Modeling and Optimization of Multilayer Minichannel Heat Sinks in Single-Phase Flow

2007 ◽  
Author(s):  
Ning Lei ◽  
Alfonso Ortega ◽  
Ranji Vaidyanathan
Keyword(s):  
Pressure Drop ◽  
Aspect Ratio ◽  
Thermal Resistance ◽  
Heat Sink ◽  
Single Phase ◽  
Single Layer ◽  
High Heat ◽  
Heat Sinks ◽  
Single Phase Flow ◽  
Number Of Layers

Liquid-cooled small channel heat sinks are a promising heat dissipation method for high power electronic devices. Traditional mini and microchannel heat sinks consist of a single layer of high aspect ratio rectangular channels. An alternative approach investigated in this paper is to stack multiple layers of low aspect ratio (circular or square cross-section) channels together to create multiple layer minichannel heat sinks. These multilayer heat sinks can achieve high heat flux due to the high heat transfer coefficients from small channels coupled with the large surface areas from the multilayer structure. In this research, multilayer copper and silicon carbide (SiC) minichannel heat sinks were experimentally and computationally characterized in single-phase flow over various flow rates. The experimental data indicated that in many cases, multilayer heat sinks have significant advantages over single-layer equivalents with reductions in thermal resistance and pressure drop. In order to investigate the optimal design of such structures, a detailed 3-D resistance network model was developed and used to predict the heat sink surface temperature and fluid pressure drop. The model uses an uncoupled approach and was validated by compared with conjugate CFD simulations and the experimental data. An extensive parametric study was performed on copper and SiC heat sinks with respect to channel geometry, number of layers, and thermal conductivity. The simulations indicated that for a fixed overall heat sink flow rate, an optimum number of channel layers exists for copper and SiC because of the competing trends of increasing surface area and decreasing per channel flow rate as the number of layers increases. In addition, the heat sink “effectiveness” decreases with increasing number of layers as the thermal resistance from the top surface, where heat is applied, to the lower layers of the heat sink becomes excessive. In the simulation the optimized number of layers is highly dependent on material, channel width, channel aspect ratio, and wall thickness. If the pumping power is an important issue for the optimization, the heat sink with medium channel width is a wise choice, which achieves small thermal resistance with reasonable pressure drop.

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.

Cryogenic Single-Phase Heat Transfer in a Microscale Pin Fin Heat Sink

2013 ◽  
Author(s):  
Eric D. Truong ◽  
Erfan Rasouli ◽  
Vinod Narayanan
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Heat Sink ◽  
Single Phase ◽  
Flow Direction ◽  
Heat Sinks ◽  
Variable Cross ◽  
Transfer Coefficients ◽  
Pin Fin ◽  
Heat Transfer Coefficients

A combined experimental and computational fluid dynamics study of single-phase liquid nitrogen flow through a microscale pin-fin heat sink is presented. Such cryogenic heat sinks find use in applications such as high performance computing and spacecraft thermal management. A circular pin fin heat sink in diameter 5 cm and 250 micrometers in depth was studied herein. Unique features of the heat sink included its variable cross sectional area in the flow direction, variable pin diameters, as well as a circumferential distribution of fluid into the pin fin region. The stainless steel heat sink was fabricated using chemical etching and diffusion bonding. Experimental results indicate that the heat transfer coefficients were relatively unchanged around 2600 W/m2-K for flow rates ranging from 2–4 g/s while the pressure drop increased monotonically with the flow rate. None of the existing correlations in literature on cross flow over a tube bank or micro pin fin heat sinks were able to predict the experimental pressure drop and heat transfer characteristics. However, three dimensional simulations performed using ANSYS Fluent showed reasonable (∼7 percent difference) agreement in the average heat transfer coefficients between experiments and CFD simulations.

