Gas top-blowing technology is widely employed in the metallurgical industry to enhance gas–liquid two-phase mixing, thereby improving heat and mass transfer efficiency. However, this technology faces several challenges, including unstable flow, excessive splashing, and severe wall erosion. To address these issues, this study applies the coupled level set and volume of fluid (CLSVOF) method to investigate the macroscopic flow dynamics and droplet splashing in a three-dimensional gas–liquid system under top-blowing conditions. Using a validated model, a comprehensive analysis is conducted to assess the effects of gas blowing speed, lance immersion depth, and lance diameter on gas–liquid dynamics, turbulence characteristics, and liquid splashing. The results reveal that cavity depth increases with gas speed but decreases with larger lance diameters. Both radial and axial fluid velocities increase with higher gas speeds and larger lance diameters. Fluid dynamic pressure and turbulent viscosity fluctuations are prominent in the bubble movement region, with dynamic pressure in the central area increasing with gas blowing speed, lance immersion depth, and lance diameter. Vortices are observed in both the bubble movement and droplet splashing regions, with the latter showing the largest vortex area. Droplet distribution frequency is highest in the central region and decreases axially above the liquid surface. The Weber, Froude, and Reynolds numbers of the droplets increase with gas velocity. Additionally, the Reynolds and Weber numbers rise with increasing droplet size, but their frequency distribution declines when the droplet diameter exceeds 0.011 m. A positive correlation exists between the Weber and Froude numbers and the Reynolds number, while the Capillary and Bond numbers are positively correlated with the Weber number. Furthermore, gas speed, lance immersion depth, and lance diameter are positively correlated with the total volume of splashing droplets, with lance immersion depth exerting the greatest influence on droplet splashing. These findings provide valuable insights for optimizing gas top-blowing processes to enhance operational stability and efficiency.
