Author(s): A.M. Talmon; L. Aanen; R. Bakker-Vos
Keywords: Slurry; pipeline; sand-water-mixtures; density waves; linear stability
Abstract: High concentration solid–liquid mixtures that are conveyed by pipeline have been found to develop large amplitude concentration fluctuations.Aclosedloop laboratory circuit is used to investigate the mechanism of self-excitation. According to linear stability theory these concentration fluctuations originate from an adverse relation between the settling flux and solids concentration. Concentration variations amplify due to solids exchange with a bed layer. The internal structure of the flow is investigated by means of concentration profile measurements. The measurements show that self-excited harmonic perturbations quickly deform into sawtooth shape concentration variations. An explanatory non-linear theory is given.