The pore size distribution of non-woven fibrous filter (NWFF) was characterized by inscribed sphere within 3D NWFF model created with straight fibers arranged randomly in a 3D calculation space. The size distribution of the inscribed sphere was employed as pore size distribution of the model NWFF. The effects of design parameters of NWFF, which are fiber diameter and porosity, on the pore size distribution were studied. It was shown that the pore size distribution was geometric similarity to fiber diameter. The pore size distribution curve normalized with fiber diameter was on peculiar to porosity. The number median diameter of the pore size distribution was compared with the pore sizes characterized with actual NWFFs by bubble point test, liquid permeation test, and particle challenge test. From these observations it was demonstrated that the number median diameter can be easily estimated from the porosity and fiber diameter without complex 3D simulation and it will be useful to predict the separation performance.

非织造纤维过滤器（NWFF）的孔径分布通过3D NWFF模型中的内切球表征，该模型由在3D计算空间中随机排列的直纤维创建。内接球的尺寸分布被用作模型NWFF的孔径分布。研究了NWFF的设计参数，即纤维直径和孔隙率，对孔径分布的影响。结果表明，孔径分布与纤维直径具有几何相似性。用纤维直径归一化的孔径分布曲线是孔隙率所特有的。通过泡点测试，液体渗透测试和颗粒激发测试，将孔径分布的数均直径与以实际NWFFs表征的孔径进行比较。