CFD-DEM模拟颗粒形状对流化床二元颗粒混合特性的影响

CFD-DEM Simulation of Influence of Particle Shape on Binary Particles Mixing Characteristics in Fluidized Bed

用计算流体力学耦合离散元方法(CFD-DEM)对Goldschmidt等建立的矩形流化床床内气固混合特性进行三维数值模拟,采用欧拉体系k-ξ湍流模型模拟气相,采用拉格朗日体系离散元方法模拟固相,引入Lacey混合指数作为量化标准,研究了垃圾衍生燃料颗粒形状对混合的影响.结果表明,圆柱状颗粒的混合质量比同体积当量比的球形颗粒差,且达到混合平衡所需时间较长,垃圾衍生燃料颗粒轴向浓度分布在床层上部高于底部.

Three-dimensionally combined computational fluid dynamics （CFD） with discrete element method （DEM） were employed to investigate the gas-solid mixing characteristics of referring to the 3D rectangular fluidized bed explored by Goldschmidt et al. Eulerian turbulent model and Lagrangian particle tracking method were used to model the gas and solid phases respectively. Focused on the influence of the shape of refuse derived fuel （RDF） particle on mixing was investigated, and the Lacey mixing index was introduced as a quantitative criterion. The results showed that the mixing quality of cylindrical particles is less than that of spherical particles with the same volume equivalence ratio and the time required reaching the mixing equilibrium is longer. The distribution of the RDF particle concentration in the bed upper part is higher than the bottom.