Wall effects for spherical particle in confined shear-thickening fluids

Flow past rigid sphere in cylindrical tubes filled with shear-thickening power law fluids is simulated by Computational Fluid Dynamic (CFD) model in steady-state mode with fixed computational domain The CFD model is validated with previous researchers' work for Newtonian and shear-thinning power law rheologies in both bounded and unbounded mediums. New simulations are executed over flow conditions of Reynolds number, Re: 0.001 ≤ Re ≤ 100, diameter ratio, λ (diameter of tube to that of particle, λ = D/d): 2 ≤ λ ≤ 50, and flow behaviour index, n: 1 ≤ n ≤ 1.8. Wall effects on flow patterns and drag phenomena are investigated and found to be functions of Reynolds number, diameter ratio and flow behaviour index. Numerical results reveal that drag coefficient decreases with the increase in Reynolds number. Contribution on the drag coefficient from pressure force drops with increasing flow behaviour index, and is generally smaller than that from friction force. Length of recirculation wake increases with enhancement in flow behaviour index in the case of less severe wall effects. Wall effects on flow can be neglected if the wall is far enough from the particle.