Topic: Heat Transfer
In a pulverized fuel fired large power boiler, the heat transfer from the burning fuel to the walls of the furnace is
- A. By conduction only
- B. By convection only
- C. By conduction and convection
- D. Predominantly by radiation
Answer: D. Predominantly by radiation
Explanation: In a large power boiler fired by pulverized fuel, the temperature difference between the burning fuel (or hot flue gases) and the refractory brick walls is exceedingly large. Consequently, thermal radiation becomes the predominant mode of heat transfer, completely overshadowing conduction and convection.