The lateral variation of solids concentration in horizontal slurry pipeline flow

Abstract Measurements of the solids concentration in the horizontal plane through the pipe axis have been made for slurries of sand in water and solid polystyrene in water. The experiments were conducted in a pipeline of 51 mm dia. At low concentrations, and especially with fine particles, no variation of concentration could be detected in the central 80% of the pipe. As the concentration or the particle diameter increased, a region of reduced concentration near the wall was detected. Experiments at mean velocities of 2 and 3.4 m/s indicated that the migration tendency is insensitive to velocity, for fully suspended flow. The migration tendency seems to result from the dispersive stress effect discovered by Bagnold. Modifications to include this effect in the Schmidt-Rouse model appear to be justified.