Pressure Head

Problem 20
The 600-mm pipe shown in Figure 4-11 conducts water from reservoir A to a pressure turbine, which discharges through another 600-mm pipe into tailrace B. The loss of head from A to 1 is 5 times the velocity head in the pipe and the loss of head from 2 to B is 0.2 times the velocity head in the pipe. If the discharge is 700 L/s, what power is being given up by the water to the turbine and what are the pressure heads at 1 and 2?
 

Problem 18
Figure 4-09 shows a siphon discharging oil (sp gr 0.90). The siphon is composed of 3-in. pipe from A to B followed by 4-in. pipe from B to the open discharge at C. The head losses are from 1 to 2, 1.1 ft; from 2 to 3, 0.7 ft; from 3 to 4, 2.5 ft. Compute the discharge, and make table of heads at point 1, 2, 3, and 4.
 

Problem 17
In Figure 4-08 is shown a siphon discharging water from reservoir A into the air at B. Distance 'a' is 1.8 m, 'b' is 6 m, and the diameter is 150 mm throughout. If there is a frictional loss of 1.5 m between A and the summit, and 1.5 m between the summit and B, what is the absolute pressure at the summit in kiloPascal? Also determine the rate of discharge in cubic meter per second and in gallons per minute.
 

Problem 14
Water discharges through an orifice in the side of a large tank shown in Figure 4-06. The orifice is circular in cross section and 50 mm in diameter. The jet is the same diameter as the orifice. The liquid is water, and the surface elevation is maintained at a height h of 3.8 m above the center of the jet. Compute the discharge: (a) neglecting loss of head; (b) considering the loss of head to be 10 percent of h.
 

Problem 13
The 150-mm pipe line shown in Figure 4-05 conducts water from the reservoir and discharge at a lower elevation through a nozzle which has a discharge diameter of 50 mm. The water surface in the reservoir 1 is at elevation 30 m, the pipe intake 2 and 3 at elevation 25 m and the nozzle 4 and 5 at elevation 0. The head losses are: from 1 to 2, 0; from 2 to 3, 0.6 m; from 3 to 4, 9 m; from 4 to 5, 3 m. Compute the discharge and make a table showing elevation head, pressure head, and total head at each of the five points.
 

Problem 11
A horizontal pipe carries 30 cfs of water. At A the diameter is 18 in. and the pressure is 10 psi. At B the diameter is 36 in. and the pressure is 10.9 psi. Determine the head lost between the two points.
 

Problem 10
The diameter of a pipe carrying water changes gradually from 150 mm at A to 450 mm at B. A is 4.5 m lower than B. If the pressure at A is 70 kPa and that B is 50 kPa, when 140 L/s is flowing.
(a) Determine the direction of flow.
(b) Find the frictional loss between the two points.
 

Problem 9
The diameter of a pipe carrying water changes gradually from 150 mm at A to 450 mm at B. A is 4.5 m lower than B. What will be the difference in pressure, in kPa, between A and B, when 0.176 m³/s is flowing, loss of energy is being neglected.
 

Problem 8
In Figure 4-04, with 35 L/s of sea water (sp gr 1.03) flowing from 1 to 2, the pressure at 1 is 100 kPa and at 2 is -15 kPa. Point 2 is 6 m higher than point 1. Compute the lost energy in kPa between 1 and 2.