1998 Fiscal Year Final Research Report Summary
STUDY ON TWO PHASE FLOW BY PHASE CHANGE IN NEGATIVE PRESSURE OF WATERHAMMER
| Project/Area Number |
09650571
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
水工水理学
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| Research Institution | TOHOKU-GAKIN UNIVERSITY |
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Principal Investigator |
KONO Yukio TOHOKU-GAKUIN UNIVERSITY,DEPARTMENT OF CIVIL ENGINEERING,ASSOCIATE PROFESSOR, 工学部, 助教授 (30137583)
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| Project Period (FY) |
1997 – 1998
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| Keywords | waterhammer / phase change / two phase flow / upstream FDM |
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| Research Abstract |
The upstream finite difference method is applied to vapor mixture problem and it shows that this method is capable of solving the non-linear hyperbolic type partial differential equation and parabolic equation simultaneously.
One phase fluid flow
The both results of analysis and experiment show the oscillation of square wave pattern and the second peak of the pressure wave changes the shape as cutting off the left corner of positive pressure and negative pressure, which is considered as the influence of non-linear term of partial differential equation.
Two phase flow
1. The negative pressure of waterhammer wave reaches the evaporation point (- 10 m) at initial velocity around 0.12 mIs according to the results of analysis and experiment. The vaporization starts at this point, and the two phase flow of liquid and vapor mixture occurs at this point.
2. The results of upstream finite difference method shows the bell shape wave pattern which is concerned as influence of two phase fluid-gas mixture which is shown the same as the result of experiment.
3. The right shift and the left shift pattern of the second wave are detected from both results of analysis and experiment, which is considered the influence of non-linear term of partial deferential equation and the phenomena of vaporization. This changing pattern of the right shift, the bell shape, and the left shift cycled at velocity about 0.25 mIs.
4. The negative pressure of the second wave reaches the evaporation point at velocity around 0.32 mIs.
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