Molten slag is broken up by supersonic air into droplets through the air quenching dry slag granulation technique. The breakup process of blast furnace slag directly determines the droplet diameter and the waste heat recovery. In order to gain deep insight into the granulation mechanism and visualize the breakup process, three-dimensional unsteady numerical simulation based on the k-ω based shear stress transport turbulence model was conducted to simulate the transient breakup process of molten slag (k is the turbulent kinetic energy, and ω is the specific dissipation rate). The coupled level-set and volume-of-fluid method was utilized to capture the sharp air–liquid interface. The results show that a flat film is formed firstly under the effects of air impingement, recirculation zone and pressure gradients. Then, the axial wave and the spanwise wave appear simultaneously and the film is broken up into ligaments owing to the generation of vortex and hole structure at the intersection of axial trough and spanwise trough. Finally, the ligaments are broken up into droplets owing to Rayleigh–Taylor instability at the air–liquid interface. The droplets smaller than 3.00 mm account for 80%, with the average diameter of 1.95 mm.

通过空气淬火干渣造粒技术，超音速空气将熔渣分解成液滴。高炉矿渣的破碎过程直接决定着液滴直径和废热回收率。为了深入了解造粒机理并可视化破碎过程，基于基于k - ω的剪切应力传递湍流模型进行了三维非稳态数值模拟，以模拟熔渣的瞬时破碎过程（k为湍流）。动能和ω是特定的耗散率）。利用液位和液位的耦合方法来捕获尖锐的气液界面。结果表明，首先在空气冲击，回流区和压力梯度的作用下形成了平膜。然后，轴向波和翼展波同时出现，并且由于在轴向波谷和翼展波谷的相交处产生涡流和孔结构，膜破裂成韧带。最后，由于气液界面处的瑞利-泰勒不稳定性，韧带破裂成液滴。小于3.00毫米的液滴占80％，平均直径为1.95毫米。