Advanced numerical methods for simulating suspension flow in fibrous media: Application to the RTM process

Although significant efforts have been made to model the flow of suspensions (particle-filled resins) through fibrous media, most studies are limited to one-dimensional flows, which restricts their applicability to real-world composite manufacturing processes. This work addresses this gap by introducing a robust unstructured finite-volume solver to simulate two-dimensional suspension flow and particle filtration in fibrous media. The solver couples a flow model (solved via a pseudo-domain approach to extend the elliptic pressure equation to the whole domain) with a particle transport-retention model. The extended elliptic pressure equation is discretized using a diamond scheme, ensuring accurate resolution of pressure-velocity in complex geometries, while the advection equation governing both the saturation of the resin (tracked via a Volume-of-Fluid method) and the transport of suspended particles is discretized using a second-order upwind scheme stabilized by a Barth-Jespersen limiter. The developed model was validated by comparing the numerical results with several experimental and analytical results. Its robustness was then evaluated in different Resin Transfer Molding (RTM) applications for complex functional composite parts with singularities, such as the T-joint composite.