Experimental and numerical analysis for the derivation of a dynamic solid bed model in rotary drums considering mixing and segregation processes

在回转窑工艺模拟中，总会出现瞬态启动过程。在此过程中，充填程度和材料性能的变化引起了床层内部的偏析效应和不同的运动行为。由于混合不完全，热渗透到床层是短暂的，因此在核心和表面之间出现了温差。此外，质量流量、燃料类型、火焰控制和能量输入的变化会导致瞬态行为的发生。在本项目中，两个研究所的现有经验、实验和工具将用于模拟单分散和多分散固体床在回转窑截面内的离析和混合行为。该模型将表示床层内的瞬态传热和床层内的温度分布与颗粒大小、材料性质和操作参数的关系。然后将动态模型（单元操作模块）转换为相应的流程图仿真。工作的出发点是几个实验和由此衍生的现象学模型，这些模型是由两个研究小组中的一个在稳态情况下开发的。将这些知识转移到颗粒流动系统，以时间解析的方式反映瞬态内外边界条件的影响，将由第二个合作伙伴使用基于颗粒的离散元素（DEM）模拟进行，该模拟允许对潜在物理过程进行严格描述。这些模拟将通过已经可用的稳态实验和在计划项目中进行的新的瞬态调查来验证。得到的结果将引入正在开发的单元操作模块，并将用于补充和修改已知的关系和方程。

In a process simulation for rotary kilns always transient start-up procedures appear. During the process segregation effects and different motion behaviors arise inside the bed, which are caused by the change of the filling degree and the material properties. The heat penetration into the bed is transient due to the incomplete mixing, whereby a temperature difference between the core and the surface is emerged. Furthermore the transient behavior occurs by the change in mass flow, the type of fuel, the flame control and the energy input.In this project, the existing experiences, experiments and tools of the two research institutes will be used to model the segregation and mixing behavior of mono and poly-disperse solid beds in the cross section of a rotary kiln. This model will represent the transient heat transfer into the bed and the temperature distribution in the bed in dependence of the particle size, the material properties and the operational parameters. The dynamic model (unit operation module) will then be converted into a corresponding flow sheet simulation.Starting point of the work are several experiments and phenomenological models derived therefrom, which were developed for steady state situations by one of the two research groups cooperating on this topic. The transfer of this knowledge to particulate flow systems, reflecting in a time resolved manner the effect of transient inner and outer boundary conditions, will be carried out by the second partner, using of particle based Discrete Element (DEM) simulations, which allow a rigorous description of the underlying physical processes. These simulations will be verified with already available steady state experiments and new, transient investigations conducted within the planned project. The results obtained will be introduced into the unit operation module under development and will be used to complement and modify the already known relations and equations.