Blast wave generated by spherical flames

Journal Article · Wed Aug 01 04:00:00 EDT 1979 · Combust. Flame; (United States)

DOI:https://doi.org/10.1016/0010-2180(79)90035-X· OSTI ID:6898239

Strehlow, R A; Luckritz, R T; Adamczyk, A A; Shimpi, S A

A systematic numerical study of the structure of blast waves produced by constant-velocity and accelerating flames (H/sub 2/, CH/sub 4/, C/sub 2/H/sub 2/, C/sub 2/H/sub 4/, C/sub 2/H/sub 4/O, and C/sub 3/H/sub 8/) propagating away from the center of a spherical source region was conducted. A simple heat-addition working-fluid model appears to model quite adequately the reactive Hugoniot for ordinary hydrocarbon-air combustion processes. Calculations performed for a number of different types of acceleration behaviors show that the maximum overpressure generated by such flames is no higher than that generated by a constant-velocity flame that travels through the entire source region at the maximum velocity reached when the acceleration process ceases. Four fundamental and important conclusions are reached: (1) constant-velocity flames traveling in open spherical geometries must travel at exceedingly high effective burning velocities (about 50 times that of most hydrocarbons) before damaging blast waves can be generated by the flame; (2) acceleration processes as such cannot generate damaging blast waves; (3) positive impulse is unaffected by the details of the flame behavior; the positive impulse generated by any blast-wave source appears relatively insensitive to the nature of the source and, (4) for low-velocity flame propagation (in the range where ordinary flame propagation is expected to occur even when some augmentation arises) the character of the blast wave produced by the flame is markedly different from that produced by a high-energy-density source, such as the detonation of a high explosive charge. This means that any object in the field of the blast wave will experience impulsive loads well before the maximum overpressure is experienced and that the duration of the impulsive loads will be considerably longer than they would be for an equivalent high-energy-density source.

• OSTI ID: 6898239
• Journal Information: Combust. Flame; (United States), Journal Name: Combust. Flame; (United States) Vol. 35; ISSN CBFMA
• Country of Publication: United States
• Language: English

Related Subjects

08 HYDROGEN
080800 -- Hydrogen-- Properties & Composition
090110 -- Hydrocarbon Fuels-- Properties-- (1979-1989)
10 SYNTHETIC FUELS
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400800* -- Combustion
Pyrolysis
& High-Temperature Chemistry
ACETYLENE
ALKANES
ALKENES
ALKYNES
CHEMICAL REACTIONS
COMBUSTION
ELEMENTS
ETHYLENE
FLAME PROPAGATION
FLAMES
HYDROCARBONS
HYDROGEN
METHANE
NONMETALS
NUMERICAL SOLUTION
ORGANIC COMPOUNDS
OXIDATION
PROPANE
SHOCK WAVES
THERMOCHEMICAL PROCESSES
VELOCITY
WAVE PROPAGATION