Fluid mechanics lab experiment

1. Koya University
Faculty of Engineering
Chemical Engineering Department – 2nd Stage
Fluid Mechanics Laboratory
Experiment No: 3
Experiment Name: Dead – Weight piston gauge
Instructor: Mr. Daban
Prepared by
Safeen Yaseen Jafar
Ramazan Shkur Kakl
Rekan Kazm Jamel
Rokan Mohammed Omer
Group: B
Experiment Date: 18/11/2020
Submitted on: 25/11/2020

2. Table of Content
Aim/Objective of This Experiment..........................................................................................1
Theory/Introduction .................................................................................................................2
Apparatus/Tools.......................................................................................................................3
Procedure of The Experiment ..................................................................................................5
Table of Reading......................................................................................................................6
Sample of Calculation..............................................................................................................7
Table of Calculation.................................................................................................................9
Discussion..............................................................................................................................10
References..............................................................................................................................13

3. 1
Aim/Objective of This Experiment
The objective of this experiment is to determine Calibrating the Bourdon gauge.

4. 2
Theory/Introduction
The deadweight piston gauge (Bell and Howell) is used is to measure pressure in terms
of fundamental units - force and area. A piston is inserted into a close-fitting cylinder.
Weights are placed on one end of the piston and are supported by fluid pressure applied to
the other end. For absolute pressure measurements the assembly is placed inside an
evacuated bell jar. Pressure measurements take into account a number of parameters affecting
the instrument and its environment. they include the uncertainty of the mass of the weights
and the error in the effective area measurement of the cylinder, gravity measurement, air
buoyancy and temperature. [1]
A dead weight tester is an instrument that calibrates pressure by determining the weight of
force divided by the area the force is applied. The formula for dead weight testers is pressure
equals force divided by area of where force is applied. [2]

5. 3
Apparatus/Tools

6. 4
Name Tools:
1. Base Plate
2. Bourdon gauge
3. Weight support
4. Weights
5. overflow
6. Drain plug
*The device for calibrating pressure gauges essentially consists of two units:
1. The pressure gauge unit
This is where the pressure gauge to be calibrated is screwed in. For experimental purposes,
the unit comes supplied with a Bourdon gauge already screwed in.
2. The load unit
The load unit consists of several weights and a cylinder with a piston. An increase in the load
results in an increase in pressure. The load unit is connected to the pressure gauge unit via an
oil-filled line, enabling the Bourdon gauge to display the increase in pressure.

7. 5
Procedure of The Experiment
So, we have to perform these steps:
1. Open the overflow valve
2. Remove the transport-cap
3. If necessary topping up the hydraulik oil
4. Inserting the piston.
5. To check the zero point of Bourdon gauge, proceed as follows:
6. Press the piston out of the cylinder using the hand wheel.
7. Remove the piston and weight support.
8. Adjust the oil level in the open cylinder until the cylinder is filled up to the
edge.
9. The gauge pressure being tested should now indicate zero, as it is only
subject to ambient pressure.
10. After the zero point of Bourdon gauge has been checked, the weight
support is re-inserted into the cylinder of the pressure gauge unit. The
piston is then slowly lowered by unscrewing the counterbalance cylinder
until it is freely suspended.
11. In order to avoid static friction, set the weight support in gentle rotation.
The mass of the support is 385 g. Taking into account the piston diameter
of 12 mm, it is now possible to read the increase in pressure from Bourdon
gauge.
12. Other pressures occurring when the weight on the support is increased can
be calculated in exactly the same way. The display of 0.5 bar is achieved
by placing a weight with a mass of 193 g on the support. The other weights
weigh 578 g, which is equivalent to a pressure increase of 0.5 bar each
time.

8. 6
Table of Reading
No. Mass (Kg) Pm (bar)
1 0.193 + 0.385 = 0.578 0.46
2 2 × 0.578 = 0.97
3 3 × 0.578 = 1.48
4 4 × 0.578 = 1.98
5 5 × 0.578 = 2.49

9. 7
Sample of Calculation
𝐏𝐚𝐜𝐭 =
𝐅
𝐀
𝐅 = 𝐦 × 𝐠 𝐀 = 𝛑𝐫𝟐
r = d/2
m = 0.578 kg
d = 12 mm
𝐀 = π(
12 × 10−3
2
m)2
A = 0.000113 m2
1. For (m = 0.578)
𝐅 = 0.578 kg × 9.81
𝑚
𝑠2
= 5.67 𝑁
𝐏𝐚𝐜𝐭 =
5.67 N
0.000113 𝑚2
= 5 × 104
𝑃𝑎
Note: 1 bar = 105
Pa
5 × 104
Pa ×
1 bar
105 Pa
= 0.5 bar
2. For (m = 1.156 kg)
𝐅 = 1.156 kg × 9.81
𝑚
𝑠2
= 11.3 𝑁
𝐏𝐚𝐜𝐭 =
11.3 N
0.000113 𝑚2
= 100.3 𝑘𝑃𝑎 = 1 𝑏𝑎𝑟
3. For (m = 1.734 kg)
𝐅 = 1.734 kg × 9.81
𝑚
𝑠2
= 11.3 𝑁
𝐏𝐚𝐜𝐭 =
17.01 N
0.000113 𝑚2
= 150.53 𝑘𝑃𝑎 = 1.5 𝑏𝑎𝑟

