两力作用下粉尘运移速度变化规律

摘　要:

粉尘在气流中的运动受多种力的作用.将粉尘分为水平和垂直方向运动，研究在这2个方向上在重力及流体拖拽阻力作用下粉尘速度变化规律.研究结果表明，外力作用下，水平方向，在流体拖拽阻力作用下，0.0—0.2S时间段内，粉尘速度上升很快，基本接近于空气的流速，且粉尘粒径越小，粉尘趋近于风流的速度越快.在垂直方向上，粉尘在重力和阻力作用下具有沉降趋势，粉尘粒径越大，沉降的终速度越大，每一粒径都有对应的沉降终速度，对于5lμm的粉尘颗粒它的沉降终速度为0.5m/s.研究结果为更深层次研究粉尘运动动力学行为提供了理论基础.

关键词:

粉尘 受力分析 运移速度 沉降

分类号:　TD714.2

Research on the variation of dust transport velocity rules under effect of two forces

LI Yanqiang (National Institute for Occupation Safety, Beijing 100029, China)

Abstract:

The dust subjects to several forces when moving in the airflow. This paper divides the dust movement into horizontal/vertical directions, and studies the dust velocity variation rules in these two directions under the effect of gravity and fluid drag resistance force. Results show that in horizontal direction, under the fluid drag resistance force, during 0.0 - 0.2 s, the dust approaches to air velocity quickly, nearly the velocity of airflow, and the smaller the dust diameter is, the more quickly the dust is close to the air velocity. In the vertical direction, under the effect of gravity and resistance force, the dust has the tendency of sediment, and the bigger the dust diameter is, the bigger the final sediment velocity is. Each dust size has the corresponding final sediment velocity, and the final sediment velocity is 0.5 m/s for 5 μm diameter of dust. The research results have provided theoretic basis for further study of dust transport behavior.

Keyword:

dust; force analysis ; transport velocity ; sediment