An Experimental and Theoretical Study of Finned and Finless Heat Sinks for Low Profile Applications

2009 ◽  
Author(s):  
Jason Stafford ◽  
Ed Walsh ◽  
Vanessa Egan ◽  
Pat Walsh ◽  
Yuri S. Muzychka
Keyword(s):  
Heat Transfer ◽  
Forced Convection ◽  
Heat Sink ◽  
Theoretical Study ◽  
Convection Heat Transfer ◽  
Heat Sinks ◽  
Duct Flow ◽  
Transfer Rates ◽  
Low Profile ◽  
Small Footprint

This paper discusses the importance of developing cooling solutions for low profile devices. This is addressed with an experimental and theoretical study on forced convection cooling solution designs that could be implemented into such devices. Conventional finned and corresponding finless designs of equal exterior dimensions are considered for three different heat sink profiles ranging from 1mm to 4mm profile in combination with a commercially available radial blower. The results show that forced convection heat transfer rates can be enhanced by up to 55% using finless designs at low profiles with relatively small footprint areas. The advantages of both finned and finless geometries are presented along with the limitations of the customary finned heat sink design at low profile scales. The results also show large increases in heat transfer rates over that predicted which can be attained at the low profile scale based on geometry selection. Dimensionless comparisons are made between experimental results and combined hydrodynamic and thermally developing duct flow theory which is representative of the flow regime within both the finned and finless geometries. Overall, this paper provides optimization and geometry selection criteria which are relevant to designers of low profile cooling solutions.

A Novel Approach to Low Profile Heat Sink Design

2010 ◽  
Vol 132 (9) ◽  
Author(s):  
Jason Stafford ◽  
Ed Walsh ◽  
Vanessa Egan ◽  
Pat Walsh ◽  
Yuri S. Muzychka
Keyword(s):  
Forced Convection ◽  
Heat Sink ◽  
Theoretical Study ◽  
Convection Heat Transfer ◽  
Transfer Rates ◽  
Novel Approach ◽  
Low Profile ◽  
Small Footprint ◽  
Convection Cooling ◽  
Heat Sink Design

This paper discusses the importance of developing cooling solutions for low profile devices. This is addressed with an experimental and theoretical study on forced convection cooling solution designs that could be implemented into such devices. Conventional finned and corresponding finless designs of equal exterior dimensions are considered for three different heat sink profiles ranging from 1 mm to 4 mm in combination with a commercially available radial blower. The results show that forced convection heat transfer rates can be enhanced by up to 55% using finless designs at low profiles with relatively small footprint areas. Overall, this paper provides optimization and geometry selection criteria, which are relevant to designers of low profile cooling solutions.

A Study of Forced Convection Direct Air Cooling in the Downstream Vicinity of Heat Sinks

1990 ◽  
Vol 112 (3) ◽  
pp. 234-240 ◽  
Author(s):  
G. L. Lehmann ◽  
S. J. Kosteva
Keyword(s):  
Heat Transfer ◽  
Forced Convection ◽  
Heat Sink ◽  
Convection Heat Transfer ◽  
Heat Sinks ◽  
Air Cooling ◽  
Transfer Coefficients ◽  
Packaging System ◽  
Transfer Rates ◽  
Heat Transfer Coefficients

An experimental study of forced convection heat transfer is reported. Direct air cooling of an electronics packaging system is modeled by a channel flow, with an array of uniformly sized and spaced elements attached to one channel wall. The presence of a single or complete row of longitudinally finned heat sinks creates a modified flow pattern. Convective heat transfer rates at downstream positions are measured and compared to that of a plain array (no heat sinks). Heat transfer rates are described in terms of adiabatic heat transfer coefficients and thermal wake functions. Empirical correlations are presented for both variations in Reynolds number (5000 < Re < 20,000) and heat sink geometry. It is found that the presence of a heat sink can both enhance and degrade the heat transfer coefficient at downstream locations, depending on the relative position.

Forced Convection Air Cooling of Simulated Low Profile Electronic Components: Part 2—Heat Sink Effects

1991 ◽  
Vol 113 (1) ◽  
pp. 27-32 ◽  
Author(s):  
G. L. Lehmann ◽  
J. Pembroke
Keyword(s):  
Heat Transfer ◽  
Forced Convection ◽  
Flow Rate ◽  
Heat Sink ◽  
Heat Sinks ◽  
Air Cooling ◽  
Channel Spacing ◽  
Heat Transfer Behavior ◽  
Low Profile ◽  
Transfer Behavior

Forced convection air cooling of an array of low profile, card-mounted components has been investigated. A simulated array is attached to one wall of a low aspect ratio duct. This is the second half of a two-part study. In this second part the presence of a longitudinally finned heat sink is considered. The heat sink is a thermally passive “flow disturbance”. Laboratory measurements of the heat transfer rates downstream of the heat sink are reported and compared with the measured values which occur when no heat sinks are present. Data are presented for three heat sink geometries subject to variations in channel spacing and flow rate. In the flow range considered laminar, transitional and turbulent heat transfer behavior has been observed. The presence of a heat sink appears to “trip” the start of transition at lower Reynolds numbers than when no heat sinks are present. A Reynolds number based on component length provides a good correlation of the heat transfer behavior due to variations in flow rate and channel spacing. Heat transfer is most strongly effected by flow rate and position relative to the heat sink. Depending on the flow regime (laminar or turbulent) both relative enhancement and reductions in the component Nusselt number have been observed. The impact of introducing a heat sink is greatest for flow rates corresponding to transitional behavior.

