CIV 342 Civil Engineering Hydraulics Laboratory Energy Losses in Pipes Laboratory Experiment #3 Section

CIV 342 Civil Engineering Hydraulics Laboratory

Energy Losses in Pipes

Laboratory Experiment #3
Section: Wednesday
Experiment Date: 09/28/18
Due Date: 10/07/18

Individual Lab Report
Tashi Thakuri

Table of Contents
Introduction ————————————————————————————————- 2
Materials and Methods ———————————————————————————– 2
Test Results ————————————————————————————————– 3
Discussion —————————————————————————————————- 5
Conclusion ————————————————————————————————— 6
Sample Calculations ————————————————————————————— 7
References ————————————————————————————————— 8

1

Introduction
Energy is lost due to various reasons, while the fluid is flowing through the channel.
These losses are major losses (due to friction) and minor losses (due to change in pipe fittings).
As for this experiment, it is only concern with the major losses. The main objective of this lab
was to determine the head loss due to friction between the fluid and the pipe walls, and to
evaluate the associated friction factor defined by Darcy Weisbach. These two important variables
are to be determined through different ranges of flow rates for both laminar and turbulent flows.
The significance of this experiment is that, there are many systems in which certain flowrate
should be maintain and knowing the major loss will help us maintain the flow rate throughout the
system ?. It is hypothesized that with the increase in water flow there will be increase in loss of
energy because of the internal friction of the fluid, when the fluid flows in a very low velocity
there will be very less internal friction but as the flow increases the internal friction in the fluid
will also increase. Whereas, the friction due to roughness will be the same as it is flowing
through the same channel.
Materials and Methods
This lab experiment was performed as per the lab manual handed in class. The materials
used for this experiment were F1-10 Hydraulics bench, F1-18 pipe friction apparatus, graduated
cylinder, a stopwatch, and a thermometer. There was nothing that was changed while performing
the experiment. The experiment started by removing all the air from the system. Then, the
pressure gauge was zeroed and the flow control valve was fully open to record the head loss,
water collected and time taken to collect the water. This was repeated 6 times for both laminar
and turbulent flow for the purpose of calculating the rate of flow of the fluid.
2

Test Results

3

4

Discussion
This lab was conducted for the purpose of measuring the energy loss in the system. For
this experiment to be accomplish, the data for both laminar and turbulent flow are needed.
Turbulent flows data were collected when the pressure difference value was above 4 KPa and for
laminar when pressure difference was lower than 4 KPa. The data for the pressure difference is
important because the head loss is directly Proportional to the pressure difference. And this h?
pressure difference is due to the effects of viscosity.
This lab report had a lot of calculations, in order to calculate those we had go through
certain steps. The relative roughness value was 0.00083 which was calculated by dividing the
surface roughness ( ) to the diameter of the test pipe (d). The diameter was already provided but ?
the surface roughness value was from the corresponding value from the table in moody diagram
provided in the manual. This relative roughness played a major key to find the friction factor for
the turbulent flow, but for the laminar flow it did not affect at all because for the laminar flow we
had used the formula (64/Reynolds Number).
The data from both laminar and turbulent flow shows that the correct range for both the
flows. The Reynold Numbers for turbulent flow are 7622.6, 8810.23, 9392.62, 9554.5, 9648.7,
9705.47 which are all greater than 4000. As for the laminar flow values are 940.2, 1190.7,
1343.6, 1488.4, 1650.8, 1808.6 which are below 2000. This values corresponded to the
respective range.
Everything in this data is consistent with the increase in flow rate; velocity is increasing
and with the increase in velocity the Reynolds number is increasing and so is the pressure head
because every variable is dependent to one another and is directly proportional. But for the
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second trial of the turbulent flow is inconsistent. Although it is in the range of the turbulent flow
but the flow rate, velocity and Reynolds Number is comparatively high. This could be because of
the human error, different people reads the graduated cylinder differently and for our case we
were doing the reading turn by turn. Even the friction factor results were very consistent, the
higher the pressure difference, flow rate and velocity the lower the friction factor. This is
because they are inversely proportional in the Darcy-Weisbach equation. The friction factor
values that were calculated from the data of the experiment were very close to the values from
the moody diagram. The error percentage were also very small nothing more than 4 percent.
These errors could occur due to error in the measurement of the length or diameter of the pipe.
Error of 1 mm in the length of the 0.5 m long pipe is 0.2% and the error for the 0.0003 mm in the
diameter of the 0.003 m pipe is 0.01%. This errors looks very small but in the long run when you
carry the error all the way it will accumulate and bring you a difference.
Conclusion
In conclusion, our lab was successful. We successfully determine the head loss due to
friction between the fluid and the pipe walls, and evaluated the associated friction factor defined
by Darcy Weisbach. The results also proves that our hypothesis ?that with the increase in water
flow there will be increase in loss of energy because of the internal friction of the fluid, when the
fluid flows in a very low velocity there will be very less internal friction but as the flow increases
the internal friction in the fluid will also increase. Whereas, the friction due to roughness will be
the same as it is flowing through the same channel was correct. ? We completed the experiment
with minimal errors and for the future investigation, it would be better if we could use
transitional flow as well with fluids of different viscosity.
6

