Characteristic Study on the Optimization of Pin-Fin Micro Heat Sink

2009 ◽  
Author(s):  
T. J. John ◽  
B. Mathew ◽  
H. Hegab
Keyword(s):  
Pressure Drop ◽  
Thermal Resistance ◽  
Flow Rate ◽  
Heat Sink ◽  
Heat Dissipation ◽  
Heat Sinks ◽  
Low Flow ◽  
Pumping Power ◽  
Flow Rates ◽  
Pin Fin

The need for dissipating heat from microsystems has increased drastically in the last decade. Several methods of heat dissipation using air and liquids have been proposed by many studies, and pin-fin micro heat sinks are one among them. Researchers have developed several effective pin-fin structures for use in heat sinks, but not much effort has been taken towards the optimization of profile and dimensions of the pin-fin. In this paper the authors studied the effect of different pin-fin shapes on the thermal resistance and pressure drop in a specific micro heat-sink. Optimization subjected to two different constraints is studied in this paper. The first optimization is subjected to constant flow rate and the second one is subjected to constant pressure drop. Both optimization processes are carried out using computer simulations generated using COVENTORWARE™. Two of the best structures from each of these optimization studies are selected and further analysis is performed for optimizing their structure dimensions such as width, height and length. A section of the total micro heat-sink is modeled for the initial optimization of the pin-fin shape. The model consists of two sections, the substrate and the fluid. Six different shapes: square, circle, rectangle, triangle, oval and rhombus were analyzed in the initial optimization study. Preliminary tests were conducted using the first model described above for a flow rate of 0.6ml/min. The non dimensional overall thermal resistance of the heat sink, and the nondimensional pumping power was calculated from the results. A figure of merit (FOM) was developed using the nondimensional thermal resistance and nondimensional pumping power for each structure with different pin-fin shapes. Smaller the value of FOM better the performance of the heat sink. The study revealed that the circle and ellipse structures have the best performance and the rectangle structure had the worst performance at low flow rates. At high flow rates rectangular and square structures have the best performance.

Experimental Investigation of Liquid Cooling Through Shallow Copperclad Cavities With Etched Pin-Fin Arrays

2018 ◽  
Author(s):  
Yin Lam ◽  
Nicole Okamoto ◽  
Younes Shabany ◽  
Sang-Joon John Lee
Keyword(s):  
Pressure Drop ◽  
Thermal Resistance ◽  
Surface Area ◽  
Flow Rate ◽  
Heat Sink ◽  
Heat Removal ◽  
Heat Sinks ◽  
Liquid Cooling ◽  
Pin Fin ◽  
Pin Fin Arrays

Heat removal is an increasing engineering challenge for higher-density packaging of circuit components. Microchannel heat sinks with liquid cooling have been investigated to take advantage of high surface-to-volume ratio and higher heat capacity of liquids relative to gases. This study experimentally investigated heat removal by liquid cooling through shallow copperclad cavities with staggered pin-fin arrays. Cavities with pin-fins were fabricated by chemical etching of a copperclad layer (nominally 105 μm thick) on a printed-circuit substrate (FR-4). The overall etched cavity was 30 mm wide, 40 mm long, and 0.1 mm deep. The pins were 1.1 mm in diameter and were distributed in a staggered arrangement. The cavity was sealed with a second copperclad substrate using an elastomer gasket. This assembly was then connected to a syringe pump delivery system. Deionized water was used as the working fluid, with volumetric flow rate up to 1.5 mL/min. The heat sink was subjected to a uniform heat flux of 5 W on the underside. Performance of the heat sink was evaluated in terms of pressure drop and the convection thermal resistance. Pressure drop across the heat sinks was less than 10 kPa, dominated by wall surface area rather than the small surface area contributed by cylindrical pins. At low flow rate, caloric thermal resistance dominated the overall thermal resistance of the heat sink. When compared to a microchannel without pins, the pin-fin microchannel reduced convective thermal resistance of the heat sink by approximately a factor of 4.

