R. Meyer J. Köhler A. Homburg Explosives

Detonation
which the safety distance (in meters) is calculated from the expression
f· 3
öäM where M is the maximum amount of explosives in kg which are
present in the building at any time, whereas f is a factor which varies,
according to the required degree of safety, from 1.5 (distance between
two barricaded store houses) to 8 (distance from the non-dangerous
part of the plant). The f-value stipulated by the regulations may be as
high as 20 for residental areas in the vicinity of the plant.
The shock wave theory is easier to understand, if we consider a planar
shock wave, such as the one shown in Fig. 11, on the assumption that
the tube is indestructible (such shock wave tubes are utilized as
research instruments in gas dynamics and in solid state physics; the
shock sources are explosions or membranes bursting under pressure).
Comparative treatment of the behavior of the gas in the tube yields the
following relationships.
From the law of conservation of mass:
r0D = r1(D–W) or v1D = v0(D–W) (1)
From the law of conservation of momentum:
p1 – p0 = r0DW or v0(p1 – p0) = DW (2)
From the law of conservation of energy:
p1W = †0D (e1 – e2 + W2
); (3)
2
Rearrangements yield the so-called Hugoniot equation:
e1 – e0 = 1
2 (p1 + p0) (v0 – v1) (4)
Equation (4) represents a curve in the p – vdiagram, the Hugoniot
curve.
The following expression is obtained for the velocity D of the shock
wave and for the velocity of matter W:
p1 – p0
D = v0 öäää v0 – v1
and
W = öääääääääääää
(p1 – p0) (v0 – v1) (6)
These relationships are valid irrespective of the state of aggregation.
2. Detonation Wave Theory
If the medium is explosive, an explosive chemical reaction must be
produced immediately in the wave front because of the drastic tem-
80
(5)