10. 8
4. For (m = 2.312 kg)
𝐅 = 2.312 kg × 9.81
𝑚
𝑠2
= 22.68 𝑁
𝐏𝐚𝐜𝐭 =
11.3 N
0.000113 𝑚2
= 200.71 𝑘𝑃𝑎 = 2 𝑏𝑎𝑟
5. For (m = 1.156 kg)
𝐅 = 2.89 kg × 9.81
𝑚
𝑠2
= 28.35 𝑁
𝐏𝐚𝐜𝐭 =
11.3 N
0.000113 𝑚2
= 250.89 𝑘𝑃𝑎 = 2.5 𝑏𝑎𝑟

11. 9
Table of Calculation
No. Pm (bar) Pact (bar)
1 0.46 0.5
2 0.97 1
3 1.48 1.5
4 1.98 2
5 2.49 2.5

12. 10
Discussion
Discussion – Safeen Yaseen Jafar
1. Define the calibrating curve and explain the purpose of it.
The calibrating curve is the curve that show us the relation between Pm and Pact.
The relationship is often a straight line. Calibration curves are used to understand the varies
between Pm and Pact.
2. Draw the calibrating curve between Pm & Pact. then discuss it.
From above calibrating curve we can see (the curve shows us) how Pmeasured and Pactual
change together. Also, we see the value of measured pressure and actual pressure and we will
determine the Pm by Pact or Pact by Pm on calibrating curve.
3. for the following masses find the Pm: Mass: 0.450 kg , 0.7 kg , 1.2 kg.
a) Actual Pressure =
F
A
=
mg
πr2
=
0.45∗9.81
(3.14)(0.006)2 (105)
= 0.39 bar
From calibrations curve Pm= 0.3 bar
b) Actual Pressure =
F
A
=
mg
πr2
=
0.7∗9.81
(3.14)(0.006)2 (105)
= 0.607 bar
From calibrations curve Pm = 0.61
c) Actual Pressure =
F
A
=
mg
πr2
=
1.2∗9.81
(3.14)(0.006)2 (105)
= 1.04 bar
From calibrations curve Pm= 1 bar
0
0.5
1
1.5
2
2.5
3
0 0.5 1 1.5 2 2.5 3
P
M
PACT
(Pm and Pact)'s Relation

13. 11
Discussion – Ramazan Shkur Kakl
1- Define the calibrating curve and explain the purpose of it.
The graphic or mathematic relationship between the readings obtained in an analytic process and the quantity
of analyte in a calibration. The relationship is often a straight line rather than a curve.
Calibration curves are used to understand the instrumental response to an analyte, and to predict the
concentration of analyte in a sample.
2- Draw the calibrating curve between Pm & Pact. Then discuss it.
The calibrating curve appears because of quantity in
the ratio of pact of pm, It is a linear graph and the
curve must be straight line but it's not straight line
because have some error and P gage stand at 1 bar
and not move.
3. for the following masses find the Pm: Mass: 0.450 kg, 0.7 kg, 1.2 kg.
1. P= = = = 0.39 bar
From calibrations curve Pm= 0.3 bar
2. P= = = = 0.607 bar
From calibrations curve Pm= 0.61
3. P= = = = 1.04 bar
From calibrations curve Pm= 1 bar

14. 12
Discussion – Rokan Mohammed Omer
1- Define the calibrating curve and explain the purpose of it.
The calibrating curve is a graphic coordinate expression that expresses the relationship
between the Pact and Pm. We draw it for the purpose of knowing that the pressure gauge is
working properly as the standard set it or not by comparing the theoretical pressure and the
reading of the gauge.
2- Draw the calibrating curve between Pm & Pact. then discuss it.
As we see the curve is linear means that the pressure gauge is working properly
because when the theoretical pressure (Pm) increase also Pact i.
3. for the following masses find the Pm:
1. P=0.39 bar
From calibrations curve Pm= 0.3 bar
2. P=0.607 bar
From calibrations curve Pm= 0.61
3. P=1.04 bar
From calibrations curve Pm= 1 bar.
0
0.5
1
1.5
2
2.5
0 0.5 1 1.5 2 2.5
pm
pact
Relatonship of Pm and Pact

15. 13
References
1. archive.eol.ucar.edu. (2020). Dead Weight Piston Gauge. [online] Available at:
https://archive.eol.ucar.edu/isf/facilities/callab/deadweight.html#:~:text=The%20dead
weight%20piston%20gauge%20(Bell [Accessed 24 Nov. 2020].
2. Instrumentation Tools. (2016). What is a Dead Weight Tester ? - InstrumentationTools.
[online] Available at: https://instrumentationtools.com/dead-weight-tester/ [Accessed
14 Apr. 2020].