A large combination convection-radiation oven is used to heat-treat a small cylindrical product of diameter 25 mm and length 0.2 m. The oven walls are at a uniform temperature of 1000 K and hot air at 750 K is in cross flow over the cylinder with a velocity of 5m/s. The cylinder surface is opaque and diffuse with the spectral emissivity shown.

(a) Determine the rate of heat transfer to the cylinder when it is first placed in the oven at 300 K.

(b) What is the steady-state temperature of the cylinder?

(c) How long will it take for the cylinder to reach a temperature that is within 50°C of its steady-statevalue?

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