Rb. Wicker et Jk. Eaton, Effect of injected longitudinal vorticity on particle dispersion in a swirling, coaxial jet, J FLUID ENG, 121(4), 1999, pp. 766-772
Citations number
15
Categorie Soggetti
Mechanical Engineering
Journal title
JOURNAL OF FLUIDS ENGINEERING-TRANSACTIONS OF THE ASME
A passive particle dispersion control technique was investigated in which l
ongitudinal vortices were injected into a developing coaxial swirling jet w
ith sufficient annular swirl for Pow recirculation to occur. Four vortex ge
nerators, separated by 90 degrees and placed along the outside of the annul
ar nozzle, injected vorticity opposite in sign to the mean swirl, significa
ntly altering the structure of the swirling jet. The injected vorticity com
peted with the mean swirl to reduce azimuthal particle Pinging and to disru
pt the development of the vortex rings in the outer shear layer. Axial flow
visualization showed the formation of axial structures at the forcing freq
uency but considerable azimuthal asymmetry. Horizontal cross sections showe
d a four-lobed structure which persisted in the natural jet for at least ei
ght inner jet diameters. The particle concentration field was measured usin
g digital processing of pulsed laser sheer images. Outward radial particle
dispersion reduced while inward dispersion toward the jet centerline increa
sed indicating that the injected vorticity sufficiently reduced particle Pi
nging by large-scale vortices.