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Particulate Science and Technology, Vol.29, No.1, 89-106, 2011
Solids Transport Formula in Predictive Model for Pipe Flow of Slurry above Deposit
Recently, principles of a predictive model were proposed for pipe flows of settling slurries at low velocities for which a plane stationary bed is formed at the bottom of the pressurized pipe. The solids transport formula is an important component of the model. An analysis of experiments for 11 different solids fractions suggested that the transport formula of the MPM (Meyer-Peter and Muller) type is appropriate for relating the solids discharge with the flow conditions in a pipe provided that the empirical coefficients of the MPM equation are not considered constant. The structure of the transport formula is discussed and its validity tested in the light of the new experimental results. Recent experiments in the laboratory circuit with a pipe of inner diameter of 100mm were carried out for three different fractions of sand (median particle sizes of 0.22mm, 0.38mm, 1.36mm, respectively). Slurry flows were tested in the upper-plane bed regime within the range of velocities from 0.19 to 1.97m/s and delivered concentrations from virtually zero to 0.27. The tests confirmed that the formula holds well from relatively fine to very coarse settling slurries flowing above eroded deposit in pressurized pipes.