Mechanical dispersion of viscous liquids in sheared particulate systems

1236633PI: Wassgren这个研究项目的重点是提高对液体通过颗粒-颗粒接触转移的理解，通常被称为？机械分散?在微粒系统中。特别是，该项目旨在通过开发(1)研究颗粒系统中液体空间分布的新实验方法和(2)用于预测更复杂的工业相关制造设备中液体分散的实验验证计算模型，提高我们对这些系统的科学方法、理解和定量预测能力。实验将使用x射线断层扫描方法进行，因此保留了机械分散过程的液体空间分布和时间演变。这些原位测量不同于文献中报道的，这些文献通过从实验装置中去除颗粒来评估液体分散过程的演变。实验验证的计算模型将模拟剪切系统中粒子的动力学，考虑粒子间的接触和液桥的影响。连接两个或两个以上粒子的在许多工业过程中，粘合剂或涂层剂（如液体或固体材料）分散到颗粒上是很常见的。例如，在制药工业中，这种机制用于将非活性成分和活性成分粉末组合成颗粒，然后用于制造片剂或胶囊。大多数以前的工作都集中在涉及液体涂层的系统上，这些系统干燥迅速，并且不会在颗粒之间显著转移。通过机械分散的液体转移很少被研究，这是不幸的，因为在许多工业过程中，涂层液体太粘稠而无法喷射，因此，被倒在粉末床上并通过颗粒接触分散。目前，这些系统的设计和优化是通过试错来进行的，这导致了大量的开发时间、材料损失和潜在的产品有效性降低。本研究目标的成功完成将大大提高我们对颗粒系统中液体机械分散过程的理解，以及我们定量预测和设计机械分散驱动系统操作的能力。

1236633PI: Wassgren This research project focuses on developing an improved understanding of the transfer of liquid through particle-particle contacts, often referred to as ?mechanical dispersion?, in particulate systems. In particular, this project seeks to improve our scientific methodology, understanding, and quantitative predictive ability of these systems by developing (1) a novel experimental approach for investigating the spatial distribution of liquid in particulate systems and (2) an experimentally validated computational model for predicting the liquid dispersion in more complex, industrially relevant manufacturing equipment. The experiments will be performed in-situ using an x-ray tomography method, therefore retaining the liquid spatial distribution and time evolution of the mechanical dispersion process. These in-situ measurements differ from those reported in the literature, which assessed the evolution of the liquid dispersion process by removing particles from the experimental device. The experimentally validated computational model will simulate the dynamics of particles in a sheared system, taking into account inter-particle contacts and the effects of the liquid ?bridge? joining two or more particles. The dispersal of a binding or coating agent, such as a liquid or solid material, onto particles is commonplace in many industrial processes. In the pharmaceutical industry, for example, such a mechanism is used to combine inactive and active ingredient powders into granules, which are then used to make tablets or capsules. Most previous work focused on systems involving liquid coatings that dry quickly and do not transfer significantly from particle to particle. The transfer of liquid through mechanical dispersion has rarely been investigated, which is unfortunate since in many industrial processes the coating liquid is too viscous to be sprayed and, thus, is poured onto the powder bed and dispersed through particle contacts. At present, the design and optimization of these systems are carried out through trial and error, resulting in significant time for development, loss of materials, and potentially reduced product effectiveness. Successful completion of the objectives of the present study will greatly enhance our understanding of the processes involved in the mechanical dispersion of liquid in particulate systems, as well as our ability to quantitatively predict and design the operation of a mechanical dispersion-driven system.