Effects of different product phases in aluminum dust detonation modeling

Abstract

Modeling aluminum (Al) dust detonation is difficult due to uncertainties in the product species and fractions. Recent experiments indicate both gaseous and solid alumina may appear in the detonation product, but only the gaseous one was considered before. To resolve this drawback, we study the effects of different product phases on the detonation parameters with the hybrid combustion model proposed recently. Numerical results demonstrate that the assumption of gaseous product induces high velocity and pressure, while the assumption of solid product induces low velocity and pressure. To clarify how close-to-experiment results have been obtained with one phase assumption, we revisit previous studies and analyze the models. The inconsistency between the product phase and heat release is found, and then one model with variable heat release dependent on the product phase is proposed. Then simulations with both the gaseous and solid products are carried out, and results reveal the necessity of establishing a relationship between the heat release and reaction products. Re s = two-phase Reynolds number t= time, s T= gas temperature, K T p =particle temperature, K u= gas velocity, m/s u p = particle velocity, m/s W i =molecular weight, g/mol x= distance, m = thermal conductivity of gas, W/(m·K) = bulk density of particle, kg/m 3  = dynamic viscosity coefficient, kg/(m·s) Teng H H, et al. Sci China-Phys Mech Astron November (2013) Vol. 56 No. 11 2179 v i = stoichiometric coefficient  = gas or particle density, kg/m 3

Application: Detonations

“…8.14c, is the particle velocity lag in the velocity relaxation process, resulting in the alternative forces acting on particles and momentum transfers between the gas and particles. All these two-phase features for monodisperse Al-air detonation are similar with those obtained by Zhang et al [26] and Teng and Jiang [27,28].…”