Empirical relationships for the terminal settling velocity of spheres in cylindrical columns

The terminal settling velocity of spherical particles was experimentally in vestigated in cylindrical columns in the range of Reynolds numbers 2 less t han or equal to Re-t infinity less than or equal to 185 and of particle-to- column diameter ratios, lambda, about 0.1 to 0.9. It was observed that none of the existing equations relating the terminal settling velocity, u(t), t o the diameter ratio, lambda, is fully satisfactory. For this reason two ne w empirical calculation methods are proposed which enable the determination of u(t) in the whole range of both Reynolds number, Re-t infinity, and dia meter ratio, lambda.