Modelling of turbulent hyperconcentrated sediment transport in horizontal pipes.

In dredging applications, deep sea mining and land reclamation projects typically large amounts of sediments are transported through pipes in the form of hyperconcentrated sediment-water mixtures or slurry. This research focusses on horizontal pipe transport. In the suspended regime the sediment volume concentration can be as high as 40% and has to be kept in suspension by the turbulent flow. Dependent on the flow and sediment characteristics, three different transport regimes can be distinguished. The sediment is either (a) fully suspended, (b) partially suspended in the presence of a sliding bed at pipe bottom or (c) partially suspended with a fixed bed at pipe bottom. It is extremely challenging to accurately predict (1) the (dynamic change in) transport regime, (2) the volume flux of solids and (3) the pipe friction factor over the wide range of operating conditions found in practice. The goal of this project is to meet these requirements through the development of accurate physics-based prediction tools for the wide range of operating conditions found in practice. To this purpose fully-resolved numerical simulations will be performed of turbulent sediment transport through a small-scale horizontal pipe. Next to available experimental data, additional experiments will be conducted in two slurry flow loops. The numerical and experimental data will serve as input for the development of reliable prediction (so-called mixture and multiphase Eulerian) models for slurry flow through a horizontal pipe. This project is supported by Royal Boskalis Westminster and Van Oord.