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FLUID MECHANICS (II)
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Experiment 8
Calibration of the Laminar Flow element, the Rota meter and the Turbine Flow meter
Objectives:
To use the Laminar Flow element, the Rota meter and the Turbine Flow meter to
measure the rate of discharge.
To determine the coefficient of discharge Cd for both the Venturi Meter and the
Orifice Meter.
Apparatus:
Turbine
Flow meter
Rota meter
Laminar Flow
element
Procedure:
Turn on the air compressor
Open the air regulator valve
Take the readings
Repeat procedure for 4 different positions
Readings:
zero 1st 2nd 3rd 4th 5th
Ps (kPa) 850 790 680 565 600 630
P1 (kPa)
100 150 200 250 300
P2 (kPa)
15 22 30 42 54
P3 (kPa)
10 18 24 36 48
Rota meter 30 40 49 57 64
laminar flow (mm) 22 79 96 108 116 121
turbine rate 520 645 735 800 848
venturi Loss (cm H2O) 1.4 3.3 4.2 4.8 5.5 6.2
Diff (cm H2O) 1.5 9.8 15.5 20.7 25.8 31.8
orifice Loss (cm H2O) 1.6 9 14.8 19.8 24.5 29.3
Diff (cm H2O) 1.5 9.8 16.3 21.8 27.7 32.3
Time (sec)
11.7 9.5 7.8 6.3 4.9
Volume (m3)
0.015 0.015 0.015 0.015 0.015
Sample of calculation (5th point):
𝑄4 =∆v
𝑡=
0.15
4.9= 3.06122449 × 10−2 𝑚3/𝑠
𝜌 =𝑃4
𝑅𝑇=
48 × 103
287 × (273 + 31)= 0.5501558𝑘𝑔/𝑚3
�̇� = 𝑄 × 𝜌 = 3.06122449 × 10−2 × 0.5501558 = 1.68415 × 10−2𝑘𝑔/𝑠 Laminar Flow Element:
𝐶𝑑 =𝑚𝐿𝐹𝐸
𝐾 × ∆𝑃 × 𝜌=
1.68415 × 10−2
(11.6 × 10−3)(12.1 − 2.2)(0.5501558)= 0.266564
Rota meter:
𝜌𝑟 =(𝜌𝑠 + 𝜌𝑎𝑡𝑚) × 1000
287(273 + 𝑡)=
(0.5501558 + 1.013) × 1000
287(273 + 31)= 0.01791623𝑘𝑔/𝑚3
𝐶𝑑 =�̇�
2.14 ×𝑅
1000× √
𝜌𝑟
𝜌𝑠
=1.68415 × 10−2
2.14 ×64
1000× √0.01791623
0.5501558
= 0.650
Turbine Meter:
𝑄𝑡 = 0.14 × 𝑇𝑀𝐼 = 0.14 × 848 = 118.72 𝑙𝑖𝑡/𝑠𝑒𝑐
𝜌 =(𝜌𝑠 + 𝜌𝑎𝑡𝑚) × 1000
287(273 + 𝑡)=
(0.5501558 + 1.013) × 1000
287(273 + 31)= 0.01791623𝑘𝑔/𝑚3
𝐶𝑑 =�̇�
𝑄𝑡
1000× 𝜌
=1.68415 × 10−2
118.721000
× 0.01791623 × 60= 0.131965
Results: Q (m3/s) 0.012821 0.015789 0.019231 0.02381 0.030612
raw (kg/m3) 0.114616 0.206308 0.275078 0.412617 0.550156
m dot (kg/s) 0.001469 0.003258 0.00529 0.009824 0.016842
laminar flow element cd 0.193898 0.183941 0.19277 0.218356 0.266564
raw r 0.012924 0.013975 0.014763 0.01634 0.017916
TMI Qt 72.8 90.3 102.9 112 118.72
cd 0.026029 0.043022 0.058036 0.089471 0.131965
rota mater cd 0.068161 0.146214 0.21776 0.404724 0.681407
Graghs:
0
0.05
0.1
0.15
0.2
0.25
0.3
0 0.005 0.01 0.015 0.02
Cd
m dot
laminar flow element
Comments: - The three meters are used for measuring the flow
- Turbine meter is preferred since it allows us to take the electrical signal to
the computer and thus used in the automatic controls
0
0.02
0.04
0.06
0.08
0.1
0.12
0.14
0.16
0 0.005 0.01 0.015 0.02
Cd
m dot
TMI
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0 0.005 0.01 0.015 0.02
Cd
m dot
rota mater