scholarly journals Nonlocal Modeling and Swarm-Based Design of Heat Sinks

2013 ◽  
Vol 136 (1) ◽  
Author(s):  
David Geb ◽  
Ivan Catton
Keyword(s):  
Heat Transfer ◽  
Heat Sink ◽  
Electronics Cooling ◽  
Optimization Methods ◽  
Volume Averaging ◽  
Population Based ◽  
Design Tool ◽  
Heat Sinks ◽  
Optimal Designs ◽  
Traditional Approaches

Cooling electronic chips to satisfy the ever-increasing heat transfer demands of the electronics industry is a perpetual challenge. One approach to addressing this is through improving the heat rejection ability of air-cooled heat sinks, and nonlocal thermal-fluid-solid modeling based on volume averaging theory (VAT) has allowed for significant strides in this effort. A number of optimization methods for heat sink designers who model heat sinks with VAT can be envisioned due to VAT's singular ability to rapidly provide solutions, when compared to computational fluid dynamics (CFD) approaches. The particle swarm optimization (PSO) method appears to be an attractive multiparameter heat transfer device optimization tool; however, it has received very little attention in this field compared to its older population-based optimizer cousin, the genetic algorithm (GA). The PSO method is employed here to optimize smooth and scale-roughened straight-fin heat sinks modeled with VAT by minimizing heat sink thermal resistance for a specified pumping power. A new numerical design tool incorporates the PSO method with a VAT-based heat sink solver. Optimal designs are obtained with this new tool for both types of heat sinks, the performances of the heat sink types are compared, the performance of the PSO method is discussed with reference to the GA method, and it is observed that this new method yields optimal designs much quicker than traditional approaches. This study demonstrates, for the first time, the effectiveness of combining a VAT-based nonlocal thermal-fluid-solid model with population-based optimization methods, such as PSO, to design heat sinks for electronics cooling applications. The VAT-based nonlocal modeling method provides heat sink design capabilities, in terms of solution speed and model rigor, that existing modeling methods do not match.

Compact Modeling of Fluid Flow and Heat Transfer in Straight Fin Heat Sinks

2004 ◽  
Vol 126 (2) ◽  
pp. 247-255 ◽  
Author(s):  
Duckjong Kim ◽  
Sung Jin Kim
Keyword(s):  
Heat Transfer ◽  
Porous Medium ◽  
Fluid Flow ◽  
Pressure Drop ◽  
Heat Sink ◽  
Volume Averaging ◽  
Thermal Design ◽  
Heat Sinks ◽  
Compact Modeling ◽  
Flow And Heat Transfer

In the present work, a compact modeling method based on a volume-averaging technique is presented. Its application to an analysis of fluid flow and heat transfer in straight fin heat sinks is then analyzed. In this study, the straight fin heat sink is modeled as a porous medium through which fluid flows. The volume-averaged momentum and energy equations for developing flow in these heat sinks are obtained using the local volume-averaging method. The permeability and the interstitial heat transfer coefficient required to solve these equations are determined analytically from forced convective flow between infinite parallel plates. To validate the compact model proposed in this paper, three aluminum straight fin heat sinks having a base size of 101.43mm×101.43mm are tested with an inlet velocity ranging from 0.5 m/s to 2 m/s. In the experimental investigation, the heat sink is heated uniformly at the bottom. The resulting pressure drop across the heat sink and the temperature distribution at its bottom are then measured and are compared with those obtained through the porous medium approach. Upon comparison, the porous medium approach is shown to accurately predict the pressure drop and heat transfer characteristics of straight fin heat sinks. In addition, evidence indicates that the entrance effect should be considered in the thermal design of heat sinks when Re Dh/L>∼O10.

Thermal Optimization of Microchannel Heat Sink With Pin Fin Structures

2003 ◽  
Author(s):  
Duckjong Kim ◽  
Sung Jin Kim
Keyword(s):  
Heat Transfer ◽  
Porous Medium ◽  
Fluid Flow ◽  
Heat Sink ◽  
Volume Averaging ◽  
Heat Sinks ◽  
Pumping Power ◽  
Heat Transfer Characteristics ◽  
Pin Fin ◽  
Flow And Heat Transfer

