Optimal Arrays of Pin Fins and Plate Fins in Laminar Forced Convection

1993 ◽  
Vol 115 (1) ◽  
pp. 75-81 ◽  
Author(s):  
A. Bejan ◽  
A. M. Morega
Keyword(s):  
Thermal Resistance ◽  
Heat Sinks ◽  
Optimal Thickness ◽  
Pin Fin ◽  
Dimensionless Groups ◽  
Pin Fins ◽  
Fluid Channel ◽  
Laminar Forced Convection ◽  
Fin Thickness ◽  
Pin Fin Array

This paper reports the optimal geometry of an array of fins that minimizes the thermal resistance between the substrate and the flow forced through the fins. The flow regime is laminar. Two fin types are considered: round pin fins, and staggered parallel-plate fins. The optimization of each array proceeds in two steps: The optimal fin thickness is selected in the first step, and the optimal thickness of the fluid channel is selected in the second. The pin-fin array is modeled as a Darcy-flow porous medium. The flow past each plate fin is in the boundary layer regime. The optimal design of each array is described in terms of dimensionless groups. It is shown that the minimum thermal resistance of plate-fin arrays is approximately half of the minimum thermal resistance of heat sinks with continuous fins and fully developed laminar flow in the channels.

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.

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.

Effect of Pin Fin Density of the Thermal Performance of Unshrouded Pin Fin Heat Sinks

1994 ◽  
Vol 116 (4) ◽  
pp. 306-309 ◽  
Author(s):  
Kaveh Azar ◽  
Carlo D. Mandrone
Keyword(s):  
Thermal Resistance ◽  
Surface Area ◽  
Forced Convection ◽  
Heat Sinks ◽  
Optimum Number ◽  
Base Temperature ◽  
Pin Fin ◽  
Pin Fins ◽  
Pattern Comparison ◽  
Temperature Constant

An experimental investigation was conducted to examine the effect of pin fin density on thermal resistance of unshrouded pin fin heat sinks. Six heat sinks with different number of round pin fins were constructed. Heat sink thermal resistance was calculated by maintaining its base temperature constant. For these experiments, air flow varied from natural to high velocity forced convection. The results showed that thermal resistance did not decrease with increase of number of pin fins. An optimum number of pin fins existed beyond which thermal resistance actually increased. The study also showed that thermal resistance was a function of air velocity and governing flow pattern. Comparison of the heat transfer coefficient (h) and pin fin surface area showed that h decreased dramatically as surface area increased. The results showed that pin fin heat sinks with small number of pins had the best performance at low and moderate forced convection cooling.

Thermal Resistance of Perforated Heat Sinks with Circular Pin Fins Cooled by Natural Convection

2015 ◽  
Vol 775 ◽  
pp. 88-92
Author(s):  
Mao Yu Wen ◽  
Cheng Hsiung Yeh
Keyword(s):  
Heat Transfer ◽  
Natural Convection ◽  
Thermal Resistance ◽  
Base Plate ◽  
Type A ◽  
Heat Sinks ◽  
Type B ◽  
Pin Fin ◽  
Different Types ◽  
Pin Fins

This study examines thermal resistance under natural convection for two different types (Type A and Type B) of pin-fin heat sinks with/without a hollow in the heated base. The effects of the rate of heat transfer, the height of fin, the finning factor, the heat sink porosity and the perforated base plate on the thermal resistance were investigated and evaluated. Experimental results show that thermal resistance, using pin-fin heat sinks, is significantly different for Type A and Type B.

