FLUIDS MECHANICS II
VENTURI METER
LAB EXPERIMENT 4
Name
: Tandisizwe
Surname
: Sixaxa
Student Number
: 215017293
Submission Date
: 13th Oct 2017
1.OBJECTIVE
Aim of this experiment is to:
The main objectives of this experiment is to obtain the coefficient of discharge from experiment data by
utilizing venture meter and, also the relationship between(h1-h2) against flow rate, Coefficient of
Discharge against Flow Rate.
2.APPARATUS




Venturi meter
Two supply hoses
Hydraulic Bench or Measuring Tank
Stop Watch
3.DESCRIPTION OF THE EXPERIMENTAL SETUP



A tube is connected to each to the inlet and outlet of a venture meter
The tube connected to the outlet of Venturi meter is connected to measuring tank.
The adjustable screws are adjusted to level the venture meter.
4.EXPERIMENTAL PROCEDURE



Setup the apparatus as shown in installation and Assembly on page, so you can read all the water at
full flow
Now slightly reduce the flow rate through the meter, and wait for it to stabilize. Use the hydraulic
bench to measure the flow
Record the pressure tapping readings and the flow. Remember to convert your flow into volume
flow of m3/s
5.RESULTS

i.
Sample of calculations
4𝑙
35.28
𝑄 = 1.1337 ∗ 10−3 𝑚3 /s
ii.
iii.
iv.
ℎ1 = 0.272m
ℎ2 = 0.248m
ℎ1 − ℎ2 = 0.272-0.248 = 0.024m
v.
√ℎ1 − ℎ2 =√0.272 − 0.248 = 0.155m
vi.
𝑄(𝑡ℎ𝑒𝑜) = 𝑎2 ∗ √
2𝑔(ℎ1 −ℎ2 )
𝑎
1−(𝑎2 )^2
1
= 201.1 ∗ 10−6 ∗ √
2∗9.81∗0.024
2
201.1∗10−6
)
530.9∗10−6
1−(
=1.491 ∗ 10−4 𝑚3 /𝑠
𝐾 = 𝑎2 √
2𝑔
𝑎 2
1−( 2 )
𝑎1
= 201.1 ∗ 10−6 ∗
2 ∗ 9.81
√
201.1 ∗ 10−6
1−(
)
530.9 ∗ 10−6
=9. 627 ∗ 10−4
𝐶=
=
𝑄
𝐾√(ℎ1 −ℎ2
1.491∗10−4
9.627∗10−4 √0.272−0.248
=1
𝑄(𝑎𝑐𝑡) = 𝑎2 ∗ 𝑐𝑑 ∗ √
2𝑔(ℎ1 − ℎ2 )
𝑎
1 − (𝑎2 ) ^2
1
2
=201.1 ∗ 10−6 ∗ 1 ∗ √
2∗9.81∗0.024
2
201.1∗10−6
)
530.9∗10−6
1−(
=1.491 ∗ 10−4 𝑚3 /𝑠
Q=4/1000×30
=1.333×10-4m3/s
Qact = CdA2√2gh/1-(A2/A1)2
Cd= 1.333×10-4/√2×9.81×0.02/1-(201.1×10-6/530.9×10-4)2
=
1.333×10-4m3/s
Table 1-Experimental Values obtained for h2 and h1
Vol.
(m3)
4
5
6
7
8
Time(s) h1(mm) h2(mm) h1-h2(mm)
30
36.38
42.76
51.49
57
272
254
234
178
112
248
220
156
70
50
24
34
78
108
62
(h1-h2)½
(mm)
4.899
5.831
8.832
10.392
7.874
Qact(m³/s)
Qtheo(m³/s)
C(x10³)
1.333×10-4
1.366×10-4
1.403×10-4
1.359×10-4
1.404×10-4
1.491 ∗ 10−4
1.775×10-4
2.668×10-4
3.163×10-4
2.397×10-4
0.032
0.032
0.032
0.032
0.032
Table2-Experimental Head Values for ideal curve
Discharge
A(mm)
B(mm)
C(mm)
D(mm)
E(mm)
F(mm)
G(mm)
H(mm)
I(mm)
J(mm)
K(mm)
1st
2nd
3rd
4th
5th
Area(𝒎𝒎𝟐 )
272
254
234
138
90
530.9
268
250
208
136
86
422.7
262
244
190
114
82
265.9
248
220
156
70
52
201.1
250
224
160
80
72
221.4
254
232
178
98
88
267.9
258
240
188
118
108
319.2
268
248
196
122
116
374.6
262
244
192
128
122
434.8
264
246
199
132
128
499.2
268
248
200
136
132
530.9
6.GRAPHS
Qtheo Vs (h1-h2)^1/2
12
10,392
10
8,832
8
7,874
6
(h1-h2)^1/2
Q theo
5,831
4,899
4
2
0
4
5
6
7
8
Qtheo(m^3/S) VS C (X10^-3)
0,035
0,03
0,025
0,02
0,015
0,01
0,005
0
1
2
3
Qtheo(m^3/s)
4
C (x10^-3)
5
Ideal Curve
530,9
530,9
499,2
434,8
422,7
374,6
319,2
272
254
234
268
250
208
138
90
136
86
265,9
262
244
190
114
82
248
220
201,1
250
224
221,4
156
160
258
240
268
248
262
244
264
246
268
248
178
188
196
192
199
200
118
108
122
116
128
122
132
128
136
132
98
88
80
72
70
52
1st
267,9
254
232
2nd
3rd
4th
5th
Area(
7. CONCLUSION
As a conclusion, the experiment that have been carried out were successful, even though the data
collected are a little bit difference compared to the theoretical value. The difference between the
theoretical value and the actual value may mainly due to human and servicing factors such as parallax
error. This error occur during observer captured the value of the water level, and . Besides that, it
also may because there is bubble inside the pipe line. This is because the bubble was not properly flushed
during bleeding. There is no other relative motion between the fluid particles. There is only stress that will
be a normal stress which is equal to the pressure. There are a lot of possibilities for the experiment will
having an error. Therefore, the recommendation to overcome the error is ensure that the position of the
observer’s eye must be 90° perpendicular to the reading. Other than that, ensure that the bubble was fully
removed from the pipe line.
8.REFERENCE
1. http://www.cee.mtu.edu/~dwatkins/ce3600_labs/venturi.pdf
2. http://intro2u.net/flowmeter/orifice-meter.htm
3.http://www.roymech.co.uk/Related/Fluids/Fluids_Or_No_Ven.html#venturi
5. Fluid Mechanics Fundamentals and Applications, Yunus A.Cengel and John M.Cimbala