QUALITATIVE ASSESSMENT OF A TRANSIENT SPRAY CAUSED BY A HYDRODYNAMIC RAM EVENT

Abstract

The current paper presents a qualitative characterization of a transient spray exiting the front surface of a liquid-filled tank penetrated by a projectile with sufficient kinetic energy to produce a hydrodynamic ram. This transient spray is viewed as the fuel atomization source in aircraft dry bay fire; therefore, highlighting its characteristics is critical to understanding the dry bay fire ignition problem. A large liquid-filled tank with internal dimensions of 182.88 cm × 182.88 cm × 106.68 cm (72.00" × 72.00" × 42.00") was penetrated by spherical projectiles of 1.27 cm (0.5") diameter at velocities from 264 m/s (866 ft/s) to 434 m/s (1423 ft/s). The resulting spray characteristics were captured using a laser light sheet and high-speed imaging, providing a qualitative assessment of the exiting spray. Four distinct phases were observed in the entire transient event, each of which contained unique spray characteristics.