Abstract
of Visualisation
of the precessing vortex core in an unconfined swirling flow
W Fick, A J Griffiths and T O'Doherty, University of
Wales, Cardiff, UK.
.
Swirling devices have extensive use in industry, ranging
from dust separators through to burner systems, they offer good fluid mixing
and long residence times for complete reactions to take place. These parameters
are especially important for efficient combustion conditions. However the
flow pattern within these devices are extremely complex with limited data
available to describe the flow regime. Advanced diagnostic tools in conjunction
with phase averaging techniques have been used to experimentally evaluate
these complex flow patterns and to explain in detail the combustion principles
in a 3 D swirling flow field. The use of phase averaging does have limited
success when attempting to define and analyse particular areas of the flow
regime, this is due to the damping effecting of the averaging process. Even
so, useful information is obtained. The aim of this research was to correlate
results obtained from flow visualisation and phase average techniques. It
was observed that an additional vortex eddy structure in the rotating flame
was present. Vortex structures are beneficial to the combustion process
since they are good mixing and ignition initiators within the complex flame
structure. Finally the application of PIV aided the quantification of the
structure associated with the Precessing Vortex Core by providing instantaneous
results of the complex 3 D flow field.
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Diagnostics in Engineering, Volume 2, Part 1 Contents