#5

5) Radiation to a Tube from a Large Enclosure. A small oxidized horizontal metal tube with an OD of 0.0254m (1-inch), 0.61m ( 2ft ) long, and with a surface temperature at 472K(390F) is in a very large furnace enclosure with firebrick walls and the surrounding air at 1088K(1500F). The emissivity of the metal tube is 0.94 at 1088K and 0.79 at 472K. Calculate the heat transfer to the tube by radiation using SI and English units