Heat Transfer Enhancement in a Microchannel Heat Sink with Trapezoidal Cavities on the Side Walls

2016 ◽  
Vol 819 ◽  
pp. 127-131
Author(s):  
Navin Raja Kuppusamy ◽  
N.N.N. Ghazali ◽  
Saidur Rahman ◽  
M.A. Omar Awang ◽  
Hussein A. Mohammed

The present study focuses on the numerical study of thermal and flow characteristics in a microchannel heat sink with alternating trapezoidal cavities in sidewall (MTCS). The effects of flow rate and heat flux on friction factor and Nusselt are presented. The results showed considerable improvement heat transfer performance micro channel heat sink with alternating trapezoidal cavities in sidewall with an acceptable pressure drop. The heat transfer rate has improved in the cavity area due the greater fluid mixing in fluid vortices and thermal boundary layer disruption. The slipping over the reentrant cavities and pressure gain reduces pressure drop appears as the reason behind of only minor pressure drop due to the cavities.

2017 ◽  
Vol 21 (1 Part A) ◽  
pp. 279-288 ◽  
Author(s):  
Shuxia Qiu ◽  
Peng Xu ◽  
Liping Geng ◽  
Arun Mujumdar ◽  
Zhouting Jiang ◽  
...  

Air jet impingement is one of the effective cooling techniques employed in micro-electronic industry. To enhance the heat transfer performance, a cooling system with air jet impingement on a finned heat sink is evaluated via the computational fluid dynamics method. A two-dimensional confined slot air impinging on a finned flat plate is modeled. The numerical model is validated by comparison of the computed Nusselt number distribution on the impingement target with published experimental results. The flow characteristics and heat transfer performance of jet impingement on both of smooth and finned heat sinks are compared. It is observed that jet impingement over finned target plate improves the cooling performance significantly. A dimensionless heat transfer enhancement factor is introduced to quantify the effect of jet flow Reynolds number on the finned surface. The effect of rectangular fin dimensions on impingement heat transfer rate is discussed in order to optimize the cooling system. Also, the computed flow and thermal fields of the air impingement system are examined to explore the physical mechanisms for heat transfer enhancement.


Author(s):  
Parisa Vaziee ◽  
Omid Abouali

Effectiveness of the microchannel heat sink cooled by nanofluids with various particle volume fractions is investigated numerically using the latest theoretical models for conductivity and viscosity of the nanofluids. Both laminar and turbulent flows are considered in this research. The model of conductivity used in this research accounts for the fundamental role of Brownian motion of the nanoparticles which is in good agreement with the experimental data. The changes in viscosity of the nanofluid due to temperature variation are considered also. Final results are compared with the experimental measurements for heat transfer coefficient and pressure drop in microchannel. Enhancement in heat transfer is achieved for laminar flow with increasing of volume fraction of Al2O3 nanoparticles. But for turbulent flow an enhancement of heat removal was not seen and using higher volume fractions of nanoparticles increases the maximum substrate temperature. Pressure drop is increased with using nanofluids because of the augmentation in the viscosity and this increase is more noticeable in higher Reynolds numbers.


2020 ◽  
Vol 13 (1) ◽  
pp. 173-180
Author(s):  
R Vinoth ◽  
M Parthiban ◽  
Naveen Kumar Nagalli ◽  
S Prakash

The present work deals with study the heat transfer and pressure drop of the triangular microchannel heat sink(MCHS), along different working fluids. The nanofluids such as CuO and Al2O3are used as coolants to enhance the performance of triangular microchannel heat sinks.The modeling and analysis were done with the help of Solid works. The heat transfer performance of the triangular fins were studied with the Reynolds number varying from 96 - 460. Thenumerical result shows that the triangular oblique finned microchannel heat sink has large heat transfer rateof 12.9 % for varying Reynolds number when compared to a straight channel. Similarly, the pressure drop also increases with 38.2% for triangular microchannel flowing nanofluid. Consequently triangular microchannel is enhancing the heat removed in electronics chip cooling


2019 ◽  
Vol 141 (2) ◽  
Author(s):  
Ritunesh Kumar ◽  
Gurjeet Singh ◽  
Dariusz Mikielewicz

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.


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