Non-ideal equations of state for combusting and and detonating explosives

Abstract

This paper deals with the formulation and evaluation of the non-ideal equation of state for products developed when burning or detonating energetic solid propellants and/or solid explosives. Included is the review of non-ideal gas equations of state (EOS) based on (a) the virial EOS; (b)the Haar-Shenker EOS; (c) the Becker-Kistiakowsky-Wilson EOS; and (d) the Jacobs-Cowperthwaite-Zwisler EOS. A new methodology is presented for evaluating the parameters in the BKW formulation, based on explosion data for different loading densities of the same explosive. An alternative approach to determine the single species equivalent molecular well-depth and σ for JCZ EOS has been significantly improved by adjusting the values of γ, the equivalent specific heat ratio. Sufficient details for each EOS are included for one explosive constituent, namely HMX (Octagen). A general non-ideal EOS with a non-constant co-volume function has been obtained by utilizing a “multi-equation combination” procedure, which can be used for product densities ranging from ideal gas values to values of gas density equivalent to the condensed phase density. Comparison of the sensitivity of the general non-ideal EOS with various other forms was made by utilizing a DDT (Deflagration-to-Detonation Transition) analyses (work of Krier and Butler 4). The results show that the accuracy of predictions of the DDT modeling using this general EOS has been improved.