Brochure

8484
5. Pump losses
Figure 5.6: Moody chart:
Friction coecient for laminar (circular
cross-section) and turbulent flow (arbitrary
cross-section). The red line refers to the
values in example 5.1.
10
3
10
4
10
5
10
6
10
7
10
8
0.008
0.009
0.01
0.015
0.02
0.025
0.03
0.04
64
Re
0.05
0.06
0.07
0.08
0.09
0. 1
Reynolds number ( Re=V · D
h
/ ν )
Friction coefficient ( f )
Relative roughness ( k/D
h
)
0.05
0.04
0.03
0.02
0.015
0.01
0.008
0.006
0.004
0.002
0.001
0.0008
0.0006
0.0004
0.0002
0.0001
0.00005
0.00001
0.000005 0.000001
Smooth pipe
Laminar
Transition zone
Turbulent
Turbulent flow is an unstable flow with strong mixing. Due to eddy motion
most pipe flows are in practise turbulent. The friction coecient for turbu-
lent flow depends on the Reynold’s number and the pipe roughness.
Figure 5.6 shows a Moody chart which shows the friction coecient f as
function of Reynold’s number and surface roughness for laminar and tur-
bulent flows.