The finite element simulation of filling thin section cavities has been studied in the present research, with an emphasis on the casting application. This thesis describes the development of appropriate governing equations for filling thin section cavities and finite element analysing software used to simulate some selected filling examples as case studies. As the transverse velocity profile across a thin section can be approximated between the parabolic and plain distributions, the flow throughout the cavity can be represented by in-plane velocity components and simulated using a quasi three-dimensional formulation. By applying an appropriate velocity profile and accounting for any thickness variation, the governing filling formulation was derived using the conservation laws of mass, momentum and free surface, which produced the thickness-integrated continuity, Navier-Stokes and pseudo-concentration equations, respectively. Appropriate transformations were incorporated into the thickness-integrated Navier-Stokes equations to accommodate the three-dimensional form of the cavity. Since surface tension also affects the flow in thinner sections, a study on the inclusion of this topic was also included. The finite element flow formulation was constructed by discretising the governing equations spatially and temporally using the conventional Galerkin method and the implicit backward difference method, respectively, and was solved via a mixed formulation. This was found to be the best approach for the cavity having thickness changes. For free surface tracking, the explicit Taylor-Galerkin method was used to discretise the pseudo-concentration equation since it gave more accurate results. This filling simulation model was applied to three case studies, where the numerical results were compared with the experimental data for the benchmark gravity sand casting as gathered by other researchers, a cylindrical shaped cavity in the laboratory and a high pressure die casting in the foundry. Good agreement was obtained in each case.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:635834 |
| Date | January 1997 |
| Creators | Abdullah, S. |
| Publisher | Swansea University |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
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