| Project/Area Number |
60550125
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
Fluid engineering
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| Research Institution | Kobe University |
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Principal Investigator |
SAKAGUCHI Tadashi Professor, Faculty of Engineering, Kobe University, 工学部, 教授 (50031076)
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| Co-Investigator(Kenkyū-buntansha) |
MINAGAWA Hisato Assistant, Faculty of Engineering, Kobe University, 工学部, 助手 (60190691)
SHAKUTSUI Hideaki Lecturer, Kobe Technical College, 講師 (90154335)
OZAWA Mamoru Assoc, Prof, Faculty of Engineering, Kobe University, 工学部, 助教授 (60112009)
HAMAGUCHI Hachiro Assoc. Prof. Faculty of Education, Kobe University, 教育学部, 助教授 (70030583)
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| Project Period (FY) |
1985 – 1986
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| Project Status |
Completed (Fiscal Year 1986)
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| Budget Amount *help |
¥1,900,000 (Direct Cost: ¥1,900,000)
Fiscal Year 1986: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 1985: ¥1,200,000 (Direct Cost: ¥1,200,000)
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| Keywords | two-phase flow / vertical tube / flow pattern conversion / slug flow / bubbly flow / porous plate / 大気泡 |
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| Research Abstract |
This study concerns the flow pattern conversion from slug flow to bubbly flow in gas-liquid two-phase flow in a vertical tube. Multi-stage porous plate type converter was developed. It mainly consists of five porous plates made of ABS plastics arranged in series in a tube, and is effective to convert the flow pattern, i. e., bubbly flow exists downstream the converter in a certain length <L_B> .
Experiments were carried out for single large bubbles rising in moving liquid to obtain the fundamental chracteristics of the converter. Then, the relationship between <L_B> and the number n of the porous plate was obtained, and it was shown that the performance of the converter was possible to be predicted by the results for n=2 (2-stage type converter). Experiments were also carried out to correlate the performances for single bubbles and for two-phase flow. From those results, it is possible to predict the performance of the multi-stage type converter in two-phase flow from the results for single bubble passing through 2-stage type converter.
Then, experiments were carried out for three kinds of porous plate chosen by preliminary experiments. The results for <L_B> were expressed in <j_g> - <j_l> coordinates, and method of optimum selection of the plate according to <j_g> and <j_l> was found, where <j_g> and <j_l> are the volumetric fluxes of gas and liquid, respectively. Those results were shown to be related to the gas fraction <f_g> (in the slug flow) and ( <j_g> + <j_l> ).
Since the gas fraction was found to be an important factor, distribution of the time averaged gas fraction <f_g> was measured along the tube length. It was found that (i) the gas fraction <f_g> is larger in a certain region downstream the converter than that of fully developed slug flow, and (ii) this region is related to the bubbly region <L_B> .
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