Analysis of heat transfer enhancement of LED lamp by liquid-cooled filling with emulsion

• Main Authors: Po-Jen Tung, 童柏仁
• Other Authors: Cherng-Yuan Lin
• Format: Others
• Language: zh-TW
• Published: 2011
• Online Access: http://ndltd.ncl.edu.tw/handle/30750812388371177832

碩士 === 國立臺灣海洋大學 === 輪機工程系 === 99 === Liquid emulsion was prepared by a high-gravity rotating packed bed and a mechanical homogenizer to investigate its emulsification, fuel properties and heat transfer characteristics. The emulsion was then used as the heat dissipating liquid to be filled in LED lamps for the analysis of heat transfer. The experimental results show that the emulsion prepared by the high-gravity rotating packed bed had superior emulsion activity, smaller mean droplet size, lower kinematic viscosity and larger extent of micro-explosion than that by the mechanical homogenizer. Silicone oil was mixed with dispersed phase of triacetin or ethylene glycol to form an emulsion of dispersed phase in continuous phase. It was observed that the emulsion with the dispersed phase of triacetin had superior emulsifying activity and emulsifying stability, smaller mean droplet size, lower kinematic viscosity and higher thermal conductivity than the emulsion with the dispersed phase of ethylene glycol. The emulsion of triacetin dispersed in silicone oil was thereafter filled into LED lamps with heating rate of 1W to 4W. It was found that the LED lamps with silicone-oil emulsion had lower thermal resistance and illuminance in comparison with that with neat silicone oil. The result differences between the experiment and simulation by Icepak software were relatively small for the thermal resistance of conduction and convection while significant for the thermal resistance of lamp.