An Application of the Fractal Theory in the Design of Heat Sink for Precision Measurement Instrument

2005 ◽  
Vol 295-296 ◽  
pp. 717-722 ◽  
Author(s):  
S.R. Lee ◽  
Z.G. Li ◽  
B.G. Wang ◽  
H.S. Chiou
Keyword(s):  
Heat Transfer ◽  
Temperature Variation ◽  
Temperature Control ◽  
Heat Sink ◽  
High Performance ◽  
Laser Interferometer ◽  
Fractal Theory ◽  
Measurement Instrument ◽  
Measurement Instruments ◽  
Heat Sink Design

Temperature variation on accuracy and stability in measurement instruments is an important issue. High performance and miniaturized instruments have rigorous requirements on temperature. Heat transfer and temperature control are important in instruments design. For laser interferometer, temperature variation will adversely affect the frequency stability of the laser and the measuring precision. In order to effectively stabilize the frequency, a simple and effective heat sink design for laser interferometer is presented. It is based on the fractal theory and the heat transfer characteristics to allow higher dissipation for temperature control to generate higher heat transfer area in a finite space. Experimental results in frequency stabilization clearly show that this method is effective.

An Analytical Study of the Optimized Performance of an Impingement Heat Sink

2004 ◽  
Vol 126 (4) ◽  
pp. 528-534 ◽  
Author(s):  
S. B. Sathe ◽  
B. G. Sammakia
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Heat Sink ◽  
High Performance ◽  
Cross Flow ◽  
High Heat ◽  
Transfer Coefficients ◽  
Heat Transfer Coefficients ◽  
High Heat Transfer ◽  
Flow Through

The results of a study of a new and unique high-performance air-cooled impingement heat sink are presented. An extensive numerical investigation of the heat sink performance is conducted and is verified by experimental data. The study is relevant to cooling of high-power chips and modules in air-cooled environments and applies to workstations or mainframes. In the study, a rectangular jet impinges on a set of parallel fins and then turns into cross flow. The effects of the fin thickness, gap nozzle width and fin shape on the heat transfer and pressure drop are investigated. It is found that pressure drop is reduced by cutting the fins in the central impingement zone without sacrificing the heat transfer due to a reduction in the extent of the stagnant zone. A combination of fin thicknesses of the order of 0.5 mm and channel gaps of 0.8 mm with appropriate central cutout yielded heat transfer coefficients over 1500 W/m2 K at a pressure drop of less than 100 N/m2, as is typically available in high-end workstations. A detailed study of flow-through heat sinks subject to the same constraints as the impingement heat sink showed that the flow-through heat sink could not achieve the high heat transfer coefficients at a low pressure drop.

scholarly journals A Numerical and Experimental Study of a Novel Heat Sink Design for Natural Convection Cooling of LED Grow Lights

Energies ◽  
2020 ◽  
Vol 13 (16) ◽  
pp. 4046
Author(s):  
Ram Adhikari ◽  
Dawood Beyragh ◽  
Majid Pahlevani ◽  
David Wood
Keyword(s):  
Heat Transfer ◽  
Natural Convection ◽  
Heat Sink ◽  
Large Scale ◽  
High Efficiency ◽  
Experimental Testing ◽  
Growth Stages ◽  
Air Cooling ◽  
Convection Cooling ◽  
Heat Sink Design

Light-emitting diode (LED) grow lights are increasingly used in large-scale indoor farming to provide controlled light intensity and spectrum to maximize photosynthesis at various growth stages of plants. As well as converting electricity into light, the LED chips generate heat, so the boards must be properly cooled to maintain the high efficiency and reliability of the LED chips. Currently, LED grow lights are cooled by forced convection air cooling, the fans of which are often the points of failure and also consumers of a significant amount of power. Natural convection cooling is promising as it does not require any moving parts, but one major design challenge is to improve its relatively low heat transfer rate. This paper presents a novel heat sink design for natural convection cooling of LED grow lights. The new design consists of a large rectangular fin array with openings in the base transverse to the fins to increase air flow, and hence the heat transfer. Numerical simulations and experimental testing of a prototype LED grow light with the new heat sink showed that openings achieved their intended purpose. It was found that the new heat sink can transfer the necessary heat flux within the safe operating temperature range of LED chips, which is adequate for cooling LED grow lights.

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.

An Analytical Study of the Optimized Performance of an Impingement Heat Sink

2003 ◽  
Author(s):  
S. B. Sathe ◽  
B. G. Sammakia
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Heat Sink ◽  
High Performance ◽  
Cross Flow ◽  
High Heat ◽  
Transfer Coefficients ◽  
Heat Transfer Coefficients ◽  
High Heat Transfer ◽  
Flow Through

The results of a study of a new and unique high performance air-cooled impingement heat sink are presented. An extensive numerical investigation of the heat sink performance is conducted and is verified by experimental data. The study is relevant to cooling of high power chips and modules in air-cooled environments and applies to workstations or mainframes. In the study, a rectangular jet impinges on a set of parallel fins and then turns into cross-flow. The effects of the fin thickness and gap nozzle width and fin shape on the heat transfer and pressure drop are investigated. It is found that pressure drop is reduced by cutting the fins in the central impingement zone without sacrificing the heat transfer due to a reduction in the extent of the stagnant zone. A combination of fin thicknesses of the order of 0.5 mm and channel-gaps of 0.8 mm with appropriate central cut-out yielded heat transfer coefficients over 1500 W/m2K at a pressure drop of less than 100 N/m2, as is typically available in high-end workstations. A detailed study of flow-through heat sinks, subject to the same constraints as the impingement heat sink showed that the flow-through heat sink could not achieve the high heat transfer coefficients at a low pressure drop.

