The Macroscopic Particle Model (MPM) is a UDF-based quasi-direct numerical approach for tracking macroscopic particles [491]. The MPM is applicable to Lagrangian particulate flows that cannot be solved using conventional point-mass particle models. In such flows, the particle size cannot be neglected. In these situations, particle volume must be considered when modeling hydrodynamics and wall effects.

The MPM model provides a special treatment that accounts for the following:

In the MPM approach [8], each macroscopic particle spans several computational cells. Each particle is represented by a sphere with six degrees of freedom to account for the particle translational and rotational motion. The particle is injected in the flow domain at the beginning of a flow time step. The particle is assumed to be touching a computational cell during the time step if one or more nodes of the cell are located inside the particle volume. Each particle transport equation is solved in a Lagrangian reference frame.

• 13.1. Momentum Transfer to Fluid Flow
• 13.2. Fluid Forces and Torques on Particle
• 13.3. Particle/Particle and Particle/Wall Collisions
• 13.4. Field Forces
• 13.5. Particle Deposition and Buildup