兩力作用下粉塵運移速度變化規律

摘　要:

粉塵在氣流中的運動受多種力的作用.將粉塵分為水平和垂直方向運動，研究在這2個方向上在重力及流體拖拽阻力作用下粉塵速度變化規律.研究結果表明，外力作用下，水平方向，在流體拖拽阻力作用下，0.0—0.2S時間段內，粉塵速度上升很快，基本接近於空氣的流速，且粉塵粒徑越小，粉塵趨近於風流的速度越快.在垂直方向上，粉塵在重力和阻力作用下具有沉降趨勢，粉塵粒徑越大，沉降的終速度越大，每一粒徑都有對應的沉降終速度，對於5lμm的粉塵顆粒它的沉降終速度為0.5m/s.研究結果為更深層次研究粉塵運動動力學行為提供了理論基礎.

關鍵詞:

粉塵 受力分析 運移速度 沉降

分類號:　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