Numerical Simulation of Nanofluids for Improved Cooling Efficiency in Microchannel Heat Sink

2014 ◽  
Vol 695 ◽  
pp. 403-407 ◽  
Author(s):  
Nur Hazwani Mohamad Noh ◽  
Nor Azwadi Che Sidik
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Heat Sink ◽  
Rectangular Cross Section ◽  
Fluid Dynamic ◽  
Constant Heat Flux ◽  
Working Fluid ◽  
Microchannel Heat Sink ◽  
Rectangular Microchannel ◽  
3 Dimensional

Numerical simulation on 3-dimensional rectangular cross section of microchannel heat sink is conducted to investigate the effect of various type coolant consist of water and different type of nanofluids on the cooling performance of microchannel heat sink. FLUENT, a Computational Fluid Dynamic (CFD) is used as the solver of simulation. A rectangular microchannel with hydraulic diameter of 86um and length of 10mm under the boundary condition of constant heat flux and laminar flow with uniform inlet velocity with five sets of working fluid with different nanofluids. The defined model is validated with previous studies of numerical analysis. Results of present work show that using Diamond-H2O as cooling lead to higher efficiency of heat transfer in microchannel heat sink in comparison to others nanofluid and base fluid. Numerical results show that increasing the thermal conductivity of working fluid can enhanced heat transfer. Nusselt number follows the incremental in Reynolds number.

Effect of 1D Cu Nanostructures on Heat Transfer Characteristics of Single Phase Microchannel Heat Sink

2011 ◽  
Author(s):  
M. Yakut Ali ◽  
Fanghao Yang ◽  
Ruixian Fang ◽  
Chen Li ◽  
Jamil Khan
Keyword(s):  
Heat Transfer ◽  
Heat Sink ◽  
Single Phase ◽  
Working Fluid ◽  
Microchannel Heat Sink ◽  
Heat Transfer Characteristics ◽  
Rectangular Microchannel ◽  
Maximum Enhancement ◽  
Cu Nanowires ◽  
Transfer Characteristics

This study experimentally assesses single phase heat transfer characteristics of a shallow rectangular microchannel heat sink whose surface is enhanced with copper nanowires (CuNWs). The hydraulic diameter of the channel is 672 μm and the bottom wall is coated with Cu nanowires (CuNWs) of 200 nm in diameter and 50 μm in length. CuNWs are grown on the Cu heat sink by electrochemical synthesis technique which is inexpensive and readily scalable. The heat transfer and pressure drop results of CuNWs enhanced heat sink are compared with that of bare copper heat sink using deionized (DI) water as the working fluid at Reynolds Number (Re) ranging from 106–636. The experimental results indicate an enhancement in Nusselt Number (Nu) at all Re with a maximum enhancement of 24% at Re = 106. The enhanced thermal performance is attributed to two properties of Cu nanowire arrays — improvement in surface wettability characteristics and increased heat transfer surface area.

scholarly journals Influence of moist air in copper heat sinks: Analysis through the entropy generation minimization criterion

2015 ◽  
Vol 35 (3) ◽  
pp. 44-52 ◽  
Author(s):  
Jorge Mario Cruz ◽  
Iván Mauricio Amaya ◽  
Carlos Rodrigo Correa
Keyword(s):  
Heat Transfer ◽  
Relative Humidity ◽  
Heat Sink ◽  
Bulk Material ◽  
Heat Transfer Process ◽  
Heat Sinks ◽  
Working Fluid ◽  
Microchannel Heat Sink ◽  
Rectangular Microchannel ◽  
Humidified Air

Many factors affect heat transfer during the cooling of modern electronic devices. Today, knowledge accrues from modeling, simu-lation, and experimentation. This allows predicting and calculating features of heat transfer phenomena, to some extent. Examples include the amount of heat generated and removed, the required physical properties of the working fluid, and the required material properties of the heat sink, among other parameters. This article describes some simulation results of using air with a given relative humidity (10 %, 50 % and 90 %). Its influence on the heat transfer process was also analyzed. Results show a measurable effect of using humidified air instead of dry air and copper as a bulk material. The heat transfer rate increased about 20 % when using air with 90 % relative humidity passing through a rectangular microchannel heat sink made of copper.

