Dependence of Particle Fluctuation Velocity on Gas Flow, and Particle Diameter in Gas Fluidized Beds of Spheres in the Geldart B and A Fluidization Regimes

Abstract

We review new experimental data, published in 2008, on the steady‐state fluctuation velocity, Vn, of polymer, glass, nickel, and stainless steel monodispersed spheres in the Geldart B fluidization regime, and glass spheres in the Geldart A fluidization regime. The fluctuation velocity data, extends to polymer and metallic spheres the conclusion of a 1996 paper on glass spheres that: [Vn/Us][D/DoA/B)] = F(U = Us/Umf) where Us is the gas superficial velocity, Umf its value at fluidization; D is the sphere diameter; and DoA/B is a length scale whose magnitude is defined by F(U = 2)≡1. The magnitude, and density dependence of DoB, agrees with the predictions of the dense kinetic fluidization model of Buyevich and Kapbasov that: DoB = CD*, where C is a numerical constant proportional to the cube root of the energy loss per collision, and D* = (μf2/ρp2g)1/3 where μf is the viscosity of the fluidizing gas, ρp is the sphere density and g is the gravitational constant. The new data, defines DoB = 60 D* over a rang...