Study On Heat Transfer For The High-power LED Modules And High Bay Lamp

Light-emitting diode (LED) is considered as the fourth-generation light source,because of its excellent advantages such as environmental-protection, energy-saving,high reliability and long life and other advantages. Nowadays, incandescent andfluorescent lamps have been gradually replaced by LED. However, the electro-opticalconversion efficiency of the LED is relative low, poor of LED heat dissipation effectwhich leads to sharply degrade of the LED life and the light-emitting performance.Therefore, thermal management of the LED is a key issue for the LED development, inparticular, for the high-power LED. We must continue to improve the thermal design ofthe LED devices and the application process.The natural convection for LED heat dissipation was chosen in the thesis. Byimproving the LED interface material’s thermal properties and thermal resistance ofheat sink, combing theoretical analysis, numerical simulation and experimental test isadopted to exploit the novel structure and contact model of heat sink between differentcomponents, thermal analysis and research for different power and uses of LED werepreceded from materials, structures and other aspects.The experimental result had validated that the cooling effect of LED made withstraight cold spray welding technology is better than LED lights produced by traditionalcrimping process, after that, this paper carries out a study on heat dissipation influenceof the covering size and shape of the cold sprayed copper layer. The heat dissipation of30W LED lamp has been analyzed by ANSYS steady state thermal analysis, and theexperimental study has also been carried out using the thermocouple and the infraredtemperature measurement method. The good performance of heat dissipation can beachieved by different sprayed layer, it is mainly determined by the ability of heattransfer of the copper spray bagel.A concept of replacing aluminum alloy by pure aluminum is proposed to design thenew LED heat sink. In addition, the technology of cold spray-direct welding proposedin the thesis offers one route to enhance heat dissipation and reduce the material cost.The comparison and analysis between the experimental and simulation result areperformed and simulation result agree well with the experimental data. Furthermore, theambient temperature is changed to study the ability of heat dissipation on the badcondition, it is proved that the cooling solution proposed can meets the cooling requirement of the200W and250W LED high bay designed on the different operatingcondition.Finally, on the basis of the pure aluminum composite radiator structure optimized,we design and assemble the LED high bay lighting with the power of210W, based onthe previous proposed novel structure and technology, it can also meet the coolingrequirement by experiment.Integrating the novel technology of cold spray-direct welding with the newstructure of pure aluminum laminated radiator can provide one effective route to solvethe present bottleneck of heat dissipation for the high-power LED.