Spheronization process particle kinematics determined by discrete element simulations and particle image velocimentry measurements.
Spheronization process particle kinematics determined by discrete element simulations and particle image velocimentry measurements.
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通过离散元模拟和颗粒图像速度测量确定滚圆过程颗粒运动学。
DOI：
10.1016/j.ijpharm.2014.10.007
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发表时间：
2014
影响因子：
5.8
通讯作者：
M. Thommes
中科院分区：
文献类型：
--
作者：
Martin Koester;R. García;M. Thommes
球化是一种重要的医药生产技术，可生产直径0.5-2 mm的球形团块。这些颗粒具有狭窄的尺寸分布和球形。在球化过程中，挤压出的柱状丝在变形和摩擦/团聚机制下断裂成短柱状，由柱状演变成球形。采用离散元方法，建立了一个完整的模型-实验框架，以捕捉球化过程中的粒子运动。模拟结果与单分散球形和干燥γ- al2o3颗粒图像测速（PIV）实验结果进行了直接比较和验证。结果表明，颗粒的速度比摩擦片的旋转速度慢约三倍，具有典型的环面流型。确定了控制球化过程的五个特征区：区I，颗粒受到剪切力，有利于摩擦并为团聚过程提供材料；II区，静壁有助于粒子间的质量交换；III区，引力与粒子运动相结合，导致粒子与运动板块碰撞，重新进入I区；IV区，当与摩擦板结构接触时，其中的一小部分颗粒被喷射到空气中；在V区，低极向速度有利于停滞的粒子群，完全由批量大小控制。这些对颗粒运动的新见解正在导致更深层次的过程理解，例如，负载和转速对颗粒形成动力学的影响。这可能有利于制造过程的优化以及新配方的开发。
Spheronization is an important pharmaceutical manufacturing technique to produce spherical agglomerates of 0.5–2 mm diameter. These pellets have a narrow size distribution and a spherical shape. During the spheronization process, the extruded cylindrical strands break in short cylinders and evolve from a cylindrical to a spherical state by deformation and attrition/agglomeration mechanisms. Using the discrete element method, an integrated modeling-experimental framework is presented, that captures the particle motion during the spheronization process. Simulations were directly compared and validated against particle image velocimetry (PIV) experiments with monodisperse spherical and dry γ-Al2O3particles.Resultdemonstrate a characteristic torus like flow pattern, with particle velocities about three times slower than the rotation speed of the friction plate. Five characteristic zones controlling the spheronization process are identified: Zone I, where particles undergo shear forces that favors attrition and contributes material to the agglomeration process; Zone II, where the static wall contributes to the mass exchange between particles; Zone III, where gravitational forces combined with particle motion induce particles to collide with the moving plate and re-enter Zone I; Zone IV, where a subpopulation of particles are ejected into the air when in contact with the friction plate structure; and Zone V where the low poloidal velocity favors a stagnant particle population and is entirely controlled by the batch size.These new insights in to the particle motion are leading to deeper process understanding, e.g., the effect of load and rotation speed to the pellet formation kinetics. This could be beneficial for the optimization of a manufacturing process as well as for the development of new formulations.
影响因子：
5.3
作者：
Fan Li;Jingzhe Pan;C. Sinka
通讯作者：
Fan Li;Jingzhe Pan;C. Sinka