DOI: 10.1615/ICHMT.2009.TurbulHeatMassTransf
ISBN Print: 978-1-56700-262-1
ISSN: 2377-2816
Active control of swirling coaxial jet mixing with manipulation of large-scale vortical structures
RESUMO
Large-scale vortical structures and associated mixing in methane/air swirling coaxial jets are actively controlled by manipulating the outer shear layer of the outer swirling coaxial jet with miniature flap actuators. In order to investigate the control mechanism, stereoscopic PIV and PLIF techniques are employed. As a result, intense vortex rings are produced in the outer shear layer in phase with the periodic flap motion regardless of the swirl rate examined. Vortical structures in the inner shear layer, however, are strongly dependent on the swirl rate. This is due to the fact that the central methane jet is accelerated by the swirl in the outer jet. At a relatively low swirl rate, the inner vortices are shed continuously and the methane jet is pinched off. This particular mode promotes the mixing of methane and air, so that the flammable mixture can be formed in an earlier stage of jet flow development.