Experimental and Numerical Study of a Stacked Microchannel Heat Sink for Liquid Cooling of Microelectronic Devices

2007 ◽  
Vol 129 (10) ◽  
pp. 1432-1444 ◽  
Author(s):  
Xiaojin Wei ◽  
Yogendra Joshi ◽  
Michael K. Patterson
Keyword(s):  
Thin Film ◽  
Numerical Simulations ◽  
Flow Rate ◽  
Heat Sink ◽  
Numerical Study ◽  
Design Guidelines ◽  
Nonuniform Heating ◽  
Microchannel Heat Sink ◽  
Temperature Uniformity ◽  
Liquid Cooling

One of the promising liquid cooling techniques for microelectronics is attaching a microchannel heat sink to, or directly fabricating microchannels on, the inactive side of the chip. A stacked microchannel heat sink integrates many layers of microchannels and manifold layers into one stack. Compared with single-layered microchannels, stacked microchannels provide larger flow passages, so that for a fixed heat load the required pressure drop is significantly reduced. Better temperature uniformity can be achieved by arranging counterflow in adjacent microchannel layers. The dedicated manifolds help to distribute coolant uniformly to microchannels. In the present work, a stacked microchannel heat sink is fabricated using silicon micromachining techniques. Thermal performance of the stacked microchannel heat sink is characterized through experimental measurements and numerical simulations. Effects of coolant flow direction, flow rate allocation among layers, and nonuniform heating are studied. Wall temperature profiles are measured using an array of nine platinum thin-film resistive temperature detectors deposited simultaneously with thin-film platinum heaters on the backside of the stacked structure. Excellent overall cooling performance (0.09°C∕Wcm2) for the stacked microchannel heat sink has been shown in the experiments. It has also been identified that over the tested flow rate range, counterflow arrangement provides better temperature uniformity, while parallel flow has the best performance in reducing the peak temperature. Conjugate heat transfer effects for stacked microchannels for different flow conditions are investigated through numerical simulations. Based on the results, some general design guidelines for stacked microchannel heat sinks are provided.

Performance of Concentrator Photovoltaic Systems Integrated With Double Layer Microchannel Heat Sink

2019 ◽  
Author(s):  
Ali Radwan ◽  
Mohamed M. Awad ◽  
Shinichi Ookawara ◽  
Mahmoud Ahmed
Keyword(s):  
Solar Cell ◽  
Double Layer ◽  
Heat Sink ◽  
Flow Boiling ◽  
Microchannel Heat Sink ◽  
Temperature Uniformity ◽  
Liquid Cooling ◽  
Cell Temperature ◽  
Wide Range ◽  
Phase Liquid

Abstract In this study, a new design of double layer microchannel heat sink (DL-MCHS) has been monolithically fabricated using 3D metal printer and experimentally examined as a heat sink for concentrator photovoltaic (CPV) systems. Single phase liquid cooling using ethanol and flow boiling cooling using NOVEC-7000 coolant in the designed DL-MCHS are experimentally compared. The results proved that using the flow boiling cooling technique for the CPV systems attained a lower solar cell temperature with high temperature uniformity. In more details, flow boiling in counterflow (CF) operated DL-MCHS, attained a very low solar cell temperature close to the NOVEC-7000 boiling point with temperature uniformity of 0.2 °C over a wide range of coolant flow rate from 25–250 ml/hr.

Circular Microchannel Heat Sink Optimization Using Entropy Generation Minimization Method

2020 ◽  
Vol 45 (4) ◽  
pp. 333-342
Author(s):  
Krishan Kumar ◽  
Rajan Kumar ◽  
Rabinder Singh Bharj
Keyword(s):  
Entropy Generation ◽  
Flow Rate ◽  
Heat Sink ◽  
Numerical Study ◽  
Bejan Number ◽  
Optimum Number ◽  
Microchannel Heat Sink ◽  
Heat Flow Rate ◽  
Entropy Generation Number ◽  
Entropy Generation Minimization

