Geometrical Effects in Optimal Performance of Energy Dissipation of Pin Fin Heat Sinks

2009 ◽  
Author(s):  
J. L. Zu´n˜iga-Cerroblanco ◽  
A. Herna´ndez-Guerrero ◽  
G. J. Kowalski ◽  
J. C. Rubio-Arana
Keyword(s):  
Heat Sink ◽  
Optimization Model ◽  
Constant Heat Flux ◽  
Heat Sinks ◽  
Design Parameters ◽  
Transfer Coefficients ◽  
Technical Literature ◽  
Pin Fin ◽  
Friction Factors ◽  
Geometrical Effects

This work describes the hydraulic and thermal behavior of pin-fin heat sinks when subjected to a constant heat flux with values equivalent to those generated incurrent electronic devices. The fin geometries analyzed are rectangular, circular and elliptical. The experimental analysis is performed for pin-fin in-line arrangement. The heat sink arrangement is also analyzed numerically for pin-fin in-line and staggered arrangements; and the results are compared. The thermal resistance and pressure drop is reported for all arrangements for different air velocities. The experimental and numerical results are compared and validated with recent technical literature. The Entropy Generation Minimization (EGM) is used to obtain an optimization of the heat sink pin fin arrangement. Analytical and empirical correlations for heat transfer coefficients and friction factors are used in the optimization model. This optimization model considers all relevant design parameters for pin-fin heat sinks, including geometric parameters, material properties and flow.

Hydoroil-Based Micro Pin Fin Heat Sink

2006 ◽  
Author(s):  
Ali Kosar ◽  
Chih-Jung Kuo ◽  
Yoav Peles
Keyword(s):  
Heat Sink ◽  
Hydraulic Performance ◽  
Heat Fluxes ◽  
Heat Sinks ◽  
Transfer Coefficients ◽  
Pin Fin ◽  
Nusselt Numbers ◽  
Friction Factors ◽  
Pin Fins ◽  
Micro Pin Fins

An experimental study on thermal-hydraulic performance of de-ionized water over a bank of shrouded NACA 66-021 hydrofoil micro pin fins with wetted perimeter of 1030-μm and chord thickness of 100 μm has been performed. Average heat transfer coefficients have been obtained over effective heat fluxes ranging from 4.0 to 308 W/cm2 and mass velocities from 134 to 6600 kg/m2s. The experimental data is reduced to the Nusselt numbers, Reynolds numbers, total thermal resistances, and friction factors in order to determine the thermal-hydraulic performance of the heat sink. It has been found that prodigious hydrodynamic improvement can be obtained with the hydrofoil-based micro pin fin heat sink compared to the circular pin fin device. Fluid flow over pin fin heat sinks comprised from hydrofoils yielded radically lower thermal resistances than circular pin fins for a similar pressure drop.

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.

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.

scholarly journals Optimization of Pin Fin Heat Sink by Application of CFD Simulations and Doe Methodology with Neural Network Approximation

2013 ◽  
Vol 18 (2) ◽  
pp. 365-381 ◽  
Author(s):  
K. Kasza ◽  
Ł. Malinowski ◽  
I. Królikowski
Keyword(s):  
Neural Network ◽  
Thermal Efficiency ◽  
Heat Sink ◽  
Performance Metrics ◽  
Conductive Polymer ◽  
Pso Algorithm ◽  
Design Parameters ◽  
Transfer Coefficients ◽  
Pin Fin ◽  
Thermally Conductive

A design optimization of a staggered pin fin heat sink made of a thermally conductive polymer is presented. The influence of several design parameters like the pin fin height, the diameter, or the number of pins on thermal efficiency of the natural convection heat sink is studied. A limited number of representative heat sink designs were selected by application of the design of experiments (DOE) methodology and their thermal efficiency was evaluated by application of the antecedently validated and verified numerical model. The obtained results were utilized for the development of a response surface and a typical polynomial model was replaced with a neural network approximation. The particle swarm optimization (PSO) algorithm was applied for the neural network training providing very accurate characterization of the heat sink type under consideration. The quasi-complete search of defined solution domain was then performed and the different heat sink designs were compared by means of thermal performance metrics, i.e., array, space claim and mass based heat transfer coefficients. The computational fluid dynamics (CFD) calculations were repeated for the most effective heat sink designs.

