A water well is dug 100m down into the ground The pipe laid

A water well is dug 100m down into the ground. The pipe laid in the well is cast iron, 4in in diameter. The well is to deliver water to a ranch residence located 50m away from the wellhead and 10m up slope from it. The house water system demands 65psig with a flow rate of 10 gallons per minute. What is the minimum pumping pressure difference required at the wellhead?

Solution

solution:

1)here we are using cast iron pipe to carry waterfrom well bottom to house at 10 m above the well head hence here

2)suction lift=hs=100 m

delivery lift=hd=10 m

static head=Hs=hs+hd=110 m or 360.89 ft

3)pressure loss in cast iron pipe is given by hagen william equation as follows

hfd=.2083*(100/c)^1.852Q^1.852/d^4.8655

ft/100 ft of pipe

for cast iron c=130

hfd=.018 ft ofwater

3)velocity head at house=Hv=65 psig=149.92 ft

4)total head devloped by pump is

Hm=Hs+hfd+Hv=360.89+.018+149.92=510.83 ft of water

5)pressuredifference at well head is

p=221.45 psig