ABSTRACT
The fundamental means of exchanging the stored chemical energy of a propellant into the kinetic energy of the projectile is through the generation of gas and the accompanying pressure rise. We shall proceed in a disciplined approach, whereby, we introduce concepts at their simplest level and then add the complications associated with the real world. Every material exists in some physical state of either solid, liquid, or gas. There are
several variables that we can directly measure and some that we cannot but which are related to one another through some functional relationship. This functional relationship varies from substance to substance and is known as an equation of state. Thermodynamically, the number of independent properties required to define the state
of a substance is given by the so-called state postulate, which is described in Ref. [1]. For all of the substances examined in this text we shall assume they behave in a simple manner. This essentially means that the equilibrium state of all of our substances can be defined by specification of two independent, intrinsic properties. In this sense, an intrinsic property is a property that is characteristic of (in other words, governed by) molecular behavior. The ideal gas law is essentially a combination of three relationships [2]. Charles’s law
states that volume of a gas is directly proportional to its temperature. Avogadro’s principle states that the volume of a gas is directly proportional to the number of moles of gas present. Boyle’s law states that volume is inversely proportional to pressure. If we combine these three relationships,we arrive at the famous ideal gas law,which states in extensive form.