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.

scholarly journals Experimental and Numerical Examinations of Temperature Distributions along SSF Pin Fins Cast through Semisolid Materials Processing

2019 ◽  
Vol 8 (12) ◽  
pp. 500-503
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Stainless Steel ◽  
Heat Sinks ◽  
Materials Processing ◽  
Length Scale ◽  
Pin Fin ◽  
Temperature Distributions ◽  
Pin Fins ◽  
Enhancing Heat Transfer

Heat sinks or fins stand deployed for enhancing heat transfer. That’s why, planned experiments remain fortified for examining the impacts of SSF pin fin on thermal dispersal concerning constant thermal value 6 W/cm2 . For that five chromel-alumel thermocouples are preferred, above and beyond, SSF pin fins materials of stainless steel and aluminum. As anticipated, for both the stated SSF pin fins, temperature declines for increasing length scale. Besides, both results are comparable with each other. However, temperature distributions over SSF aluminum pin fin declines relatively at faster rate comparable to that over SSF stainless steel pin fin. Obviously, it may be owing to higher thermal conductivity of SSF aluminum pin fin. Therefore, it carries superior, pleasant and momentous thermal performances.

scholarly journals Meta-Study on Integrated Cooling of Modern Integrated Circuits using Microfluidics

2020 ◽  
Vol 7 ◽  
Author(s):  
System Administrator ◽  
Ben Andrew ◽  
Jesse McNamara ◽  
Michael Karanikolas
Keyword(s):  
Integrated Circuits ◽  
Heat Sinks ◽  
Microfluidic Channels ◽  
Negative Effects ◽  
Cooling Channels ◽  
Pin Fin ◽  
Pin Fins ◽  
Varied Size ◽  
Thermal Interfaces ◽  
Exchange Medium

The substantial increase in the transistor density of integrated circuits (ICs) in recent times has allowed considerable improvements in computing power. With increasing transistor and power density, the heat produced by modern ICs has increased significantly. This in turn has negative effects on the performance, reliability, and power consumption of the ICs. A solution to the IC’s complications caused by overheating is integrated cooling, in which cooling fluid is delivered through microchannel heat sinks on the backside of an IC. This meta-study will investigate two microfluidic cooling technologies. First, implementing varied size microfluidic channels close to the silicone substrate of the IC. Additionally, a micro-pin fin heat sink is integrated into the ICs’ fluidic microchannels. Different sized pin fins were used, to achieve a wider understanding of the application of pin fins in microfluidic cooling and compare the thermal performances of each cooling method. Integrated cooling subverts the need for suboptimal thermal interfaces and bulky heat-sinks, as well as reducing the intensity of localised hotspots commonly present in high-power electronics. Further, by locating the main heat exchange medium closer to the die of an IC, we reduce the number of thermal interfaces. This meta-study suggests that cylindrical micro-pin fin arrays with pitch longitude and latitude of 60μm and 120μm, are more thermally efficient than plain microfluidic cooling channels.  

Numerical Study of the Endwall Effects on Water Single-Phase Pressure Drop Across a Circular Micro-Pin-Fin Array

2011 ◽  
Author(s):  
Jonathan R. Mita ◽  
Weilin Qu ◽  
Frank E. Pfefferkorn
Keyword(s):  
Pressure Drop ◽  
Single Phase ◽  
Numerical Study ◽  
Circular Cross Section ◽  
Reynolds Numbers ◽  
Pin Fin ◽  
Pin Fins ◽  
Micron Diameter ◽  
Micro Pin Fins ◽  
Pin Fin Array

This paper presents a numerical study of pressure drop associated with water liquid single-phase flow across an array of staggered micro-pin-fins having circular cross-section. The numerical simulations were validated against previously obtained experimental results using an array of staggered circular micro-pin-fins having the following dimensions: 180 micron diameter and 683 micron height. The longitudinal pitch and transverse pitch of the micro-pin-fins are equal to 399 microns. The effects of endwalls on pressure drop characteristics were then explored numerically. Six different micro-pin-fin height to diameter ratios were studied with seven different Reynolds numbers. All simulations were performed at room temperature (23°C). It was seen that for any given Reynolds number, as the pin height to diameter ratio increased, the pressure drop and resulting non-dimensional friction factor decreased.

Sign in / Sign up

Export Citation Format

Share Document