HYDRODYNAMICS OF A FLOWING GAS SOLIDS SUSPENSION IN A TUBE AT HIGH ANGLES OF INCLINATION

A study was made of pneumatic transport of particles of sand suspended in air in a 31.8 mm diameter Plexiglas tube inclined at either 72 or 90 degrees with respect to the horizontal plane. The solids holdup. pr essure gradient and pressure drop fluctuations over a 4.55 m test sect ion were measured as functions of the air velocity and the solids flux . Previously observed sudden changes in slope of plots of solids holdu p versus solids flux at constant gas velocity in a vertical tube (Mok et al., 1989), which were identified as transition points between dilu te and dense phases, were confirmed and extended to inclined tubes. Br eaks were also found in plots of pressure drop fluctuations versus sol ids flux at constant gas velocity.