If an energy/mass balance can be done, please show that too.

A packed bed reactor design is proposed which uses downward flow through a 6.0m long bed which is packed with 12.0mm diameter spherical particles. The diameter of the (cylindrical) bed (perpendicular to the flow) is 2.0m, and the solidity of the bed is 0.61 . The pressure head at the inlet to the column (where QN enters in the diagram below) is 42.0m(H2O); the pressure head at the outlet (where QOUT exits in the diagram below) is 5.0m(H2O). The process fluid has a specific gravity of 1.05 and a viscosity of 1.4 centipoise. Determine the volume flow rate passing through the bed under these conditions