Flow correlations and transport behaviour of turbulent slurries in partially filled pipes

Transportation of fluids in partially filled pipes is common to many areas of industry (e.g. sewerage, min ing, and nuclear), yet many aspects remain under-developed, particularly for multiphase and nonNewtonian flows. In this paper a simple framework to enable the accurate prediction of the bulk flow behaviour and settling characteristics of slurries in open conduits is developed and validated experimentally. The experiments involve measurements of flow rate, flow depth and the settling regime for two different solids concentrations of two types of non-colloidal suspensions across a broad range of channel slopes, Reynolds numbers, and Froude numbers. A method is presented that can be used to make a priori predictions of critical sedimentation velocities, which can inform future pipeline designs and operations to minimise the environmental and commercial costs of slurry transfers, including reducing the risk of pipe blockages. Only one parameter required for this technique is not related to the measurable physical properties of the pipeline or fluid. However, it is empirically shown to be well represented by a single, dimensionless constant for all fluids and pipelines tested. (c) 2021 Elsevier Ltd. All rights reserved.