One-dimensional modeling of concentration distribution in pipe flow of combined-load slurry

• We model concentration profiles in stratified slurry flows in pipe.
• We compare model predictions with experimentally determined profiles.
• Proportions of contact load and suspended load are determined in flowing slurry.
• Sliding bed develops under suitable conditions given by shear stress distribution.

A one-dimensional profile of solids concentration is modeled in a cross section of partially stratified flow of slurry in a pipe. In the flow, a certain proportion of solids is transported as contact load and occupies a sliding bed and a transport layer above the bed. The rest of solid particles is transported as suspended load within and above the transport layer. A model based on a vertical distribution of shear stress is proposed to predict a concentration profile in a cross section of such flow. Besides the concentration profile, the model predicts the thickness and velocity of the bed. Furthermore, the model determines a vertical position of the top of the transport layer and a position of the hydrodynamic axis of the flow. Model predictions show a satisfactory match with new experimentally determined profiles collected in slurry flows of four different fractions of glass beads in a 100-mm pipe of our laboratory loop.

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