平板型迴路式熱管毛細結構之研究

• Main Authors: Peng Jen-Chieh, 彭仁頡
• Other Authors: 孔健君
• Format: Others
• Language: zh-TW
• Published: 2010
• Online Access: http://ndltd.ncl.edu.tw/handle/00878301619350872458

碩士 === 國防大學理工學院 === 機械工程碩士班 === 98 === Loop heat pipes (LHPs), which are generally and widely used with cylindrical evaporators, have a great potential for applications of spacecrafts and electronic cooling due to the advantages of high transfer capacity, low thermal resistance and long transport distances. However, the cylindrical evaporators of loop heat pipes cannot work on a flat thermo-contact surface without saddle. The saddle not only creates an extra thermal resistance but also makes evaporators less isothermal. To avoid the above disadvantages, we adopt the flat evaporators of loop heat pipes. According to the literature, to improve the thermal efficiency of Flat Loop Heat Pipes, we have to overcome three challenges: Heat Leakage Problem, Optimize Wick Parameter and Vapor Blanket Problem. In this study, we developed different strategies to be directed against those problems. On Heat Leakage Problem, after the thermal path analysis, we choose two strategies to prevent the effect of Heat Leakage Problem: the Evaporator Wall Blocking Effect and the Wick Structure Thickness Effect. To optimize the wick parameters, because of the parameters are unable to accurate control, so we control the wick manufacture parameters instead of the wick parameters. We are going to find out the relations between manufacture parameters and wick parameters, and the relations between manufacture parameters and thermal performance. By doing so, we can find out the better manufacture parameters and wick parameters. On the Vapor Blanket Problem, we present two different strategies: First, Increasing the vapor channel hydraulic radius and second, using the biporous wick structure. This study successfully increase the efficiency of F-LHP, by applying the heat leakage suppress strategy, the F-LHP starts working and reaches 100W, then we use the best wick parameters makes the F-LHP reaches 175W. After all, by applying the strategy of decreasing the effect of Vapor Blanket Effect, the maximum watts increased to 250W. Minimum thermal resistance was 0.25K/W, power density was 20W/cm2, Wick structure parameters were: porosity 70%, pore radius 3.7μm and permeability 3.02×10-12m-2. The thermal efficiency was at top class of recent literatures.