Investigation of transport property of fibrous media: 3D virtual modeling and permeability calculation

摘要

Porous Metal Fiber Sintered Sheet (PMFSS) shows a significant potential in the development of high-performance and compact fuel cell. To achieve optimized PMFSS structural design, it is essential to evaluate permeability, i.e., the correlation between fiber structures and the transport property. To perform pre-scale simulation, a method is proposed in this research to construct 3D virtual PMFSS models using morphological features extracted from X-ray images. A length-weighted orientation method is used to evaluate the anisotropy of fiber arrangement in the through-thickness direction, and a numerical model is proposed to evaluate the flow property through the gaps between fibers. Simulation results confirm that the Forchheimer law dominates flow behavior as flow rate rises. Permeability of both the transverse and the parallel flow directions are investigated and the simulation data obtained are compared with results obtained from various sources such as the analytical equations in the literature, numerical calculations based on the Lattice Boltzmann Method (LBM) as well as material testing experiments. It is found in the comparison that the permeability results obtained in this work are consistent with the values predicted by the analytical models of layered fiber arrangement proposed by Spielman and Goren. The proposed method thus provides an efficient way of PMFSS design optimization using virtual models.