Page 169 - Water Engineering Hydraulics, Distribution and Treatment

From Appendix 25, K = 0.37.
c
From Table 5.2, K = 0.37.
From Appendix 17, equivalent length of 6 in. pipe = 5.5 ft = 1.676 m.
Q = A v = Q = A v .
1
2
1 1
2
0.01416 = ( ∕4)(0.3048) v = ( ∕4)(0.1504) v .
1
v = 0.194 m∕s.
1
v = 0.797 m∕s.
2
(v ) 2 2 2 2 2 5.2 Fluid Transport 147
2
h = K .
f
2g
2
h = 0.37(0.797) ∕(2 × 9.80) = 0.012 m = 12 mm.
f
EXAMPLE 5.43 PLOTTING OF HYDRAULIC AND ENERGY GRADE LINES
A water transmission line consists of three pipes connected in series, pipes AB, CD, and EF, to carry the required water flow from A
to F (see Fig. 5.19). There is a sudden reduction BC and a sudden enlargement DE.
a. Draw the HGLs by calculating/plotting H , H , H , H , H , and H .
1 2 3 4 5 6
b. Draw the energy grade lines by calculating/plotting E , E ,E ,E ,E , and E .
3
4
6
2
1
5
The following data are given:
Pipe AB is 200 ft long (61 m) and 12 in. (30.48 cm) in diameter, f = 0.020.

Pipe CD is 100 ft long (30.5 m) and 6 in. (15.24 cm) in diameter, f = 0.015.

Pipe EF is 100 ft long (30.5 m) and 12 in. (30.48 cm) in diameter, f = 0.020.

Velocity in pipes AB and EF is 8.025 ft/s (2.446 m/s).
Pressure head at point A is 300 ft (91.44 m).
Sudden reduction K = 0.37.
E 1
E 2
H 1
H 2 E 3
H 3
E 4
E
5
E 6
H 5 H 6
H 4
A B C D E F
Figure 5.19 Plotting of hydraulic and energy grade lines.