Abstract
An equation for dynamic holdup of cocurrent gas-liquid downflow in packed beds was developed on the basis of models in which the interactions among liquid holdup, pressure gradient and liquid flow rate for the gravity-viscosity and the gravity-inertia regimes were taken into account. The dynamic holdup data for beds of glass spheres (0.12-0.43 cm in diameter) with air-water flow were correlated well, in terms of static pressure gradient and total holdup together with the operating variables, by the equation
hφ=13.5[(Rel)/(Gal†)]1/3+1.20(Rel)(Gal†)-1/2
where Rel=Gldp/μl and Gal†=ρl2gdp3{1-(gc/ρlgh)(dp/dz)}/μl2.
A procedure was also shown for evaluating the dynamic and the total holdups and the static pressure gradient using only such operating variables as particle diameter and superficial velocities of gas and liquid.
