Explosion Features of Liquid Explosive Materials - Liquid Explosives - page 89

Fig. 2.39 The pressure relationship of reflection waves and incident shock waves [ 21 ]

The peak super pressure of re fl ection waves is Eq. 2.96 .

ð

k þ

Þ D P 1

1

D P 2 ¼

2

D P 1 þ

ð 2 : 96 Þ

ð k 1 Þ D P 1 þ 2kP 0

For air, k = 1.4. Substitute it into 2.96 , the super pressure of shock waves is 2.97 .

D P 1
D P 1 þ

6

D P 2 ¼

2

D P 1 þ

ð 2 : 97 Þ

7P 0

For strong shock waves,

P 1 P 0

so

D P 2
D P 1

8

For weak shock waves, P 1 P 0 P 0 so

D P 2 = D P 1

2

The above conditions conclude that in semiclosed space, the pressure of re fl ection

wave is 2 8 times of the pressure from incident shock waves. It is listed in Fig. 2.39 .

One thing is worth noticing that under strong shock waves, the pressure of

-

re ection waves is 8 times of that from incident, which is not always correct. The

strong shock waves are high-temperature and high-pressure, and perfect gas is
different from the real air. D

fl

ering, Burkhardt, Shear, and Mecane referred that if
the dissociation and ionization of gases are in consideration,

ö

D P 2 = D P 1 is much

larger than eight, and it reaches twenty or even more.
The transportation velocity of re fl ection shock waves D 2 is Eq. 2.98 .