Optimization Design the Configuration Sizes of Multi-Layer Rectangle Micro-Channel Heat Sink

2013 ◽  
Vol 444-445 ◽  
pp. 1101-1106
Author(s):  
Li Feng Wang ◽  
Bao Dong Shao ◽  
He Ming Cheng ◽  
Ying He
Keyword(s):  
Pressure Drop ◽  
Thermal Resistance ◽  
Heat Sink ◽  
Optimization Design ◽  
High Heat ◽  
Micro Channel ◽  
Compact Structure ◽  
Total Thermal Resistance ◽  
High Heat Transfer ◽  
High Heat Transfer Coefficient

The configuration sizes of multi-layer rectangle micro-channel heat sink are optimized, which has been widely used to cool electronic chip for its high heat transfer coefficient and compact structure. Taking the thermal resistance and the pressure drop as goal functions, a binary-objective optimization model was proposed for the multi-layer rectangle micro-channel heat sink based on Sequential Quadratic Programming (SQP) method. The number of optimized micro-channel in width n1 and that in height n2 are 24 and 3, the width of optimized micro-channel Wc and fin Wf are 360 and 55μm, the height of optimized micro-channel Hc is 1000μm, and the corresponding total thermal resistance of the whole micro-channel heat sink is 1.5429 °C/W. The corresponding pressure drop is about 2.3454 Pa. When the velocity of liquid is larger than 0.3 m/s, the effect of change of velocity of liquid on the thermal resistance and pressure drop can be neglected.

Multi-Objective Optimization Design of Multi-Layer Rectangle Micro-Channel Heat Sink for Single-Phase Flow and Heat Transfer

2013 ◽  
Vol 709 ◽  
pp. 286-291 ◽  
Author(s):  
Li Feng Wang ◽  
Bao Dong Shao ◽  
He Ming Cheng
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Thermal Resistance ◽  
Heat Sink ◽  
Optimization Design ◽  
High Heat ◽  
Micro Channel ◽  
Compact Structure ◽  
Total Thermal Resistance ◽  
High Heat Transfer

The purpose of this paper is to optimize the structural sizes of multi-layer rectangle micro-channel heat sink, which has been widely used to cool electronic chip for its high heat transfer coefficient and compact structure. Taking the thermal resistance and the pressure drop as goal functions, a binary-objective optimization model was proposed for the multi-layer rectangle micro-channel heat sink based on Sequential Quadratic Programming (SQP) method. The number of optimized micro-channel in width n1 and that in height n2 are 21 and 7, the width of optimized micro-channel Wc and fin Wf are 340 and 130μm, the height of optimized micro-channel Hc is 415μm, and the corresponding total thermal resistance of the whole micro-channel heat sink is 1.3354 °C/W. The corresponding pressure drop is about 1.3377 Pa. When the velocity of liquid is larger than 0.3 m/s, the effect of change of velocity of liquid on the thermal resistance and pressure drop can be neglected.

scholarly journals Thermal analysis and parametric optimization of plate fin heat sinks under forced air convection

2021 ◽  
pp. 81-81
Author(s):  
Zulfiqar Khattak ◽  
Hafiz Ali
Keyword(s):  
Pressure Drop ◽  
Thermal Resistance ◽  
Heat Sink ◽  
Heat Dissipation ◽  
Parametric Optimization ◽  
Heat Sinks ◽  
Air Velocity ◽  
Forced Air ◽  
Theoretical Results ◽  
Plate Type

Heat dissipation is becoming more and more challenging with the preface of new electronic components having staggering heat generation levels. Present day solutions should have optimized outcomes with reference to the heat sink scenarios. The experimental and theoretical results for plate type heat sink based on mathematical models have been presented in the first part of the paper. Then the parametric optimization (topology optimization) of plate type heat sink using Levenberg-Marquardt technique employed in the COMSOL Multiphysics? software is discussed. Thermal resistance of heat sink is taken as objective function against the variable length in a predefined range. Single as well as multi-parametric optimization of plate type heat sink is reported in the context of pressure drop and air velocity (Reynolds number) inside the tunnel. The results reported are compared with the numerical modeled data and experimental investigation to establish the conformity of results for applied usage. Mutual reimbursements of greater heat dissipation with minimum flow rates are confidently achievable through balanced, heat sink geometry as evident by the presented simulation outcome. About 12% enhancement in pressure drop and up to 51% improvement in thermal resistance is reported for the optimized plate fin heat sink as per data manifested.

