A packed bed consisting of uniform spherical particles of diameter 3 mm and density 4200 kg/m, is fluidised by means of a liquid of viscosity 1 mN s/m2 and density 1100 kg/m. Using Ergun's equation for the pressure drop through a bed height 7 and voidage e as a function of superficial velocity, calculate the minimum fluidizing velocity in terms of the settling velocity of the particles in the bed. State clearly any assumptions made and indicate how closely the results (14 marks might be confirmed by an experiment.