An equation of state and detonation properties of hydrazine–nitromethane liquid mixtures

Abstract

Binary mixtures of hydrazine and nitromethane were found to be non-ideal associated solutions. An equation of state (EOS) of the hydrazine-nitromethane solutions has been developed. This EOS takes into account the possibility of the formation of associated molecules due to interactions between hydrazine and nitromethane molecules. EOS parameters, including a possible chemical formula for the associate and its standard heat of formation and entropy, have been determined. Thermodynamic calculations of detonation parameters of the hydrazine-nitromethane system have been done by means of the TDS code for a wide range of hydrazine content in the explosive mixture (0-80 wt.%). The reliability of the results is guaranteed by using both an accurate, theoretically justified EOS for detonation products, which is derived from first principles of statistical mechanics, and realistic potentials for intermolecular interactions. It was shown that the use of the proposed EOS of the hydrazine-nitromethane solutions considerably improves the accuracy of the predicted detonation properties of the solutions and, furthermore, allows one to evaluate their shock sensitivity.

Equation of State of Detonation Products Based on Exponential‐6 Potential Model and Analytical Representation of the Excess Helmholtz Free Energy

“…He approximated the excess thermodynamic data by trivariate polynomial coefficients of order 4 3 4 3 4 in rotated canonical variables (x,y,z), for domain 11 a 14, 3 T* 100, and 0 z 1. Victorov et al [10] incorporated Byers Brown's one-domain approximation, extended to account temperature-dependent well depth, in their thermochemical code TDS. The authors derived an improved KLRR perturbation theory and use it to generate the excess thermodynamic data.…”

“…The parameters in EOS of condensed carbon are taken from [19]. For graphite and diamond we used corrections proposed by Victorov et al [10]: a) correction that takes into account small carbon particle size on their thermodynamic properties (correction consists in taking increased heats of formation of both graphite and diamond; D f H (diamond) = 28.24 kJ mol À1 , D f H (graphite) = 20.08 kJ mol À1 ) and b) slightly changed densities (1 (graphite) = 2.32 g cm À3 , 1 (diamond) = 3.3 g cm À3 ).…”

“…The analysis also suggests that there is a great need for generating accurate values of potential parameters for all fluid species, particularly for polar species. In addition, some studies have shown that there is a great need for generating more accurate equation of state of condensed carbon [10,28], and more accurate mixture rule [15] in order to improve the accuracy of thermochemical calculations.…”

“…So far, several authors reported that the accuracy and capabilities of thermochemical codes can be improved by implementing sophisticated theoretically based fluid equations of state [8][9][10][11][12][13][14][15]. Such equations are based on a reliable description of the energy of interaction of a classical fluid and reliable statistical mechanical theories.…”