Papers presented to the 11th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, South Africa, 20-23 July 2015.
A typical CLC unit consists of a circulating fluidised bed as
the air reactor and a bubbling fluidised bed as the fuel reactor. A
number of studies on the hydrodynamics behaviours of the CLC
process in fuel reactor have been documented in the open
literature and some are focused on numerical modelling of
dynamic processes in the fuel reactors but 3D numerical
modelling of the multiphase flow coupled with chemical reaction
dynamics in the fuel reactor is still rarely undertaken. This paper
aims to investigate the CLC process in a fuel reactor using the
3D-CFD modelling, coupled with the heterogeneous reactions,
the hydrodynamics and reaction kinetics of the CLC process in
the fuel reactor. A parameter used for relating the timedependent
bubble occurance to the local eddies is proposed by
correlating the local velocity fluctuation with the pressure
fluctuation. The relation between the concentration of gaseous
reactants or products and local vortices is also investigated. The
results obtained clearly indicate that the CFD modelling
conducted in the current study reasonably forecasts the
hydrodynamic behaviours and important phenomena observed in
the fuel reactor. The parameter correlating the bubble occurabce
with local velocity fluctuation may be used in the CLC for
controlling the bubbling phenomenon because the occurrence of
the bubbles at specific positions is strongly associated with the
locally embedded large eddies.
