HYDRODYNAMIC MODELING OF VERTICAL NON-ACCELERATING GAS-SOLIDS FLOW

The one-dimensional steady-state model for vertical non-accelerating liquid-solids flow of coarse spherical particles recently formulated and verified (Grbavcic et al., Powder Technol., 53 (1992) 182) has been extended to vertical pneumatic transport. Experiments were performed by transporting spherical glass particles of 1.20, 1.94 and 2.98 mm diameter with air in a 30 mm i.d. glass pipe. Slip Reynolds number for the particles ranged from 592 to 3813 and the pipe Reynolds number from 16 200 to 49 000. The loading ratio was varied from to 5.4 to 30.8. For these ratios, line voidage ranged from 0.9153 to 0.9913 and superficial gas velocity was in the range (0.91-2.2)U-t, where U-t represents single particle terminal velocity. Model predictions of fluid-particle interphase drag coefficient and voidages in the transport line are in good agreement with experimental data for particle mass flux W-p<250 kg/(m(2) s). A new correlation for particle-wall friction coefficient in an air-spherical glass particle-glass pipe system is presented.