重力场作用下微粒在静止流体中的沉降特性

Settlement characteristics of micro- particles under the action of gravity in still fluid

中文关键词: 微尺度  粒子  沉降  输运过程  输运系数  全息光学实验系统

英文关键词: microscale  particle  sedimentation  transport process  transport coefficient  digital holographic optical system

中文摘要:

      论文建立了微米级颗粒物在静止流体中运动的物理模型和几何模型,通过分析颗粒物的受力情况,得到其运动速度的解析解。结果表明：微粒在静止流体中的运动速度是微粒物理属性(密度、粒径)和流体物理属性(密度,粘度)的函数,其运动包括加速段和匀速段,固液密度比大,其输运速度更快。根据该结果,结合菲克定律的经典表达式得出了净输运颗粒通量进而得出颗粒物的输运系数表达式,结果表明：微粒在静止流体中的输运系数是浓度,速度的函数。小颗粒物的输运现象较大颗粒更强烈。论文还通过全息光学实验系统建立实验模型与理论结果进行比较,结果表明二者吻合良好。

英文摘要:

      The physical and mathematical model were set up to research the settlement character of micro- particles under the action of gravity in still fluid in this paper.After analyzing the forces acting on micro-particles, the analytic solutions of velocity was obtained.It shows that the velocity of micro-particles in static water is the function of physics properties of micro-particles( diameter and density) and physics properties of fluid(density and viscosity). The motion process consists of accelerating section and uniform section, for larger ratio of density of the solid and liquid, its velocity is much larger . Based on the results, combined with the Fick Law, the net flux of a control-volume in the flow field and the transport coefficient can be obtained. It shows that the transport coefficient is the function of density and velocity, the transport phenomena of smaller particles are more strong. With the digital holographic optical system, the experimental model is set up to test and verify the theoretical solutions. It shows that there is quantitatively agreement between them.