Water flows in a heated round tube at a rate of 3 kg/s. The heated section of the tube is 4 m long. The tube wall is maintained at 90 C. Water enters the tube at 35 C and leaves the heated section at...

Water flows in a heated round tube at a rate of 3 kg/s. The heated section of the tube is 4 m long. The tube wall is maintained at 90 C. Water enters the tube at 35 C and leaves the heated section at 45 C. Find the tube diameter.

Water is flowing in a smooth pipe of diameter
D. A section of this pipe having a length of
L
is heated. Water at the inlet to the heated section has a temperature of
T<sub>f

1</sub>. Water temperature at the exit of the heated section is
T<sub>f

2</sub>. The heated section of the pipe wall is maintained at
T_s
. Show that for turbulent flow in the pipe and a specified heated length and pipe diameter, pressure drop in the heated section is given by:

[Hint: Use Newton’s law of cooling in conjunction with Equations IIIb.3.6, IIIb.3.7, and IVb.2.20].

Equations IIIb.3.6

Equations IIIb.3.7

Equations IVb.2.20