Simulation of non-Newtonian fluid seepage into porous media stacked by carbon fibers using micro-scale reconstruction model

Abstract

Ceramic matrix composite of carbon fiber framework reinforced by silicon carbide (Cf/SiC) is a new material with excellent properties. In order to improve its preparation process, the flow of polycarbosilane solution in carbon fiber is studied based on the computational fluid dynamics method. CT images of carbon fiber porous media are obtained by Micro-CT imaging technology and optimized by means of ImageJ software. The 3D solid matrix and pore space models of carbon fiber porous media are established by using Mimics software, and the pore space model is meshed. Using the computational fluid dynamics software Fluent, the VOF multiphase flow model is adopted, the surface tension model and contact angle model are introduced considering the micro-pore effect of porous media, and a suitable mathematical model for the transport of gas–liquid two-phase flow in carbon fiber porous media is established. The validity of CFD mathematical model is verified by comparing experimental data with simulation results. Based on the CFD simulation results, the effects of feed pressure, surface tension coefficient and contact angle on fluid flow are studied. It is found that the larger the feed pressure and contact angle, the more uniform the distribution of liquid phase, pressure and velocity in the medium, which is conducive to the flow of liquid phase in porous media. The larger the surface tension coefficient, the longer the breakthrough time of liquid, and the more uneven the liquid distribution. This study is helpful to understand the law of fluid transport in porous media and provides theoretical basis for the preparation of Cf/SiC composites.