GammaV EOS for Detonation Products

Abstract

The standard way to start the derivation of an equation of state for detonation products is by defining a trial function P_s(V) along the principal isentrope of the products (where P_s is pressure and V is specific volume), with parameters to be determined from a cylinder expansion test. If that specific function turns out not to be good enough, a different function needs to be tried. We propose here a different approach which is to use instead the function g_s(V), where g_s is the adiabatic gamma along the principal isentrope, as defined by Eq. (2) below. By choosing g_s we don’t have to assume the form of the function from the outset. Instead, we define the function by a set of points (n≥4), and we’re able to define the amplitudes of these points recursively. In what follows we first write down the equations for determining the values of g_si for the specific volumes V_i, and then work out an example with n=4. We show that even for n=4 the reproduction of test data is quite good, and also that the results are not sensitive to the exact choice of the values of V_i.