Modeling and metrology in high performance heat sink design

1999 ◽  
Vol 21 (2) ◽  
pp. 201
Author(s):  
Chandrakant D. Patel ◽  
Christian L. Belady
Keyword(s):  
Heat Sink ◽  
High Performance ◽  
Heat Sink Design

Natural Convection Heat Transfer of Annular Metal Porous Medium Heat Sink of LED

2013 ◽  
Vol 284-287 ◽  
pp. 844-848
Author(s):  
Sheng Chung Tzeng ◽  
Tzer Ming Jeng ◽  
Zhi Ting Yeh
Keyword(s):  
Heat Transfer ◽  
Porous Medium ◽  
Natural Convection ◽  
Heat Sink ◽  
High Performance ◽  
Cooling System ◽  
Convection Heat Transfer ◽  
Natural Convection Heat Transfer ◽  
Convection Heat ◽  
Transfer Capability

This study used metal porous medium heat sink to replace traditional cooling fins to form a high performance LED cooling system. The metal foamed material has high permeability and cooling area as large as several times of that of traditional fins. With a proper configuration design, it can improve the heat transfer capability of natural convection effectively. This study experimentally investigated the natural convection heat transfer characteristics of the annular metal foamed material, and determined the optimal configuration. The experimental results showed that 1) the heat transfer coefficient (h) increased with ΔT; 2) the (h) decreased as PPI (pores per inch) increased when the thickness (t) of the annular metal foams equaled 5 mm, but the (h) increased as PPI increased when t=11 and 14.5 mm; 3) the (h) increased and then decreased as (t) increased, and there was better heat transfer effect when t=11 mm as shown in the experimental data.

Novel Heat Sink Design Utilizing Ionic Wind for Efficient Passive Thermal Management of Grid-Scale Power Routers

2015 ◽  
Vol 7 (3) ◽  
Author(s):  
Noris Gallandat ◽  
J. Rhett Mayor
Keyword(s):  
Heat Transfer ◽  
Natural Convection ◽  
Numerical Model ◽  
Heat Transfer Enhancement ◽  
Thermal Management ◽  
Heat Sink ◽  
Ionic Wind ◽  
Transfer Enhancement ◽  
Enhancement Method ◽  
Heat Sink Design

This paper presents a numerical model assessing the potential of ionic wind as a heat transfer enhancement method for the cooling of grid distribution assets. Distribution scale power routers (13–37 kV, 1–10 MW) have stringent requirements regarding lifetime and reliability, so that any cooling technique involving moving parts such as fans or pumps are not viable. A new heat sink design combining corona electrodes with bonded fin arrays is presented. The model of the suggested design is solved numerically. It is predicted that applying a voltage of 5 kV on the corona electrodes could increase the heat removed by a factor of five as compared to natural convection.

scholarly journals Erratum: “A Novel Approach to Low Profile Heat Sink Design” [Journal of Heat Transfer, 2010, 132(9), p. 091401]

2010 ◽  
Vol 132 (12) ◽  
Author(s):  
J. Stafford ◽  
E. Walsh ◽  
V. Egan ◽  
P. Walsh ◽  
Y. S. Muzychka
Keyword(s):  
Heat Transfer ◽  
Heat Sink ◽  
Novel Approach ◽  
Low Profile ◽  
Heat Sink Design

Performance of an Air-Cooled Heat Sink Channel With Microscale Dimples Under Transitional Flow Conditions

2013 ◽  
Vol 135 (11) ◽  
Author(s):  
Krishna Kota ◽  
Ludovic Burton ◽  
Yogendra Joshi
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Heat Sink ◽  
High Performance ◽  
Heat Sinks ◽  
Transitional Flow ◽  
Design Parameters ◽  
Flow Conditions ◽  
Walled Channel ◽  
Heat Transfer Improvement

The objective of this effort is to pursue artificial microscale surface roughness features in the form of dimples, on the walls of an air-cooled heat sink channel, as a passive option to energy-efficiently augment heat transfer in forced convection flows. High fidelity numerical simulations were employed for realizing an optimized dimple configuration and to comprehend the behavior of microsized dimples under high velocity (∼17 m/s) transitional flow conditions. Fully developed flow simulations were performed, and design of experiments with response surface methodology was employed for the numerical optimization. The results showed ∼30% heat transfer improvement and ∼15% pressure drop increase in the fully developed region compared to a smooth-walled channel. Practicability of manufacturing 200 μm deep dimples on a 600 μm thin aluminum fin was demonstrated. Experiments were also carried out to assess the performance of the aforementioned optimized configuration in a custom built setup in the laboratory, which showed up to 10.5% heat transfer improvement and ∼12% pressure drop increase over a corresponding smooth-walled channel. The above results indicate that the performance of dimples is allied with the flow development characteristics. In addition, experiments performed at Reynolds numbers other than one at which the dimples were optimized showed inferior performance showing that application-specific optimization of dimples is crucial. With further exploration of shape and design parameters, dimples might have the potential to improve thermal performance passively and form an attractive candidate to realize high-performance air-cooled heat sinks in the future.

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