Specify a suitable pump for the system shown in Fig. 13.57. It is a combination series/parallel system that operates as follows.

• Water at 160°F is drawn at the rate of 275 gal /min from a tank into the 4-in suction line of the pump. The suction line has a total length of 10 ft.

• The 3-in discharge line elevates the water 15 ft to the level of a large heat exchanger. The discharge line has a total length of 40 ft.

• The flow splits into two branches with the primary 3-in line feeding a large heat exchanger that has a K-factor of 12 based on the velocity head in the pipe. The total length of pipe in this branch is 8 ft.

• The 1-in line is a bypass around the heat exchanger with a total length of 30 ft.

• The two lines join at the right and discharge to the atmosphere through a short 3-in pipe.

• All pipes are Schedule 40 steel.

For this system, operating at the desired operating conditions, determine the following:

a. The pressure at the pump inlet

b. The NPSH available at the pump inlet

c. The pressure at point A before the branches

d. The volume flow rate through the heat exchanger line

e. The volume flow rate through the bypass line

f. The total head on the pump

g. The power delivered to the water by the pump.

Then specify a suitable pump for this system that will deliver at least the desired 275 gal/min of flow. For the selected pump, determine the following:

h. The actual expected flow rate produced by the pump at the operating point

i. The power input to the pump

j. The NPSH required

k. The efficiency at the operating point.