90°エルボ内の物質と運動量輸送に関する実験的研究
| Autor: | Ikarashi, Yuya |
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| Jazyk: | angličtina |
| Rok vydání: | 2019 |
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| Popis: | Mass and momentum transfer characteristics in and downstream of a 90°elbow are studied experimentally with the aid of the plaster dissolution method, surface flow visualization, and the particle image velocimetry (PIV) in and downstream of the elbow. The experiments are carried out for the elbow with the radius to diameter ratio 1.0, 1.2, and 1.5 in a Reynolds number Re = (3-15) × 10^4. The mass transfer measurements in the elbow indicate that the major change of mass transfer coefficient is observed along the inner wall of the elbow, where low mass transfer coefficient is found in the first half of the inner wall and it increases abruptly in the second half of the elbow, which is followed by a gradual recovery of the mass transfer in the downstream. However, the mass transfer on other wall does not change so much with that of the straight pipe. These features are mainly due to the flow acceleration in the first half of the inner wall and the following flow separation in the second half of the inner wall, where the high turbulence energy production is found in the PIV measurement. These results indicate that the mass transfer coefficient in and downstream of the elbow is highly modified by the flow separation in the elbow, which generates high turbulence energy in the second half of the inner wall in the elbow. Furthermore, these flow phenomena are highly promoted by increasing the elbow curvature and magnify the mass transfer on the inner wall of the elbow and they are function of the Reynolds number in the range of present experiments. 学位の種類: 博士（工学）. 報告番号: 甲第4609号. 学位記番号: 新大院博（工）甲第486号. 学位授与年月日: 平成31年3月25日 新大院博（工）甲第486号 |
| Databáze: | OpenAIRE |
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