A Distinct Element Granular Solver/fictitious Domain Method for the Numerical Simulation of Particulate Flows

In the Oil and Gas industry, many situations are representative of particulate flows : cutting removal in drilling operations, sand management in production, dispersed hydrates transportation in pipeline, ... Particles may be of arbitrary shape and the fluid itself may exhibit non-Newtonian properties. To enhance the comprehension of complex phenomena occurring in moderately or highly concentrated suspensions, we developed a coupled solver based on a Distinct Element Method (DEM) for the granular part and a Finite Element Method for the fluid part. The scale of description is the particle, which implies that our approach may be regarded as a direct numerical simulation. The coupling is achieved by a Distributed Lagrange Multipliers/Fictitious Domain method (DLM/FD) and an operator-splitting algorithm. The DEM enables us to account for actual contacts between particles and consider particles of (polyhedral) arbitrary shape. Simulations up to a few thousands of particles in 2D situations are presented. We illustrate the capabilities of the numerical tool on the sedimentation of particles of polygonal or circular shape in Newtonian and nonNewtonian shear-thinning and thixotropic fluids. Obtained results underline the strong alteration of flow characteristics and the particles pattern.