| As a new generation of light sources,white light emitting diodes(LEDs)have gradually replaced traditional light sources in all types of practical applications.However,the photoelectric conversion efficiency of white LEDs is low.Most of the energy is transferred into heat,and if this heat cannot dissipate in time,the LED junction temperature will increase significantly,adversely affecting the performance and lifetime of the LED.Therefore,We built a three-dimensional model in Solidworks and use its Flow Simulation plugin to simulate our model,based on the principle of chimney effect.This article describes adding a chimney structure to the LED lamp and radiator,causing the air flow to form rapidly as a type of natural convection,thereby enhancing the LED heat dissipation effect.In this paper,we will discuss our method for reducing the weight and production cost of LED lamps.In order to achieve this goal,we designed a special-shaped LED lamp without radiator.Studies have shown that the height and diameter of chimney are both 45 mm,the heat dissipation performance of it is optimal,the highest temperature is 70.94 ℃.Then,we optimized the heat source distribution and substrate thickness.Results showed that the design produced its optimal cooling in a substrate with an upper extension length L of 35 mm,a lower extension length D of 8mm,and a thickness of 1 mm.For a substrate of those dimensions,the highest LED chip temperature was 64.78 ℃.Finally,in order to make the LED special-shaped lamp can work safety under the greater input power,an improved scheme of joining the sunfolower and honeycomb radiator in the middle of the substrate was put forward.In addition,the fin number,inner diameter,and fin thickness of the sunflower-and honeycomb-type radiators as well as the honeycomb length and thickness of the honeycomb-type radiator were adjusted to obtain the optimal parameter combination.Studies have shown that special-shaped lamps can achieve the highest performance under 19-W power LED safety work requirements after being fitted with a radiator.This special-shaped LED lamp provides a novel type ofcooling mode for LED lamps.In order to select better radiator,a comparison based on the principle of the chimney effect is made between comb radiator and sunflower radiator.The study demonstrated that sunflower radiator has a better performance in heat dissipation than comb radiator.Subsequently,we designed an LED cylinder sunflower radiator;studies have shown that when radiator is fitted with a cylinder,the LED junction temperature drops by 6.44 ℃.Finally,we incorporated a slotted and crisscross design into the traditional sunflower radiator;in addition to the weight of the radiator being reduced,the 26-W LED junction temperature dropped by 8.68 ℃.These studies can improve the cooling performance of traditional sunflower radiators.To enhance the cooling capacity of LED radiators,this study designed two types of porous radiator.First,we designed an LED lamp with a chimney structure-type radiator.Subsequently,according to the problem of the cost of the traditional chimney structure-type radiator being too high,we proposed another LED radiator with a simple configuration for processing.Through the optimization of the parameters,compared with the traditional radiator,the two radiators achieved temperature decreases of 4.41 ℃ and 8.89 ℃,respectively,thus satisfying LED requirements in natural convection. |
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