Micro-mechanics of wet solids in gas-solid contactors

在这个项目中，我们将研究涉及液体注入的气-颗粒过程的动态行为。这些系统在化学、制药和食品工业中使用的各种气固接触过程中都遇到过。众所周知，湿颗粒的行为与干颗粒完全不同。然而，对湿粒子动力学的基本描述主要是缺失的。两名博士生将通过实验和数值研究相结合的方法对湿粒子动力学进行定量描述。第一个项目将致力于开发和应用碰撞实验，根据颗粒材料特性、润湿性、润湿程度、撞击速度和物理特性，对颗粒碰撞行为进行系统的参数研究。两台高速摄像机将用于量化碰撞过程中速度的变化和粒子的粘附。由于力和能量平衡的求解，将分析其影响。另一名博士生将借助先进的计算模型对粒子碰撞机制进行数值研究，该模型描述了粒子与湿壁或另一个干或湿粒子碰撞的动力学，而无需任何事先假设。基于实验和数值数据，我们将能够确定湿粒子碰撞过程中能量耗散、粘滞和质量和动量传递的机制，并提供可用于粗粒度DEM模型的定量描述性闭合方程。这些可用于设计、优化和解决涉及液体注入的气固接触器的故障。

In this project, we will investigate the dynamic behaviour of gas-particle processes involving liquid injection. These systems are encountered in a wide variety of gas-solid contacting processes used in the chemical, pharmaceutical and food industries. It is well known that wet particles behave completely different from dry particles. Yet, a fundamental description of the dynamics of wet particles is predominantly missing. Two PhD students will mutually work on a quantitative description of wet particle dynamics through a combined experimental and numerical study. The first will work on development and application of collision experiments to perform a systematic parameter study of particle collisional behaviour depending on particle material properties, wettability, degree of wetting, impact velocity and physical properties. Two high speed cameras will be used to quantify the changes in velocity and the sticking of particles during a collision. The effects will be analysed due to solving of force and energy balances. The other PhD student will numerically study the mechanisms of particle collisions with the aid of an advanced computational model that describes the dynamics of a particle colliding with a wet wall or another dry or wet particle without any prior assumptions. Based on the experimental and numerical data we will be able to identify the mechanisms of energy dissipation, sticking and transfer of mass and momentum during a collision of a wet particle and to provide quantitatively descriptive closure equations that can be used in coarse grained DEM models. These can be used in the design, optimization and trouble shooting of gas-solid contactors involving liquid injection.