Solve the following problem:
Q: An aluminum cooling fin for a heat exchanger is situated parallel to an atmospheric pressure air stream. The fin is 0.075 m high, 0.005 m thick, and 0.45 m in the flow direction. Its base temperature is 88°C, and the air is at 10°C. The velocity of the air is 27 m/s. Determine the total drag force and the total rate of heat transfer from the fin to the air.
GIVEN
Air flow over a heat exchanger fin
Fin length (L) = 0.45 m
Fin height (w) = 0.075
Fin thickness = 0.005 m
Fin base temperature (Tb) = 88°C
Air temperature (T∞) = 10°C
Air velocity (U∞) = 27 m/s
ASSUMPTIONS
Steady state
Edge effects are negligible
Both sides of the fin are exposed to the air
Transition to a turbulent boundary layer occurs at
Rex = 5×105
Fin thickness is negligible
Radiation isnegligible
