Modelling the dynamics of the tilt-casting process and the effect of the mould design on the casting quality
Wang, H., Djambazov, G., Pericleous, K.A., Harding, R.A. and Wickins, M. (2011) Modelling the dynamics of the tilt-casting process and the effect of the mould design on the casting quality. Computers & Fluids, 42 (1). pp. 92-101. ISSN 0045-7930 (doi:10.1016/j.compfluid.2010.11.010)Full text not available from this repository.
All titanium alloys are highly reactive in the molten condition and so are usually melted in a water-cooled copper crucible to avoid contamination using processes such as Induction Skull Melting (ISM). These provide only limited superheat which, coupled with the surface turbulence inherent in most conventional mould filling processes, results in entrainment defects such as bubbles in the castings. To overcome these problems, a novel tilt-casting process has been developed in which the mould is attached directly to the ISM crucible holding the melt and the two are then rotated together to achieve a tranquil transfer of the metal into the mould. From the modelling point of view, this process involves complex three-phase flow, heat transfer and solidification. In this paper, the development of a numerical model of the tilt-casting process is presented featuring several novel algorithm developments introduced into a general CFD package (PHYSICA) to model the complex dynamic interaction of the liquid metal and melting atmosphere. These developments relate to the front tracking and heat transfer representations and to a casting-specific adaptation of the turbulence model to account for an advancing solid front. Calculations have been performed for a 0.4 m long turbine blade cast in a titanium aluminide alloy using different mould designs. It is shown that the feeder/basin configuration has a crucial influence on the casting quality. The computational results are validated against actual castings and are used to support an experimental programme. Although fluid flow and heat transfer are inseparable in a casting, the emphasis in this paper will be on the fluid dynamics of mould filling and its influence on cast quality rather than heat transfer and solidification which has been reported elsewhere.
|Uncontrolled Keywords:||tilt-casting, mould design, 3-D computational model|
|Subjects:||Q Science > QA Mathematics > QA75 Electronic computers. Computer science|
T Technology > TN Mining engineering. Metallurgy
|School / Department / Research Groups:||School of Computing & Mathematical Sciences|
School of Computing & Mathematical Sciences > Centre for Numerical Modelling & Process Analysis
School of Computing & Mathematical Sciences > Department of Mathematical Sciences
|Last Modified:||17 Sep 2013 11:04|
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