The FSI Simulation Between Hot Metal Flow and the Hearth of a Blast Furnace During Opening Stage of Tapping

The start-tapping stage is the most unsteady stage for hearth operation in a blast furnace; this causes highly alternating stress in the hearth brickwork, which disrupts the design and operation of the blast furnace. In this paper, the fluid–structure interaction (FSI) model to simulate the interaction between the metal–slag–air mixture flow and hearth refractory during the start-tapping stage is established to study the magnitude and vibration type of the stress caused by tapping flow. The following conclusions are obtained: In 0.86 s after the start of tapping, the area where the velocity of molten iron exceeds 0.04 m/s is expanded to one quarter of the free area. The pressure in the tapping hole drops sharply, and the rate exceeds 1 MPa/s, which has a great impact on the refractory around the tapping hole. In the tapping hole and around the furnace, there is a vortex with a period of 0.07 s, which causes the fluctuation of hot metal in the hearth. During the start-tapping stage, the highest tensile stress of 2.78 MPa in the hearth occurs at the corner of the hearth ceramic cup. The highest compressive stress of 1.94 MPa in the hearth occurs at the upper layer of the bottom carbon brick. The tensile stress or compressive stress in the hearth vibrates with a cycle of 0.07 s.