Detonation velocity, detonation pressure, and detonation heat are usually used as a measure of explosive's performance. However, they do not answer the question how fast an explosive can accelerate the surrounding metal liner. A semi‐empirical solution to this problem was proposed by R. W. Gurney in 1943. In this paper we used thermochemical calculations to calculate energy of detonation products along the expansion isentrope and to estimate the Gurney energy and cylinder wall velocity from it. It was found that for the same degree of the products expansion, experimentally determined Gurney energy is systematically less than calculated detonation energy due to the energy losses. At about threefold expansion of the products, the detonation energy matches very well with an experimental Gurney energy.

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A hundred years ago (in 1921) Becker proposed an equation of state in which the repulsive term in van der Waals equation of state was replaced by an exponential function. Twenty years later, Kistiakowsky and Wilson modified Becker's equation and used it to calculate the detonation properties of nitroglycerine and mercury fulminate. The resulting equation of state, commonly called the BKW equation of state, is attributed to Becker, Kistiakowsky, and Wilson. Although it was not founded on a strict theoretical background, the BKW equation of state has been widely adopted in thermochemical codes to predict the detonation properties of explosives. Throughout the years, the accuracy of BKW has been significantly improved through proper calibration of the BKW constants and covolumes. This paper presents the concept of temperature-dependent covolumes of polar molecules (H 2 O and NH 3 ) as a way to improve the accuracy of prediction of detonation properties of explosives, especially those explosives producing larger amounts of H 2 O and NH 3 . It was demonstrated that temperature-dependent covolumes describe more accurately experimental shock Hugoniots of polar molecules than constant covolumes, and the accuracy of prediction of detonation properties of HNO types of explosives is greatly improved.

Theoretical prediction of performance indicators of explosives plays an important role in the development of new explosives and explosive formulations. Of particular interest is the possibility to estimate the velocity of metal liner driven by an explosive charge. We present a theoretical model for estimation of metal cylinder wall velocity profiles of non‐ideal ANFO explosives. The model is based on thermochemical calculations using EXPLO5 code, expressing the Gurney energy in terms of JWL equation of state, and using hydro‐code simulation. The Wood‐Kirkwood detonation theory, incorporated in EXPLO5, is applied for calculation of detonation parameters of non‐ideal ANFO explosives. It was found that this approach enables prediction of cylinder wall velocity for ANFO explosives, with the error at V/V0=7 expansion ratio not exceeding 100 m/s.

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One of the most important tasks associated with theoretical prediction of performance of explosives by thermochemical calculation is accurate description of the equation of state (EOS) of detonation products. Widely used empirical equations of state, such is Becker‐Kistiakowsky‐Wilson (BKW EOS), have limited accuracy when it comes to energetic materials with unusual elemental composition. Replacing empirical EOS with more sophisticated and theoretically based EOS, the accuracy of thermochemical calculations can be increase. We present an equation of state of detonation products based on the Buckingham α‐exponential‐6 equation (Exp‐6) and an analytical representation of the excess thermodynamic functions for classical fluid mixture. The excess Helmholtz free energy, as a function of reduced density, temperature, and stiffness parameter, is calculated applying KLRR perturbation statistical mechanical theory, and so obtained data are approximated by multinomial coefficients. The interpolation domain is defined so to describe accurately the range of pressures, densities, and temperatures relevant for detonation studies. The equation is incorporated in EXPLO5 thermochemical code. Good agreement with Monte‐Carlo calculations is obtained, as well as between calculated and experimental detonation parameters for a series of explosives.

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