scholarly journals Modelling and Numerical Simulations of Heat Distribution for LED Heat Sink

2016 ◽  
Vol 2016 ◽  
pp. 1-8 ◽  
Author(s):  
Jianxin Zhu ◽  
Lixia Sun
Keyword(s):  
Heat Sink ◽  
Optimization Design ◽  
Evaluation Method ◽  
Light Emitting Diode ◽  
Vertical Direction ◽  
Heat Sinks ◽  
Heat Distribution ◽  
Spherical Coordinate ◽  
Light Emitting ◽  
Implicit Finite Difference

Light-emitting diode (LED) has higher efficiency and longer lifetime when compared with the conventional lighting. However, the efficiency and lifetime will be degraded greatly when it is operated at a high temperature. Now, both previous simulation and experimental results have already indicated that the heat transfer in vertical direction of the LED lamp by conduction is the most critical component. In this paper, a simplified numerical simulation model is built to estimate the heat distribution of the LED heat sink in the spherical coordinate system, which would be useful for its shape optimization design. With this model, some mathematical treatments are provided to a heat conduction equation, in order to rapidly compute the static heat distribution and the temperature of different designs of LED heat sinks. The built rapid heat sink evaluation method, implicit finite difference method (IFDM), is unconditionally stable. Several heat distribution simulations could demonstrate that our built mathematical model conforms well to the reality and our method is full of feasibility and effectiveness.

scholarly journals A Novel Heat Sink Design and Prototyping for LED Desk Lamps

2015 ◽  
Vol 2015 ◽  
pp. 1-8
Author(s):  
Li-Ming Chu ◽  
Wei-Chin Chang ◽  
Ting Hsuan Huang
Keyword(s):  
Heat Sink ◽  
Light Emitting Diode ◽  
Base Plate ◽  
Life Time ◽  
Heat Sinks ◽  
Light Emitting ◽  
Lighting Device ◽  
Different Types ◽  
Heat Sink Design ◽  
Chimney Effect

Light-emitting diode (LED) is a modern lighting device. If the heat dissipating mechanism of LED desk lamp is not well designed, the induced high temperature will cause the reduction of illumination and life time of lamp. Therefore, the heat sink design becomes a key technology for LED lighting device. This study developed a methodology to design and analyze a heat sink for LED cooling. Four different types of heat sinks with fins in longitudinal or transverse directions and with or without vents on the base plate were compared. By using the CFD software FLUENT, heat flux and temperature around the heat sink were analyzed, and the surface temperature distribution was also investigated. The simulation outcomes were compared with experiments results to verify analysis accuracy. The comparisons show only slight differences, and the deviations were less than 4.0%. For cooling LED desk lamp, the design of using 12 vents on both sides of heat sink through natural convection to create the chimney effect was adopted; consequently, the temperature dropped 5°C in average. This design can also reduce the material of heat sink, LED lamp weight, and production cost.

Improved Radial Plane Fins Heat Sink for Light-Emitting Diode Lamps Cooling

2019 ◽  
Vol 12 (4) ◽  
Author(s):  
António M. G. Lopes ◽  
Vítor A. F. Costa
Keyword(s):  
Heat Sink ◽  
Numerical Study ◽  
Light Emitting Diode ◽  
Heat Sinks ◽  
Electronic Components ◽  
Turning Operation ◽  
Light Emitting ◽  
Radial Plane ◽  
Convection Cooling ◽  
Main Ideas

Abstract A numerical study is conducted concerning the improvement of radial plane fins heat sinks for natural convection cooling of light-emitting diode (LED) lamps. The main objective is to maintain the temperature of the heat sink base below a prescribed threshold for a given released heat flux at the heat sink, minimizing its mass and maintaining at a reasonably simple level the manufacturing processes and operations required for its production. Starting from a previously optimized heat sink for the same purpose, constituted by complete rectangular radial plane fins, the present study aims at further improvements by considering incomplete rectangular radial plane fins. The main objective of this study is to find the best profile for the turning operation to obtain the radial plane fins lighter configuration. It is found that this can be achieved by removing part of the upper internal corners of the rectangular fins, more specifically shaping a curved cut, leading to heat sink mass reduction up to 32.4%. The geometry of the improved heat sink is of cylindrical nature, obtained from cutting an aluminum extruded bar comprising a cylindrical central core and a number of uniformly distributed rectangular radial plane fins, followed by a simple turning operation to remove their upper internal corners. Even if results concern a particular LED lamp, the main ideas and approach prevail to improve other types of heat sinks for general light and/or electronic components cooling.

