PRESENTATION ON SUBJECT
• FLOW THROGHU BRANCH PIPES
• POWER TRANSMISSION THROGHU PIPE
• FLOW THROUGH NOZZEL
• WATER HAMMER IN PIPE
BE-3RD YEAR /5TH SEM
FLUID POWER ENGINEERING
FLOW THROUGH NOZZEL
•Fig. shows a nozzle fitted at the end of a long pipe. The
total energy at the end of the pipe consists of pressure
energy and kinetic energy.
•By fitting the nozzle at the end of the pipe. the total
energy is converted into kinetic energy.
•THUS NOZZLES ARE USED, WHERE HIGHER
VELOCITIES OF FLOW ARE REQUIRED.
The examples are :
1.In case of Felton turbine, the
nozzle is fitted at the end of the
pipe (called penstock) to
2.In case of the extinguishing fire,
a nozzle is fitted at the end of
the hose to increase velocity.
L = length of the pipe,
A = area of the pipe
V= velocity of flow in pipe,
H = total head at the inlet of the pipe,
d = diameter of nozzle at outlet,
V = velocity of flow at outlet of nozzle,
a = area of the nozzle at outlet
f = co-efficient of friction for pipe.
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
•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
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
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
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 :
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
FLOW THROUGH BRANCHED PIPES
When three or more reservoirs
are connected by means of
pipes, having one or more
junctions, then this
arrangement is called
branching of pipe.
As shown in figure three reservoirs at different
level connected to a single junction.
The main aim to analyze branching of pipe is
to determine the discharge at given pipe
diameters lengths and co-efficient of friction.
•When three or more reservoirs are connected
by means of pipes, having one or more
junctions, the system is called a branching pipe
• Figs how's three reservoirs at different levels
connected to a single junction. by means of
pipes which are called branched pipes
The lengths, diameters and co-efficient of
friction of each pipes is given. It is required
to find the discharge and direction of flow in
each pipe. The basic equations used for
solving such problems are:
I. Continuity equation which means the inflow of
fluid at the junction should he equal to the
outflow of fluid.
II. Bernoulli's equation. and
III. Darcy-Weisbach equation
•Also it is assumed that reservoirs are very
lagged and the water surface levels in the
reservoirs are constant so that steady conditions
exist in the pipes.
•Also minor losses are assumed very small. The
flow from reservoir A takes place to junction 0.
The flow front junction I) is towards reservoirs C.
Now the flow from junction D towards reservoir II
will take place only when piczometric head at D.
The analysis of branched pipes is useful
while studying or designing city water supply
system which involving the number of pipe
loops. Also in this case, number of lines
added in parallel to existing line when
• 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.
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 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
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.
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.
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.