From The Chemistry of Explosives, Second Edition


When an explosive is initiated either to burning or detonation, its energy is released in the form of heat. The liberation of heat under adiabatic conditions is called the heat of explosion, denoted by the letter Q. The heat of explosion provides information about the work capacity of the explosive, where the effective propellants and secondary explosives generally have high values of Q. For propellants burning in the chamber of a gun, and secondary explosives in detonating devices, the heat of explosion is conventionally expressed in terms of constant volume conditions Q v. For rocket propellants burning in the combustion chamber of a rocket motor under conditions of free expansion to the atmosphere, it is conventional to employ constant pressure conditions. In this case, the heat of explosion is expressed as Q p.

Consider an explosive which is initiated by a stimulus of negligible thermal proportions. The explosion can be represented by the irreversible process as shown in Figure 5.2, where Q is the value of the heat ultimately lost to the surroundings.

Figure 5.2: Schematic diagram of the irreversible explosion process

Under constant volume conditions Q v can be calculated from the standard internal energies of formation for the products ? U ? f (products) and the standard internal energies of formation for the explosive components ? U ? f (explosive components) as shown in Equation 5.4.

A similar expression is given for the heat of explosion under...

Copyright The Royal Society of Chemistry 2004 under license agreement with Books24x7

Products & Services
Explosives and Energetic Materials
Explosives and energetic materials store and rapidly release large amounts of energy for demolition, munitions, missile propulsion, and explosive-forming applications.
Explosives Storage Magazines
Explosives Storage magazines are designed to store low explosive and/or high explosive materials.
Explosion Proof Heaters
Explosion proof heaters are constructed with housings that can withstand explosions, protecting the materials being heated.  This classification may also include housings, which can withstand sparking and flames.
Gas Transmitters
Gas transmitters consist of an enclosure, sensor, and electronics that convert a signal from a gas sensor into an analog output signal (typically 4-20 mA).
Boilers (industrial)
Industrial boilers are closed vessels that use a fuel source or electricity to heat water or generate steam for industrial heating and humidification applications.

Topics of Interest

VOLUME OF GASEOUS PRODUCTS OF EXPLOSION The volume of gas produced during an explosion will provide information on the amount of work done by the explosive. In order to measure the volume of gas...

TEMPERATURE OF CHEMICAL EXPLOSION When an explosive detonates the reaction is extremely fast and, initially, the gases do not have time to expand to any great extent. The heat liberated by the...

INTRODUCTION TO PROPELLANTS A propellant is an explosive material which undergoes rapid and predictable combustion (without detonation) resulting in a large volume of hot gas. This gas can be used to...

EXPLOSIVE POWER AND POWER INDEX In an explosive reaction, heat and gases are liberated. The volume of gas V and the heat of explosion Q can both be calculated independently but these values can be...

FORCE AND PRESSURE OF EXPLOSION This chapter has so far described the total chemical energy released when a chemical explosion takes place. This energy is released in the form of kinetic energy and...