AbstractThe performance of the microchannel heat sink (MCHS) in electronic applications needs to be optimized corresponding to the number of channels (N). In this study optimization of the number of channels corresponding to the diameter of the microchannel ({D_{N}}) using an entropy generation minimization approach is achieved for the MCHS used in electronic applications. The numerical study is performed for constant total heat flow rate ({\dot{q}_{tot}}) and total mass flow rate ({\dot{m}_{tot}}). The results indicate that the dominance of frictional entropy generation ({S_{gen,Fr}}) increases with the reduction in diameter. However, the entropy generation due to heat transfer ({S_{gen,HT}}) decreases with the reduction in diameter. Therefore, the optimum diameter ({D^{\ast }}) is calculated corresponding to the minimum total entropy generation ({S_{gen,total}}) for the optimum number of channels ({N^{\ast }}). Furthermore, the entropy generation number ({N_{S}}) and Bejan number (Be) are also calculated.

scholarly journals Application of a Double Layer Circular Microchannel Heat Sink in Electronic Industry

2019 ◽  
Vol 8 (12) ◽  
pp. 1153-1158
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Heat Sink ◽  
Microchannel Heat Sink ◽  
Temperature Uniformity ◽  
Counter Flow ◽  
Circular Microchannel

The present paper is focused to evaluate the pressure drop and heat transfer performance of a double layer circular microchannel heat sink with numerically and experimentally. Numerical analysis is carried for various mass flow rates, with turbulent condition used in the ANSYS Fluent for two flow arrangements. The experiment is carried out by varying the mass flow rate ranges 3.32x10-4 kg/s to 27.72x10-4 kg/s with water as the cooling medium. The effect of a parallel flow and counter flow arrangements on heat transfer and flow parameters is studied for a constant heat input of 80W. The numerical result is nearly the same with the measured values. The pressure drop increases with the mass flow rate. The heat transfer enhancement is evaluated by the wall surface temperature and temperature uniformity. Even though parallel and counter flow arrangement has similar flow and thermal behavior, the latter has better temperature uniformity in the base of the heat sink for all pumping powers.

Stacked Microchannel Heat Sinks for Liquid Cooling of Microelectronics

2004 ◽  
Author(s):  
Xiaojin Wei ◽  
Yogendra Joshi ◽  
Michael K. Patterson
Keyword(s):  
Flow Rate ◽  
Heat Sink ◽  
Flow Direction ◽  
Junction Temperature ◽  
Microchannel Heat Sink ◽  
Temperature Uniformity ◽  
Beneficial Result ◽  
Flexible Control ◽  
Liquid Heat ◽  
Parallel Microchannels

Stacked microchannels provide larger flow passages, so that for a fixed heat load the required pressure drop is significantly reduced. One unique feature of the stacked microchannel heat sink is that individual layers populated with parallel microchannels or distributing manifolds can be bonded into one stack with independent flow path. As a beneficial result, flexible control over the flow direction and flow rate can be harnessed to achieve better temperature uniformity and the low junction temperature. In the present work, stacked microchannels with different flow arrangement have been fabricated on silicon wafers using micromachining techniques. Platinum thin film heaters are deposited on the backside of the stacked structure to provide heating. In a close-loop setup, water is pumped through the microchannels to carry the heat from the heaters to a remote liquid-liquid heat exchanger rejecting the heat to a recirculating chiller. Wall temperature along the flow direction is measured at nine locations using platinum resistive temperature detectors deposited at the same time as the heaters. Good overall cooling performance (0.09°C/(W/cm2)) for the stacked microchannel heat sink has been shown in the experiments. It has also been identified that over the tested flow rate range counter-flow arrangement provides better temperature uniformity, while parallel flow has the best performance in reducing the peak temperature.

scholarly journals Effect of liquid cooling on PCR performance with the parametric study of cross-section shapes of microchannels

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yousef Alihosseini ◽  
Mohammad Reza Azaddel ◽  
Sahel Moslemi ◽  
Mehdi Mohammadi ◽  
Ali Pormohammad ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Cross Section ◽  
Cross Sections ◽  
Heat Sink ◽  
Evaluation Criteria ◽  
Circular Cross Section ◽  
Microchannel Heat Sink ◽  
Liquid Cooling ◽  
Maximum Heat ◽  
Maximum Heat Transfer