3D Printed Architected Heat Sinks Cooling Performance in Free and Forced Convection Environments

2020 ◽  
Author(s):  
Mohamed I. Hassan Ali ◽  
Oraib Al-Ketan ◽  
Mohamad Khalil ◽  
Nada Baobaid ◽  
Kamran Khan ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Forced Convection ◽  
Heat Transfer Performance ◽  
Convection Heat Transfer ◽  
Heat Sinks ◽  
Cfd Modeling ◽  
Transfer Performance ◽  
Convection Heat ◽  
Performance Study

Abstract In this work, we extend our heat transfer performance study on our proposed new and novel 3D printable architected heat sinks with geometrically complex structures based on triply periodic minimal surfaces (TPMS). Computational fluid dynamics (CFD) modeling is used to assess the effect of porosity distribution, heat load, and isothermal boundary condition on the performance of the proposed TPMS-based heat sinks in active cooling using natural and forced convection heat transfer environments. The convection heat transfer coefficient, surface temperature, pressure drop are predicted using CFD method. The CFD model is validated using experimental results for the pressure drop and is verified by standard analytical results. Three TPMS structures are investigated in different orientations. Dimensionless heat transfer groups are developed to globalize the heat transfer performance of the proposed heat sinks.

Thermal Analysis of Miniature Low Profile Heat Sinks With and Without Fins

2009 ◽  
Vol 131 (3) ◽  
Author(s):  
V. Egan ◽  
P. A. Walsh ◽  
E. Walsh ◽  
R. Grimes
Keyword(s):  
Heat Transfer ◽  
Heat Sink ◽  
Volume Flow Rate ◽  
Electronic Devices ◽  
Heat Fluxes ◽  
Heat Sinks ◽  
Superior Performance ◽  
Low Profile ◽  
In Series ◽  
Heat Sink Design

Reliable and efficient cooling solutions for portable electronic devices are now at the forefront of research due to consumer demand for manufacturers to downscale existing technologies. To achieve this, the power consumed has to be dissipated over smaller areas resulting in elevated heat fluxes. With regard to cooling such devices, the most popular choice is to integrate a fan driven heat sink, which for portable electronic devices must have a low profile. This paper presents an experimental investigation into such low profile cooling solutions, which incorporate one of the smallest commercially available fans in series with two different heat sink designs. The first of these is the conventionally used finned heat sink design, which was specifically optimized and custom manufactured in the current study to complement the driving fan. While the second design proposed is a novel “finless” type heat sink suitable for use in low profile applications. Together the driving fan and heat sinks combined were constrained to have a total footprint area of 465 mm2 and a profile height of only 5 mm, making them ideal for use in portable electronics. The objective was to evaluate the performance of the proposed finless heat sink design against a conventional finned heat sink, and this was achieved by means of thermal resistance and overall heat transfer coefficient measurements. It was found that the proposed finless design proved to be the superior cooling solution when operating at low fan speeds, while at the maximum fan speed tested of 8000 rpm both provided similar performance. Particle image velocimetry measurements were used to detail the flow structures within each heat sink and highlighted methods, which could further optimize their performance. Also, these measurements along with corresponding global volume flow rate measurements were used to elucidate the enhanced heat transfer characteristics observed for the finless design. Overall, it is shown that the proposed finless type heat sink can provide superior performance compared with conventional finned designs when used in low profile applications. In addition a number of secondary benefits associated with such a design are highlighted including lower cost, lower mass, lower acoustics, and reduced fouling issues.

C222 Forced Convection Heat Transfer of Laminar Duct Flow with Micro-bubbles

2007 ◽  
Vol 2007 (0) ◽  
pp. 257-258
Author(s):  
Ryosuke Okamoto ◽  
Katsuya Kimura ◽  
Atsuhide Kitagawa ◽  
Yoshimichi Hagiwara
Keyword(s):  
Heat Transfer ◽  
Forced Convection ◽  
Convection Heat Transfer ◽  
Convection Heat ◽  
Duct Flow ◽  
Forced Convection Heat Transfer

Numerical Investigation of Various Approaches to Avoid Natural Convection Instabilities Inside the Channels of Horizontal Plate Fin Heat Sinks

2016 ◽  
Author(s):  
Ilker Tari ◽  
Mehmet Erdem Ozet
Keyword(s):  
Heat Transfer ◽  
Fluid Dynamics ◽  
Heat Sink ◽  
Heat Sinks ◽  
Heat Transfer Area ◽  
Horizontal Plate ◽  
Transfer Rates ◽  
Longitudinal Vortices ◽  
Pin Fins ◽  
Natural Heat Convection

In case of natural heat convection from a horizontal plate fin heat sink, heat transfer rates highly depend on the geometric parameters. It is observed that if the fin height is very low, fresh cooler air may not be able to reach middle parts of the heat sink causing an ineffective use of the extended heat transfer area. Using a validated numerical model of an underperforming heat sink, various ways of improving heat sink geometry has been investigated. The tried approaches include leaving gaps in the length of the fins in different patterns, adding two different shape pin fins in the channels between the plate fins and raising the height of the fins on the edges. The last approach is shown to be effective in improving heat transfer by blocking the side flows over the heat sink. By numerical simulations, causes of the unwanted in-channel longitudinal vortices were also investigated in detail with the help of powerful flow visualization capability of Computational Fluid Dynamics.

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