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

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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.