Machinery's Handbook, 31st Edition
2780
ENERGY LOSS IN PIPES Table 22. Surface Roughness of Common Pipe and Tube
Surface Roughness
Surface Roughness ft × 10 – 6 m × 10 – 6
Material
Material
ft × 10 – 6 0.0003
m × 10 – 6 0.0001
Glass Plastic
Ductile Iron (Coated)
400 400 500 800
120 120 150 240
0.0003–0.0023 0.0001–0.0007 Concrete (Smooth)
Drawn Metal Tubing
5
2
Galvanized Iron Ductile Iron (Uncoated)
Carbon Steel Wrought Iron Rubber Tubing
150 150 230
46 46 70
Cast Iron Riveted Steel
850 6000
260 1800
0.10 0.09 0.08 0.07 0.06 0.05
0.02 0.03 0.04 0.05
0.002 0.004 0.006 0.008 0.010 0.015
Fully Rough
0.04
0.03
0.02
0.00005 0.00010 0.0002 0.0004 0.0006 0.0008 0.0010
Smooth Pipe
0.015
Transition Region
Laminar
Turbulent
0.010 0.009 0.008
0.00001
10 3 2 3 5
10 4
10 5
10 6
10 7
10 8
2 3 5
2 3 5
2 3 5
2 3 5
Reynolds Number, Re
Fig. 1. Moody Diagram Hazen-Williams Equation for Water Flow: For the special case of 60°F water in pipes between 2 inch and 6 feet in diameter, at velocities less than 10 ft/s, the Hazen- Williams formula or nomograph (Fig. 2 ) can be used. The coefficient values of common pipes can be found in Table 23. The nomograph is read by aligning a straightedge with the known values and reading the unknowns at the intersection points. The Hazen-Williams formula for US units is: v 1.32 C h R 0.63 h L L --- 0.54 = where v is average velocity (ft/s), R is hydraulic radius (ft), L is length of pipe (ft), h L is head loss (ft), and C h is the Hazen-Williams coefficient (see Table 23). The Hazen-Wil- liams formula for SI units, with R , h , and L in meters, and v in m/s is: v 0.85 C h R 0.63 h L L --- 0.54 =
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