2017年4月1日
Effects of column diameter and liquid height on gas holdup in air-water bubble columns
Experimental Thermal and Fluid Science
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- ,
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- 巻
- 82
- 号
- 開始ページ
- 359
- 終了ページ
- 366
- 記述言語
- 英語
- 掲載種別
- 研究論文(学術雑誌)
- DOI
- 10.1016/j.expthermflusci.2016.11.032
- 出版者・発行元
- Elsevier Inc.
Experiments on the total gas holdup, αG, in air–water cylindrical bubble columns were carried out to investigate effects of the column diameter, DH, and the initial liquid height, H0, on αG. Ranges of DH and H0 were 160 ⩽ DH ⩽ 2000 mm and 400 ⩽ H0 ⩽ 4000 mm, respectively. The superficial gas velocity, JG, was varied from 0.025 to 0.35 m/s. The characteristics of gas holdup showed that all the flows in the present experiments were pure heterogeneous. The following conclusions were obtained for αG in air–water bubble columns: (1) the effects of DH and H0 on αG are negligible when scaling up from small to large bubble columns, provided that αG in the small columns are obtained for DH ⩾ 200 mm and H0 ≳ 2200 mm. The height-to-diameter ratio is useless in evaluation of the critical height, above which αG does not depend on H0, (2) for the above ranges of DH and H0, Akita-Yoshida's and Koide's correlations can give good evaluations of αG for a wide range of JG by tuning the model constants, (3) for DH <
200 mm, the decrease in DH increases the population of large bubbles, which results in the decrease in αG, and (4) for H0 ≲ 2200 mm and DH ⩾ 200 mm, αG at a constant JG decreases with increasing H0 and approaches an asymptotic value, and the Froude number using JG and H0 as the characteristic scales well correlates αG in this regime.
200 mm, the decrease in DH increases the population of large bubbles, which results in the decrease in αG, and (4) for H0 ≲ 2200 mm and DH ⩾ 200 mm, αG at a constant JG decreases with increasing H0 and approaches an asymptotic value, and the Froude number using JG and H0 as the characteristic scales well correlates αG in this regime.
- ID情報
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- DOI : 10.1016/j.expthermflusci.2016.11.032
- ISSN : 0894-1777
- SCOPUS ID : 85003875931