In the present work, a novel compact modeling method based on the volume-averaging technique and its application to the analysis of fluid flow and heat transfer in pin fin heat sinks are presented. The pin fin heat sink is modeled as a porous medium. The volume-averaged momentum and energy equations for fluid flow and heat transfer in pin fin heat sinks are obtained using the local volume-averaging method. The permeability, the Ergun constant and the interstitial heat transfer coefficient required to solve these equations are determined experimentally. To validate the compact model proposed in this paper, 20 aluminum pin fin heat sinks having a 101.43 mm × 101.43 mm base size are tested with an inlet velocity ranging from 1 m/s to 5 m/s. In the experimental investigation, the heat sink is heated uniformly at the bottom. Pressure drop and heat transfer characteristics of pin fin heat sinks obtained from the porous medium approach are compared with experimental results. Upon comparison, the porous medium approach is shown to predict accurately the pressure drop and heat transfer characteristics of pin fin heat sinks. Finally, surface porosities of the pin fin heat sink for which the thermal resistance of the heat sink is minimal are obtained under constraints on pumping power and heat sink size. The optimized pin fin heat sinks are shown to be superior to the optimized straight fin heat sinks in thermal performance by about 50% under the same constraints on pumping power and heat sink size.

CFD Analysis of Flow and Heat Transfer in a Novel Heat Sink for Electronic Devices

2010 ◽  
Author(s):  
Bladimir Ramos-Alvarado ◽  
Peiwen Li ◽  
Hong Liu ◽  
Abel Hernandez-Guerrero
Keyword(s):  
Heat Transfer ◽  
Power Consumption ◽  
Heat Sink ◽  
Electronics Cooling ◽  
Flow Channel ◽  
Heat Sinks ◽  
Temperature Fields ◽  
Pumping Power ◽  
Pressure Losses ◽  
Channel Configuration

Novel flow channel configurations in heat sinks for electronics cooling were proposed in this paper. Computational analyses were carried out to better understand the heat transfer performance, the uniformity of temperature fields of the heat sinking surface, as well as the pressure losses and pumping power in the operation of heat sinks. Comparison of the overall performance regarding to temperature uniformity on the heat sink surface and pumping power consumption was made for heat sinks having novel flow channel configurations and having traditional flow channel configurations. It has been found that the novel flow channel configuration dramatically reduces the pressure loss in the flow field. Giving the same pumping power consumption of an electronics cooling process, the temperature difference on surface of the heat sink which has novel flow channel configuration can be much lower than that of the heat sinks which have traditional flow channel configurations.

An Experimental Study of Pin Fin Heat Sinks and Determination of End Wall Heat Transfer

2003 ◽  
Author(s):  
Massimiliano Rizzi ◽  
Ivan Catton
Keyword(s):  
Heat Transfer ◽  
Experimental Study ◽  
Heat Sink ◽  
Optimization Methods ◽  
Heat Sinks ◽  
Base Region ◽  
Transfer Coefficients ◽  
Media Type ◽  
Pin Fin ◽  
Heat Transfer Coefficients

An experimental study of a pin fin heat sink was carried out in support of the development of heat sink optimization methods requiring more detailed measurements be made. Measurements of heat flux and temperature are used to separately determine heat transfer coefficients for the pins and the base region between the pins. Three pitch to diameter ratios (distance from pin center to pin center measured diagonally) were studied: P/d = 3/1, 9/4, 3/2. Heat generation was accomplished using cartridge heaters inserted into a copper block. The high thermal conductivity of the copper ensured that the surface beneath the heat sink would be at a constant temperature. The cooling fluid was air and the experiments were conducted with a Reynolds numbers based on a porous media type hydraulic diameter ranging from 500 to 25000. The channel had a shroud that touches the fin tips, eliminating any flow bypass. The pin surface heat transfer coefficients match the values reported by Kays and London and by Zukauskas. The base region heat transfer coefficients were, surprisngly, larger than the pin values.

Effects of Channel Aspect Ratio on Convective Heat Transfer in an Electronics Cooling Heat Sink Having Agitation and Fan-Induced Throughflow

2013 ◽  
Author(s):  
Smita Agrawal ◽  
Longzhong Huang ◽  
Terrence Simon ◽  
Mark North ◽  
Tianhong Cui
Keyword(s):  
Heat Transfer ◽  
Aspect Ratio ◽  
Heat Sink ◽  
Single Channel ◽  
Electronics Cooling ◽  
Heat Sinks ◽  
Channel Width ◽  
Channel Height ◽  
Transfer Coefficients ◽  
Multiple Channel