Pressure Drop and Heat Transfer in a Single-Phase Micro-Pin-Fin Heat Sink

2006 ◽  
Author(s):  
Abel M. Siu Ho ◽  
Weilin Qu ◽  
Frank Pfefferkorn
Keyword(s):  
Heat Transfer ◽  
Nusselt Number ◽  
Pressure Drop ◽  
Friction Factor ◽  
Heat Sink ◽  
Single Phase ◽  
Fluid Transport ◽  
Heat Sinks ◽  
Inlet Temperature ◽  
Pin Fin

The pressure drop and heat transfer characteristics of a single-phase micro-pin-fin heat sink were investigated experimentally. Fabricated from 110 copper, the heat sink consisted of 1950 staggered micro-pins with 200×200 μm2 cross-section by 670 μm height. Deionized water was employed as the cooling liquid. A coolant inlet temperature of 25°C, and two heat flux levels, q" eff = 50 W/cm2 and q" eff = 100 W/cm2, defined relative to the planform area of the heat sink, were tested. The inlet Reynolds number ranged from 93 to 634 for q" eff = 50 W/cm2, and 127 to 634 for q" eff = 100 W/cm2. The measured pressure drop and temperature distribution were used to evaluate average friction factor and local averaged heat transfer coefficient/Nusselt number. Predictions of the Moores and Joshi friction factor correlation and the Chyu et al. heat transfer correlation that were developed using macro-size pin-fin arrays were compared to micro-pin-fin heat sink data. While the Moores and Joshi correlation provide acceptable predictions, the Chyu et al. correlation overpredicted local Nusselt number data by a fairly large margin. These findings point to the need for further study of single-phase thermal/fluid transport process in micro-pin-fin heat sinks.

Multi Layer Micro Pin-Fins Heat Sinks for Better Performance

2010 ◽  
Author(s):  
T. J. John ◽  
B. Mathew ◽  
H. Hegab
Keyword(s):  
Temperature Distribution ◽  
Thermal Resistance ◽  
Heat Sink ◽  
Single Layer ◽  
Heat Sinks ◽  
Substrate Thickness ◽  
Pin Fin ◽  
Micro Channels ◽  
Pin Fins ◽  
Overall Performance

This study numerically investigates the feasibility and advantages of using a multilayer pin-fin heat sink to increase the overall performance of the heat sink. For the purpose of determining overall performance of the pin-fin heat sink a figure of merit (FOM) term is introduced in this paper, which constituted of both the thermal resistance and the pumping power of the heat sink. Higher the FOM of a heat sink better is its overall performance. A computational fluid dynamics software CoventorWARE™ is used for the analysis of micro heat sink performance. A small portion of the entire heat sink is modeled in this study assuming repeatability towards both sides for the ease of analysis. The developed models consist of two sections, the substrate (silicon) and the fluid (water at 278K). A uniform heat flux is applied to the base of the heat sink. A single layer micro pin-fin heat sinks with same dimensions as of the multi layer heat sink was also modeled for the comparison purpose. Temperature distribution at five different locations from the inlet to the outlet section is also analyzed to study the temperature distribution over the heat sink. Circular pin-fins were used in both the multilayer and single layer micro heat sinks. Feasibility of using micro channels as the second layer was also investigated in this paper and it proved to have advantages over using pin-fin structures on both layers. A geometric optimization based on the substrate thickness of the second layer of the double layer heat sink showed that the substrate thickness of the second layer doesn’t have any effect on the overall thermal resistance of the heat sink.

