Homework #2

Hydraulics and Flow in Pipes

1. Water Pressure

a) What is the hydraulic head in ft equivalent to a pressure of 30 lbs per square inch (psi)?

b) What is the pressure in psi equivalent to 80 ft of head?

2. Use the Darcy Weisbach equation to choose a pipe size (diameter in inches) given the following information: ductile iron pipe with roughness (ε) of 2x10^-4 ft, flow of 600 gpm, pipe length of 3000 ft, and frictional head loss as close to 12 ft as feasible but do not exceed. Choose a pipe diameter that is a common nominal pipe diameter.

3. Do Problem #2 but now use the Hazen Williams equation with a C of 140. Compare your answer to that obtained in Problem #2.

4. Water is pumped 8 miles from a reservoir at an elevation of 120 ft to a second reservoir at an elevation of 280 ft. The pipeline connecting the reservoirs is 54 inches in diameter. It is concrete with a C of 100, the flow is 25 MGD, and the pump efficiency is 82%. What is the monthly power bill if electricity costs 8.5 cents per kilowatt-hour? (ignore minor losses)

Assigned: 18 Sept 09

Due: 28 Sept 09