TABLE 4.4 Turbulence losses in pipes
Head loss coefficient for intakes (Kentrance)
Entrance profile
CIVIL WORKS GUIDELINES FOR MICRO-HYDROPOWER IN NEPAL
63
K
Entrance
1.0
0.8
Head loss coefficients for bends (K )
bend
Bend Profile
0.5
0.2
r/d 1 2
Kbend( θ = 20°)
Kbend( θ = 45°)
Kbend( θ = 90°)
0.20
0.40
0.75
0.15
0.30
0.50
Mitred bends with r/d = 1.5, maximum 30o per mitred joint.
3
0.12
0.25
0.25
Head loss coefficients for sudden contractions (Kcontraction)
Contraction profile
5
0.10
0.20
0.20
MITRED*
0.10
0.22
0.45
d1 /d2
Kcontraction
1.0 1.5 2.0
0
0.25
0.35
Head loss coefficient for valves (Kvalve)
TYPE OF VALVE
SPEHRICAL
Kvalve
0
2.5
0.40
5.0
0.50
GATE
0.1
BUTTERFLY
0.3