Optimal Design Of The Components In High-power LED Lamps Thermal Package

LED has a series of advantages such as low power consumption, high light efficiency, longlifetime, that has been considered the new lighting replacing traditional lighting. High-power LEDlamps have been widely applied to the lighting field in our daily lives currently. By the existingtechnical conditions, the poor heat dissipation of the LED lamps is still the technical bottleneckrestricting the development of this industry. Using finite element analysis method to carry out thecooling research of high-power LED lamps has gradually been recognized since the developmentof computer technology and the popularity of finite element analysis in engineering. In this study,an in-depth research focusing on the optimal design of high-power LED lighting packagecomponents is done by the method of finite element analysis combined with experimentalverification. All this study is based on the heat transfer theory.In this work, a finite element analysis of a real high-power LED tube light was finished, andthe temperature testing experimental was done to verify the correctness of the finite elementanalysis. The work also completed the optimal design of a comb heat sink used in tube light, and acolumnar heat sink used in down-light. Next, the "chimney effect" working on the heat sink designwas explored, and successfully completed a highly efficient heat sink design based on the“chimney effect”. At last, the work investigated the effect of irradiation angle on the thermal designof high-power LED tube lamps and down-lights.The thesis introduction part mainly analyzes the context of the current study and theapplications of high-power LED lighting. Pointed out that poor heat dissipation is the bottleneckrestricting the development of LED industry.4We discussed the study Status of high-power LEDPackage thermal at home and abroad. Finally, we introduced the content, methods and significanceof this study.In chapter two, the physics basis of high-power LED lighting package thermal study aredescribed. The content include the principle of LED light and heat, the thermal characteristics ofthe LED, junction temperature test methods, packaging components and modeling introduction, thedefinition of the irradiation angle and heat transfer theory introduction. All of introductions lay thefoundation for further study.The third chapter introduces the principle of finite element analysis and the use method offinite element analysis software “Fluent”. And then, modeling and simulation of an entity lamp are finished. Later, by testing the junction temperature, the correctness of the finite element analysisresults is verified.In chapter four, this study firstly carries out the optimal designs of a comb heat sink and acolumnar heat sink. Results show that, the best comb heat sink sizes are fin height of10mm and finspacing of4.1mm. For columnar heat sink, the best sizes are fin height of40mm, and fin numberof75. Thus, the research points out that the design of heat sink should take care both heatdissipation surface area and air flowing. And then, the study explores the "chimney effect" in heatsink design. Results show that the chimney flue pore size should not be less than6mm, and thechimney flue height could be40-50mm. Finally, a heat sink based on "chimney effect" is designed.The simulation results show that the junction temperature of101°C, proved the highly efficientperformance of the design.In chapter five, this work explores the effect of irradiation angle on high-power LED tubelights and down-lights Thermal performance. The results show that the tube light irradiation angledesign should exceed60°. And for down-lights, when the lighting irradiation angle less than30°,the structure of heat sink has little effect on the heat lamps’ thermal performance. But when theirradiation angle exceeds30°, the lamp with a radial heat sink has a bad thermal performance. Andfor the plate-like heat sink, the design of the rotary shaft should be pay attention to, i.e. thedirection of rotation of the lamp should be beneficial for movement of the air. Columnar heat sinkhas a relatively good thermal performance at any irradiation angle because of the bypassphenomenon. It is recommended that columnar heat sink is suitable for down-lights in multi-angledesign.The sixth chapter is the conclusion and outlook. Here, the conclusions of this study aresummarized. And at the same time, we make an outlook of the thermal package technology in thenext generation.