| Summary: | 碩士 === 國立臺灣大學 === 機械工程學研究所 === 105 === In recent years, due to the progress of semiconductor manufacturing process, electronic equipment goes toward high-density and high-performance goals. While the wafer size is minimizing, the unit area that contains the number of transistors is continuously increased, and the heat released per unit area reached a new high. The problem of heat dissipation has always been a technical bottleneck and challenge for notebooks, which relates to the overall stability and performance of notebooks. At present, the cooling methods of notebook computer are fans, heat pipes and fins, but with the progress made by the wafer continued to evolve, the heat released per unit area will gradually increase in the future, it will make the traditional cooling method not enough to use. The development of new cooling methods has its necessity.
Therefore, this study aims to develop a Hybrid Loop Heat Pipe system for high-performance notebook computer cooling. At first, this study develop a technology in wick structure with liquid grooves for the traditional Loop Heat Pipe to reduce the flow resistance and increase the absorption of working fluid surface area, in order to improve the Flat Plate Loop Heat Pipe heat transfer performance, then add the micro-fluid pump and reservoir in traditional Loop Heat Pipe, it uses small amount of power in exchange for exponential growth in the heat transfer performance, in addition to capillary force provided by wick structure itself, there are micro-liquid pump to overcome pressure drop of the overall system cycle, The reservoir is able to keep sufficient working fluid to the wick structure in order not to make it dry out, In addition, this study further explores the effect of different flow rate on the performance of the Hybrid Loop Heat Pipe, and then develops a heat dissipation module suitable for high performance notebook computers.
The experimental results show that the maximum heat transfer of wick structure with liquid grooves can reach 225W (heat flux is 33.3 W/cm2) in the Teflon wick structure with acetone as working fluid, the thermal resistance is 0.63℃/W, increased by about 50% than the traditional Loop Heat Pipe. The maximum heat transfer of Hybrid Loop Heat Pipe system can reach 400W (heat flux is 59.2 W/cm2), and the total thermal resistance is 0.22℃/W, which the temperature is controlled at 100℃ .The performance of Hybrid Loop Heat Pipe is improved by about 700% than traditional Loop Heat Pipe. It is found that the increase of the flow rate can increase the maximum heat transfer and reduce the thermal resistance, but the heat transfer performance improvement is not significant at excessive flow rate, at this time, it will waste the pumping power. The results show that the maximum heat transfer can reach 400W and the total thermal resistance is 0.22℃/W when the flow rate of liquid pump is 100ml / min.
Based on the results of this study, with a small amount of kinetic energy input, the Hybrid Heat Pipe system can effectively enhance the heat transfer performance of traditional Loop Heat Pipe system, for the future high-performance notebook and other high-power industry, the Hybrid Loop Heat Pipe system has great potential for development.
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