Pipes and Fittings (1)

7/23/2019 Pipes and Fittings (1)

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Energy Analysis of Pipes and Fittings

Clifford Hansel Fel A. Sagarino1, Eros Tristan A. Jabines2, and Dewey Siong

Abstra!t" Losses are always present in a piping system and this should be taken into

consideration. The experiment deals with the losses on pipes and fittings. The head losses in the

system are observed as a drop in the hydraulic and energy grade line. When fluid flows through

any passage which in the experiment it passes through pipes and fittings there is hydraulic drop

due friction and some restrictions and this head losses can be determined by the use of

manometers installed along the piping system. Losses can be read as the change of height of the

fluid seen from the manometer. The head of the tank is maintained at a constant to achieve.

Corresponding pipe coefficients (K are determined by getting the volume flow rate hence

obtaining the velocity of the fluid along the pipes. The K values of the similar and identical

fittings calculated is used to calculate the head loss for the piping system that do not have

manometers installed in similar and identical fittings. Lastly! the hydraulic and energy grade line

of each pipe is plotted in a graph to observe the head losses along the pipes.

A#t$or %eywords""ressure drop# "ipe friction# $ischarge loss# Losses in "ipe %ittings#

&ydraulic grade# 'nergy grade line# anometer# "ie)ometer

*************************

+,tudent! $epartment of echanical 'ngineering! -niversity of ,an Carlos! Cebu City!

"hilippines. 'mail/ chf*saga012yahoo.com

0,tudent! $epartment of echanical 'ngineering! -niversity of ,an Carlos! Cebu City!

"hilippines. 'mail/ eros3abines2yahoo.com

4,tudent! $epartment of echanical 'ngineering! -niversity of ,an Carlos! Cebu City!

"hilippines. 'mail/d3ohn*+12yahoo.com

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mailto:[email protected]:[email protected]


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&ntrod#!tion

%luid experiences losses along a piping system and is taken into consideration in piping

construction. "ipe losses happens along the pipe length and pipe fittings which includes the gate

valve. The losses in pipe length may be computed using the $arcyWeisbach e5uation("otter!

06+0. 7ther cause of this losses may be due to sudden expansion and contraction of the flow of

the fluid (Cengel! 0668! installations of orifice! venture flow meters! rotameter! and flow no))les

(Cimbala! 0661! installations of pipe fittings ('sposito! 0666! and the pressure losses due to

some leaks along the fittings(orse! +9:4.The list can contribute to the decreasing of the

hydraulic and energy grade line wherein the greater the slope upward! the greater the loss per

unit length (Kundu! 066;. "iping systems installations and materials used must follow the


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>eynolds number which the properties of the fluid flowing through the pipe and pipe

characteristics are parameters used to determine the friction factor with the use of the moody

diagram. With the >eynolds number! it will be utili)e which ultimately solve the losses along

pipes by the use of the $arcyWeibach e5uation ("otter! 06+0. The velocity head plays a key

role in establishing the energy grade line of the pipeline. &ydraulic grade line is defined as

elevation head plus pressure head and energy grade line is the hydraulic grade line plus the

velocity head (White! 066;.

E'peri(ental )et$ods

?n doing the experiment! some safety ha)ards were observe to safeguard the student. @efore

doing the experiment a centrifugal pump! as shown in %ig. 0 is re5uired to provide a steady flow

of water to the tank. The centrifugal pump re5uires an axial pump at is used to deliver water to

the centrifugal pump as in a method of priming. ?nitially air pocketswere removed from the

centrifugal pump when the axial pump is delivering water to it! if not done! this will cause

damage to the pump by virtue of cavitation(Wright! +999."riming was needed for the

centrifugal pump because pumping air will cause the centrifugal pump to reach speed of Arun

awayB that will lead to overheating('sposito! 0666. When there is a steady flow of water

coming out of the centrifugal pump gate valve the axial pump is turned off.

The experiment proper was started by choosing a tank head by turning the crank head control to

+66cm from the cylinder reading. Water was then operated to flow to a single pipe line at a time.

%low is measured by the use of a 00 liter bucket with the help of a timer. The method must be

done with two person and the velocities of each pipe flow were then calculated. 'ach pipe fitting

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were studied by the use of manometers in between the fitting but some do not have manometers

to determine the head loss along it. The difference in manometer height is recorded to be the

head loss due to the pipe fitting and in some connections because of the pipe length. The head

loss caused by the fitting may be computed by this e5uation/

hLfitting=K V

2

2g (+


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The relative roughness! ! is assumed to be 6.66+: for galvani)ed pipe. Re is the >eynolds

number.

The measured and calculated data of the experiment are shown on Tables +8.