Sample Calculations
r o s s S e c t i o n a l A r e a o f T e s t P i p e , A )C = ? × (
2d 2

) . 0 7 1 0 mA = ? × (
20 . 0 0 3 m 2
= 7 × 1 ? 6
2

u r f a c e R o u g h n e s s ,S ?
d
. 0 0 0 8 3?
d =
( 3 m m )( 0 . 0 0 2 5 m m )
= 0

l o w R a t e , QF
t =
T i m e T o C o l l e c t , t ( s )V o l u m e C o l l e c t e d , V ( m )3

. 3 8 1 0 m / sQ
T =
( 9 . 3 4 s )( 0 . 0 0 0 2 1 9 m )3
= 1 × 1 ? 5
3

e l o c i t y , vV =
? d 24 Q
t

. 9 5 m / sv =
? × ( 0 . 0 0 3 m ) 24 × ( 1 . 3 8 1 × 1 0 m / s )? 5
3
= 1

e y n o l d s N u m b e r , R eR =
?v d

e 6 2 2 . 6 4R =
( 7 . 6 9 × 1 0 m / s )? 7
2( 1 . 9 5 m / s ) × ( 0 . 0 0 3 m )
= 7

e a d l o s s , ? hH =
? g? P

h . 1 6 m? = ( 1 1 4 0 0 P a )
( 1 0 0 0 k g / m ) × ( 9 . 8 1 m / s )3 2 = 1

r i c t i o n F a c t o r f o r L a m i n a r F l o w , fF = 6 4
R e
Friction Factor for Laminar Flow : . 0 6 8 1f = 6 4
9 4 0 . 1 5 6 = 0

r i c t i o n F a c t o r f o r T u r b u l e n t F l o w , fF =
?v d

Friction Factor for Turbulent Flow: . 0 3 5 8f =
( 7 . 6 9 × 1 0 m / s )? 7
2( 1 . 9 5 m / s ) × ( 0 . 0 0 3 m )
= 0

Error Percentage, ? ?E ? = 0 0 %
T h e o r e t i c a l V a l u eE x p e r i m e n t a l V a l u e ? T h e o r e t i c a l V a l u e
× 1
Error Percentage: = 2.3%0 0 %E =
0 . 0 0 3 50 . 0 0 3 5 8 ? 0 . 0 0 3 5
× 1

a t u r a l l o g o f F r i c t i o n F a c t o r , l n fN
n f n ( 0 . 0 3 5 8 ) . 3 3l = l = ? 3

a t u r a l l o g o f R e y n o l d s N u m b e r , l n R eN
n R e n ( 7 6 2 2 . 6 4 ) . 9 4l = l = 8

a t u r a l l o g o f H e a d L o s s , l n hN
n h n ( 1 . 1 6 ) 0 . 1 5 0l = l =

a t u r a l l o g o f V e l o c i t y , l n vN
n v n ( 1 . 9 5 ) 0 . 0 2 5l = l =
7

Reference

1 Chaudhry, M.H. (2008). ?Open Channel Flow ? (2nd.ed.). Springer.
2 CIV342 Laboratory Manual Energy Loss in Pipes, ?Stony Brook University Civil Engineering
Department ?, 2018, Sogut, Deniz Velioglu
3 Sogut, D.V . “Week 4: Lecture Notes” Stony Brook University. 5 October 2018. Lecture.

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