The effect of particle shape on pipeline friction for Newtonian slurries of fine particles

Experiments have been conducted to assess the effect of particle shape on p ipeline friction in turbulent flow, using laboratory pipelines of nominal d iameter 50 mm and 150 mm. The experiments were intended to examine the exte nt to which a fluid model is appropriate for slurries of this type, especia lly at high solids concentrations. The experiments confirm that fluid frict ion at low and moderate solids concentrations is proportional to slurry den sity, with particle shape being of minor importance. At high solids concent rations, additional increases in friction are observed and these depend upo n the ratio of the solids concentration to the maximum settled concentratio n. Although this friction increase is qualitatively similar to that which w ould result from increased slurry viscosity, the evidence suggests that par ticle-wall contact is the mechanism. However, the transition from turbulent to laminar flow indicates that an effective viscosity should be used in ca lculating critical Reynolds numbers.