CAPILLARY-DRIVEN FLOW ANALYSIS OF A MICRO-GROOVED PIPE

• Main Author: Nguyen Dang Tien Dung
• Other Authors: Associate Professor Fu-Sheng Chuang
• Format: Others
• Language: en_US
• Published: 2011
• Online Access: http://ndltd.ncl.edu.tw/handle/k73c2v

碩士 === 國立臺灣科技大學 === 機械工程系 === 99 === As solar energy provides significant opportunities to all of our power needs, there are a number of investigations into the applications of solar energy. Since, the performance of heat operation is directly proportional to temperature difference of operation, the bigger the temperature difference, the higher the efficiency of heat operation. However, there is a temperature limit of 600℃ because of the limitation of materials and techniques. There are three main designs to fulfill this requirement of power generation process. Parabolic trough is one of them and has many prominent benefits comparing to others. For that reason, parabolic trough technology has been the main research target for this study. Pipes with micro-grooves etched in the inner wall have been widely taken on the absorber receiver in parabolic trough and cooling systems for both solar thermal absorbers and air-conditioning because this sort of pipe improves heat transfer by enhancing convective boiling and capillary-driven such as pumping of liquid in the micro-grooves. This thesis proposes to incorporate capillary systems on the inner surface of absorber pipes for parabolic trough. Moreover, it presents the effect of parameters to liquid front position and velocity with an aim of appropriate design for grooved-pipe. The results show that liquid front position is directly proportional to value of inner radius and is not affected significantly by width of micro-groove while it is indirectly proportional to saturated temperature. On top of that, water and triangular groove have good impacts to liquid front position. A better design of micro-grooved pipe is proposed at the end of study. Furthermore, the mass of evaporation in micro-groove will be computed as function of time in order to be able to supply enough water for absorber pipe in parabolic trough during the working process of solar thermal power plant.