CFD investigation of dense phase pneumatic conveying at a pipeline enlargement

The practice of stepping a conveying line is not new and there are many examples in industry; however, the details of the flow behaviour at the step have not been extensively studied. Three step geometries were modelled: an ‘abrupt’ step and two ‘gradual’ step-up geometries from a pipe bore of 75–100 mm. The flow behaviour of a single plug of material passing through these geometries was investigated using the ‘Eulerian’ CFD model from Fluent. Solids volume fractions were recorded at 0.01 s time steps at several point locations, and visualised throughout the pipe.