Entwicklungsstand und Perspektiven der Modellierung von Transportvorgängen in durchströmten Festbetten

New model equations enable the consistent and accurate calculation of heat transport, mass transport and chemical reactions in packed beds with fluid flow. The main features of this approach are reviewed and summarized, and selected aspects are discussed. The modelling approach may be a good starting point for the development of, for instance, membrane reactors and separation processes such as chromatography or freeze drying for thermally sensitive products.     

Modellierung der Einlaufstrecke und deren Auswirkungen auf die Verweilzeitverteilung in laminar durchströmten Rohren und Kanälen

A one‐range and a two‐range model for the laminar velocity distribution in the entrance region of tubes and ducts are presented. These allow the calculation of the residence time distribution under the impact of the flow development in the hydrodynamic entrance region. For the dispersion‐free case, an analytical solution is given. A cell model with place‐changing probability (ZEMP) is applied for the consideration of dispersion. This approach allows the fast quantification of the influence of different parameters on the residence time distribution for relatively short pipes and ducts. The numerical results are compared with earlier presented results of semi‐empirical models.