Question

Water flows at the rate of 500gal/min through a 400-ft-long line. The first and last 100ft of the line are 6-in.-diameter cast-iron pipe, while the middle 200 ft consists of two 4.24-in.-diameter cast-iron pipes.

(a) the average velocity in each section of pipe

(b) the pressure drop in each length of pipe

(c) the total pressure drop

Answer 1

Q=500 gal/min=500x0.00378541/60 m³/s

Q=0.03154 m³/s

a)

1st section and last section

velocity=Q/A

=0.03154/(3.14x(6x2.54x.01)^2)/4

=1.73 m/s

middle section

velocity=0.03154/(3.14x(4.24x2.54x.01)^2)/4

=3.462m/s

b)

1st and last section

P=

=72.651 Pa

middle section

P=

=582.268 pa

c)

total pressure drop

=72.651+582.268

=655 Pa