ENGINEERNG INSTRUMENTATION
MESB2014 2021/2022
INDIVIDUAL SHORT REPORT
LAB 2: VELOCITY MEASUREMENT AND
DETERMINATION OF DISCHARGE
COEFFICIENT
NAME
: DUEREH NADER
ID
: ME 0107788
SECTION: 01D
GROUP NO: 4
LAB NO: 2
Group members: Alafif Abudulaziz Omar Ahmed, ME0105549
Jayshren Velavan, ME0106049
Muhammad Irfan Aiman Bin Rosman, ME0107793
Muhammad Izharul Aimin Bin Samsuddin, ME0107794
Muhammad Hafizuddin Bin Shikh Awadz, ME0107798
Nurul Aliaa Binti Azlan, ME0105143
Safrizal Amirul Annas Bin Kartolo, ME0105425
PERFORMED DATE
SUBMISSION DATE
8 OCTOBER 2021
18 OCTOBER 2021
PRE-LAB QUESTION
The Pitot tube is inserted into the
duct with the tip pointed toward
the airflow. The positive port of
the manometer is connected to the
total pressure port (Pt) and the
negative to the static pressure port
(Ps). The manometer will then
display velocity pressure which
can be converted to velocity.
EXPERIMENT 1: Velocity Measurement Using Pitot Tube
OBJECTIVE
To learn the method of measuring air flow velocity using pitot tube. The student will
understand the working principle of pitot tube as well as the importance of Bernoulli equation
in deriving and calculating the velocity.
APPARATUS
DATA AND RESULTS
Data Sheet for Velocity Measurement Using Pitot Tube
Pitot Tube at 54 mm
Pitot Tube at 294 mm
TRAVERSE
Static 'Pressure' Reading
Static 'Pressure' Reading
POSITION
______81______(mm)
_____103_______(mm)
(mm)
Stagnation
velocity Stagnation
velocity
∆p
∆p
∆x
∆x
'Pressure'
'Pressure'
(m/s)
(m/s)
(N/m2)
(mm)
(mm) (N/m2)
Reading
Reading
(mm)
(mm)
0
10
20
30
40
50
60
70
80
TRAVERSE
POSITION
(mm)
0
10
20
30
40
50
60
70
80
80
79
77
78
77
78
79
78
79
1
2
4
3
4
3
2
3
2
7.72
15.44
30.88
23.16
30.88
23.16
15.44
23.16
15.44
3.60
5.07
7.17
6.21
7.17
6.21
5.07
6.21
5.07
Pitot Tube at 774 mm
Static 'Pressure' Reading
______110______(mm)
Stagnation
velocity
∆p
∆x
'Pressure'
(m/s)
(mm) (N/m2)
Reading
(mm)
80
82
80
78
78
79
80
90
92
30
28
30
32
32
31
30
20
18
231.60
216.16
231.60
243.04
243.04
239.32
231.60
154.40
138.96
19.65
18.98
19.65
20.29
20.29
19.97
19.65
16.04
15.22
80
79
77
78
77
78
79
78
79
23
24
26
25
26
25
24
25
24
177.56
185.88
200.72
193.00
200.72
193.00
185.28
193.00
185.28
17.20
17.57
18.29
17.94
18.29
17.94
17.57
17.94
17.57
Pitot Tube at 1594 mm
Static 'Pressure' Reading
_____115_______(mm)
Stagnation
velocity
∆p
∆x
'Pressure' (mm)
(m/s)
(N/m2)
Reading
(mm)
80
82
84
80
82
86
86
86
84
35
33
31
35
33
29
29
29
31
270.20
254.76
239.32
270.20
254.76
223.88
223.88
223.88
129.32
21.22
20.61
19.97
21.22
20.61
19.32
19.32
19.32
19.97
TRAVERSE
POSITION
(mm)
0
10
20
30
40
50
60
70
80
Pitot Tube at 2534 mm
Static 'Pressure' Reading
_______120_____(mm)
Stagnation
velocity
∆p
∆x
'Pressure'
(m/s)
(N/m2)
(mm)
Reading
(mm)
80
86
90
92
90
90
92
92
100
40
34
30
28
30
30
28
28
20
308.80
262.48
231.60
216.16
231.60
231.60
216.16
216.16
154.40
22.67
20.92
19.65
18.98
19.65
19.65
18.98
18.98
16.04
SAMPLE OF CALCULATION
DISCUSSION
This fluid velocity is achieved under ideal conditions where there is no loss of constant
incompressible flow. Pitot tube losses and friction losses on all surfaces, as well as
compressibility and unstable flow effects must be taken into account. As the fluid velocity
increases, so does the differential head of the gauge. The Pitot tube is used primarily for
temporary flow measurements, but in some cases, it is also used for permanent flow
monitoring.
