纤维过滤介质在容尘阶段的非稳态过滤效率

基于黏性牛顿流体的N-S方程,从一般控制方程的通用形式,结合纤维过滤介质的积尘填充率与粉尘颗粒或气溶胶微粒沉积量,推导出纤维多孔过滤介质内粒子浓度分布的非线性微分方程.分析了过滤效率经验公式中无量纲参数之间的内在联系及其对纤维滤料在容尘阶段过滤效率的影响,利用非线性回归方法拟合出纤维过滤介质的非稳态过滤效率经验公式.结果表明:微粒的Re数均小于1,即空气的流动均处于斯托克斯区域,同时其流动状态为层流;计算得到的拦截参数为0.086～0.559.根据实验结果拟合的纤维滤料在容尘阶段的过滤效率经验公式适用于St小于1的场合.

The dynamic filtration efficiency of the particle-loaded fibrous media

A nonlinear differential equation for aerosol concentration distribution of the particle loaded porous fibrous media was established based on the transport equation, N S equation in the applications for Newton viscous fluid. The general governing equation for aerosol concentration with the packing density of the particle loaded porous fibrous media was calculated by the mass deposition of dust or aerosol particle. In addition, laboratory experiments were carried out to study the close correlation among the classical dimensionless parameters and their influence on the filtration efficiency of particle loaded fibers. The empirical formulas about the dynamic filtration efficiency were developed through nonlinear regression. The experimental results show that the air flow lies in the Stokes region and in the laminar flow as the Reynolds number is less than 1. The calculated interception parameter was between 0.086 and 0.559. However, the fitted empirical formulas about the dynamic filtration efficiency can only apply to the case where Stokes number is less than 1.