Abstract: Liquid film formation is an important part of the air quenching dry slag granulation process and the granulation effect of slag depends on the film flow characteristics. To investigate the flow behavior of slag and the effects of different operating parameters and slag properties on the film flow characteristics, a three-dimensional unsteady numerical model was established using k?? based shear stress transport (k?? SST) turbulence model and the coupled level-set, and the volume of fluid (CLSVOF) method was utilized to capture the sharp air?liquid interface. The film formation mechanism and the influence of different operating parameters and slag properties on the film flow characteristics were discussed. Also, dimension analysis of the film edge thickness was conducted. The results indicate that the flat film was formed because of flow deformation due to air impingement, recirculation zone, and pressure gradients. An unstable wave appeared on the film surface owing to the gas?liquid velocity difference. The wavelength of surface wave decreased first and then increased along the axis, and the film thickness gradually decreased along the axis. The wavelength of surface wave and the film thickness decreased with the increasing airflow velocity and increased with the rise in slag mass flow rate. The wavelength of surface wave and film thickness decreased with the increasing slag density and increased with the rise in slag viscosity. A dimensionless was developed which indicates that the film thickness had exponent relation to the airflow velocity, slag mass flow rate, slag density, and viscosity.

Key words: Slag granulation, air quenching, liquid film, flow characteristic, CFD

摘要： 基于k?? SST湍流模型，采用CLSVOF方法，对气淬粒化过程中熔渣的流动行为进行数值模拟，研究了熔渣液膜形成机理和不同操作参数及熔渣物性对液膜流动特性的影响，并对液膜边缘厚度进行量纲分析。结果表明，熔渣在气动力、回流区及压力梯度的共同作用下，流动变形形成扁平液膜；由于气?液速度差液膜表面出现不稳定表面波；液膜表面波波长沿轴向先减小后增加，厚度沿轴向逐渐减小；表面波波长及液膜厚度随气流速度增加而降低，随熔渣质量流量增加而升高；表面波波长及液膜厚度随熔渣密度增加而降低，随熔渣黏度增加而升高；得到的无量纲关系式表明，液膜边缘厚度与气流速度、熔渣质量流量、熔渣密度和黏度呈指数关系。

关键词: 高炉渣粒化, 气淬, 液膜, 流动特性, CFD