Water at 20◦C is pumped through 1000 ft of 0.425 ft diameter pipe at a volumetric flowrate of 1 ft3/s through a cast iron pipe t

Question

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Water at 20◦C is pumped through 1000 ft of 0.425 ft diameter pipe at a volumetric flowrate of 1 ft3/s through a cast iron pipe t

hat connects to connects two reservoirs. The elevation difference between the two reserviors is 120 ft. Find the pumping power delivered to the water. The minor losses only include a wide-open globe valve with KL = 10. Use a density of 1.94 slug/ft3 and a dynamic viscosity of 2.32 × 10−5 lbf·s/ft2 .

Engineering

1 answer:

vichka [17] · Answer 1 · 2022-08-09T14:34:22+03:00

Answer:

7582.9 ft.Ibf/s

Explanation:

Given

L=1000ft,d=0.425ft,Q=1ft^3/s,z2-z1=120ft,Kl=10,d=1.94slug/ft^3, vicosity u= 2.32*10-5ibf.s/ft2

Reynold Re= Density*diameter*velocity/ viscosity

But Q=AV

V= 4/3.142*0.425=2.99ft/s

Re= 1.94*0.425*2.99/2.32*10-5)=106455.3

Friction factor=1/√f=-1.8log[((e/d)/3.7)^1.11+6.9/Re] is very neglible hence equals 0

Pump head Hp= z2-z1+v^2/2g[FL/f+KL]

Hp=120+2.99^2/2*32.2(0+10)=121.4ft

Pump power = density*g*Q*hp

1.94*32.2*121.4=7582.9 ft.Ibf/s