Numerical Investigations of the Effect of Flow Arrangement and Number of Layers on the Performance of Multi-Layer Microchannel Heat Sinks

2015 ◽  
Author(s):  
M. B. Effat ◽  
M. S. AbdelKarim ◽  
O. Hassan ◽  
M. Abdelgawad
Keyword(s):  
Heat Flux ◽  
Temperature Distribution ◽  
Heat Sink ◽  
Single Layer ◽  
Heat Sinks ◽  
Uniform Heat Flux ◽  
Microchannel Heat Sink ◽  
Electronic Components ◽  
Number Of Layers ◽  
Microchannel Heat Sinks

With the advance of miniaturization technology, more and more electronic components are placed onto small electronic chips. This leads to the generation of high amounts of thermal energy that should be removed for the safe operation of these electronic components. Microchannel heat sinks, where electronic chips are liquid cooled instead of the conventional air cooling techniques, were proposed as a means to improve cooling rates. Later on, double layer micro channel heat sinks were suggested as an upgrade to single layer microchannel heat sinks with a better thermal performance. In the present study the effects of increasing the number of layers of the microchannel heat sink to three-layers as well as the effect of changing the flow arrangements (counter and parallel flows) within the three channel layers on the thermal performance of the heat sink were investigated. In all investigated cases the temperature distribution over the base of the microchannel heat sink system and the total pressure drop are reported. A range of mass flow rates from 1×10−4 to 5×10−4 kg/s was considered. Uniform heat flux conditions were considered during the study. COMSOL Multiphysics finite element package was employed for the numerical analysis. Results indicate significant enhancement in the uniformity of the temperature on the processor surface when multi-layer channels were employed, compared to the single-layer case. The uniformity in the temperature distribution was accompanied by reduction of pressure drop across channels for the same mass flow rate and heat flux conditions. The counter flow arrangement showed the best temperature distribution with the uniform heat flux cases.

A Genetic Algorithm Based Multi-Objective Thermal Design Optimization of Liquid Cooled Offset Strip Fin Heat Sinks

2009 ◽  
Author(s):  
Sidy Ndao ◽  
Yoav Peles ◽  
Michael K. Jensen
Keyword(s):  
Genetic Algorithm ◽  
Pressure Drop ◽  
Aspect Ratio ◽  
Power Consumption ◽  
Thermal Resistance ◽  
Thermal Design ◽  
Heat Sinks ◽  
Total Thermal Resistance ◽  
Offset Strip Fin ◽  
Fin Length

A genetic algorithm based multi-objective thermal design optimization of liquid cooled offset strip fin heat sinks is presented. Using water and HFE-7000 as coolants, Matlab’s genetic algorithm and direct search toolbox functions were utilized to determine the optimal thermal design of the offset strip fin heat sink based on the total thermal resistance and power consumption under constant pressure drop. For a relatively small fin length, the total thermal resistance decreases with increasing fin length and aspect ratio α. For larger fin lengths, the total thermal resistance increases with increasing fin length whereas the power consumption continuously increases with increasing fin length and aspect ratio α for a given pressure drop. A plot of the Pareto front indicates a trade-off between the total thermal resistance and pumping power consumption.

Analysis of Pin-Fin Heat Sinks With an Unconventional Fin Profile

2013 ◽  
Author(s):  
Jose-Luis Gonzalez-Hernandez ◽  
Abel Hernandez-Guerrero ◽  
Carlos Rubio-Jimenez ◽  
Cuauhtemoc Rubio-Arana
Keyword(s):  
Wave Function ◽  
Pressure Drop ◽  
Thermal Resistance ◽  
Geometric Parameter ◽  
Entropy Generation ◽  
Heat Sink ◽  
Total Pressure ◽  
Heat Sinks ◽  
Pin Fin ◽  
Sinusoidal Function

In this work the performance of pin-fin heat sinks having an unconventional fin profile is compared with the use of cylindrical fins. The fin profile is a sinusoidal function and a staggered array is considered. The overall thermal resistance and total pressure drop are reported for the pin-fin heat sinks. The effect of using a wave function for the fin is studied for different number of complete waves along the height of the fins and a geometric parameter defined as the ratio of the higher to the lower radius of the fins is proposed. The study is carried out for two different inlet velocities, and for two different fin densities, corresponding to 5×5 and 7×7 arrays. An entropy generation analysis for each pin fin heat sink configuration is carried out and reported. The results of the present analysis reveal that the proposed geometry has an improvement as compared to the conventional heat sinks profiles when there is a high number of waves per fin. The effect of the geometric parameters defined in this study for the thermal and hydraulic performance is identified and discussed as well.

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