Paper presented at the 6th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, South Africa, 30 June - 2 July, 2008.
A 3-D network of voids (NoV) model was developed to
study the discrete flow and heat transfer phenomena in
multi-tubular packed-bed reactors. The model utilised does
not place severe demands on computational resources.
Hence, the model can probably easily be developed to
simulate a fully packed tube and also a large number of
tubes in the case of multi-tube reactors. Illustrative studies
of the NoV model on a packed bed of spheres predict
phenomenal variations of discrete angular velocities and
consequently wall heat transfer coefficients within a single
tube. The phenomenal variations of discrete wall heat
transfer coefficients within a single tube imply that the
different angular sections of the tube will transfer heat at
radically different rates resulting in potentially large
temperature differences in different segments of the tube.
This may possibly result in temperature runaway and/ or
hot spots development leading to several potentially
unanticipated consequences for safety and integrity of the
reactor.
