Characterization of microparticle velocities in converging-diverging nozzle systems

Present day flight vehicles are capable of reaching very high speeds and scientific literature suggests that atmospheric aerosols may cause damage to them. Ongoing work in particle impact damage modeling, aerosol deposition methods, and fundamental studies of particle impact dynamics require acceleration of particles to high speeds and associated measurements, models, and simulations to characterize particle velocities. This thesis utilizes an experimental system incorporating a converging-diverging nozzle to accelerate well characterized particles to high speeds via aerodynamic drag force on the particle and measures the resulting velocities. Velocity measurements in the range of 0.3 - 1 km s-1 were taken for singularly sized of particles in the range of 1 - 10 µm. Particle velocities beyond the nozzle exit are dependent on size and carrier gas. The particles exhibit varying degrees of mach lag, in which the particle velocity is less than the velocity of the surrounding gas. A proposed scaling relating particle mach lag and stokes number results in good data collapse across all gas and particle conditions and shows good agreement to simulation and other work.

Author dc:creator

• Bellefeuille, Nathan

• Nozzle
• Particle
• Supersonic

Language dc:language.iso

en

Handle dc:identifier.uri

https://hdl.handle.net/11299/278736

OAI identifier oai:identifier

oai:conservancy.umn.edu:11299/278736