Simulation of Centrifugal Casting via STAR-Cast

In centrifugal casting processes the casting domain is rotated during the casting process. Consequently, for this type of casting process simulation, STAR-Cast solves the governing equations in a rotating coordinate system. In other words, the terms arising due to rotation, such as rotation rate, coriolis force and centrifugal force are directly modeled in the governing equations, thus solving these equations according to a coordinate system which rotates with the casting domain.

Enhanced simulation of mold filling and solidification in centrifugal casting processes relies on STAR-Cast’s multiphase approach, taking into account a pressure-dependent gas atmosphere in the mold cavity. For accurate and sharp capturing of the filling front, STAR-Cast provides the HRIC algorithm (High Resolution Interface Capturing). A so-called porous baffle boundary condition allows simulation of the pressure-dependent outflow of gas through porous mold materials.

Left: Simulation model for centrifugal casting of a cluster of 8 turbocharger wheels, including the ceramic shell mold. The melt crucible rotates with the mold.

Right: Temperature-coupled mold-filling simulation based on an accelerated rotation.

In centrifugal casting processes, mold-filling is determined by the rotation speed of the casting mold and the movement of the crucible relative to the mold:

Case 1: The crucible with liquid melt rotates with the mold. Due to the accelerating crucible, the melt experiences centrifugal and coriolis force and therefore flows out of the crucible into the mold cavity. This mold-filling or inlet-condition is exactly defined by the rotation speed and thus allows accurate modeling of mold-filling.

Case 2: The crucible is stationary relative to the rotating mold. The melt experiences an angular momentum via a boundary condition imposed on the walls of the cavity.