S-Shaped Pin-Fins for Enhancement of Overall Performance of the Pin-Fin Heat Sink

2010 ◽  
Author(s):  
T. J. John ◽  
B. Mathew ◽  
H. Hegab
Keyword(s):  
Reynolds Number ◽  
Thermal Resistance ◽  
Thermal Performance ◽  
Heat Sink ◽  
Heat Sinks ◽  
Uniform Heat Flux ◽  
Pumping Power ◽  
Pin Fin ◽  
Pin Fins ◽  
Overall Performance

In this paper the authors are studying the effect of introducing S-shaped pin-fin structures in a micro pin-fin heat sink to enhance the overall thermal performance of the heat sinks. For the purpose of evaluating the overall thermal performance of the heat sink a figure of merit (FOM) term comprising both thermal resistance and pumping power is introduced in this paper. An optimization study of the overall performance based on the pitch distance of the pin-fin structures both in the axial and the transverse direction, and based on the curvature at the ends of S-shape fins is also carried out in this paper. The value of the Reynolds number of liquid flow at the entrance of the heat sink is kept constant for the optimization purpose and the study is carried out over a range of Reynolds number from 50 to 500. All the optimization processes are carried out using computational fluid dynamics software CoventorWARE™. The models generated for the study consists of two sections, the substrate (silicon) and the fluid (water at 278K). The pin fins are 150 micrometers tall and the total structure is 500 micrometer thick and a uniform heat flux of 500KW is applied to the base of the model. The non dimensional thermal resistance and nondimensional pumping power calculated from the results is used in determining the FOM term. The study proved the superiority of the S-shaped pin-fin heat sinks over the conventional pin-fin heat sinks in terms of both FOM and flow distribution. S-shaped pin-fins with pointed tips provided the best performance compared to pin-fins with straight and circular tips.

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.

Thermal Performance of High-Flow Single-Phase Liquid-Cooled Heat Sinks

2012 ◽  
Author(s):  
Ildar F. Akhmadullin ◽  
Randall D. Manteufel ◽  
Christopher Greene
Keyword(s):  
Thermal Resistance ◽  
Flow Rate ◽  
Heat Sink ◽  
Heat Removal ◽  
Internal Flow ◽  
Maximum Flow ◽  
High Flow ◽  
Repeated Measurements ◽  
Heat Sinks ◽  
Flow Rates

Experimental measurements are reported for high-flow liquid-cooled heat sinks designed for cooling electronics components such as a CPU. The flow rate is up to 2 GPM with internal flow passage length scales on the order of 0.1 to 1.0 mm in the primary heat transfer region. Of the designs tested, three achieved maximum flow rates with pressure drops of less than 1.5 psi. Two have lower maximum flow rates because of higher internal flow resistance. In the experiments, particular attention is given to sources of experimental uncertainty and the propagation of uncertainty through the calculations to reported thermal resistance, R (°C/W). Analysis includes bias and precision errors for direct measurement of temperature, flow rate, and pressure drop. Additionally, a separate thermocouple calibration test is reported to establish measurement uncertainties for the system. Main emphasis is made to the error propagation in thermal resistance calculations of each heat sink and measurement of heat removal rate from the CPU. Data is used to determine the standard error for R which ranges up to about 0.05 °C/W with the maximum for one heat sink up to 0.07 °C/W. Averaging of repeated measurements at the same flow rate without accounting for the range of the original data will result in lower uncertainties in the reported results.

scholarly journals The flow and heat performance of tree-like network heat sink with diverging–converging channel

2021 ◽  
Vol 236 ◽  
pp. 01027
Author(s):  
Xiugen Zhu ◽  
Peng Qian ◽  
Zizhen Huang ◽  
Chengyuan Luo ◽  
Minghou Liu
Keyword(s):  
Pressure Drop ◽  
Flow Rate ◽  
Heat Sink ◽  
Heat Dissipation ◽  
Maximum Temperature ◽  
Pumping Power ◽  
Flow Recirculation ◽  
Converging Channel ◽  
Converging Angle ◽  
Good Heat

A tree-like network heat sink with diverging–converging channel is designed, and effect of flow rate, channel diverging-converging angles on the flow and heat dissipation performance of the tree-like network heat sink is analysed and compared by numerical simulation. Results show that the diverging– converging angle of 2° can reduce the pressure drop by 14% when inlet mass flow rate is 0.00499kg/s. And the maximum temperature, the temperature difference between the maximum and minimum of the heat sink increases by 0.63K and 0.92K respectively. As the diverging-converging angle increases to 4°, however, it only reduces the pressure drop by 13% and can not bring more pressure drop due to formation of flow recirculation inside the tree-like network heat sink channel. Therefore, the diverging–converging fractal micro-channel heat sink with 2° has good heat dissipation performance with obvious lower pumping power.

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.

