Three-dimensional mesoscopic modelling of shock wave propagation and attenuation in gravel granular filter

Abstract

The gravel granular filter has been widely used to eliminate the strong shock waves induced by deliberated and occasional explosions. The modelling of shock wave propagation and attenuation in the gravel granular filter is still not well resolved and is a topic of current research. In this study, a new three-dimensional mesoscopic model of gravel granular filter is presented. This involves establishing the geometric model of three-dimensional gravel particles with the consideration of random shape based on the Voronoi algorithm, then generating the corresponding FE mesh based on the mapping grid algorithm and finally precisely controlling the porosity by applying a given displacement load. The three-dimensional mesoscopic model is then validated by numerically simulating two field tests on shock wave propagation and attenuation in a gravel granular filter. Detailed analysis of numerical simulations demonstrates that the drag force between gaseous phase and solid filter and the multiple complex reflection and diffraction between the particles are the main causes of the attenuation of shock wave with low amplitude. Finally, parametric study on the five dominant characteristics of filter, i.e., the particle shape, filter porosity, filter length, particle size and particle wave impedance are conducted. It is found that the particle shape, porosity, and wave impedance of filter have a strong influence on the capability of shock wave attenuation, and the filter length has limited influence beyond a critical optimal length, while the particle size has negligible effect.