Liquid sodium is to be heated from 500 K to 600 K by passing it at a flow rate of 5.0 kg/s through a 5-cm-ID tube whose surface is maintained at 620 K. What length of tube is required?
GIVEN
FIND
The length of tube (L) required
ASSUMPTIONS
Surface temperature is constant and uniform
SKETCH
PROPERTIES AND CONSTANTS
for liquid sodium at the average bulk temperature of 550 K
The Reynolds number is
This is within the range of
Solving for the length
Note that L/D = 2.93 m/0.05 m = 58.6 > 30. Therefore, use of is a valid
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