Flow Through Pipes

1. Gandhinagar Institute of
Technology(012)
Subject : Fluid Mechanics (2141906)
Active Learning Assignment
Branch : Mechanical
Batch : 4 A / 4A3
Prepared by : - Jain Bhavesh (160120119032)
Guided By: Prof. Shaival Parikh
Topic Name:
Flow Through Pipes

2. Learning Objective
1.Losses in pipe(Major and Minor losses)
2.Flow through pipe in series,parallel and equivalent
pipe

3. ENERGY LOSSES IN
PIPE
• When a fluid is flowing through a pipe, the fluid
experiences some resistance due to which some of the
energy of fluid is lost.
1.MAJOR ENERGY
LOSSES:-
This is due to
friction.
2.MINOR
ENERGY LOSSES

4. LOSS OF ENERGY DUE TO FRICTION
 A.Darcy- Weisbach Formula:-The loss of head in pipes due to
friction is calculated by this formula,and is given by;
Where; loss of head due to friction
f=co-efficient of friction which is function of Reynolds number
L=length of pipe
V=mean velocity of flow
d=diameter of pipe

5. (b).Chezy’s Formula for loss of head due to friction in pipes:- it is
expressed as;
where;
c=Chezy’s constant

6. MINOR ENERGY LOSSES
 The loss of energy due to change of velocity of the
following fluid in magnitude or direction is called minor
loss of energy. The minor loss of energy includes:-
1)Loss of head due to sudden enlargement
2)Loss of head due to sudden contraction
3)Loss of head due to bend in pipe
4)Loss of head in various pipe fittings.
5)Loss of head due to an obstruction in pipe
6)Loss of head due to bend in pipe
7)Loss of head due to various pipe fitting

7. 1.Loss of head due to sudden enlargement:-
2.Loss of head due to sudden contraction:-
3.Loss of head at the entrance of the pipe:-

8. 4.Loss of head at the exit of the pipe:-
5.Loss of head due to an obstruction in the pipe:
6.Loss of head due to bend in a pipe:-
7.Loss of head in various pipe fitting:-

9. 1)Flow through pipe in series or flow through
compound pipe:-
If a pipe line connecting two reserviour is made up several pipes of
different diameter D1,D2,D3 etc..,and length L1,L2,L3, etc...all
connected in series(end to end),then the system is called pipes in series,in
such case.
a)The difference in liquid surface level in this two reserviour is equal to
sum of the head losses in all the section.
i.e.,

10. FIG:-Flow through pipe in series

11. 2.FLOW THROUGH PIPE IN PARALLEL:-
When a main pipe line divides into two or more parallel pipes which again join
together downstream side and continue as a main line, the pipe are said to be
parallel.

12. 3.FLOW THROUGH EQUIVALENT PIPE:-
Often a compound pipe consisting of several pipes of
varying diameter and length is to be replaced by a pipe of
uniform diameter, known as Equivalent pipe. The
uniform diameter of equivalent pipe is known as
Equivalent diameter.

13. SYPHON
Syphon is a long bent pipe which is used to Convey
liquid from a reservoir at a higher elevation when the two
are separated by a high level ground or hill
Syphon is is long bent pipe which is used to transfer
liquid from a reservoir at it higher elevation to another
reservoir at a lower level when the two reservoirs are
separated by a hill or high level ground

14. •As shown in figure two reservoirs A and B are
separated by the hill. In order to transfer liquid
from A to B reservoirs,
•They are connected by syphon. The highest point
is called summit.
•The flow through the siphon is only possible if
the pressure at the point S is below the
atmospheric pressure, Therefore pressure
difference will cause the flow of liquid through
syphon.

15.  The point C which is at the highest of the syphon is
called the summit.
 As the point C is above the free surface of the water
in the tank A. the pressure at C will be less than
atmospheric pressure.
 Theoretically, the pressure at C may he reduced to
— 10.3 in of water but in actual practice this
pressure is only — 7.6 m of water or 10.3 - 7.6 = 2.7
in of water absolute. If the pressure at C becomes
less than 2.7 in of water absolute, the dissolved air
and other gases would come out from water and
collect at the summit.
 The flow of water will be obstructed

16. APPLICATION
1 To carry water from one reservoir to another
reservoir separated by a hill or ridge.
2.To take out the liquid from a tank which is not
having any outlet.
3.To empty a channel not provided with any
outlet sluice

17. POWER IS TRANSMITTED
THROUGH
Power is transmitted through pipes by flowing water or other
liquids flowing through them.
The power transmitted depends upon :
The weight of liquid flowing through the pipe and the total
head available at the end of the pipe.
Consider a pipe AB connected to a tank as shown in Fig.. The
power available at the end B of the pipe and the condition for
maximum transmission of power will be obtained as
mentioned below :

18. L = length of the Pipe,
d = diameter of the pipe,
H = total head available at the inlet of pipe,
V = velocity of flow in pipe,
hf = loss of head due to friction, and
f = co-efficient of friction

21. • Consider a long pipe AB as shown in Fig. connected at one end to a tank
containing water at a height of H from the centre of the pipe.
• At the other end of the pipe, a valve to regulate the flow of water is
provided. When the valve is completely open, the water is flowing with a
velocity. V in the pipe. If now the valve is suddenly closed, the momentum
of the flowing water will be destroyed and consequently a wave of high
pressure will be set up.
• This wave of high pressure will be transmitted along the pipe with a
velocity equal to the velocity of sound wave and may create noise called
knock-ing. Also this wave of high pressure has the effect of hammering
action on the walls of the pipe and hence it is also known as water hammer.
WATER HAMMER IN PIPE

22. The pressure rise due to water
hammer depends upon :
(i) The velocity of flow of water in pipe,
(ii) The length of pipe,
(iii) Time taken to close the valve,
(iv) Elastic properties of the material of the pipe.

23. The following cases of water hammer in
pipes will he considered :
I.Gradual closure of valve,
II.Sudden closure of valve and considering
pipe rigid. and

24. Consider a pipe All in which water is flowing as shown in Fig.
Let the pipe is rigid and valve fitted at the end B is closed
suddenly.
Let
A = Area of cross-section of pipe AB.
L = Length of pipe.
V = Velocity of flow of water through pipe,
p = Intensity of pressure wave produced.
K = Bulk modulus of water.

25. When the valve is closed suddenly, the kinetic energy of the flowing water is
converted into strain energy of water if the effect of friction is neglected and pipe wall
is assumed perfectly rigid.

26. THANKING YOU