Numerical Analysis of Multiphase Flow and Post-Combustion Characteristics in a Top-Blown Converter with Various Operating Parameters

To describe the characteristics of multiphase flow and post-combustion in the converter, two separate 3D models are established in present work. The first model, known as the jet-cavity model, focuses on the interaction between oxygen jet and liquid bath, and discusses the effects of different operating parameters (lance height and operating pressure) on gas-slag-metal behavior. The results show that the impact of oxygen jet on bath surface produces rough surface waves, cavities and some metal sheets on the slag surface. Decreasing lance height or increasing operating pressure may enhance the impact of oxygen jet on molten bath. With the decrease of lance height, the penetration depth increases, while the impact diameter decreases. Increasing the operating pressure increases the penetration depth, but it has little effect on the impact diameter. The second model is called the post-combustion model, which is to describe post-combustion of CO in converter space. It is based on the cavity size (impact diameter and penetration depth) obtained by the above jet-cavity model, and analyzes the post-combustion characteristics with the single-flow post-combustion lance (SF-PCL) under different operating parameters. The results indicate that high-temperature zones and CO2 produced by post-combustion reaction are mainly located in the jet boundaries and the regions among multiple jets. Increasing lance height or operating pressure helps to burn more CO. The post-combustion ratio of converter at the lance height of 1.6 m is 1.08 and 1.04 times than that of H = 1.2 m and H = 1.4 m, respectively. When the operating pressure is 0.89 MPa, it is 1.05 and 1.03 times than that of P = 0.69 MPa and P = 0.79 MPa, respectively.