Numerical simulation of capillary-induced flow in a powder-embedded porous matrix

Capillary-induced fluid motions in an isotropic powder-embedded porous matrix are studied by the Monte-Carlo simulation method. The concept of random walk and a two-block hexagonal network model are employed to accomplish the simulation procedures. The pressure field, intrinsically representing the internal collision effects among fluid particles, is correlated by the Laplace equation and can facilitate the determination of the pressure-orienteddisplacing strength, Γ, of the random walk. Also, a set of normalized random numbers on the interval (0, 1) is used to modify the displacing strength for ‘chance’ variation. Simulated conditions are selected to coincide with the practical capillary-wick debinding process in metal powder injection molding. The numerical results agree well with the theoretical and experimental ones in the literature. This shows that capillary fingering in the wicking material tends to lift the potential of the local suction malfunction of the leading front. Methods that shorten the length of the liquid column in the wick will reduce the debinding time.