Numerical Simulation of Seepage Phenomenon in Metal Powder Injection Filling

In metal powder injection filling, seepage occurs when the velocity of the metal powder phase is zero at the regions of high volume fraction of the powder phase. However, the seepage phenomenon has not been simulated. The two-phase fluid mathematical model can be used for the simulation of the seepage. However, the viscosity of the powder phase and coefficient of interaction due to velocity difference between the two phases were considered to be the same at the regions of high and low volume fraction of the powder phase in the previous studies. The strong interaction within the powder phase and the strong momentum exchange between the two phases when the seepage occurs can not be accurately simulated by the simplified model, and the seepage phenomenon can not be simulated. In this work, a method is proposed to simulate the seepage phenomenon by modelling the viscosity of the powder phase and the interaction coefficient. The injection filling in the contracted rectangular pipe is simulated by using the proposed method. The results show that seepage occurs in the contraction region. It can also be found that the seepage phenomenon causes the inhomogeneous distribution of the volume fraction of the powder phase.