Understanding Longitudinal Fin Heat Sink Orientation Sensitivity for Light Emitting Diode (LED) Lighting Applications

2003 ◽  
Author(s):  
James Petroski
Keyword(s):  
Heat Transfer ◽  
Heat Sink ◽  
Cooling System ◽  
Light Emitting Diode ◽  
Radiant Energy ◽  
Cylindrical Tube ◽  
Heat Sinks ◽  
Radiant Heat Transfer ◽  
Light Sources ◽  
Light Emitting

Light Emitting Diodes (LEDs) have progressed in recent years from emitting indicator level lighting to emitting enough light for illumination applications. This has opened a new field for LED applications, resulting in significant advantages over conventional light sources and creating some application challenges unique to LEDs. Conventional lighting methods provide little guidance for LED thermal problems since these usually involve a very high temperature source, such as a filament or an arc, and radiant heat transfer dissipates the thermal energy. LED junction temperatures are limited to much lower values and hence the heat transfer system cannot depend upon radiant energy transfer. This means the cooling methods for lighting now shift from primarily radiation to conduction and natural convection, and this paradigm shift lighting designers must recognize when moving to LEDs. In this paper, the development of a LED-based spot module heat sink in a free convective cooling system is discussed. The rationale for choosing a cylindrical tube, longitudinal fin (CTLF) heat sink is shown, as is the performance of five different configurations of the heat sink in various orientations. The requirement for using heat sinks in various orientations comes from lighting applications, where the light may be installed in various directions, such as vertical up, vertical down, horizontal, or at almost any other angle. Heat sink test results are plotted for Nussult number versus standard and modified channel Rayleigh number, showing a similar correlation to the parallel plate heat sinks investigated first by Elenbaas. A different correlation for the isolated-plate limit section is proposed for CTLF heat sinks, as well as a proposed area of operation on these Nu-Ra curves for orientation-insensitive heat sinks. Finally, explanations for the different levels of sensitivities observed in different areas of the Nu-Ra curves are offered.

scholarly journals Thermal performance of heat sink with fluid pockets for high power light emitting diode

2017 ◽  
Vol 14 (4) ◽  
pp. 4846-4862
Author(s):  
Sangmesh ◽  
◽  
Gopalakrishna Keshava Narayana ◽  
Manjunath Shiraganhalli Honnaiah ◽  
Krishna Venkatesh ◽  
...  
Keyword(s):  
Thermal Performance ◽  
High Power ◽  
Heat Sink ◽  
Light Emitting Diode ◽  
Light Emitting

Low Cost Cooling Device for High Power LED Lamps

2020 ◽  
Author(s):  
Pamela Martinez-Vega ◽  
Araceli Lopez-Badillo ◽  
J. Luis Luviano-Ortiz ◽  
Abel Hernandez-Guerrero ◽  
Jaime G. Cervantes
Keyword(s):  
Reference Model ◽  
Light Emitting Diode ◽  
Low Cost ◽  
Cost Effective ◽  
Heat Sinks ◽  
Modern World ◽  
Type Model ◽  
Light Emitting

Abstract The modern world progressively demands more energy; according to forecasts energy consumption will grow at an average annual rate of 3 percent. Therefore, it is necessary to purchase products or devices that are efficient and environmentally friendly. Technology in LED (Light Emitting Diode) lighting is presented as an alternative to energy saving, since LEDs have proven to be extremely efficient, have a long service life and their cost-effective ratio is very good. However, the heat emitted by the LED chip must be dissipated effectively, since the overheating of the chip reduces the efficiency and lifetime of the lamp. Therefore, heat sinks that are reliable, efficient and inexpensive should be designed and built. The present work proposes new designs for heat sinks in LED lamps, some of the models in the design of the fins refer to the Fibonacci series. The models proposed in the present work that have a significant advantage are the Type 1E Model (5.2% mass savings and better thermal efficiency of 8.33%), GR Type 1 Model (3.12% lighter and 3.33% more efficient) and the GRL Type Model (4. 51% mass savings and 5.55% thermally more efficient) compared to the Type 2 Reference Model proposed by Jang et al. [12].

scholarly journals 3D Microlithography Using an Integrated System of 5-mm UV-LEDs with a Tilt-Rotational Sample Holder

