Research of LED Heat-Sink Cooling with Aluminum Flake Graphite

• Main Authors: Tsung-Hung Lu, 呂宗鴻
• Other Authors: Jenn-Kun Kuo
• Format: Others
• Language: zh-TW
• Published: 2015
• Online Access: http://ndltd.ncl.edu.tw/handle/42274035901704331798

碩士 === 國立臺南大學 === 綠色能源學科技學系碩士在職專班 === 103 === We called the LED(Light Emitting Diode) for green light because it equiped energy saving, environmental protection, long life, small size and so on. LED luminous efficiency and lifetime of work display the inverse relationship with temperature, when the temperature exceeds 120 ℃, will accelerate the deterioration of the lamp body and packaging materials. This paper would analyzed the interface-temperature of the substrate with the Heat-Sink. Generally,because the engineer would like to increase the cooling-speed and efficiency of Heat- Sink, the engineer must try to increase the volume of fins and improve the height of fins, improving the ventilation channel between the cooling fins and try to equiped the exhaust fans, etc., In the monent, Heat-Sink was made by the aluminum alloy material. The study will test the cooling effect of the aluminum alloy Heat-sink and aluminum flake graphite composite Heat-sink under different ambient-temperature(35℃、70℃) and natural-convection of air velocity(0.5ms-1、2 ms-1、4 ms-1) by computational fluid dynamics simulation software.According to the data and then can be found,the interface average-temperature of aluminum flake graphite Heat-sink contact with the substrate is lower than the aluminum alloy Heat-sink contact with the substrate , therefore, the Heat-sink more able to protect the chip of the LED, and then the LED can not be broken when the temperature is too high and excessive.The Heat-sink of the aluminum flake graphite will to extend the service life of LED lights.The study depending on the simulation test result of the different ratio of aluminum flake graphite (flake graphite: 10%、 20%、 30%、 40%、 50%、 60%、70%、 80%、90%) which displayed the test result when the flake graphite ratio was 60% and the ambient-temperature was 35℃ and the natural-convection of air velocity was 0.5ms-1、2 ms-1、4 ms-1 and the cooling effect of Heat-sink was 38.5℃、46.8℃、51.4℃(aluminum alloy Heat-sink was 29.6℃、36.1℃、41.1℃),the ambient-temperature was 70℃ and the natural-convection of air velocity was 0.5ms-1、2 ms-1、4 ms-1 and then the cooling effect of Heat-sink was 4.4℃、11.8℃、16.4℃(aluminum alloy Heat-sink was -4.2℃、2.2℃、6.1℃),because the engineer tried to add more flake graphite and the way would increased the pore which display on the interface of flake graphite and aluminum-liquid and the way would to reduce the efficiency of heat transfer.The study would indicated the aluminum flake graphite Heat-sink(AlGr-60%) was the best design.