Preliminary investigation of aluminum combustion in air and steam.

Abstract

The goal of the experiment is to understand the role of metal-steam combustion in the explosion of underwater shaped cnarges. An apparatus was constructed to investigate combustion of aluminum in stes.m. For background information, aluminum wires (1 mm diameter, 50 mm length) were ignited in air by high current (480 amperes) . Tests in air and steam were photographed using 35 mm color slides and 16 mm movies (4300 frames/ sec) . Two types of diffusion flames associated with the complete wire were observed, one type of diffusion flame had diffuse pale blue radic.tion centered on the wire, and another type of flame had intense yellow radiation above the wire. Also, radiation from the wires was measured using Photomultiplier Tubes. Ejected ciluminum particles exhibit different combustion properties depending on the environment, air or steam. Particles in air attain velocities of 7 to 11 meters/ second and exhibit erratic trajectories before burn out. Particles in steam move at slower speed (2 to 4 m/sec) ; the particles burn out and re-ignite.