MECHANICAL VIBRATION - A DRIVING MECHANISM FOR COMBUSTION INSTABILITY IN ROCKET ENGINES.
Final technical rept.,
DARTMOUTH COLL HANOVER N H THAYER SCHOOL OF ENGINEERING
Pagination or Media Count:
A far-field analysis and experimental investigation of the mixing of a gas jet in the presence of a vibration driven source of periodic vorticity at the orifice was completed. The main claim made is that the vibration driven vortices form the large eddy component of the turbulent far-field mixing region. Also that these eddies predominate at the outer edges of the jet and are responsible for the increased rate of spreading angle. This leads to an effectively increased eddy coefficient of viscosity. Hot-wire investigations of the far-field velocity problem tend to confirm this. An experimental investigation of liquid jets in the presence of vibration - produced pressure variation at the orifice, revealed the oscillatory pressure profiles expected on the basis of vortex rings in the jet. The intense localized vorticity near the jet surface, it is claimed, will endow droplets atomized from such regions with considerable angular momentum spin. An initial analytical investigation which attempts to predict the effect of droplet spin on evaporation rates was completed. Author
- Combustion and Ignition
- Rocket Engines