Fan-driven throughflow is frequently used for convective cooling of electronics. Channels with walls behaving like fins are common. In the present study, the flow inside the channels is agitated by means of translationally oscillating plates called agitators. Effectiveness of agitation by oscillating blades is found to be dependent on the channel width, a parameter studied herein. Heat sinks having narrower channels have a greater number of channels in total for the fixed size of heat sink and therefore greater heat transfer area than heat sinks with wider channels. Thus, with the same channel height, as the aspect ratio increases, channel width decreases, and it is found that opportunities for agitation are reduced and the generated turbulence is more strongly damped, thus reducing heat transfer coefficients. A study was carried out to find direction toward an optimal number of channels for a given heat sink using the agitation strategy. As part of the study, fluid damping and power consumption to drive the agitator assembly were addressed. The study was done numerically using ANSYS FLUENT on a representative single channel of the heat sink and the results were extended to the full size, multiple-channel heat sink system. Recommendations for moving toward an optimum geometry, based on thermal performance and agitator power are made.

High Dense Plate Fin Heat Sinks Characterization and Validation

2005 ◽  
Author(s):  
Guoping Xu ◽  
Chakravarthy Akella ◽  
Lee Follmer
Keyword(s):  
Heat Transfer ◽  
Laminar Flow ◽  
Turbulent Flows ◽  
Heat Sink ◽  
Analytical Methods ◽  
Parallel Plate ◽  
Electronics Cooling ◽  
Heat Sinks ◽  
Laminar And Turbulent Regimes ◽  
Laminar And Turbulent Flows

Plate fin heat sinks are commonly used in electronics cooling including high end processors. A number of empirical and analytical methods are available to predict their performance but most of the models are valid for fin pitch larger than 3 mm heat sinks in laminar flow. The present work is to investigate high dense plate fin heat sink in both laminar and turbulent regimes. Thermal and hydraulic performance of several dense plate-fin heat sinks were characterized for high end processors in a fully-ducted wind tunnel. All the three heat sinks tested have the same dimensions of 89 mm (L) × 56 mm (W) × 50 mm (H), and fin number varied between 23 and 33. Heat sink base for all heat sinks was made of solid copper, while different fin materials of Aluminum and Copper are used. Several analytical methods for laminar flow from literature were reviewed in this study. A new heat transfer analytical method was proposed for both laminar and turbulent flows. The characterization data from these three parallel plate heat sinks were compared with the analytical methods. Finally, empirical heat transfer correlations were developed for both laminar and turbulent flows.

VAT Based Modeling of Plate-Pin Fin Heat Sink and Obtaining Closure From CFD Solution

2011 ◽  
Author(s):  
Feng Zhou ◽  
Nicholas Hansen ◽  
Ivan Catton
Keyword(s):  
Heat Transfer ◽  
Porous Media ◽  
Heat Sink ◽  
Volume Averaging ◽  
Heat Sinks ◽  
Averaging Theory ◽  
Conservation Of Energy ◽  
Pin Fin ◽  
Fast Running ◽  
Volume Averaging Theory

A plate-pin fin heat sink (PPFHS) is composed of a plate fin heat sink (PFHS) and some pin fins planted between the flow channels. Just as the other kinds of heat sinks, it is a hierarchical multilevel device with many parameters required for its description. Volume Averaging Theory (VAT) is used to rigorously cast the point-wise conservation of energy, momentum and mass equations into a form that represents the thermal and hydraulic properties of the plate-pin fin (porous media) morphology and to describe the hierarchical nature of the heat sink. Closure for the upper level is obtained using VAT to describe the lower level. At the lower level, the media is described by a representative elementary volume (REV). Closure terms in the VAT equations are related to a local friction factor and a heat transfer coefficient of the REV. The terms in the closure expressions are complex and relating experimental data to the closure terms resulting from VAT is difficult. In this work, we model the plate-pin fin heat sink based on Volume Averaging Theory and use CFD to obtain detailed solutions of flow through an element of PPFHS and use these results to evaluate the closure terms needed for a fast running VAT based code. The VAT based code can then be used to solve the heat transfer characteristics of the higher level heat sink. The objective is to show how plate-pin fin heat sinks can be modeled as porous media based on Volume Averaging Theory and how CFD can be used in place of a detailed, often formidable, experimental effort.

