Particulate Scale Computational Fluid Dynamics-Discrete Element Method Modeling on Raceway Evolution Process with Coke Mass Consumption

In this article, the coupled computational fluid dynamics-discrete element method is used to numerically simulate the evolution of the blast furnace raceway from particulate scale. This study systematically analyzes the motion characteristics, particle size distribution, and inter-particle contact behavior of coke particles during raceway evolution. The results indicate that airflow within the raceway induces a cyclonic motion of the coke, while a stagnant zone forms at the center of the raceway. As blowing time increases, the proportion of coke particles sized 0.6–1.2 mm grows, particularly for particles around 0.9 mm. Particle stratification is observed at the edges of the raceway, with the highest degree of densification occurring in the “bird's nest” structure facing to the tuyere. After the raceway stabilizes, this region exhibits a void ratio of 0.4. Additionally, the inter-particle contact force in the coke bed decreases from 100 to 10 times the particle gravity, eventually forming force chains in the dead stock region. Meanwhile, particles with low coordination numbers are predominantly located within the cavity and along the edges of the raceway, suggesting a higher degree of fluidization of coke particles at the raceway boundaries. These findings have significant theoretical implication for optimizing blast furnace operations.