Electret filter media are nonwovens with electrostatically charged fibers and are commonly applied for separation of fine particles from gases. However, the distribution of the electrostatic charge on the fiber surfaces - which dependens on the applied charging method - could not be completely clarified so far. The aim of this work is to determine the amount of electrostatic charge and its distribution in the porous structure of the nonwoven by comparison of experiments and 3D DirectNumerical Simulations coupling the gas flow and electrostatic field to the particle movement.

As example, corona and triboelectrically charged filter media were investigated. The charge distributions on the fibrous structure were estimated by comparison of the numerically and experimentally obtained fractional deposition efficiencies. Furthermore, the simulations showed that different charge distributions led to significant differences in the fractional deposition efficiency up to 15 %, even if the amount of charge and the area ratio of positive and negative charges were constant.

驻极体过滤介质是带有静电纤维的非织造布，通常用于从气体中分离细颗粒。然而，到目前为止，尚不能完全弄清纤维表面上的静电荷分布，这取决于所应用的充电方法。这项工作的目的是通过比较实验和将气流和静电场耦合到粒子运动的3D DirectNumerical Simulations（3D直接数值模拟）的比较，确定无纺布多孔结构中的静电荷量及其分布。

例如，研究了电晕和摩擦带电的过滤介质。通过比较数值和实验获得的分数沉积效率，可以估算纤维结构上的电荷分布。此外，模拟表明，即使电荷量以及正负电荷的面积比恒定，不同的电荷分布也会导致分数沉积效率出现显着差异，最高可达15％。