Light Emitting Diode Heat Sink Research Articles

Guide Vane for Thermal Enhancement of a LED Heat Sink

A guide vane was installed on a heat sink to enhance the cooling effect of light-emitting diode (LED) lights. The validity of the numerical analysis was verified against the experimental results and the result of the previous studies. The effect of the guide vane on the heat dissipation performance of the heat sink was identified. The effect of the guide vane on the heat sink was qualitatively studied using the streamline and temperature contour. The cooling effect of the heat sink was enhanced by increased air supplement to the center-bottom part. A parametric study was conducted to determine the thermal resistance according to the guide vane angle, installation height, and vane length. Optimization was performed to minimize the thermal resistance using the Kriging model and micro-genetic algorithm (MGA). The cooling performance of the heat sink was enhanced by a maximum of 17.2% when the guide vane was installed.

Heat transfer enhancement in a p-shape finned radial heat sink subjected to natural convection: Thermal significance of slot and dimples in fin

This study presents the optimum design of the radial heat sink for light-emitting diode (LED) under natural convection. A radial heat sink with a hollow circular base and a P-shape fin type incorporated with either slots or both slots and dimples was numerically investigated using the ANSYS (Fluent) commercial code, with the aim of achieving better cooling performance at a lower heat sink mass.  The average temperature (Tavg) and mass of the HS for various model designs, namely; Type A (HS with plain fin), Type B (HS with slot) and Type C (HS with both dimples and slot) were compared to select the best configuration. The effect of heat flux (700≤q ̇≤1900)  on average temperature of radial heat sink was investigated. It was found that for all three models, the temperature difference between the HS and the ambient air of the fluid domain linearly increased with heat flux. At q ̇=1900W/m2 , when compared to Type A (HS with plain fins), Type C (HS with slot and dimples) models offered the best cooling performance, followed by Type B where the mass and average temperature of the heat sink is reduced by 13.7% and 5.1%, 8.3% and 1%, respectively.

Heat-dissipation performance of cylindrical heat sink with perforated fins

The temperature of light-emitting diode (LED) light bulbs must be managed to maintain their performance and increase their lifespan, and the design and application of an appropriate LED heat sink are particularly important for temperature management. This study investigated the heat-dissipation performance of a heat sink with perforated fins on a cylindrical base. To improve the heat-dissipation performance of the heat sink, the effects of the size and number of perforations per fin were examined. A larger number of perforations with a smaller size were found to be favorable for the improvement of the heat-dissipation performance. Both the size and number of perforations, however, had threshold values for lowering the thermal resistance. Moreover, the heat-dissipation performance was numerically analyzed according to the Rayleigh number, number of fins, fin inclination angle, and orientation angle of the heat sink. In addition, the numerical analysis method used was experimentally verified. As the number of fins increased, the thermal resistance decreased because of the corresponding increase in the heat-dissipation area of the heat sink. Furthermore, the thermal resistance was found to vary with respect to the fin inclination angle, making it possible to reduce the degradation of the heat-dissipation performance by varying the orientation angle. On this basis, a correlation was derived for predicting the thermal resistance of the cylindrical heat sink with perforated fins. The derived correlation accurately predicted the thermal resistance within a maximum error of 5.25%.

A design problem to estimate the optimal fin shape of LED lighting heat sinks

A fin shape design problem is considered in the present work utilizing the Levenberg-Marquardt Method (LMM) and a commercial package CFD-ACE+. The objective is to design the optimal fin shape of radial heat sink for light-emitting diode (LED) lighting devices and to enhance the cooling performance of the heat sink. The design process is to obtain the optimal design variables for the external fin shape of the heat sink and then minimize the average temperature of the bottom surface of heat sink. The natural convection working condition of the heat sink is assumed as the working condition, besides, the effect of radiation heat transfer between heat sink and air is also included. Numerical results indicate that by utilizing the fin heights as the design variables, the best heat sink performance can be obtained and the middle and center fin height both become negligible. The system thermal resistance of the optimal design can be reduced further by 16.8% and 11.0% than the initial and Type 2 design heat sinks, respectively. Finally, three types of heat sinks with fins are carried on the experimental verification. The results from experiments show that with the designed optimal fin shapes the cooling performance of the heat sink is indeed better than those with the initial and existing fin designs, besides, the numerical and experimental temperature distributions on the measured surfaces are very much similar. The physical argumentation of this work lies in that the approach presented in this work could result in a better design for fin shape of LED lighting heat sinks and can be applied in reality.

Modelling and Numerical Simulations of Heat Distribution for LED Heat Sink

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.

Thermal and Physical Performance of Heat Sink for Light-Emitting Diode Improved with Expanded Graphite

Thermal and Physical Performance of Heat Sink for Light-Emitting Diode Improved with Expanded Graphite