Fluid-structure interaction phenomenon related to the expulsion and subsequent motion of multiple macroscopic particles

摘要

Phenomena related to the expulsion and subsequent motion of multiple macroscopic particles are studied through numerical methods. Two basic systems are investigated: The first involves a set of particles set into motion in quiescent air and the second involves particle and free piston motion in the surroundings as the particles exit a flow channel under the influence of the gas driven piston motion. A fully coupled rigid body fluid structure interaction is utilized for up to a ten particle arrangement. The Navier-Stokes equations are solved for the in the fluid region with turbulence taken into account. The fluid induced pressure and viscous forces and moments as well as the effects of the interactions between the solid bodies are used in the calculations of the rigid body motion of the solid entities. A quaternion based kinematic formulation is implemented to prevent indeterminate system conditions. A soft collision model is applied to simulate the effects of the solid-body interactions. A moving and deforming fluid mesh facilitates the motion of the distinct bodies through the fluid with dynamic mesh adaption to ensure proper mesh size is maintained. With the modelling techniques developed, parametric studies were conducted to determine the influence of the particle size and density and the initial particle spacing and configuration on the paths the particles take and the spread of the particles after an equivalent time. The knowledge gained can improve the understanding of expelled particle motion and the means of controlling overall particle spread.