稀释体系气溶胶粒子近壁动力特性及壁面影响

Dynamics of wall-adjacent aerosol particles in a dilute system and wall effect

以极端稀释气溶胶体系中单个粒子为研究对象,建立了考虑受重力浮升力、表面势力和布朗热动力作用的运动控制方程,运用布朗动力学方法数值模拟了近壁处气溶胶粒子的动力特性规律.结果表明,壁面之上一定范围内(约50个气溶胶粒子半径)存在一个壁面影响区,区域中气溶胶粒子的动力特性有别于无界大空间中的气溶胶粒子,且其厚度远大于壁面对粒子作用力的范围(约1个粒子半径).最后讨论了不同表面特性、不同粒子半径时壁面影响区的变化规律.

The trajectory function of a single aerosol particle in a dilute gas system close to a wall was theoretically studied with consideration of different forces such as gravity-buoyancy, particle-wall interaction and Brownian force. The results indicate that there is a wall effect layer in which the particle shows a different dynamic characteristic from that in unlimited space. The wall effect layer is about 50 radii of the particle, which is much higher than the effective range of particle-waU interaction, about 1 radius. Finally, associated discussion was made to understand the effects of surface characteristic and particle size on the wall effect layer.