Compact Modeling of Fluid Flow and Heat Transfer in Pin Fin Heat Sinks

2004 ◽  
Vol 126 (3) ◽  
pp. 342-350 ◽  
Author(s):  
Duckjong Kim ◽  
Sung Jin Kim ◽  
Alfonso Ortega
Keyword(s):  
Heat Transfer ◽  
Porous Medium ◽  
Fluid Flow ◽  
Heat Sink ◽  
Volume Averaging ◽  
Heat Sinks ◽  
Compact Modeling ◽  
Pumping Power ◽  
Pin Fin ◽  
Flow And Heat Transfer

In this work, a novel compact modeling method based on the volume-averaging technique is presented. Its application to the analysis of fluid flow and heat transfer in pin fin heat sinks are further analyzed. The pin fin heat sink is modeled as a porous medium. The volume-averaged momentum and energy equations for fluid flow and heat transfer in pin fin heat sinks are obtained by using the local volume-averaging method. The permeability, the Ergun constant, and the interstitial heat transfer coefficient required to solve these equations are determined experimentally and correlations for them are presented. To validate the compact model proposed in this paper, 20 aluminum pin fin heat sinks having a 101.43 mm×101.43 mm base size are tested with an inlet velocity ranging from 1 m/s to 5 m/s. In the experimental investigation, the heat sink is heated uniformly at the bottom. Pressure drop and heat transfer characteristics of pin fin heat sinks obtained from the porous medium approach are compared with experimental results. Upon comparison, the porous medium approach is shown to predict accurately the pressure drop and heat transfer characteristics of pin fin heat sinks. Finally, for minimal thermal resistance, the optimum surface porosities of the pin fin heat sink are obtained under constraints on pumping power and heat sink size. The optimized pin fin heat sinks are shown to be superior to the optimized straight fin heat sinks in thermal performance by about 50% under the same constraints on pumping power and heat sink size.

scholarly journals Experimental study on heat transfer performance of variable area straight fin heat sinks with PCM

2021 ◽  
pp. 299-299
Author(s):  
Rajasekaran Madhaiyan ◽  
Kannan Thannir Pandal Palayam Kandasamy ◽  
Kumaragurubaran Balasubramanian ◽  
Mohan Raman
Keyword(s):  
Heat Transfer ◽  
Thermal Performance ◽  
Heat Sink ◽  
Heat Transfer Performance ◽  
Electronics Cooling ◽  
Reynolds Numbers ◽  
Heat Sinks ◽  
Base Temperature ◽  
Pin Fin ◽  
Constant Area

The thermal performance of heat sinks with variable area straight fins with and without PCM is quantitatively explored in this article. The effects of diverse fin geometries (constant area straight fin, variable area straight fin, circular pin fin, hemispherical pin fin, and elliptical pin fin), varying Reynolds numbers, and fin densities on boosting electronics cooling performance were investigated. The goal of this research is to develop the best fin geometry for electronics cooling technologies. This research demonstrates that altering fin density can improve heat sink thermal performance while also reducing heat sink weight. The base temperature of the heat sink is found to be lower in variable area straight fins. In comparison to alternative configurations for heat transfer with PCM, the results show that variable area straight fin heat sinks are the most effective. The thermal resistance of the improved heat sink with variable fin density was reduced by 9%.

Performance of a Heat Sink With Interrupted and Staggered Elliptic Fins

2010 ◽  
Author(s):  
Suabsakul Gururatana ◽  
Xianchang Li
Keyword(s):  
Heat Transfer ◽  
Heat Sink ◽  
Technology Development ◽  
Hot Spot ◽  
Flow Direction ◽  
Electronics Cooling ◽  
Heat Transfer Process ◽  
Heat Sinks ◽  
Temperature Fields ◽  
Base Surface

The power density of electronic devices has been increasing along with the rapid technology development. Cooling of electronic systems is therefore essential in controlling the component temperature and avoiding any hot spot. Heat sinks are commonly adopted in electronics cooling together with different technologies to enhance heat transfer process. Fin-based heat sinks are commonly designed so that coolants (gas or liquid) are forced to pass through the narrow straight channel. A driving fan is then needed to overcome the viscous pressure loss and maintain the coolant flow. As part of effort to improve the heat sink performance, this study simulated the details of the flow and temperature fields of heat sinks with interrupted and staggered elliptic fins cooled by forced convection. The focus of this study lies on three scenarios: Heat transfer before the flow reaches the periodic condition in the flow direction; effect of the heat sink base surface on flow and heat transfer; and conjugate heat transfer between convection and heat conduction inside the fins. In addition, studies were also conducted on the effect of the Reynolds number. The results of this paper can help design heat sinks for electronics cooling by employing the new concept of interrupted and staggered fins.

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