Flow Boiling Heat Transfer in a Silicon Microchannel Heat Sink Using Liquid Crystal Thermography

2008 ◽  
Author(s):  
Ayman Megahed ◽  
Ibrahim Hassan ◽  
Tariq Ahmad
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Pressure Drop ◽  
Transfer Coefficient ◽  
Heat Sink ◽  
Boiling Heat Transfer ◽  
Flow Boiling ◽  
Heat Fluxes ◽  
Working Fluid ◽  
Microchannel Heat Sink

The present study focuses on the experimental investigation of boiling heat transfer characteristics and pressure drop in a silicon microchannel heat sink. The microchannel heat sink consists of a rectangular silicon chip in which 45 rectangular microchannels were chemically etched with a depth of 295 μm, width of 254 μm, and a length of 16 mm. Un-encapsulated Thermochromic liquid Crystals (TLC) are used in the present work to enable nonintrusive and high spatial resolution temperature measurements. This measuring technique is used to provide accurate full and local surface-temperature and heat transfer coefficient measurements. Experiments are carried out for mass velocities ranging between 290 to 457 kg/m2.s and heat fluxes from 6.04 to 13.06 W/cm2 using FC-72 as the working fluid. Experimental results show that the pressure drop increases as the exit quality and the flow rate increase. High values of heat transfer coefficient can be obtained at low exit quality (xe < 0.2). However, the heat transfer coefficient decreases sharply and remains almost constant as the quality increases for an exit quality higher than 0.2.

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.

Experimental Investigation of Silicon-Based Oblique Finned Microchannel Heat Sinks

2010 ◽  
Author(s):  
Yong-Jiun Lee ◽  
Poh-Seng Lee ◽  
Siaw-Kiang Chou
Keyword(s):  
Heat Transfer ◽  
Experimental Investigation ◽  
Heat Sink ◽  
Leading Edge ◽  
Secondary Flows ◽  
Heat Sinks ◽  
Fluid Mixing ◽  
Working Fluid ◽  
Microchannel Heat Sink ◽  
Silicon Based

Sectional oblique fins are employed in contrast to the continuous fins in order to modulate the flow in microchannel heat sink. Experimental investigation of silicon based oblique finned microchannel heat sink demonstrated a highly augmented and uniform heat transfer performance against the conventional microchannel. The breakage of continuous fin into oblique sections leads to the re-initialization of the thermal boundary layers at the leading edge of each oblique fin, effectively reducing the boundary-layer thickness. This regeneration of the entrance effect causes the flow to be always in a developing state thus resulting in better heat transfer. In addition, the presence of smaller oblique channels diverts a fraction of the flow into the adjacent main channels. The secondary flows thus created improve fluid mixing which serves to further enhance the heat transfer. The average Nusselt number, Nuave, for the silicon microchannel heat sink which uses water as the working fluid can increase as much as 55%, from 8.8 to 13.6. Besides, the augmented convective heat transfer leads to reduction in both maximum chip temperature and its temperature gradient, by 8.6°C and 47% respectively. Interestingly, there is only little or negligible pressure drop penalty associated with this novel heat transfer enhancement scheme in contrast to conventional enhancement techniques.

Thermal Performance of Microchannels With Dimples for Electronics Cooling

2013 ◽  
Author(s):  
Hui Lu ◽  
Liang Gong ◽  
Minghai Xu
Keyword(s):  
Heat Transfer ◽  
Laminar Flow ◽  
Integrated Circuits ◽  
Heat Sink ◽  
Electronics Cooling ◽  
Cooling Capacity ◽  
Constant Heat Flux ◽  
Microchannel Heat Sink ◽  
Transfer Enhancement ◽  
Different Types

The thermal management of integrated circuits becomes more and more serious since the density of transistors grows gradually. Recently, a new cooling method is dedicated to develop microchannel heat sink with high integrated and high cooling efficiency. In view of above purpose, the heat transfer enhancement and pressure drop reduction in microchannel with dimples are investigated in this paper. A single module of 1mm×1mm×20mm with a microchannel was employed, which hydraulic diameter and aspect ratio are 500 μm and 2:1 respectively. For replacing the running integrated circuits, a constant heat flux of 1W/mm2 was arranged on the bottom of the heat sink. Six different types of microchannels with dimples were designed and numerically studied under the condition of laminar flow. The results show that dimple could enhance heat transfer and decrease flow resistance under the condition of laminar flow. Compared with traditional microchannel heat sink, dimple-microchannel heat sink has stronger cooling capacity, could be an attractive choice for cooling of future microelectronics.

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