The figure shows a vertical cross-section through the center of an enclosed barbecue system. The pile of
Question:
The figure shows a vertical cross-section through the center of an enclosed barbecue system. The pile of charcoal (T1 = 800C) is shaped as a disk of diameter D = 0.5 m. The thin-walled metallic enclosure is shaped as a 0.5-m diameter hemisphere. The enclosure wall can be modeled as isothermal (T2). The heat transfer from the outside of the enclosure to the ambient (T3 = 25C) is by radiation and convection. The convection coefficient is characterized by the overall (forced and natural convection) heat transfer coefficient h = 25 W/m2K. The charcoal, enclosure, and ambient can be modeled as black surfaces.
Determine the temperature of the enclosure wall, T2
Determine the radiation contribution to the total heat transfer rate from the outer surface of the enclosure; that is, from surface 2 to surface 3, which may be viewed as the surroundings. In addition, you may neglect convective heat transfer on the inside surface.