1. The document describes an experiment to calibrate an electronic pressure sensor by measuring hydrostatic pressure in a communicating tube system and with the sensor. 2. The experiment involves filling communicating tubes with water to equal levels, then using an equation to calculate actual pressure (Pact) based on height and measuring indicated pressure (Psen) with the sensor. 3. A graph shows the calibrating curve for the pressure sensor, with Pact along the x-axis and Psen along the y-axis forming a linear relationship, demonstrating the sensor was accurately calibrated.

1. Faculty of Engineering Petroleum
Engineering Department
Fluid Mechanics Laboratory, 2nd stage
Experiment Name:
Prepared by: Muhammed Fuad Rashid
Ahmad Jalal Hassan
Muhammad Hassan Aziz
Safwan Tofiq Ameen
Group: A
Supervised by: Mr. Dara & Mr. Awara

2. Aim of the experiment
1- aim to calibrate the electronic pressure sensor apparatus.
2- the hydrostatic pressure depends only on water level(height).

3. Introduction
If a force of equally presses on a surface, then the pressure that acts on the surface
can be calculated by this equation
A
F
p  …………………... (1)
The unit of the pressure is always measured with bar:
1 bar = 105
N/m2
= 105
Pa
If we have a flask which is filled with a fluid, for
example filled with water,the pressure pf the liquid is equal from all of the sides of
the flask, also the pressure of the fluid has the biggest value in the bottom of the
flask. It is dependent on the height h of the liquid level above bottom of the
flask and the density of the liquid,
Pascal’s law to measure hydrostatic pressure;
p =  . g. h …………….. (2) (g=9.81m/s

4. Tools used in experiment A (communicating tubes)
Communicating tubes.
Tool used in experiment B(The electronic pressure sensor)
The electronic pressure sensor apparatus (hydrostatic pressure).

5. Procedure of experiment A (communicating tube)
First a communicating tub is three or more vessels that have different shapes that
means different volume, to perform the experiment.
first we fill the communicating tube with s specific fluid that we want to measure
its pressure in the bottom of communicating tube, usually the fluid is water that we
want to measure its pressure, by seeing the level water in the communicating tube
we observe that the level water is equal in all the different shapes of the vessels,
thus that meant if the hydrostatic pressure was dependent on volume then the
level of the water was different in each vessel but no, according to the Pascal’s law
the hydrostatic pressure is only depend on the height of the water
Pascal’s law
p =  . g. h ………….. (2) (g=9.81m/s2)

6. procedure of experiment B (electronic sensor pressure apertures)
this procedure of measuring the hydrostatic pressure is done by a electronic apertur
called (electronic sensor pressure gauge) which measures the pressure digitally in t
switch box.
the procedure
1-first we must turning on the electronic sensor pressure
2-then we have to close all the cocks expect number
cock that we want to measure the pressure in it.
3-after that we should to open the vent valve on t
number 9 vessel.
4-then we press on the green nob which is on the switch b
to turn on the immersion pump and let water com
inside number 9 vessel which has d=133cm
5-finally we observe the water level of the vessel (9) which measured in (cm), hence-for
the hydrostatic pressure appears on the digital box which this one is measured in mBar

7. Discussion
1-Discuss the difference between the pact. & psen..
2- Draw the calibrating curve for the electronic pressure sensor.
Answers by Safwan Tofiq Ameen
1-Discuss the difference between the pact. & psen..
aSensor is device that senses a physical property such as temperature, pressure.
A transducer is a device that converts one form of energy to another by
relating the physical quantity to resistance. Transmitter is an
electromechanical device measures the equivalent current relating to the
resistance generated by the transducer, amplifying it and transmitting same
to the control system
2- Draw the calibrating curve for the electronic pressure sensor.
3-What is a pressure sensor used for?
Pressure sensors are used for control and monitoring in thousands of everyday
applications. Pressure sensors can also be used to indirectly measure other
variables such as fluid/gas flow, speed, water level, and altitude
2.6
6.4
13.6
18.5
26.3
0
5
10
15
20
25
30
2.5 7.5 12.5 17.5 22.5 27.5
P
act
P sen.
Sensor pressure Calibrating curve
Psen.

8. 4-How does a differential pressure sensor work?
Differential pressure sensors are at the heart of various instruments that measure
flow, pressure and liquid level of industrial processes. ... The diaphragm flexes and
is sensed as an electrical signal that is proportional to the difference in the
twopressures
5-What are the types of pressure sensors?
Pressure sensors are instruments that can be designed and configured to
detectpressure across these variables. ... These sensors can also measure
atmosphericpressure. Similarly, a gauge pressure sensor detects values relative to
atmospheric pressure, and part of the device is usually exposed to ambient
conditions.
Answers by Muhammad Hassan Aziz
1-In this experiment we found a hydrostatic pressure for the liquid sample which it
was (water) by using two different ways:
By a practical way which is to find out p.sensor of water by the special machine
called (hydraulic bench) using a special procedure to do it and it is up to our
experience.
Second was the theoretical way by using the special equation which it was (P=
ρ.g.h) to find out P.actual.
So P.sensor finding by a practically way while a P.actual finding by a theoretically
way.

9. 2.
3.additional question;
why the pressure of the communicating tube is equal when it filled with a liquid at
the same level and at the different shapes?
A/Because according to hydrostatic law the pressure is equal to
(P=p.g.h), and because the density and gravity is constant so just the level of the
water (Height) will make a difference in the pressure and because the level of the
water is same so the pressure is equal and the different shapes will not since any
changing in the pressure.
Answers by Muhammed Fuad Rashid
1.relative of the numbers and wrong read due to making different between this
numbers that we found.
Pressure in fluid doesn’t depends on direction which means that vertical pressure
at a certain point in the fluid is equal to horizontal pressure =lateral
pressure.
2.
2.6
6.4
13.6
18.5
26.3
0
5
10
15
20
25
30
2.5 7.5 12.5 17.5 22.5 27.5
P
act
P sen.
Sensor pressure Calibrating curve
Psen.

10. Answers by Ahmad Jalal Hassan
1-Discuss the difference between the pact. & psen ?
The two terms (Pact. & Psen) were used to calibrate the electronic pressure sensor
apparatus.
Pact is the pressure that theoretically obtained using and calculating the pressure
according to Pascal’s law.
Psen is the pressure which obtained practically by using the electronic pressure
sensor apparatus in way of reading the value of the pressure on the digital display
on the apparatus.
in this experiment that we done in lab the two values were very precise according
to the calibrating curve which shows a liner graph. Do finally I would say the
electronic sensor apparatus works well.
2-Draw the calibrating curve for the electronic pressure sensor?
2.6
6.4
13.6
18.5
26.3
0
5
10
15
20
25
30
2.5 7.5 12.5 17.5 22.5 27.5
P
act
P sen.
Sensor pressure Calibrating curve
Psen.

11. Additional question;
3-why we should open the vent valve above the vessel (9)?
Because when we are turning on the immersion pump to let the water comes
inside the vessel, if the valve was closed then the immersion pump can’t push the
water high up to the vessel because the molecules on the surface of the water
won’t be release if the valve is closed and stay trapped in the vessel, after that the
molecules of the air push the waters molecules towards dawn, so that’s why we
have to open the immersion vent valve in the experiment.
2.6
6.4
13.6
18.5
26.3
0
5
10
15
20
25
30
2.5 7.5 12.5 17.5 22.5 27.5
P
act
P sen.
Sensor pressure Calibrating curve
Psen.