According to the graph, its showing that the maximum velocity of Pitot Tube at 2534mm is at
0 mm of Traverse position. In opposite way, the velocity is lowest at Pitot Tube 54mm. while
the others are showing the similar value. As the Bernoulli’s equations that use to calculate the
velocity from difference pressure, we can say that at the initially the velocity can’t be
determined due to friction force but we can record the maximum velocity when its reach the
middle path where the air can flow freely.
Random error, fixed error, and experimental error are three types of errors that can contribute
to different results when conducting experiments. Parallax errors should be avoided when
measuring manometer tubes, as they can affect the calculation used to measure air velocity.
CONCLUSION
The air velocity does not remain constant throughout the experiment. The forces that occur at
specific locations have an impact on this conclusion. A pitot tube can be used to determine the
velocity profile of a pipe. To obtain a reasonably accurate velocity value, a correction factor
must be included.
EXPERIMENT 2: Determination of discharge coefficient
OBJECTIVE
To determine the discharge coefficients, CD for orifice plate and the small nozzle.
APPARATUS
DATA AND RESULTS
Static ‘Pressure’ Readings when using Standard Nozzle (80 mm)
Damper Openings (% Openings)
POINTS
Room
“pressure”
After nozzle
54mm
294mm
774mm
Before
Orifice
After Orifice
1574mm
2534mm
0%
25%
75%
100%
78
50%
mm of kerosene
78
80
78
78
81
81
82
83
84
82
82
83
84
85
82
84
85
86
88
82
84
85
87
88
83
83
85
857
88
102
98
96
172
156
140
188
178
152
194
172
154
198
176
156
Static ‘Pressure’ Readings when using Standard Nozzle (50 mm)
Damper Openings (% Openings)
POINTS
Room
“pressure”
After nozzle
54mm
294mm
774mm
Before
Orifice
After Orifice
1574mm
2534mm
0%
25%
75%
100%
77
50%
mm of kerosene
45
80
75
75
85
87
85
84
85
108
109
96
97
98
113
115
100
101
102
115
117
101
103
104
115
117
100
102
103
100
97
95
167
152
142
180
163
149
186
168
154
189
169
155
Discharge, Qi and coefficient of discharge, Cᴅ for both
Damper
Standard nozzle
Openings (%) Discharge, Qi
Orifice, CD
(m^3/s)
0
1.72 x 10-4
0.229
25
3.45 x 10-4
0.208
50
3.45 x 10.-4
0.194
75
3.45 x 10-4
0.188
100
3.85 x 10-4
0.207
Small nozzle
Discharge, Qi
Nozzle, CD
(m^3/s)
3.55 x 10-5
0.132
8.03 x 10-5
0.139
0.194 x 10-5
0.181
8.27 x 10-5
0.131
9.08 x 10-5
0.141
Reynolds number for both nozzle at corresponding damper opening
Damper opening (%)
REYNOLDS NUMBER
Standard nozzle
Small nozzle
0
1190.21
627.30
25
2380.43
1420.94
50
2380.43
1962.95
75
2380.43
1462.29
100
2661.40
1604.89
SAMPLE OF CALCULATION
DISCUSSION
1.An orifice is a small aperture through which the fluid passes. The thickness of an orifice in
the direction of flow is very small in comparison to its other dimensions. If a tank containing a
liquid has a hole made on the side or base through which liquid flows, then such a hole may be
termed as an orifice. When the fluid will enter its velocity will increase and the pressure will
decrease in the direction of the orifice.
2.The release coefficient Cd is defined as the ratio of the actual flow rate from the hole to the
theoretical flow rate of the hole (Qact / Qth). Flow coefficients usually range from 0.6 to 0.9
for most holes, and the value depends on the diameter of the orifice and the pipe and Reynolds
number.
3.Cd will increase with increase in damper opening.
4.When damper opening increase Cd increase, so the losses will increase. Due to the more
losses head loss will be more, so the reading height of the manometer will increase.
5.When the pressure decreasing because of velocity of air, Kerosene reading increases after
orifice plate. If the pressure increases at some particular point, then the reading will decrease.
CONCLUSION
Finally, the transverse position at the pitot tube influences the velocity of the liquid. The speed
is proportional to the value of the pitot tube position. Furthermore, the nozzle size influences
the speed value because a small nozzle produces faster liquid than a standard nozzle. The
outflow coefficient of the small nozzle is greater than that of the conventional nozzle. Because
the discharge coefficient is a dimensionless range, it is used in fluid systems to describe the
flow and pressure loss behaviour of nozzles and orifices.