1989 Fiscal Year Final Research Report Summary
Dispersion Phenomena of Bubbles and Particles in Liquid Metal Bathes at High Temperature during Injection of Them into the Bathes
| Project/Area Number |
63550491
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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 |
金属精錬・金属化学
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| Research Institution | Toyohashi University of Technology |
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Principal Investigator |
KAWAKAMI Masahiro Toyohashi University of Technology, Faculty of Engineering, Professor, 工学部, 教授 (30016597)
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| Project Period (FY) |
1988 – 1989
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| Keywords | Liquid metal bath at high temperature / Water and mercury bathes / Electro-resistivity probe method / Thermal expansion of bubbles / Boundary of bubble dispersion zone / Mean bubble diameter / Bubble rising velocity / Bubble dispersion phenomena |
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| Research Abstract |
Bubble dispersion phenomena in liquid metal bathes at high temperature have not been investigated so much, because of experimental difficulties. Many investigators have tried to simulate those with water and/or mercury model experiments. But such attempts have not been shown valid. In the present work, the dispersion phenomena in liquid copper and iron bathes at 1259ﾟC are compared with those in water and mercury bathes at room temperature, under such condition that the bath geometry and modified Froude No. are adjusted.
Spatial distribution of bubble frequency, gas hold-up and bubble rising velocity in each bath were measured by the electro-resistivity probe method with graphite rod of 0.5 mmphi. The bubble dispersion phenomena were described by the above data, and boundary of bubble dispersion zone, gas flow rate at different height in the bath and mean bubble diameter which could be estimated by combining the above data.
Radial distribution of bubble frequency is well expressed by the
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two dimensional Gaussian distribution function. Thus, the boundary of bubble dispersion zone is defined by two hold standard deviation of the function. The boundary is wider in the order of water < mercury < liquid copper = liquid iron bathes. The boundaries of the former two bathes are independent of gas flow rate, but those in the latter two bathes get more narrow as gas flow rate increase. The bubble rising velocity is larger in the same order as above. The gas flow rate at different height in the bath is estimated with data of gas hold-up and bubble rising velocity, and compared to the gas injection rate. In water bath, the both rates accord to each other. In mercury bath, the both rates accord to each other, if the former rate is modified with respect to hydrostatic pressure in the bath. In liquid copper and iron bathes, the former rate is smaller than the latter, showing that the thermal expansion of injected gas is not completed. The mean bubble diameter is estimated by 1.5 hold mean chord length which is estimated by the product of bubble rising velocity and residential time of probe in a bubble. The mean bubble diameter is larger in the same order as above.
It is concluded that the bubble dispersion phenomena in liquid metal bathes is very different from that in water and mercury bathes, even if the bath geometry and the modified Froude No. are adjusted. Less
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Research Products
(6 results)
