Condensation heat transfer characteristics study for refrigerant R-410A flowing through a helical coil heat exchanger

• Main Authors: Lin Jhe-Wei, 林哲緯
• Other Authors: 施陽正
• Language: zh-TW
• Online Access: http://ndltd.ncl.edu.tw/handle/pu3r2g

碩士 === 國立臺北科技大學 === 能源與冷凍空調工程系碩士班 === 103 === Helical coil heat exchanger has many features on its applications, such as simple construction, easy manufacturing, and so on. Owing to its higher heat transfer performance, caused by second-flow effect through curvature motion. Parameters, such as coil diameter, coil pitch, coil number, curvature ratio(r/R), and Reynolds number are known as the key to the heat transfer. In this study, the heat transfer effect was investigated for a series of helical coil heat exchanger under various coil diameters, coil numbers, coil pitches, and coil heights, while restricting on the same heat transfer area. Meanwhile, the heat transfer effect of condensation process was also investigated. When refrigerant R-410A flowed through the tube-side of helical coil heat exchanger. The experiments was divided into two stages. In the first stage, the Wilson-plot method was employed to estimate the shell-side heat transfer coefficient, h_o, and then, the tube-side fluid was shifted to refrigerant R-410A to estimate tube-side heat transfer coefficient, h_i in condensing process. The uncertainty of the measured h_o and h_i were also estimated around 11.3% and 18.45%. The results show that the heat transfer effect of helical coil heat exchanger strongly related to coil diameter, coil pitch, fluid entrances and exits position, and the Reynolds number.