A GENERALIZED APPROACH TO FLOW THROUGH FIXED BEDS FLUIDIZATION AND HINDERED SEDIMENTATION

Abstract

A generalized approach for a unified description of flow through mono and polydisperse uniform fixed and distended beds, particulate fluidization and hindered sedimentation is presented. Drag forces exerted by fluids on individual particles are used to evaluate friction factors and pressure drops across fixed beds. Extended definitions of drag coefficient and of its correlation with Reynolds number are evaluated and compared with literature data. It is shown that the new approach can be used reliably for creeping and turbulent flows, and also that it applies to the full range of packing densities which characterize dispersions and different types of beds comprising spherical particles. Finally effect of size distribution, bed structure, and particle segregation, on pressure drop, and implication of the new model for analysis of onset of fluidization are considered.