In this case study, the focus was a sea-water dredging system and the purpose was to evaluate the sediment flow path of fine silt injected into the stream. The client was concerned that inline concentration measurements of sediment were far lower than expected values. They were interested in gaining a better understanding of how sediment was distributed through their pipe system. For the CFD consulting team at Predictive Engineering, this analysis was an interesting opportunity to showcase the multi-phase capabilities of STAR-CCM+.

The sediment is injected at the far end of the pipe, down stream of the main inlet, and is modeled as a Lagrangian Multiphase. Here, the motion of the sediment particles is calculated through the main continuum phase of the fluid in the pipe. The particles varied in size as defined by a distribution provided by the end-client. The fluid makes two 90° bends through a pipe coupling and a sharp bend through a tee, which causes a significant amount of swirl in the fluid.

Our analysis showed much of the injected sediment was getting caught up in this swirl and pushed to the outside of the pipe walls. The results were able to clarify measurement observations the end-client had from test.