Implementations of Deflectors to Improve the Performance of Heat Sinks

2012 ◽  
Author(s):  
J. P. Ramirez-Vazquez ◽  
A. Hernandez-Guerrero ◽  
J. L. Zuñiga-Cerroblanco ◽  
J. C. Rubio-Arana
Keyword(s):  
Heat Sink ◽  
Numerical Study ◽  
Electronic Devices ◽  
Constant Heat Flux ◽  
Heat Fluxes ◽  
Heat Sinks ◽  
Hydrodynamic Behavior ◽  
Constant Heat ◽  
Pin Fin ◽  
Global Performance

This work presents a numerical study of the thermal and hydrodynamic behavior of a pin-fin heat sink where deflectors are placed along the flow of the coolant air; the effect of the arrangement of the fins and deflectors in the global performance of the heat sink is investigated. The fin geometry analyzed is rectangular, and the arrangement of the fins is inline. The heat sink is placed in a channel in which air flows, and a constant heat flux is applied at the bottom wall of the heat sink with values equivalent to the heat fluxes generated by current electronic devices. Deflectors are placed in the top of the channel in order to drive the air flow into the front and end of the heat sink. The results for the Nusselt number and for the pressure drop along the heat sink are reported. The best dimension of deflectors and pitch for the arrangement based on the thermal and hydraulic performance is attained.

Hydrodynamics and Heat Transfer Characteristics of a Miniature Plate Pin-Fin Heat Sink Utilizing Al2O3–Water and TiO2–Water Nanofluids

2015 ◽  
Vol 7 (3) ◽  
Author(s):  
Majid Roshani ◽  
Seyed Ziaeddin Miry ◽  
Pedram Hanafizadeh ◽  
Mehdi Ashjaee
Keyword(s):  
Heat Transfer ◽  
Thermal Performance ◽  
Heat Sink ◽  
Base Plate ◽  
Constant Heat Flux ◽  
Hydrodynamic Performance ◽  
Bottom Surface ◽  
Inlet Temperature ◽  
Transfer Coefficients ◽  
Pin Fin

In this paper, the hydrodynamic and thermal performance of a miniature plate pin-finned heat sink is investigated experimentally by utilizing two widely used nanofluids, Al2O3–water and TiO2–water. The heat sink base plate, which is used in the cooling process of electronic devices, has the dimensions of 42 mm (L) × 42 mm (W) × 14 mm (H) and is made of aluminum and placed in a plexiglass case which is isolated from the environment using an insulator foam. The thermal performance of the heat sink is investigated by passing the nanofluid at constant inlet temperature while applying a constant heat flux of 124.8 kW/m2 to the bottom surface of the heat sink. The nanofluids are prepared in volume concentrations of 0.5, 1, 1.5, and 2% and their performances are measured considering water as the base fluid. Measuring the pressure difference between the entrance and exit of the heat sink made it possible to study the hydrodynamic performance of the heat sink. Although the measurements showed 15% and 30% increase in the pumping power for the volume concentration of 2% of Al2O3–water and TiO2–water nanofluids, respectively, the average heat transfer coefficients increased by 16% and 14% and the thermal resistance decreased by 17% and 14% for each nanofluid.

