Solidification is a complex heat transfer process accompanying with phase change. It widely appears in engineering practice, like the casting, metallurgy and so on. Recently, a new technique to produce steel ingot is advanced in which the hollow of core is resided. In such a case, the shape, the position and the speed of the advancement of the interface between phases become important to realize the technique and to guarantee the quality of the product. In the present paper, a new model is advanced to simulate the process in which the heat conduction, molten convection, radiation and phase transition are all taken into consideration. Numerical simulation for a 6 ton steel ingot (Fe-C alloy) with the size of Φ 0.685m × 2.1m was performed. From the results of simulation it is known that: at the primary stage of solidification, the temperature of the molten liquid near the cooling side walls drops down gradually. Thus the natural convection occurs in the whole region. It enhances the heat transfer in the system, thus to accelerate the solidification speed. As the time goes on, the averaged temperature of the molten liquid tends to be closer and closer to the melting point of the metal, thus the natural convection in the system turns weaker and a solid shell is formed. The front surface of the solid phase moves toward the center and upward from the bottom. In the paper, the vectorial field of the flow of the melt and the distribution of the isotherms are shown along with evolution of the process. In addition, the advancement of the interface is also shown for different evolution time.
展开▼
