Length Effects on PRCFD-Derived Fixed-Bed Radial Heat Transfer Parameters

The pseudo homogeneous 2D kr–hw fixed bed heat transfer model can give estimates of the two parameters from radial temperature profiles that depend on the length of bed at which the profiles are measured. For experiments, the length dependence has been attributed to preheating of the inlet flow by conduction along calming section tube walls, if this is not included in the model. Particle-resolved computational fluid dynamics (PRCFD) in computer-generated packed tubes has demonstrated that length effects are still present despite there being no possibility of preheating the fluid flow. The present work reports PRCFD simulations of heat transfer experiment setups with and without calming sections. It shows that there are two sources of length effects: flow preheating, which is significant for experiments with a calming section, and discrete particle effects on heat conduction and convection at very short bed depths that cause the length effects observed in PRCFD simulations.