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Movement of Foreign Particles in Liquid Driven by Interfacial Tension Gradient under Microgravity

微重力下界面张力梯度驱动液体中异物的运动

基本信息

批准号：
11450286
负责人：
MUKAI Kusuhiro
金额：
$ 9.54万
依托单位：
KYUSHU INSTITUTE OF TECHNOLOGY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B).
财政年份：
1999
资助国家：
日本
起止时间：
1999 至 2000
项目状态：
已结题

项目摘要

The behaviors of fine foreign particles in liquids (distilled water and silicone oil) with a vertical temperature were investigated under 1g and microgravity (10^<-5>g). In a drop experiment using a drop shaft of MGLAB in Toki city, water particles, which had kept falling down in silicone oil under 1g, came to a standstill as microgravity was reached when no temperature gradient existed in silicone oil. In contrast, water particles were found to move up after a very short stop as microgravity was reached when a positive temperature gradient was built up in silicone oil. The upwards velocity of the water particle show a tendency to increase with increasing radius of the particle and temperature gradient in the silicone oil.Analysis based on the previous study by our research group indicated that around the interface between particle and liquid, temperature gradient could result in interfacial tension gradient that propels particle in the direction of decreasing interfacial tension. The Dependencies of the particle velocity on the radius of the particle and the temperature gradient are also explained qualitatively based on the analysis using our previous study. In addition, this research also indicates that a much longer period of microgravity is needed in order to clarify more clearly the effect of interfacial tension gradient on the behavior of foreign particles in liquid. A parabolic flight experiment has much more feasibility for clarifying accurately the behavior of foreign particles in liquid for various kinds of systems.

在1g和微重力（10^<-5>g）条件下，研究了细颗粒在垂直温度液体（蒸馏水和硅油）中的行为。在东木市利用MGLAB滴轴进行的滴下实验中，当硅油中没有温度梯度时，在1g以下的硅油中一直持续下落的水颗粒在微重力下停止了下落。相比之下，当硅油中的温度梯度为正时，当达到微重力时，水颗粒在很短的时间内就会向上移动。在硅油中，随着颗粒半径的增大和温度梯度的增大，水颗粒的上升速度有增大的趋势。在课题组前期研究的基础上分析表明，在颗粒与液体的界面周围，温度梯度会产生界面张力梯度，促使颗粒向界面张力减小的方向运动。在前人研究的基础上定性地解释了粒子速度对粒子半径和温度梯度的依赖关系。此外，本研究还表明，为了更清楚地阐明界面张力梯度对液体中外来颗粒行为的影响，需要更长的微重力周期。抛物线飞行实验更能准确地阐明各种体系中液体中外来粒子的行为。