碩士 / 國立勤益科技大學 / 冷凍空調系 / 102 / The heat transfer and pressure drop performance of X type louver fin and tube exchangers are studied. The plate type and curved shape heat exchangers characteristics are compared to provide design reference of louver fin and tube heat exchangers. The geometries of the fin and tube heat exchangers are: one-row and two-row, the longitudinal tube pitch is 12.7mm, the transverse tube pitch is 21mm, the tube collar is 7.53mm, the fin thickness is 0.1mm, four fin pitches:3mm、2.5mm、1.66mm、1mm are studied. The louver angle is 25°. Ten frontal velocities are considered: 0.5m/s、1 m/s、1.5 m/s、2 m/s、2.5 m/s、3 m/s、3.5 m/s、4 m/s、4.5 m/s、5 m/s. The results show that the pressure drops and heat transfer rates are varied greatly by the fin pitch of the louver fin and tube exchangers.
With the gain of fin pitch from the one row type streamline, less air flow pass through the louver fin, parallel flow are the main fluid channel, it will also generate a vortex in the sixth block of louver fin. In two row Fp=1mm it too small to effectively take away the heat, in a larger fin pitch will see more unstable flow field at the second row. This shows that increase the heat exchanger fin pitches may not be able to achieve the effect of increased heat transfer rate, especially in the two row tube, not only did not increase the heat transfer rate but also lower than Fp=1mm at last.
| Identifer | oai:union.ndltd.org:TW/102NCIT5680011 |
| Date | January 2014 |
| Creators | Tsai,Ping-Hsien, 蔡秉憲 |
| Contributors | Hsieh,Wen-Chien, 謝文健 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 97 |
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