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A plain carbon steel ball 2 mm in diameter is heated to 1200 K in an...

A plain carbon steel ball 2 mm in diameter is heated to 1200 K in an oven and then cooled slowly in ambient air at 300 K. The convection heat transfer coefficient between air and this steel ball is 20 W / (m2 * K). You can find the density, specific heat and thermal conductivity from the property tables attached in text book with reasonable assumptions. Please derive an equation estimating the changes of the temperature of this ball with time, and the time needed for this steel ball to be cooled to 400 K with the radiation heat loss ignored. Please comments if the ignorance of radiation heat loss in this question in reasonable by checking the possible contribution of radiation to heat loss at three temperature points.

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Expert Solution

Bi=Biot number

samet mamat answered 2 years ago
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