Water is to be pumped from one large open tank to a second l

Water is to be pumped from one large, open tank to a second large, open tank as shown in Fig. The pipe diameter throughout is 6 in. and the total length of the pipe between the pipe entrance and exit is 200 ft. Minor loss coefficients for the entrance, exit, and the elbow are shown on the figure, and the friction factor for the pipe can be assumed constant and equal to 0.02. A certain centrifugal pump having the performance characteristics shown in Fig. is suggested as a good pump for this flow system. With the pump, what would be the flowrate between the tanks? Do you think this pump would be a good choice?

Solution

Given friction factor 0.02 and L/d = 200/.6 =400, head loss factor =8

head loss due to other bends etc = 1/2*1.5*1 =0.75

Now from the characteristic curve for a head of 10 ft need 2400 gal/mt = 5.352 cfs

for area of pipe of 6in dia, velocity = 27.26 fps

V^2/2g = 11.53 ft head

Here to push water up 11.53 ft with a loss of 8 , need head of 92 ft. Along with other losses comes to extreme left of performance curve. Hence pump not good.