Papers by Author: Jing Hao

Abstract: Level Set Method is an appropriate mathematical tool for solving two-phase flow problems. The main advantage of Level Set Method is its efficiency to deal with complex interfaces, even if topology changes. In this paper, the liquid-gas two-phase flow is simulated using a combination of Level Set Method and SOLA method. SOLA is used to compute the Navier-Stokes equation, and Level Set Method is used to track the interfaces between the liquid and the gas during mold filling process. The difficulty in the simulation of two-phase flow comes from great change of physical parameters (e.g., density and viscosity) across the interfaces. Level Set Method allows for large density ratio and jump in viscosity without reconstructing the numerical grid. In this work, the forming and moving of the gas bubbles in liquid were numerically simulated by Level Set approach. The numerical simulation results and experiments suggest that Level Set Method is quite reliable and effective for the simulation of liquid-gas two-phase flow during mold filling.

Abstract: The heat transfer during the casting solidification process includes: the heat radiation of the high temperature casting and the mold, the heat convection between the casting and the mold, and the heat conduction in the casting and the casting to the mold. In this paper, a formula of time step in simulation of solidification is derived, considering the heat radiation, convection and conduction based on the conservation of energy. The different heat transfer condition between the ordinary sand casting and the permanent mold casting is taken into account in this formula. The characteristic of heat transfer in the interior and surface of the casting is also considered. The numerical experiments show that this formula can avoid radiation of the computation, and can improve the computational efficiency about 20% in the simulation of solidification process.