Answer Happy

A hollow metallic sphere of diameter 0.58 m surrounds a concentric metallic sphere of diameter 0.32 m. The space between the two spheres is filled with an insulation material with thermal conductivity of 9.5 W/(m⋅K). The inner and outer spheres are maintained at 182∘C and 132∘C respectively. The outer surface of the outer sphere is exposed to air at temperature T∞​. Meanwhile, the surrounding area can be considered isothermal with temperature Tsur​=45∘C. The emissivity of the surface of the outer sphere, ε is 0.66 and heat transfer coefficient of air, h is 12 W/(m2⋅K). Assume that heat is lost from the outer surface of the outer sphere through convection and radiation. a) Calculate the heat passes from the inner sphere to the outer sphere. b) Determine the temperature of air, T∞​. [ c) Identify the thermal resistance resulted from heat transfer by convection.