Very high-temperature furnaces (such as soaking pits operating around 1250°C) accomplish the majority of heat transfer via__________________?
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Answer: C. Radiation
Explanation
At very high temperatures such as 1250°C in soaking pits, radiation dominates. Radiant heat transfer depends on the fourth power of absolute temperature. Convective heat transfer becomes relatively minor compared to intense radiation. Stefan Boltzmann law dictates that thermal radiation increases dramatically with temperature. Soaking pits maintain steel ingots at uniform high rolling temperatures. Hot refractory walls emit massive amounts of infrared radiation toward the stock.
Steel mill soaking pits rely entirely on radiation to equalize ingot temperatures. Designing high temperature furnaces requires selecting materials with high emittance values. Convection plays a negligible role in heat delivery inside enclosed soaking pits. Conduction is limited to internal heat transfer through the solid metal stock. Convection contributes very little to heat transfer at extreme industrial temperatures. Cannot be predicted is false because radiation dominance is a thermodynamic certainty.
- Subject
- Engineering
- Category
- Chemical Engineering
- Topic
- —
- Difficulty
- medium
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