Velocity Head

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.
 

Problem 7
Compute the velocity head of the jet in Figure 4-03 if D₁ = 75 mm, D₂ = 25 mm, the pressure head at 1 is 30 m of the liquid flowing, and the lost head between points 1 and 2 is 5 percent of the velocity head at point 2.
 

Problem 6
As shown in Figure 4-03, the smaller pipe is cut off a short distance past the reducer so that the jet springs free into the air. Compute the pressure at 1 if Q = 5 cfs of water. D₁ = 12 inches and D₂ = 4 inches. Assume that the jet has the diameter D₂, that the pressure in the jet is atmospheric and that the loss of head from point 1 to point 2 is 5 ft of water.
 

Problem 5
With 30 L/s of water flowing in Figure 4-02, what pressure must be maintained at 1 if the pressure at 2 is to be 70 kPa and the loss of head between 1 and 2 is 5 percent of the difference in pressure head at 1 and 2.
 

Problem 4
In Figure 4-02, with 15 L/s of water flowing from 1 to 2 the pressure at 1 is 100 kPa and at 2 is 70 kPa. Compute the loss of head between 1 and 2.
 

Problem 3
A 300-mm pipe is connected by a reducer to a 100-mm pipe. See Figure 4-02. Points 1 and 2 are at the same elevation, the pressure at 1 is 200 kPa. The discharge Q is 30 liters per second flowing from 1 to 2 and the energy lost from 1 to 2 is equivalent to 20 kPa.

1. Compute the pressure at 2 if the liquid is water.
2. Compute the pressure at 2 if the liquid is oil (sp gr = 0.80).
3. Compute the pressure at 2 if the liquid is molasses (sp gr = 1.5).

Problem 2
From Figure 4-01, the following head losses are known: From (1) to (2), 0 m; from (2) to (3), 0.60 m; from (3) to (4), 2.1 m; from (4) to (5), 0.3 m. Make a table showing elevation head, velocity head, pressure head, and total head at each of the five points. How high above the center of the pipe will water stands in the piezometer tubes (3) and (4)?