HYDRAULISCS & PNEUMATICS LAB – 15ME45P 2020-21
MAJOR (FRICTION) LOSSES IN PIPES
AIM: To determine the co-efficient of friction (friction factor) for the given pipe.
APPARATUS: Pipe friction apparatus, Differential monometer, Stop watch, Measuring tank,
Piezometer, Scale etc.
THEORY: Various fluids are transported through pipes. When the fluid flows through pipes,
energy losses occur due to various reasons, among which friction loss is the predominant one.
In a fluid carrying system there will be some loss due to friction. The major factor
contributing to the energy loss in any pipe flow is due to friction. Estimation of frictional losses
is important from engineering point of view as the design of pipe mains carrying water from
any reservoir to the township over a long distance mainly depends upon the friction factors. In
the water distribution systems one should find out the total head loss due to friction along with
other losses, in order to decide the required height of overhead tank and also to choose the
capacity of pump required.
An idea of head loss due to friction is necessary to arrive at the head to be maintained
at the supply point, so that certain minimum head is made available at the tail end of the
distribution system.
The Darcy-Weisbach equation can be used to calculate the major head loss due to
friction in pipes or tubes.
4 f l v2
hf =
2 gd
Where hf – head loss due to friction.
f - co-efficient of friction.
l - length of pipe.
v – velocity of flow.
g – acceleration due to gravity – 9.81 m/sec2.
d - diameter of pipe.
DEPARTMENT OF TECHNICAL & COLLEGIATE EDUCATION, BENGALURU, KARNATAKA Page 1
HYDRAULISCS & PNEUMATICS LAB – 15ME45P 2020-21
PROCEDURE:
Note down the diameter & length of the pipe. Also record the dimensions of collecting
tank.
Allow the water to flow through pipe by opening the discharge valve and maintain the
steady flow.
Remove any air bubbles present in the pipe & monometer completely.
Note down the monometer readings (h1 & h2).
Note down the time ‘t’ taken for ‘H’ cm (say 0.1 m) rise of water in Measuring tank.
Repeat the experiment by increasing the flow rate.
Tabulate the results.
OBSERVATIONS:
Diameter of pipe d= m
Length of pipe (length between pressure tapping) l= m
Area of pipe a= m2
Area of measuring tank A=LxB= m2
TABULAR COLUMN:
Monometer readings Time for ‘H’ m rise Co-efficient
Sl. Discharge Velocity of flow
of water in tank of friction
No. ‘h1’ m ‘h2’ m hf =12.6(h1~h2) m ‘Q’ m3/s ‘v’ m/s
‘t’ sec ‘f ’
DEPARTMENT OF TECHNICAL & COLLEGIATE EDUCATION, BENGALURU, KARNATAKA Page 2
HYDRAULISCS & PNEUMATICS LAB – 15ME45P 2020-21
CALCULATIONS:
Volume of water collected in measuring tank, V = A x H = m3
V
Actual Discharge Q = m3/s
t
Q
Velocity of water v = m/s
a
2 g d hf
Co-efficient of friction f =
4 l v2
RESULT:
Co-efficient of friction of the given pipe f =
REFERENCE:
1. Bansal. R. K., “Fluid Mechanics and Hydraulics Machines”, 9th Edition,
Laxmi Publications Private Limited, New Delhi. 2011.
2. R. S. Khurmi, “Fluid Mechanics and Machinery”, S. Chand and Company, 2nd
Edition, 2007.
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