One end of a 0.3-m-long steel rod is connected to a wall at 204°C. The other end is connected to a wall that is maintained at 93°C. Air is blown across the rod so that a heat transfer coefficient of 17 W/(m2 K) is maintained over the entire surface. If the diameter of the rod is 5 cm and the temperature of the air is 38°C, what is the net rate of heat loss to the air?
GIVEN
FIND
The net rate of heat loss to the air (qf)
ASSUMPTIONS
The wall temperatures are constant
The system is in steady state
The rod is 1% carbon steel
The thermal conductivity of the rod is uniform and not dependent on temperature
One dimensional conduction along the rod
SKETCH
The rod can be idealized as a fin of uniform cross section with fixed temperatures at both ends. The rate of heat loss is.
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