Energy of mechanical explosions

For mechanical explosions a reaction does not occur and the energy is obtained from the energy content of the contained substance. If this energy is released rapidly, an explosion may result. Examples of this type of explosion are the sudden failure of a tire full of compressed air and the sudden catastrophic rupture of a compressed gas tank. 

Four methods are used to estimate the energy of explosion for a pressurized gas Brode s equation, isentropic expansion, isothermal expansion, and thermodynamic availability. Brode s method21 is perhaps the simplest approach. It determines the energy required to raise the pressure of the gas at constant volume from atmospheric pressure to the final gas pressure in the vessel. The resulting expression is 

E is the energy of explosion (energy), P] is the ambient pressure (force/area), 

Blast Waves from a Spherical Charge, Physics of Fluids (1959), 2 17. 

V is the volume of expanding gas in the vessel (volume), and y is the heat capacity ratio for the gas (unitless). 

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