The Numerical Simulation In Two-scale Porous Media LCM Containing Sink Term

This paper is supported by the National Natural Science Fund "resin in dual-scale porous fiber perform unsaturated flow mechanism and numerical simulation ". Project number:51073125Liquid composite molding process (LCM) is a low-cost technology which is suitable for the manufacture of large complex composite structure. It plays an important role in aircraft, ships and other composite materials key components. Rational selection of technological parameters and the optimization of mold design is the key to get high quality products. The method through repeated experiments to optimize the LCM parameters is not only high cost but also time-costing. So the numerical simulation of LCM mold filling process becomes indispensable for the optimization of mold design and process parameters. The wide application of reinforcing material in Composite material manufacturing industry is made of fibrous bundle weaving, stitching or knitting the fabric. Fiber bundle between the pore is far greater than the fiber bundles within single fiber between the pores, so the fabric can be regarded dual-scale porous media. When resin flows in dual-scale porous fiber perform, it first flows big pore places between fiber bundles and then flows small pores in fiber bundle. So the upstream of flow front will appear half saturation region, the filling process of resin in dual-scale porous media is a unsaturated flow process.This paper bases on the mathematical model of unsaturated flow containing sink term, uses control volume/finite element method, analyses the radial flow of the resin in the dual-scale porous fiber media at constant pressure,studies control equation algorithm, writes the computer program and obtains the pressure distribution and the saturation distribution when flow front arrives different position through some calculation examples and is compared with the single-scale porous media.The main work and achievements are as follows:1、A simple introduction of the finite element method and the interpolation function of one-dimensional linear unit and2D triangle elements as well as rectangular element.2、This paper uses volume averaging method to give the global flow control equation and the local flow control equation in dual-scale porous media.3、This paper focuses on the simulation of resin in the disc-shaped mold filling process under isothermal conditions.and uses finite element method to solve resin pressure distribution at any time, uses a control volume method to track the resin flow front position at any time and resin saturation distribution,as well as writes MATLAB procedures based on the finite element control volume and is compared with single scale porous media.4、The results show that:in the dual-scale porous medium, the resin flow zone near the flow front exists half-saturation region, and the location of half-saturation moves with the movement of the flow front, but the width remains unchanged; when the flow front radius is the same, dual-scale porous media flow field pressure distribution is smaller than in the single-scale porous medium.