A copper sphere 2.5 cm in diameter is suspended by a fine wire in the center of

Question:

A copper sphere 2.5 cm in diameter is suspended by a fine wire in the center of an experimental hollow cylindrical furnace whose inside wall is maintained uniformly at 430?C. Dry air at a temperature of 90?C and a pressure of 1.2 atm is blown steadily through the furnace at a velocity of 14 m/s. The interior surface of the furnace wall is black. The copper is slightly oxidized, and its emissivity is 0.4. Assuming that the air is completely transparent to radiation, calculate for the steady state (a) the convective heat transfer coefficient between the copper sphere and the air, and (b) the temperature of the sphere.GIVENA copper sphere suspended in a furnace with air flowing over itSphere diameter (D) = 2.5 cm = 0.025 mSphere emissivity (ε) = 0.4Furnace wall temperature (Tw) = 430?C = 703 KAir temperature (Ta) = 90?C = 363 KAir pressure (pa) = 1.2 atmAir velocity (U??) = 14 m/sASSUMPTIONSSteady stateThe air behaves as an ideal gasThe furnace can be treated as a black body enclosureOnly the density of the air varies withtemperature