Investigation of the Multi-particle Arch Formation on the Single Slot of a Sand Filter: CFD–DEM Study in Packed-Bed of Sand Particles

In this study, we present a successful application of the Computational Fluid Dynamics–Discrete Element Method (CFD–DEM) for simulating the complex phenomenon of multi-particle arch formation within high-concentration packed-bed environments. We investigate the roles of physical forces in this phenomenon, shedding light on aspects that are challenging to explore through experimentation. Our research is motivated by the desire to comprehend the conditions and parameters influencing the formation, stability, disruption, and reformation of multi-particle sand arches within filter openings. This arching phenomenon serves as an efficient particle retention mechanism, particularly in heavy oil production wells. We delve into factors like particle size, shape, and particle size distribution that may impact multi-particle arch performance. Additionally, we explore the physics behind multi-particle arching by examining the effects of various physical forces on arch performance. Utilizing a Computational Fluid Dynamics–Discrete Element Model, we investigate the multi-particle arching phenomenon under steady-state flow conditions in packed-bed environments. Our approach employs the unresolved coupling method in STAR-CCM+ (Siemens PLM). We test various filter slot geometries, including straight slots, keystone slots, wire-wrapped screens (WWS), and seamed slots, all under laminar flow conditions. Our findings highlight the significance of gravity, inter-particle forces, and interactions between the filter wall and the particles in multi-particle arch formation at both the slot opening and microscale levels. We confirm that a multi-particle arch can be formed within a specific slot width. Interestingly, while maintaining a constant slot width, we observe that the slot length has an insignificant effect on multi-particle arch formation and stability. In summary, our CFD–DEM model successfully simulates and predicts multi-particle arch formation, stabilization, breakage, and reformation, allowing for comprehensive testing of the effects of various parameters. This research offers valuable insights into a complex phenomenon that is crucial in packed-bed filtration systems.