| Summary: | 碩士 === 明志科技大學 === 材料工程研究所 === 99 === The desulfurization process of Magnesium injection is to utilize inert gas as the carrier gas to carry desulfurization agent from the lance into molten metal and mixing with the molten metal. The inert gas, desulfurization agent and molten metal are mixed sufficiently to desulfurize. However, this is a high-temperature process and is difficult to observe the fluid flow of molten iron and mixing situation directly. Therefore, it is necessary to realize the relative physical phenomena by numerical simulation experiments.
Because the desulfurization process of Magnesium injection is a complex two-phase (gas and liquid) flow phenomena, a commercial software-FLUENT was adopted to treat the two-phase flow problem. We also built programs to analyze various indices of process evaluation. The computer simulation system is based on a PISO (Pressure-Implicit with Splitting of Operators) scheme for the solution of velocity and pressure fields. It is coupled with VOF (Volume of Fluid) techniques for the transport of volume fractions of liquid in the cells. For the treatment of surface tension effects, a CSF (Continuum Surface Force) model is employed.
The effect of process parameters, including gas flow rate, immersion depth, inner diameter and bell angle, on the various indices of evaluation was studied by the two-dimensional simulation and Taguchi methods. The simulation results showed that the optimization condition for the largest active zone is: gas flow rate at 150 Nm3/hr, immersion depth at 350 cm, inner diameter at 0.9 cm and bell angle at 45 degree. The increasing of gas flow, immersion depth and bell angle will increase the active zone and decrease the dead zone. The increasing of inner diameter will decrease the active zone and increase the dead zone.
|
|---|
