Some aspects of secondary atomization of aluminum/hydrocarbon slurrypropellants

A theoretical and experimental investigation of the secondary atomization of Al/RP-1 slurry propellants was conducted. Theoretical efforts examined the effects of aluminum particle size in particle shell/crust formation on the surface of a burning slurry droplet. A model was developed for the pressure buildup and mechanical stresses in the shell for the time period after the shell becomes impermeable. Experimental efforts focused on the ignition and combustion of a dilute stream of slurry droplets. Measurements of individual particle diameters and velocities were made at various axial locations in the stream. Radiant emission from the particles was also monitored to determine whether aluminum was actively burning. Experimental aluminum agglomerate ignition times were found to be comparable to theoretical estimates. The experimentally measured minimum initial slurry droplet diameter for secondary atomization was 20-25 /*m, compared to a theoretical diameter of 35 /an.