Study of Flow Behaviour in Vertical Centrifugal Casting

Abstract In centrifugal casting processes, flow of fluid layers determines the quality of the cast. However flow visualization is not possible, as mould and molten metal are opaque in nature. Therefore many research workers have resorted to understand the flow visualization process by carrying out simulation studies. Literature survey indicates that earlier investigators have studied the melt flow in horizontal centrifugal casting process by conducting cold modeling experiment using horizontal transparent mould and fluids of different viscosity. However it appears that there is no published information available in the area of influence of various parameters in the case of vertical centrifugal casting process. Therefore in this research work the cold modeling experimentation on fluids of different viscosity like water, Glycerin and SAE 90 rotated in a transparent mould at a constant room temperature had been conducted with an objective of understanding the influence of rotational speed and aspect ratio on flow patterns of different fluids subjected to vertical axis rotation. Later the flow behavior had been studied by numerical simulation through Ansys fluent software. Further for the purpose of comparison, casts of paraffin wax at different rotational speeds had been obtained and the trend of variation of the lift with the variation of rotational speed had been compared with the trend predicted using cold modeling studies and using Ansys software. From cold modeling studies it can be concluded that of the dimensional accuracy of fluid cylinder in terms of lift had been increased with increase in viscosity. The possibility of formation of complete fluid cylinder increases with increase in rotational speed and mould diameter. Howvere, at aspect ratio of 1.0 the formation of complete fluid cylinder had not been obtained.The trend of result observed in CFD study was found to be similar to the trend of results observed in cold modeling study. The study of actual paraffin cast confirmed the result obtained in cold modeling and CFD.