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, pressure gradient and pressure drop fluctuations over a 4.55 m test section were measured as functions of the air velocity and the solids flux. Previously observed sudden changes in slope of plots of solids holdup versus solids flux at constant gas velocity in a vertical tube (Mok et al., 1989), which were identified as transition points between dilute and dense phases, were confirmed and extended to inclined tubes. Breaks were also found in plots of pressure drop fluctuations versus solids flux at constant gas velocity. On a etudie le transport pneumatique de particules de sable suspendues dans ľair dans un tube de plexiglas de 31,8 mm de diametre inclinee a 72 ou a 90 degres par rapport au plan horizontal. La retention des solides, le gradient de pression et les fluctuations de perte de charge dans une veine ďessai de 4,55 m ont ete mesures en fonction de la vitesse de ľair et du flux de solides. Les changements subits observes anterieurement dans la pente des courbes de retention des solides en fonction du flux de solides a une vitesse de gaz constante dans un tube vertical (Mok et al., 1989), et qui ont ete identifies eomme etant des points de transition entre les phases diluee et dense, ont ete confirmes et etendus aux tubes inclines. Des interruptions ont egalement ete trouvees dans les courbes de fluctuations de perte de charge en fonction du flux de solides a vitesse de gaz constante.