Prediction of gas defects by mold-filling simulation with consideration of surface tension

• Published in: Chūzō kōgaku Vol. 76; no. 7; pp. 562 - 569
• Main Author: SAKURAGI, Takuya
• Format: Journal Article
• Language: Japanese
• Published: Tokyo Nihon Chuzo Kogakukai 01.07.2004
• ISSN: 1342-0429

The algorithm for mold-filling simulation with consideration of surface tension has been developed based on a high-accuracy numerical scheme. As the governing equations, the Navier-Stokes equations for incompressible, unsteady laminar flows were used. In this study, we proposed a way of considering surface tension in mold-filling simulation. The proposed scheme for surface tension was based on the continuum surface force (CSF) model, which is a typical model of treating surface tension as the volume force. As a test problem, squeeze casting simulation was taken up. When the physical properties of the molten metal were assumed to be the same as those of zinc alloy, we could confirm the remarkable effectiveness of the surface tension. As an application to a practical casting problem, we also applied this scheme to die-casting simulation and compared the numerical results with experimental data on the size and position of blow holes. Numerical results both with and without surface tension predicted the exis-tence of blow holes. However, it was found that simulation without surface tension tended to underestimate the size of blow holes. These numerical results confirm that the consideration of surface tension is very important for predicting the size and position of blow holes remaining in mold cavities.