The square duct shown in Figure P13–28 carries hot gases such that its surface temperatu...

The square duct shown in Figure P13–28 carries hot gases such that its surface temperature is 570 ° F. The duct is insulated by a layer of circular fiberglass that has a thermal conductivity of K = 0:020 Btu/(h-ft-° F). The outside surface temperature of

the fiberglass is maintained at 110 ° F. Determine the temperature distribution within the fiberglass.