(738e) Separation Effects within the Vortex Finder Zone of an Uniflow Cyclone

Uniflow cyclones have gas and particles
passing through them in only one direction and are preferably used for
applications with space limitations. Recently comprehensive information has
been gained on the design criteria of uniflow cyclones by systematic
experiments.

Analysis on experimental studies of uniflow
cyclones with an inner diameter of 100 mm showed main influences to the
separation performance of this separator type.

The expected influence of the vortex finder
diameter is the result of two main effects. The behavior of the radial velocity
component at the inlet zone of the vortex finder is reciprocal. An increased
vortex finder diameter results in a lower radial velocity. This velocity
component could prevent particles to be separated into the particle outlet, see
Figure 1 (left). The second effect is a result of a secondary flow witch is
winding around the outer vortex finder tube in reverse direction of the main
flow through the separator. At smaller vortex finder diameters this component
increases and may transport already separated particles out of the particle
outlet chamber into the vortex finder tube, see Figure 1 (right).

Figure 1: Influences of
the vortex finder tube to the separation performance of uniflow cyclones

Current studies on uniflow cyclones are
carried out in order to identify a critical particle zone of radial particle
movement in downstream direction in the separation chamber, see Figure 2. Due
to non-invasive measurement methods including laser illuminated particles the flow
pattern through the separator is unaffected. The evaluation is realized with
optical methods identifying partial particle accumulation due to obscuration
effects.

Figure 2: Particle
sedimentation zone

[1] Kraxner
M. ?Empirische Ermittlung von Auslegungskriterien für Gleichstromzyklone in
Multizyklonblöcken? PhD-thesis (2013)