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Instruction Manual
FM.C. 008 Pipe Friction Apparatus
MECHMATICS, India
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FM.C.008 PIPE FRICTION APPRATUS
Aim of the Experiment:
To determine Fluid friction factor for the given pipes.
Introduction and Theory
The flow of liquid through a pipe is resisted by viscous shear stresses within the
liquid and the turbulence that occurs along the internal walls of the pipe, created
by the roughness of the pipe material. This resistance is usually known as pipe
friction and is measured is meters head of the fluid, thus the term head loss is
also used to express the resistance to flow.
Many factors affect the head loss in pipes, the viscosity of the fluid being handled,
the size of the pipes, the roughness of the internal surface of the pipes, the
changes in elevations within the system and the length of travel of the fluid.
The resistance through various valves and fittings will also contribute to the
overall head loss. In a well designed system the resistance through valves and
fittings will be of minor significance to the overall head loss and thus are called
Major losses in fluid flow.
The Darcy-Weisbach equation
Weisbach first proposed the equation we now know as the Darcy-Weisbach
formula or Darcy-Weisbach equation:
hf = f (L/D) x (v2/2g)
where:
hf = head loss (m)
f = Darcy friction factor
L = length of pipe work (m)
d = inner diameter of pipe work (m)
v = velocity of fluid (m/s)
g = acceleration due to gravity (m/s²)
The Darcy Friction factor used with Weisbach equation has now become the
standard head loss equation for calculating head loss in pipes where the flow is
turbulent.
Apparatus Description
The experimental set up consists of a large number of pipes of different
diameters. The pipes have tapping at certain distance so that a head loss can be
measure with the help of a U – Tube manometer. The flow of water through a
pipeline is regulated by operating a control valve which is provided in main supply
line. Actual discharge through pipeline is calculated by collecting the water in
measuring tank and by noting the time for collection.
TECHNICAL SPECIFICATION:
Pipe:
MOC = S.S./ UPVC
Test length = 1000 mm
Pipe Diameter:
Pipe 1: ID: 15.50 mm (1/2” UPVC 40 Schedule)
Pipe 2: ID: 15.76 mm (1/2” SS 40 Schedule)
Pipe 3: ID: 20.96 mm (3/4” SS 40 Schedule)
Experimental Procedure
1) Fill up sufficient clean water in the sump tank
2Connect the Inverted tube water manometer to required pipe.
3) Connect the electric supply. See that the flow control valve and bypass valve
are fully open.
4) Start the pump and adjust the flow rate.
5) Now open the manometer valve and let the manometer be filled with water.
6) Pump some air in the manometer such that it reaches suitable level at approx.
half the length.
7) Note down the manometer reading and flow rate.
6) Close the cocks and similarly, note down the readings for other fittings. Repeat
the procedure for different flow rates.
Observations Table
Length of test section (L) = 1000 mm = 1 m
Pipe 1
Internal Diameter of Pipe D = 15.50 mm
Cross Sectional Area of Pipe = 1.89 x 10-4 m2
h1 – h2
Sr. No. Qty (litre) t (sec) V (m/s)
(mtr)
1
2
3
Pipe 2
Internal Diameter of Pipe, D = 15.76 mm
Cross Sectional Area of Pipe = 2.01 x 10-4 m2
h1 – h2
Sr. No. Qty(litre) t (sec) V (m/s)
(mtr)
1
2
3
Pipe 3
Internal Diameter of Pipe D = 20.96 mm
Cross Sectional Area of Pipe = 3.45 x 10-4 m2
h1 – h2
Sr. No. Qty(litre) t (sec) V (m/s)
(mtr)
1
2
3
Calculations
Mean velocity of flow, V = Q/A m/s
Where, Q = 0.01/time required for 10 lit in m3/sec
According to Darcy- Weisbach Equation for frictional loss of head due to pipe
friction:-
hf = h1-h2 = f.L.V2
D x 2g
In the above equation, everything is known to us except “f”
Conclusion
1) The friction factor for pipe is as follows:
Pipe 1 =
Pipe 2 =
Pipe 3 =
2) For same size pipe SS./P.U. has more frictional loss compared to SS/PU
pipes
