A transient, three-dimensional, multi-phase particle-in-cell approach is used to solve for the flow of polystyrene beads in complex three dimensional geometries which represent patterns used for lost-foam casting. The numerical method solves the gas conservation equations on an Eulerian grid and the motion of polystyrene beads is calculated in a Lagrangian frame of reference. The true particle size distribution is modeled, and the particle flow ranges from dilute to close-pack. Predicted fill behavior is compared to experimentally blown patterns using colored beads and to the measured transient filling of a pattern. The colored beads show a complex fill pattern which is calculated well by the numerical method. The transient calculation compares very well with measured video data, and the particle motion has unique particle behavior unlike a fluid. Because of uncertainties in boundary conditions in production lost-foam tooling, the sensitivity of lost-foam pattern filling to boundary conditions is examined.

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