Chapter 12 Radiation Heat Transfer12-28The base, top, and side surfaces of a furnace of cylindrical shape are black, and are maintained at uniform temperatures. The net rate of radiation heat transfer to or from the top surface is to be determined. Assumptions1Steady operating conditions exist 2The surfaces are black. 3Convection heat transfer is not considered.PropertiesThe emissivity of all surfaces are ε= 1 since they are black. T1= 700 K ε1= 1 r1= 2 m T2= 1200 K ε2= 1 r2= 2 m T3= 500 K ε3= 1 h =2 mAnalysisWe consider the top surface to be surface 1, the base surface to be surface 2 and the side surfaces to be surface 3. The cylindrical furnace can be considered to be three-surface enclosure. We assume that steady-state conditions exist. Since all surfaces are black, the radiosities are equal to the emissive power of surfaces, and the net rate of radiation heat transfer
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