Example 1.3: A steel pipc (k = 45.0W/w.K) having a 5.0 cmn outer diameter is covered with a 4.2 cm thick layer of magnesia (k = 0.07W/m.K) which is in turn covered with a 2.4 cm layer of fibreglass insulation (k = 0.048W/m.K). The pipe wall outside temperature is 370K and the outside surface temperature of the fiberglass is 305K. What is the interfacial temperature between the magnesia and the fibreglass? NB: For radial conductive heat transfer in a spherical wall, the area at a given radius is 4πr-2 dr Recall Fourier's law q -kA dr

Example 1.3: A steel pipc (k = 45.0W/w.K) having a 5.0 cmn outer diameter is covered with a 4.2 cm thick layer of magnesia (k = 0.07W/m.K) which is in turn covered with a 2.4 cm layer of fibreglass insulation (k = 0.048W/m.K). The pipe wall outside temperature is 370K and the outside surface temperature of the fiberglass is 305K. What is the interfacial temperature between the magnesia and the fibreglass? NB: For radial conductive heat transfer in a spherical wall, the area at a given radius is 4πr-2 dr Recall Fourier's law q -kA dr