Model for Nonlinear Transient Burning of Hydrazinium Nitroformate

Abstract

Transient burning of solid propellants is a topic that still contains a large number of questions. The transient burning of neat hydrazinium nitroformate is calculated within the quasi-steady gas-phase, homogeneous onedimensional condensed phase approach. We focus on the effect of the condensed phase on the transient burning of solid propellants by showing the effect of temperature-dependent thermal properties, phase transitions, and chemical reactions in the solid phase. By solving the governing equations numerically, the nonlinear effects are conserved. Nomenclature A = preexponentionalfactor, s ¡1 , m/s c = speci c heat, J/kg¢K E = activation energy, J/mol k = thermal conductivity, W/m¢K n = integer 0, 1, 2, : : : p = pressure, Pa Q = heat release, J/kg R = universal gas constant, J/mol¢K R P = pressure-driven response function r b = propellant regression rate, m/s T = temperature, K t = time, s x = space coordinate, m ® = thermal diffusivity, m 2 /s ² = heat release rate, W/m 3 ½ = density, kg/m 3 ¿ = nondimensional time Subscripts and Superscripts c = condensed phase f = ame g = gas phase m = melting of hydrazinium nitroformate s = surface 0 = initial ¡ = on the negative side of C = on the positive side of ref = reference value -= steady-state value

Combustion models for energetic materials with completely gaseous reaction products

“…The same model was used in [26][27][28] (and taking into account that the heating zone of the condensed phase is nonstationary in [29]) for HNF; the results are in good agreement with experimental data on the burning rate over wide ranges of pressures and initial temperatures. In these papers, too, the problem of the dominant role of a particular zone in burning rate control was not considered.…”