observed in a microchannel due to vapor bubbles choking the narrow channel, still remains as an issue under flow boiling conditions in the minichannel. Finally, heat transfer performance of the fin-installed porous heat sink is numerically predicted by the control volume method. The simulation confirms that the heat transfer coefficient at each wall superheat of 0 and 30 degrees has performance 2.5 times and 2.0 times higher than that of the normal fins, which indicates that this heat sink coupling the micro and mini channels has high potential as efficient cooling method under high heat flux conditions exceeding 10MW/m2.

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