Micromachines ◽  
2020 ◽  
Vol 11 (2) ◽  
pp. 157 ◽  
Author(s):  
Sabera Fahmida Shiba ◽  
Hyeongmin Jeon ◽  
Jong-Soo Kim ◽  
Jong-Eun Kim ◽  
Jungkwun Kim
Keyword(s):  
Light Source ◽  
Light Emitting Diode ◽  
Vertical Direction ◽  
Ultra Violet ◽  
Integrated System ◽  
Sample Holder ◽  
Large Area ◽  
Light Emitting ◽  
Uv Led ◽  
Uv Leds

This paper demonstrates a 3D microlithography system where an array of 5 mm Ultra Violet-Light Emitting Diode (UV-LED) acts as a light source. The unit of the light source is a UV-LED, which comes with a length of about 8.9 mm and a diameter of 5 mm. The whole light source comprises 20 × 20 matrix of such 5 mm UV-LEDs giving a total number of 400 LEDs which makes it a very favorable source with a large area for having a batch production of the desired microstructures. This light source is able to give a level of precision in microfabrication which cannot be obtained using commercial 3D printers. The whole light source performs continuous rotational movement once it is turned on. This can also move up and down in a vertical direction. This multidirectional light source also comprises a multidirectional sample holder. The light source teaming up with the multidirectional sample holder highly facilitates the process of fabrication of a huge range of 3D structures. This article also describes the different levels of characterization of the system and demonstrates several fabricated 3D microstructures including high aspect ratio vertical micro towers, twisted turbine structures, triangles, inclined pillar ‘V’ structures, and hollow horn structures as well.

Performance of Hybrid Fin Heat Sinks for Thermal Control of Light Emitting Diode Lighting Modules

2013 ◽  
Vol 136 (1) ◽  
Author(s):  
Kyoung Joon Kim
Keyword(s):  
Forced Convection ◽  
Thermal Performance ◽  
Heat Sink ◽  
Light Emitting Diode ◽  
Internal Flow ◽  
Thermal Control ◽  
Numerical Prediction ◽  
Light Emitting ◽  
Convection Condition ◽  
Pin Fins

In this paper we introduce a hybrid fin heat sink (HFH) proposed for the thermal control of light emitting diode (LED) lighting modules. The HFH consists of the array of hybrid fins which are hollow pin fins having internal channels and integrated with plate fins. The thermal performance of the HFH under either natural or forced convection condition is both experimentally and numerically investigated, and then its performance is compared with that of a pin fin heat sink (PFH). The observed maximum discrepancies of the numerical prediction to the measurement for the HFH are 7% and 6% for natural and forced convection conditions. The reasonable discrepancies demonstrate the tight correlation between the numerical prediction and the measurement. The thermal performance of the HFH is found to be 12–14% better than the PFH for the natural convection condition. The better performance might be explained by the enlarged external surface and the internal flow via the channel of the HF. The reference HFH is about 14% lighter than the reference PFH. The better thermal performance and the lighter weight of the HFH show the feasibility as the promising heat sink especially for the thermal control of LED street and flood lighting modules.

Enhanced Emission from a Light-Emitting Diode Modified by a Photonic Crystal

2000 ◽  
Vol 637 ◽  
Author(s):  
Alexei A. Erchak ◽  
Daniel J. Ripin ◽  
Shanhui Fan ◽  
John D. Joannopoulos ◽  
Erich P. Ippen ◽  
...  
Keyword(s):  
Photonic Crystal ◽  
Planar Waveguide ◽  
Optical Pumping ◽  
Extraction Efficiency ◽  
Light Emitting Diode ◽  
Active Material ◽  
Light Output ◽  
Vertical Direction ◽  
Light Emitting ◽  
Spectrally Resolved

AbstractEnhanced light output is observed from a light-emitting diode (LED) structure containing a two-dimensional (2D) photonic crystal. The capture of emitted light into planar waveguide modes reduces the extraction efficiency of LEDs. Here, 2D photonic crystals are utilized to: 1) enhance the extraction of light in the vertical direction from an LED and 2) enhance optical pumping by directly coupling light from a pump laser into the LED structure. Spatially and spectrally-resolved photoluminescence (PL) is used to characterize the enhancements. A 100-fold enhancement in extraction for a single wavelength into the vertical direction is obtained without the photonic crystal penetrating the active material.

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