Fractal Properties of a Falling Particle Curtain in Air

Abstract

Abstract The formation of a gravity-driven falling particle curtain is important for many problems, including solar tower particle receivers and setting the correct initial conditions for modeling shock interaction with multiphase media. One important characteristic of the curtain is the time history of its fractal dimension that characterizes the evolutionary growth of perturbations along the curtain's extent. For multiphase flows, fractal dimension can be used to help predict the types of instabilities that will occur within the flow. Our experiment aimed to establish the transient and stationary-value fractal dimension of a dense particle curtain with varying thickness containing particles with a density of 1.44 gm/cm3 and nominal diameter of 40 μm. High-speed video of the curtain was captured and analyzed. This data from this experiment, besides providing insights into the relevant physical processes, will be used to validate numerical models for multiphase flows.