Modeling Wurster coater

A Wurster coater similar to the equipment of Fig. 7.35 was simulated by DPM. The original geometry and the meshed model are shown in Fig. 7.49. 

Figure 6 Application of the mesoscale model on Wurster coater.

The real coating process in the studied Wurster coater apparatus with the bed mass of 3 kg contains about 21.8x10 particles with the size of 550 im. Unfortunately, the numerical effort for the calculation of the DPM model increases with increasing the number of simulated particles. The DPM model is unable to represent this number of particles, at least with the actually available computing power. However, the number of particles can be reduced by conservation of the particle and fluid dynamics in the simulated apparatus and its real geometry. In this work a scaling approach proposed by Link et al. (2009) and extended by Sutkar et al. (2013) has been used, in which the scahng of the particle size was carried out. Due to the size increase, the adequate properties of sohd and gas phase have been adapted to keep the dimensionless numbers Archimedes At) and Reynolds Re) and the velocities of minimal fluidization and elutriation constant. 

The sugar pellets SUGLETS produced by Colorcon (UK) are processed in the simulated Wurster coater. These particles are studied in the compression, shear, and impact tests to estimate the material parameters for the Hertz-Mindlin contact model of particles used in DEM on the microscale of the simulation. 

Kadsson S, Rasmuson A, van Wachem B, Bjorn IN CFD modeling of the Wurster bed coater, AIChEJ 55 2578-2590, 2009. 

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