EFFECTS OF SOLID FRICTIONAL INTERACTIONS ON THE APPLICABILITY OF THE FLUID-DYNAMIC SCALING RULES FOR FLUIDIZATION

Experimental results are reported which confirm the validity of the fl uid dynamic scaling rules for gas-solid fluidised beds operated in the bubbling regime, regardless of the particle and wall. roughness. Thes e rules still apply for shallow beds operated in the slugging regime f or cases in which the ratio (H-mf/D-t) of inital bed height to bed dia meter is less than the tangent of the angle of internal friction of th e particles; however, for higher values of H-mf/D-t, which permit the formation of fully developed dense-phase slugs, the scaling rules beco me invalid. This is considered to be due to particle-particle particle -wall interactions, and evidence is reported for both these effects in the slugging regime.