Fireball and shock wave anomalies observed in chemical explosions

• Published in: Combustion and flame 1972-01, Vol.19 (1), p.25-32
• Main Authors: Patterson, A.M., Kingery, C.N., Rowe, R.D., Petes, J., Dewey, J.M.
• Format: Article
• Language: English
• ISSN: 0010-2180; 1556-2921
• DOI: 10.1016/S0010-2180(72)80083-X

Fireball and shock wave anomalies in the form of precursor phenomena moving ahead of the shock front have been observed on the majority of a large number of explosions of solid uncased chemical charges. Several types of anomaly have been observed and are described here. Luminous and nonluminous precursor jets can be related to inhomogeneities in the charge material and construction, and have been observed on explosions of charges constructed in a variety of ways, with various chemical compositions and ranging in size from 0.15 g to 500 ton. A more homogeneous charge appears less likely to produce these anomalies. Nonluminous ground surface precursor jets can be related to ground shock effects over compacted areas and have been observed only on explosions of charges with energies greater than 50-ton TNT equivalent. Charges developing low initial overpressures (e.g., detonable gas) would not be expected to generate this type of anomaly. Some shock front perturbations appear not to contain solid material or dense gaseous products. These may be related to the peripheral characteristics of the charge, ground effects in dust-free areas, or to weak fireball perturbations. It appears from these observations that the types of anomaly described are characteristic of explosions of solid chemical charges.