Description

This CFD study models sludge settling in a pipe using ANSYS Fluent. Water carrying sludge particles enters the pipe at 0.01 m/s with gravity set to −9.81 m/s² along the y-axis.

Geometry & Mesh

The geometry (DesignModeler) has two sections: a lower region of quiescent water and an upper region containing the inlet and outlet. Meshing (ANSYS Meshing) uses an unstructured grid with 390,742 cells.

Sludge Flow Method

Because the flow contains suspended solids, it’s treated as multiphase. Among VOF, Mixture, and Eulerian options, the Eulerian model—commonly used for sludge flows due to its higher fidelity—is selected to represent the interaction between the water phase and sludge particles.

Conclusion

Post-processing provides 2D contours of velocity and the volume fractions of water and sludge, plus an animation of phase distribution. The mixture enters the pipe uniformly, then sludge progressively settles while the lighter water continues downstream. The pipe’s U-shaped layout promotes accumulation and sedimentation of the sludge phase.