A study of liquid dispersions in a spray drying tower
A study has been undertaken of drop formation from
swirl nozzles as encountered in spray drying operations.
Four swirl nozzles of different sizes and geometry
have been studied experimentally and theoretically in
order to characterise the nozzle and establish a model
that could predict drop size as a function of throughput,
pressure drop and the physical properties of the slurry.
The mechanism of drop formation was observed using
high speed cine and flash photography. The drop size
was estimated from photographs using a Zeiss particle
size analyser and the results were confirmed by a
Knollenburg particle size analyser.
A mathematical model has been developed which is an
extension of Taylor's model for conical swirl chambers
but which is more generally applicable irrespective of
the geometry and the agreement between the experimental
discharge velocities and drop sizes, and those predicted were very good.