Minimum Transport Velocity of Granular Materials at High Concentration in a Horizontal Pipe

Abstract

The minimum transport velocity required to prevent the accumulation of particles on the bottom of a horizontal conduit was determined theoretically and experimentally in a 50 mm pipe for cereals having mean diameters from 2.0 to 4.1 mm. When the flow rate ratio of solids to air m_TC is so large as for m_TC to be from 10 to 60, the correlation between particle settling velocity w_sε and minimum transport air velocity v_c is well expressed by v_c=2.87w_sε√(f<SUB)K>, where f_K is a kinetic coefficient of friction between solids and pipe wall. This characteristic equation for minimum transport velocity was confirmed to be in good agreement with the values of the experimental data published in and outside Japan.