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Dispersion Phenomena of Bubbles and Particles in Liquid Metal Bathes at High Temperature during Injection of Them into the Bathes

高温液态金属熔液注射过程中气泡和颗粒的弥散现象

基本信息

批准号：
63550491
负责人：
KAWAKAMI Masahiro
金额：
$ 1.73万
依托单位：
Toyohashi University of Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1988
资助国家：
日本
起止时间：
1988 至 1989
项目状态：
已结题

项目摘要

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 … More 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

由于实验困难，高温液态金属浴中的气泡分散现象尚未得到充分研究。许多研究人员尝试用水和/或汞模型实验来模拟这些实验。但此类尝试并未被证明是有效的。本工作在调整镀液几何形状和修正弗劳德数的条件下，将1259℃液态铜和铁镀液中的分散现象与室温下水和汞镀液中的分散现象进行了比较。采用0.5 mmphi石墨棒电阻率探针法测量了各镀液中气泡频率、含气量和气泡上升速度的空间分布。上述数据描述了气泡分散现象，结合上述数据可以估算出气泡分散区的边界、槽内不同高度处的气体流量和平均气泡直径。气泡频率的径向分布可以用二维高斯分布函数很好地表达。因此，气泡分散区的边界由函数的两个保持标准差来定义。边界较宽，顺序为水 < 汞 < 液态铜 = 液态铁浴。前两个浴的边界与气体流速无关，但后两个浴的边界随着气体流速的增加而变得更窄。气泡上升速度与上述顺序相同。根据气体滞留量和气泡上升速度的数据估计浴中不同高度处的气体流速，并与气体注入速率进行比较。在水浴中，两个速率彼此一致。在汞浴中，如果前一个速率相对于浴中的静水压力进行修改，则两个速率彼此一致。在液态铜和铁浴中，前者的速率小于后者，表明注入气体的热膨胀尚未完成。平均气泡直径由1.5保持平均弦长估计，该平均弦长由气泡上升速度和探针在气泡中的停留时间的乘积估计。平均气泡直径与上述顺序相同。结论是，即使调整镀液几何形状和修正弗劳德数，液态金属镀液中的气泡分散现象与水和汞镀液中的气泡分散现象有很大不同。较少的