Effects of ultrasonic stimulation on the transport of different-sized particles in porous media

Abstract

Seismic waves can influence subsurface fluid and mass transport and can be used for aquifer remediation, carbon dioxide sequestration, and oil production. The influence of particle size on transport was investigated using three particle-size classes in sand-column experiments. For each size class, three flow rates and five ultrasonic powers were used to examine the roles of hydrodynamic force and ultrasonic stimulation. The number of particles captured in porous media (by straining, wedging, fouling and interaction) increased with increasing particle size and decreasing hydrodynamic force. The particle concentration peak and its tailing increased with increasing ultrasonic stimulation, and the effects of ultrasonic stimulation on the transportation and retention of particles were highly dependent upon hydrodynamic force and particle size. In particular, the effects of ultrasonic stimulation on particle transport and release were most obvious at larger hydrodynamic forces, corresponding to larger particle sizes. Furthermore, particle transport was mathematically modelled to identify the intrinsic mechanism of transportation and retention. Mean particle velocity decreased with increasing ultrasonic stimulation for the 10.119 and 14.675-μm particles, while it remained constant with increasing ultrasonic stimulation for the 5.214-μm particles. Furthermore, particle dispersivity increased with increasing ultrasonic stimulation. The deposition rate decreased and the release rate increased with increasing ultrasonic stimulation. These findings highlight various implications for possible particle–ultrasound interactions at the subpore scale.