Explosion of Liquid Explosives in Semienclosed Space

The explosion of liquid explosives releases more gases. The super pressure of explosion on the ground within 0.5-1.0 m is lower than condensed explosives. But the detonation positive pressure impacts longer time than condensed explosive, especially the places, which are far from the explosion center, for example, the zone outside of explosion reactions. The explosions of liquid explosives are more powerful in semienclosed space, especially in semiunderground or under ground. 

1 Reflection of Shock Waves from Rigid Barriers 

When the air shock waves of explosion from liquid explosive meet the vertical rigid wall (barrier), the velocity of air mass points drops down to zero suddenly, which accumulates the mass point, and the pressure and density increase dramatically until certain degrees. Then the mass points reflect to the opposite direction, the reverse shock waves are produced. Semienclosed space is diiferent from free space. The superposition of reverse waves rises the pressure to an extremely high level. 

From the basic functions of shock waves, below equations are obtained. 

Because the direction of reflection waves are opposite from the incident ones, the incident waves are positive, the reflection waves are negative, and = t 2 = 0, so 

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