Mixtures of granular materials made of different-sized particles may segregate when subjected to vibration or shear rate and in the presence of a gravitational field. This leads to highly inhomogeneous mixtures, which are undesirable in many industrial processes. This work focuses on size-driven segregation in polydisperse mixtures. We described the evolution of the particle size distribution through a Population Balance Equation (PBE), which we solved numerically with the Direct Quadrature Method of Moments. To allow segregation and micromixing to occur, we closed the size-conditioned velocity of the particles with a segregation-remixing model. The PBE was then included in an Eulerian-Eulerian model and solved in a commercial Computational Fluid Dynamics (CFD) code. We used the model to study granular flows down inclined planes. The numerical results were then compared with those obtained from Discrete Element Method simulations. The CFD-PBE model predicts well segregation and micromixing in packed beds of polydisperse powders.

当受到振动或剪切速率以及存在重力场时，由不同尺寸颗粒制成的颗粒材料的混合物可能会分离。这导致高度不均匀的混合物，这在许多工业过程中是不希望的。这项工作的重点是多分散混合物中尺寸驱动的分离。我们通过种群平衡方程 (PBE) 描述了粒度分布的演变，我们使用矩的直接正交法对其进行了数值求解。为了允许发生分离和微混合，我们用分离-再混合模型关闭了颗粒的尺寸条件速度。然后将 PBE 包含在欧拉-欧拉模型中，并在商业计算流体动力学 (CFD) 代码中求解。我们使用该模型来研究倾斜平面上的颗粒流。然后将数值结果与从离散元方法模拟中获得的结果进行比较。CFD-PBE 模型预测多分散粉末填充床中的井离析和微混合。