Characterization of the fluid dynamics and discrete particle modelling of a novel spouted bed apparatus

计划研究的目标是对具有两个水平进气口和可调供气量的新型狭缝喷动床内的流体动力学进行实验和理论研究。喷动床为气固体系的密集接触提供了非常有效的可能性，这对精细和多分散粉末的形成、处理和加工至关重要。此外，在喷动床中，颗粒可以流态化，这在传统的流态化床中是不可能的，特别是当颗粒的尺寸分布很宽时，当它们很小很轻或很大时，当它们是强烈的非球形时，或者当它们是粘性的时候。喷动床的可调式供气系统可在关闭喷动床时防止颗粒排放，并允许在运行期间清洁床。稳定的运行模式将根据喷动床内压力波动的测量和傅立叶分析获得的频谱来确定。这些马厩模式将被浓缩到制度地图中。为此，喷动床的尺寸、工艺参数以及颗粒系统将有所不同。重点研究了供气钢瓶旋转对气体流量和有效自由气体进口面积的影响。当得到这些结果后，将与其他喷动和沸腾床结构的稳定运行状态图进行比较。特别是，考虑到相间耦合的离散粒子模型(DPM)将被用来优化装置的几何形状。应用DPM的优势是有机会计算出设备的最优设计，而模拟将基于几个选定的实验进行验证。除了干条件下的研究外，还将探索湿条件下喷动床的流动、传热和传质，即通过喷嘴喷雾液滴，可用于颗粒的造粒和包覆。同样，在这种情况下，将使用DPM。

The goal of the planned research is the experimental and theoretical investigation of the fluid dynamics in a novel slit-shaped spouted bed with two horizontal gas inlets and adjustable gas supply. Spouted beds offer very effective possibilities for intensive contacting of gas-solid systems, which is of prime importance for the formation, treatment and processing of fine and poly-disperse powders. Furthermore, in spouted beds particles can be fluidized, which would not be possible in conventional fluidized beds, especially when the particles have a broad size distribution, when they are small and light or very large, when they are strongly non-spherical or when they are sticky. The adjustable gas supply system of the spouted bed prevents the discharge of particles when the bed is switched off and allows for cleaning the bed during operation.The stable modes of operation will be determined based on measurements of the pressure fluctuations in the spouted bed and frequency spectra obtained from Fourier analysis. These stables modes will be condensed into regime maps. To this end, the dimensions of the spouted bed, the process parameters, as well as the particulate system will be varied. Especially the influence of the gas flow rate and the effective free gas inlet area through the rotation of the gas supply cylinders will be investigated. When these results have been obtained, a comparison with the stable operation regime maps of other spouted and fluidized bed constructions will be made. In particular a discrete particle model (DPM) that takes into account the coupling between the phases will be employed to optimize the apparatus geometry. The advantage of applying the DPM is the opportunity to calculate an optimal design of the apparatus, while the simulations will be validated based on a few selected experiments. In addition to the investigations under dry conditions, the flow, heat and mass transfer of a spouted bed under wet conditions will be explored, i.e. by spraying droplets with a nozzle, which can be used for granulation and coating of particles. Also in this case the DPM will be used.