Computational Fluid Dynamics Simulation on Particulate Distribution in Gyro Casting for the Manufacture of Al/SiC Particulate Metal Matrix Composite

The enhanced specific strength of SiC Particulate Metal Matrix Composites (PMMC) has been the major contributing factor which helps to find applications in the aerospace and automotive industries. Uniform distribution of the particulates in PMMC controls the attainment of better mechanical properties. The most accepted method for producing such a composite is stir casting in which the homogeneity of particulate reinforcement is a significant challenge. This research work proposes a new method for mixing the particulate reinforcement with the liquid and semi-solid aluminium matrix to ensure a uniform mix of the particulates using a gyro shaker. Gyro shaker is a dual rotation mixer commonly used for mixing high viscous fluids. It rotates about two mutually perpendicular axes which help in thoroughly mixing of the ingredients. Developed Computational Fluid Dynamics (CFD) simulation model of the mixing device in finding the mixing performance while mixing SiC particulates with glycerol. The results of the simulation were also validated by experimentation. Analogue fluid simulation of gyro casting was carried out using water and glycerol/water mixture which are having a closer value of viscosity as that of liquid aluminium and semi-solid aluminium. The mixing time obtained in the water system at gyration speeds of ۲۹.۶۳ rpm, ۵۸.۱۸ rpm, ۷۲.۷۳ rpm and ۸۷.۲۷ rpm was ۶۱.۸۴ sec, ۴۳.۴۴ sec, ۲۶.۸۵ sec and ۲۷.۲۴ sec respectively. The mixing time obtained in glycerol/water system at gyration speeds of ۵۸.۱۸ rpm, ۸۷.۲۷ rpm, ۱۱۶.۳۶ rpm and ۱۴۵.۴۵ rpm was ۲۶.۳۴ sec, ۱۵.۹۷ sec, ۹.۸ sec and ۶.۲۶ sec respectively. The distribution of the SiC particulates obtained from simulation was compared with stir casting simulations. The homogeneous distribution of particulates was observed in the gyro casting simulation.

Keywords:

Gyro casting , Computational fluid dynamics , Mixing power , Stir casting , Grid independence study , Mixing index