Compact Modeling of Forced Flow in Longitudinal Fin Heat Sinks With Tip Bypass

2003 ◽  
Vol 125 (3) ◽  
pp. 319-324 ◽  
Author(s):  
C. B. Coetzer ◽  
J. A. Visser
Keyword(s):  
Pressure Drop ◽  
Heat Sink ◽  
Heat Sinks ◽  
Compact Model ◽  
Forced Flow ◽  
Compact Modeling ◽  
Transfer Coefficients ◽  
Wide Range ◽  
Laminar And Turbulent Flow ◽  
Improved Accuracy

This paper introduces a compact model to predict the interfin velocity and the resulting pressure drop across a longitudinal fin heat sink with tip bypass. The compact model is based on results obtained from a comprehensive study into the behavior of both laminar and turbulent flow in longitudinal fin heat sinks with tip bypass using CFD analysis. The new compact flow prediction model is critically compared to existing compact models as well as to the results obtained from the CFD simulations. The results indicate that the new compact model shows at least a 4.5% improvement in accuracy predicting the pressure drop over a wide range of heat sink geometries and Reynolds numbers simulated. The improved accuracy in velocity distribution between the fins also increases the accuracy of the calculated heat transfer coefficients applied to the heat sinks.

Pin-Fin Heat Sink With Horizontal Base and Blocked Edges

2008 ◽  
Author(s):  
D. Sahray ◽  
H. Shmueli ◽  
N. Segal ◽  
G. Ziskind ◽  
R. Letan
Keyword(s):  
Heat Transfer ◽  
Free Convection ◽  
Contact Resistance ◽  
Cross Section ◽  
Heat Input ◽  
Heat Sink ◽  
Numerical Study ◽  
Heat Sinks ◽  
Transfer Enhancement ◽  
Pin Fin

In the present work, horizontal-base pin fin heat sinks exposed to free convection in air are studied. They are made of aluminum, and there is no contact resistance between the base and the fins. For the same base dimensions the fin height and pitch vary. The fins have a constant square cross-section. The edges of the sink are blocked: the surrounding insulation is flush with the fin tips. The effect of fin height and pitch on the performance of the sink is studied experimentally and numerically. In the experiments, the heat sinks are heated using foil electrical heaters. The heat input is set, and temperatures of the base and fins are measured. In the corresponding numerical study, the sinks and their environment are modeled using the Fluent 6 software. The results show that heat transfer enhancement due to the fins is not monotonic. The differences between sparsely and densely populated sinks are analyzed for various fin heights. Also assessed are effects of the blocked edges as compared to the previously studied cases where the sink edges were exposed to the surroundings.

Relating Semiconductor Heat Sink Local and Non-Local Experimental and Simulation Data to Upper Scale Design Goals

2001 ◽  
Author(s):  
V. S. Travkin
Keyword(s):  
Heat Sink ◽  
Solid Phase ◽  
Physical Characteristics ◽  
Heat Sinks ◽  
Maximum Temperature ◽  
Pin Fin ◽  
Three Samples ◽  
Non Local ◽  
Scale Design ◽  
Research And Design

Abstract The primary difficulty in semiconductor heat sink (and many other types of heat exchangers) research and design is not a lack of interest or money, but rather confusion with what being looked for and adequacy of the tools used for the search. As recently shown, there are few meaningful parameters (apart from sizes and weight) or physical characteristics of interest in semiconductor cooler design are local values. Even the maximum temperature of the base Tmax or semiconductor temperature are not local. In this work outlined the description in detail of arguments on how, and for what reasons, the measured data are to be simulated or measured and represented in a way that allows design goals to be formulated primarily with bulk physical characteristics. We demonstrate why studies of only averaged local integrated variables are not enough. Four sample semiconductor heat sinks of two morphologies (three samples of round pin fin and one sample of longitudinal rib fin sinks) were studied by different techniques and models. There were changes in by-pass values, external heat flux and flow rate. The results are depicted with using new parameters that better represent the needs of a design process as well as the usual parameters used in the past. Characteristics reported are the heat transfer rate in solid phase, relative fin effectiveness, and influence of only morphology features among others. Some suggestions for heat sink design are discussed.

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.

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