,ample Calculations/

The K values of the =ate valve at pipe line +at tank head of +66cm is calculated as follows/

(K V2

2g)gatevalve1=HLGate valve1 (4

( K(70.35s )

2

2(32.2fts2 )(12ft))gatevalve1=2 (1KGatevalve 1=KGatevalve2=KGatevalve3=0.3123 (:

,ince the other gate valve head loss cannot be measured! they may be calculated as follows/

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2(32.2ft

s2)()=1.2119

0.3123(54.7625 s)2

HL Gatevalve2=

(8

12

2(32.2ft

s2)()=0.2838

0.3123(26.5 s)2

HLGate valve3=

(D

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The experiment performed shows that each fitting corresponds to a head loss that is uni5ue to

each other. These losses can be termed as the decrease energy of the piping system along the

pipes and fittings. This is stated in (Kundu! 066; that when the slope of the &ydraulic or 'nergy

grade line increases with respect to the pipe length and fittings. The head loss also increases

corresponding to the increase in velocity. This observation is observed in ("otter! 06+0 that head

loss is proportional to the average velocity. This is due to the decrease in velocity since velocity

is directly proportional to the losses in the fitting.


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g E gravitational constant! 40.4 inGs0

HV E Felocity &ead! in

*eferen!es


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Kundu! ". K. (066;. %luid mechanics.

orse! %. (+9:4. "ower "lant 'ngineering

"otter! . C. (06+0. echanics of %luids. Cengage learning

White! %. . (066;. %luid mechanics

Wright! T. (+999. %luid achinery/ "erformance!


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%ig 0. 'xperimental ,et up

%ig 4. List of coefficient of loss K in "ipe fittings

%ig. 1. &ydraulic and 'nergy grade line of "ipeline + ('xperimental and Theoretical vs. ,ection

%ig. :. &ydraulic and 'nergy grade line of "ipeline 0 ('xperimental and Theoretical vs. ,ection

%ig. 8. &ydraulic and 'nergy grade line of "ipeline 4 ('xperimental and Theoretical vs. ,ection

Table +/ easured and computed data on "ipeline + at Tank &ead of +66cm

%low rate (in4Gs 0D9.D+4

$iameter of outlet! in 0.0:

velocity at outlet! inGs D6.4:

&ead of outlet! in

"ipeline +

,ection number &ead loss! in

+ 0

0 +9.;:+D

4 4

1 06.6;0:

: 1.9:

8 +4.;:

D 4

; 4.180:

9 4+6 +4.D418

Table 0/ Theoretical data on "ipeline +

"ipeline + %ittings &ead loss! in %low rate (in4Gs 0D9.D+4

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=ate

valve +.6;;D $iameter of outlet! in 0.0:

-nion 6.0:8+D velocity at outlet! inGs D6.4:

%ittings 6.0:8+D &ead of outlet! in

1: bend 0.01+:

1: bend 0.01+:

Table 4/ easured and computed data on "ipeline 0 at Tank &ead of +66cm

%low rate (in4Gs 0+D.D1

$iameter of outlet! in 0.0:

velocity at outlet! inGs :1.D80:

&ead of outlet! in

"ipeline 0


+ +.0++9

0 6.8+:4 48.4

1 +.;D8

: +.;+D;

8 1.48D

D 4

; +.;D8

9 +6.4D1

+6 +.:8;4

Table 1/ Theoretical data on "ipeline 0

"ipeline 0 %ittings &ead loss! in %low rate (in4Gs 0+D.D1

=ate valve 6.8:9D $iameter of outlet! in 0.0:

%low meter 0D.+810 velocity at outlet! inGs :1.D80

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-nion 6.+::0 &ead of outlet! in

%ittings 6.+::0

96 bend 0.9+6:

Table :/ easured and computed data on "ipeline 4 at Tank &ead of +66cm

%low rate (in4Gs 40.:++4:

$iameter of outlet! in +.0:

velocity at outlet! inGs 08.:&ead of outlet! in

"ipeline 4


+ 6.0;4;

0 6.D:0

4 81

1 6.0;:+8

: 6.816D

8 6.+D:6

D ;.:; 0.0::4:

9 8.109

+6 6.:D64

Table 8/ Theoretical data on "ipeline 4

"ipeline 4

%ittings &ead loss! in %low rate (in4Gs

40.:++4

:

=ate valve 6.040: $iameter of outlet! in +.0:

-nion 6.6:1D

velocity at outlet! inGs 08.:

&ead of outlet! in

%low meter 8.48

96 bend +.60:;

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%ig +. Commonly used "ipe %ittings

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%ig 0. 'xperimental ,et up

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%ig 4. List of coefficient of loss K in "ipe fittings

Courtesy of engineering toolbox

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Experimental (HGL)

Theoretical (HGL)

Experimental (EGL)

Theoretical (EGL)

%ig. 1. &ydraulic and 'nergy grade line of "ipeline +

('xperimental and Theoretical vs. ,ection

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Experimental(HGL)

Theoretical(HGL)

Experimental(EGL)

Theoretical(EGL)

%ig. :. &ydraulic and 'nergy grade line of "ipeline 0

('xperimental and Theoretical vs. ,ection

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Experimental(HGL)

Theoretical9HGL)

Experimental(EGL)

Theoretical(EGL)

%ig. 8. &ydraulic and 'nergy grade line of "ipeline 4

'xperimental and Theoretical vs. ,ection

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Date post:	13-Feb-2018
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