AbstractIn recent years, PCR-based methods as a rapid and high accurate technique in the industry and medical fields have been expanded rapidly. Where we are faced with the COVID-19 pandemic, the necessity of a rapid diagnosis has felt more than ever. In the current interdisciplinary study, we have proposed, developed, and characterized a state-of-the-art liquid cooling design to accelerate the PCR procedure. A numerical simulation approach is utilized to evaluate 15 different cross-sections of the microchannel heat sink and select the best shape to achieve this goal. Also, crucial heat sink parameters are characterized, e.g., heat transfer coefficient, pressure drop, performance evaluation criteria, and fluid flow. The achieved result showed that the circular cross-section is the most efficient shape for the microchannel heat sink, which has a maximum heat transfer enhancement of 25% compared to the square shape at the Reynolds number of 1150. In the next phase of the study, the circular cross-section microchannel is located below the PCR device to evaluate the cooling rate of the PCR. Also, the results demonstrate that it takes 16.5 s to cool saliva samples in the PCR well, which saves up to 157.5 s for the whole amplification procedure compared to the conventional air fans. Another advantage of using the microchannel heat sink is that it takes up a little space compared to other common cooling methods.

Stacked Microchannel Heat Sinks for Liquid Cooling of Microelectronic Components

2000 ◽  
Author(s):  
X. Wei ◽  
Y. Joshi
Keyword(s):  
Flow Rate ◽  
Heat Sink ◽  
Water Flow Rate ◽  
Heat Removal ◽  
Single Layer ◽  
Heat Sinks ◽  
Computationally Efficient ◽  
Liquid Cooling ◽  
Number Of Layers ◽  
Microelectronic Components

Abstract A novel heat sink based on a multi-layer stack of liquid cooled microchannels is investigated. For a given pumping power and heat removal capability for the heat sink, the flow rate across a stack of microchannels is lower compared to a single layer of microchannels. Numerical simulations using a computationally efficient multigrid method [1] were carried out to investigate the detailed conjugate transport within the heat sink. The effects of the microchannel aspect ratio and total number of layers on thermal performance were studied for water as coolant. A heat sink of base area 10 mm by 10 mm with a height in the range 1.8 to 4.5 mm (2–5 layers) was considered with water flow rate in the range 0.83×10−6 m3/s (50 ml/min) to 6.67×10−6 m3/s (400 ml/min). The results of the computational simulations were also compared with a simplified thermal resistance network analysis.

Numerical Study of Microchannel Heat Sinks With Non-Uniform Heat Flux Conditions

2011 ◽  
Author(s):  
Ling Ling ◽  
Yanfeng Fan ◽  
Ibrahim Hassan
Keyword(s):  
Heat Flux ◽  
Heat Sink ◽  
Numerical Study ◽  
Heat Sinks ◽  
Maximum Temperature ◽  
Bottom Surface ◽  
Nonuniform Heating ◽  
Uniform Heat Flux ◽  
Computational Domain ◽  
Uniform Heating

Higher heat flux is produced by Micro-Electro-Mechanical Systems (MEMS) because of their reduced size and increased clock speed. At the mean time, studies of non-uniform heating conditions which are more practical than uniform heating conditions are inadequate and needed urgently. Four nonuniform heating conditions are simulated in the paper. Three heat sinks with different widths of cross-linked channels locating above the center of hotspots are studied and compared to conventional straight microchannel heat sink. Half of the module geometry is chosen to be the computational domain. Two hotspots are placed at the bottom surface. The coolant is water, whose properties are dependent on temperature. Two inlet velocities, 0.5 m/s and 1 m/s, are tested for each heat sink. Temperature profile at the hotspots, pressure drop and total thermal resistance are selected as criteria of evaluating heat sink performance. All heat sinks have better performance when there is an upstream hotspot or the upstream hotspot is subjected to a higher heat flux. Cross-linked channel width of 0.5 mm has the best benefit to obtain better temperature uniformity without increasing the maximum temperature on the bottom surface.

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