Concentration at the pipe bottom at deposition velocity for transportation of commercial slurries through pipeline

In commercial slurries, the solids being transported are multisized and their size may span three orders of magnitude. The minimum operating velocity is usually kept as 0.5 m/s more than the deposition velocity. Deposition velocity is the flow velocity at which the deposition of solids occurs. In the present study, Kaushal [D.R. Kaushal, Prediction of particle distribution in the flow of multisized particulate slurries through closed ducts and open channels, PhD Thesis, Department of Applied Mechanics, I.I.T. Delhi, 1995], Mukhtar [A. Mukhtar, Investigations of the flow of multisized heterogeneous slurries in straight pipe and pipe Bends, PhD Thesis, Department of Applied Mechanics, I.I.T. Delhi, 1991] and Seshadri et al. [V. Seshadri, R.C. Malhotra, S. Anand, Hydraulic transportation of mineral ores, a state of the art report, Internal Report, Fluid Mechanics Laboratory, I.I.T. Delhi, 1975; V. Seshadri, R.C. Malhotra, Rheological properties of iron ore slimes slurries at high concentrations, Internal Report, Fluid Mechanics Laboratory, I.I.T. Delhi, 1980] data with multisized particulate iron ore slimes, copper tailings and zinc tailings slurries flowing through 105 and 55 mm diameter pipelines have been considered. Based on extensive analysis of experimental data, the Karabelas [AIChE J. 23 (1977) 426] model for prediction of concentration profile has been modified. On the basis of predicted concentration profiles, it is concluded that solid concentration at the pipe bottom reaches approximately 3.0 times the product of efflux concentration and static settled concentration by volume at deposition velocity.