Chernyakov A L, Kirsch A A, Kirsch V A
National Research Center Kurchatov Institute, Kurchatov Square 1, 123182 Moscow, Russia.
Phys Rev E Stat Nonlin Soft Matter Phys. 2011 May;83(5 Pt 2):056303. doi: 10.1103/PhysRevE.83.056303. Epub 2011 May 4.
The excitation of sound vibrations of a cylindrical fine fiber due to the impact of a spherical aerosol particle is investigated. The equations describing the dynamics of impact are derived for an arbitrary shooting parameter. The coefficient of restitution is calculated, and its analytical approximation is obtained. It is shown, for the case of long fibers, that the coefficient of restitution depends upon a single parameter λ(c). The parameter λ(c) depends on the particle radial velocity component near the fiber surface, the mass of the particle, the density of the fiber, the modulus of elasticity, and the geometric parameters of the fiber and the particle. The inertial deposition of submicron aerosol particles on fine fibers in a filter is considered. The efficiency of filtration is studied as a function of the gas flow velocity. The existence of a critical flow velocity U(*), below which the losses of particle energy during collision have no effect on the efficiency, is demonstrated. For velocities higher than the critical velocity, the filtration efficiency is dependent on the mechanisms of nonelastic losses of the particle's energy. Its value can be significantly lower than that estimated when particle rebound effects are neglected. After they have rebounded, some particles are not able to attain the initial high velocities in the stream, thus depositing on neighboring fibers. The dynamics of these particles is investigated. For this case, it is shown that the filtration efficiency is dependent on the velocity distribution of the rebounded particles and that it increases with the packing density of fibers. A qualitative difference between the asymptotic behavior of a fiber and that of a flat plate is found long after the initial impulse.
研究了球形气溶胶颗粒撞击圆柱形细纤维时，细纤维声振动的激发情况。针对任意射击参数，推导了描述撞击动力学的方程。计算了恢复系数，并得到了其解析近似值。结果表明，对于长纤维的情况，恢复系数取决于单个参数λ(c)。参数λ(c)取决于纤维表面附近颗粒的径向速度分量、颗粒质量、纤维密度、弹性模量以及纤维和颗粒的几何参数。考虑了亚微米气溶胶颗粒在过滤器中细纤维上的惯性沉积。研究了过滤效率作为气流速度的函数。证明了存在临界流速U(*)，低于该临界流速时，碰撞过程中颗粒能量的损失对效率没有影响。对于高于临界速度的流速，过滤效率取决于颗粒能量的非弹性损失机制。其值可能显著低于忽略颗粒反弹效应时的估计值。一些颗粒反弹后，无法在气流中达到初始的高速度，从而沉积在相邻的纤维上。研究了这些颗粒的动力学。对于这种情况，结果表明过滤效率取决于反弹颗粒的速度分布，并且随着纤维的堆积密度增加而增加。在初始冲击很久之后，发现了纤维和平板渐近行为的定性差异。