Two-Phase Stacked Microchannel Heat Sinks for Microelectronics Cooling

2005 ◽  
Vol 2 (2) ◽  
pp. 122-131
Author(s):  
Pradeep Hegde ◽  
K.N. Seetharamu ◽  
P.A. Aswatha Narayana ◽  
Zulkifly Abdullah
Keyword(s):  
Finite Element ◽  
Pressure Drop ◽  
Thermal Resistance ◽  
Heat Sink ◽  
Two Phase Flow ◽  
Heat Sinks ◽  
Phase Flow ◽  
Pumping Power ◽  
Two Phase ◽  
Microchannel Heat Sinks

Stacked microchannel heat sinks with two-phase flow have been analyzed using the Finite Element Method (FEM). The present method is a simple and practical approach for analyzing the thermal performance of single or multi layered microchannel heat sinks with either single or two-phase flow. A unique 10 noded finite element is used for the channel discretization. Two-phase thermal resistance, pressure drop and pumping power of single, double and triple stack microchannel heat sinks are determined at different base heat fluxes ranging from 150 W/cm2 to 300 W/cm2. The temperature distribution along the length of the microchannel is also plotted. It is found that stacked microchannel heat sinks with two-phase flow are thermally more efficient than two-phase single layer microchannel heat sinks, both in terms of thermal resistance and pumping power requirements. It is observed that the thermal resistance of a double stack microchannel heat sink with two-phase flow is about 40% less than that for a single stack heat sink. A triple stack heat sink yields a further 20% reduction in the thermal resistance and at the same time operates with about 30% less pumping power compared to a single stack heat sink. The effect of channel aspect ratio on the thermal resistance and pressure drop of stacked microchannel heat sinks with two-phase flow are also studied.

Thermal Performance Comparison for Five Liquid Heat Sink Designs

2011 ◽  
Author(s):  
Christopher Greene ◽  
Randall D. Manteufel ◽  
Amir Karimi
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Thermal Resistance ◽  
Flow Rate ◽  
Heat Sink ◽  
Fluid Velocity ◽  
Water Flow Rate ◽  
High Flow ◽  
Heat Transfer Area ◽  
Flow Rates

Five high-flow liquid-cooled heat sink designs are compared for the cooling of a single chip CPU. Five distinctive design configurations are considered with regard to the introduction, passage, and extraction of cooling fluid. The typical water flow rate is about 3.8 liters per minute (lpm) with flow passages in the primary heat transfer area ranging from 2 to 0.1mm. The design configurations are summarized and compared, considering: the primary convective heat transfer area, flow passage streamlining, acceleration mechanisms, and nominal fluid velocity in the primary heat transfer area. Overall pressure drop and thermal resistance are compared for varying flow rates of water. At the nominal flow, the pressure drops ranged from 1 kPa to 20 kPa. In the restrictive designs, such as nozzles, flow acceleration accounts for the largest source of pressure drop. In some designs, a large fraction of the overall pressure drop is due to circuitous flow associated with the introduction and/or extraction of flow which contributes little to heat removal. At the nominal flow, the overall thermal resistance varied from 0.14 to 0.18 C/W. As flow rate increases the overall thermal resistance decreases. Results indicated that 80 to 85% of the total thermal resistance is due to conduction and about 15 to 20% attributed to convection at the nominal flow rate. There is minimal thermal benefit for flow rates beyond twice the nominal while this substantially increases fluid pumping requirements. This study highlights design features which yield above average heat transfer performance with minimal pressure drop for high-flow liquid-cooled heat sinks.

Thermal Behaviors of Passively-Cooled Hybrid Fin Heat Sinks for Lightweight and High Performance Thermal Management

2015 ◽  
Author(s):  
Nico Setiawan Effendi ◽  
Kyoung Joon Kim
Keyword(s):  
Thermal Resistance ◽  
Heat Sink ◽  
High Performance ◽  
Heat Dissipation ◽  
Computational Study ◽  
Heat Sinks ◽  
Channel Diameter ◽  
Internal Channel ◽  
Study Results ◽  
Parametric Effects

A computational study is conducted to explore thermal performances of natural convection hybrid fin heat sinks (HF HSs). The proposed HF HSs are a hollow hybrid fin heat sink (HHF HS) and a solid hybrid fin heat sink (SHF HS). Parametric effects such as a fin spacing, an internal channel diameter, a heat dissipation on the performance of HF HSs are investigated by CFD analysis. Study results show that the thermal resistance of the HS increases while the mass-multiplied thermal resistance of the HS decreases associated with the increase of the channel diameter. The results also shows the thermal resistance of the SHF HS is 13% smaller, and the mass-multiplied thermal resistance of the HHF HS is 32% smaller compared with the pin fin heat sink (PF HS). These interesting results are mainly due to integrated effects of the mass-reduction, the surface area enhancement, and the heat pumping via the internal channel. Such better performances of HF HSs show the feasibility of alternatives to the conventional PF HS especially for passive cooling of LED lighting modules.

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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