VISUALIZATION OF AERODYNAMICALLY FOCUSED SUBSONIC AEROSOL JETS

The phenomenon of aerosol focusing in jets is illustrated by photograp hing the light scattered from 3 mum polystyrene spheres suspended in a ir accelerating at near atmospheric pressure through a thin plate orif ice nozzle. The effect of varying particle inertia (Stokes number S) a nd percentage of sheath air surrounding the aerosol is studied for mod erately compressible jets at Mach numbers ranging from 0.7 to 0.04. Je t Reynolds numbers ranged from 250 to 7500, corresponding to nearly in viscid flows for a thin plate orifice. Enrichments of the aerosol numb er density by factors of 300 or more are demonstrated in jets driven b y a pressure difference of only 50 torr. Aerosol beam focal point widt hs as narrow as 1% of the nozzle diameter are observed.