Estimation of void fraction of a packed column, a tube of 146 sq. in. cross section and 73 in. height is packed with spherical particles of diameter 2 mm. When a pressure difference of 158 psi is maintained across the column, a 60% aqueous sucrose solution at 20^oC flows through the bed at a rate of 244 lb/min. At this temperature, the viscosity of the solution is 56.5 cp and its density is 1.2865 g/cm³. What is the void fraction of the bed? Discuss the usefulness of this method of obtaining the void fraction.