Theoretical, numerical, and experimental investigation of pressure rise due to deflagration in confined spaces

Estimating pressure rise due to deflagration in a fully or partially confined space is of practical importance in safety design of a petrochemical plant. Herein, we have developed a new theoretical model to predict the pressure rise due to deflagration in both fully and partially confined spaces. First, the theoretical model was compared and validated against experimental data from the closed-space experiments with hydrogen, methane, propane, and ethane. The theory predicted accurate pressure rises near the stoichiometric regime for all fuel types; outside the stoichiometric regime, especially, for rich mixtures of hydrocarbons with air, the theory over-predicted pressure rise since it does not account for soot formation and the associated energy losses by radiation. Experimental investigation of propane and hydrogen deflagration was conducted in a partially confined space and the theory-based predictions agreed with the data up to 5%. Parametric numerical study was performed to investigate the effect of the initial pressure and temperature of gaseous fuels on pressure rise. (C) 2017 Elsevier Masson SAS. All rights reserved

Breakup Process of Cylindrical Viscous Liquid Specimens after a Strong Explosion in the Core

Basic understanding and theoretical description of the expansion and breakup of cylindrical specimens of Newtonian viscous liquid after an explosion of an explosive material in the core are aimed in this work along with the experimental investigation of the discovered phenomena. The unperturbed motion is considered first, and then supplemented by the perturbation growth pattern in the linear approximation. It is shown that a special non-trivial case of the Rayleigh-Taylor instability sets in being triggered by the gas pressure differential between the inner and outer surfaces of the specimens. The spectrum of the growing perturbation waves is established, as well as the growth rate found, and the debris sizes evaluated. An experimental study is undertaken and both the numerical and analytical solutions developed are compared with the experimental data. A good agreement between the theory and experiment is revealed. It is shown that the debris size λ, the parameter most important practically, scales with the explosion energy E as λ ∼ E −1/2 . Another practically important parameter, the number of fingers N measured in the experiments was within 6%-9% from the values predicted numerically. Moreover, N in the experiments and numerical predictions followed the scaling law predicted theoretically, N ∼ m 1/2 e, with me being the explosive mass