A copper tube with air flowing at 85C, inside diameter of 6cm and 0.4cm thickness is being heated externally by water at 130C. A scale of 0.2cm thick is formed on the external surfaces of the tube. Calculate the overall heat transfer coefficient on the outside area basis, the water to air heat transfer and the temperature drop across the scale deposit. Consider the convective coefficient of the outside surface and inside surface as, ho=3605W/m2.K and hi=221W/m2.K, respectively, and the thermal conductivity of the copper tube as kcopper=384W/m.K and that of the scale as kscale=1.75W/m.K. Figure 2 below shows a schematic representation of the copper tube. [9] A copper tube with air flowing at 85C, inside diameter of 6cm and 0.4cm thickness is being heated externally by water at 130C. A scale of 0.2cm thick is formed on the external surfaces of the tube. Calculate the overall heat transfer coefficient on the outside area basis, the water to air heat transfer and the temperature drop across the scale deposit. Consider the convective coefficient of the outside surface and inside surface as, ho=3605W/m2.K and hi=221W/m2.K, respectively, and the thermal conductivity of the copper tube as kcopper=384W/m.K and that of the scale as kscale=1.75W/m.K. Figure 2 below shows a schematic representation of the copper tube. [9]