Study on the Falling Characteristics of Interstitial Insolubles and the Brine Flow Field Response in Salt Cavity...

During the formation of cavities through water dissolution in salt cavern storage facilities or during gas injection and production operations, insoluble particles in the interlayers may detach from the surrounding rock and collapse, thereby causing significant changes in the flow patterns of brine and gas within the cavities. To this end, the accuracy of the OpenFOAM-LIGGGHTS (LAMMPS Improved for General Granular and Granular Heat Transfer Simulations) coupling method was verified using simulations of particle free settling in water. Simulation results are in good agreement with theoretical values. The study further investigates the sedimentation characteristics of single particles, double particles, particle swarms, and rigid aggregate blocks in brine. Results indicate that the settling velocity of single particles gradually decreases with increasing brine concentration. For homogeneous double particles, lateral sedimentation exhibits three stages: steady descent, wake coupling, and equilibrium settling, with lateral repulsion induced by the Magnus effect when the initial spacing is less than four particle diameters. For heterogeneous double particles, significant lateral displacement occurs due to wake-induced drag from the larger particle. The sedimentation of particle swarms is influenced by initial spacing, particle shape, and release angle: smaller spacing enhances interparticle interactions, increases peak kinetic energy, and causes earlier lateral velocity fluctuations; higher shape factors increase fluid resistance, reducing terminal settling velocity; larger release angles prolong settling time and intensify wake-induced disturbances. These findings provide a theoretical basis for the design and remediation of salt cavern storage geometries.