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Koya University

Faculty of Engineering Chemical Engineering Department

Laboratory of Heat Transfer Experiment Number Six

Temperature Measurement

Instructor: Dr.Barham & Mrs.

Name of Student: Aree Salah Tahir

Experiment Contacted on: 13/April/2015

Report Submitted on: 20/April /2015

Group:A

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List of content:

Aim………………………………………………………….3

Introduction...…………………………….……………..….4

Background Theory ……………………………………….5

Procedure …………………………………………………..6

Equipment and components used........................................7

Calculation.............................................................................8

Plots………………………………………………………9-10

Discussion ………………………………………………….11

References ………………………………………………….12

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Aim:

The probe type is determined by the measurement task. The selection

of the most suitable temperature sensor is made according to the

following criteria:

- Measurement range

- Accuracy

- Measurement site design

- Reaction time

- Durability. {1}

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Introduction:

Temperature measurement in today’s industrial environment

encompasses a wide variety of needs and applications. To meet this

wide array of needs the process controls industry has developed a

large number of sensors and devices to handle this demand. In this

experiment you will have an opportunity to understand the concepts

and uses of many of the common transducers, and actually run an

experiment using a selection of thesemdevices. Temperature is a very

critical and widely measured variable for most mechanical engineers.

Many processes must have either a monitored or controlled

temperature. This can range from the simple monitoring of the water

temperature of an engine or load device, or as complex as the

temperature of a weld in a laser welding application. More difficult

measurements such as the temperature of smoke stack gas from a

power generating station or blast furnace or the exhaust gas of a

rocket may be need to be monitored. Much more common are the

temperatures of fluids in processes or process support applications, or

the temperature of solid objects such as metal plates, bearings and

shafts in a piece of machinery.{2}

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Background Theory:

In many engineering systems temperature constitutes an important

physical variable that needs to be monitored and controlled. For

example, temperature sensors are present in buildings, chemical

processing plants, engines, computers, vehicles, etc. Many physical

phenomena (e.g., pressure, volume, electrical resistance, expansion

coefficients, etc.) can be related to temperature through

the fundamental molecular structure. Temperature variations affect

these quantities, and hence their changes can be used to indirectly

measure temperature.

Temperature measurement devices can be classified as mechanically

operative (mercury thermometer and bimetallic strip) or electrically

operative (resistance temperature detector, thermistor, and

thermocouple). In this laboratory, we will concentrate on electric-

based temperature sensors due to their higher accuracy and ease in

providing measurements for signal processing and computer

acquisition. These sensors are based on the principle that electrical

resistance or voltage of some materials changes in a reproducible

manner with temperature.{3}

2.1. Resistance Temperature Detector (RTD)

2.2. Thermistor

2.3. Thermocouple

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Procedure:

1. Fill the insulated task with water

2. Put the immersion heater in socket and immerse it in water

(unregulated socket).

3. At room temperature which we will take it from mercury

thermometer we should all the temperatures from other sensors.

4. After that we record the temperature for each one of the sensors

with thermometer that means the mercury thermometer is our

standard method.

5. Make a table and record the data.

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Equipment and components used:

1-power-regulated socket

2-laboratory heater for water and sand

3-psychrometer to determine air humidity

4-gas pressure thermometer

5-bimetal thermometer

6-vacuum flask

7-mercury thermometer

8-digital display, thermocouple type K

9-digital display, thermistor (NTC)

10-digital display, Pt100

11-multimeter

{4}

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calculation:

Table of calculation:

NO D.D.Pt100 TNS Gas P.T B.M.TH Mercury.TH

1 22.9 22.2 19 11 22

2 88 69 70 80 90

3 86.4 69 70 79 85

4 82.5 68.2 59 77 80

5 75.5 66.5 61 70 75

6 69.5 64 58 60 70

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Plots:

Plot (1)

Plot (2)

0

10

20

30

40

50

60

70

80

90

100

11 80 79 77 70 60

bim

eta

l th

erm

om

eter

mercury thermometer

Plot between bimetal thermometer& mercury thermometer

0

10

20

30

40

50

60

70

80

90

100

19 70 70 59 61 58

ga

s p

ress

ure

th

erm

om

eter

mercury thermometer

plot between gas pressure thermometer& mercury thermometer

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Plot (3)

Plot (4)

0

10

20

30

40

50

60

70

80

90

100

22.2 69 69 68.2 66.5 64

dig

ita

l dis

pla

y, t

her

mis

tor

(NTC

)

mercury thermometer

Plot between mercury thermometer& digital display, thermistor (NTC)

0

10

20

30

40

50

60

70

80

90

100

22.9 88 86.4 82.5 75.5 69.5

dig

ital

dis

pla

y, P

t10

0

mercury thermometer

Plot between mercury thermometer

& digital display, Pt100

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Discussion:

A comparison between the Plots showing measured data reveals

differences, from plot(1 & 2 & 3) showing the data from gas pressure

thermometer and bimetal thermometer and digital display, thermistor

(NTC) is very far away to actual value of temperature can reading

from mercury thermometer but from plot (4) showing the data from

digital display, Pt100 is very near to actual value of temperature can

reading from mercury thermometer

Error's in Measurements

In statistics error is the dierence between the computed, estimated or

measured value and the true, speed or the-oretically correct value.

Errors are not mistakes. All measurements however are subject to a

variety of errors which can result in incorrect values. Several

examples are human error (simply being human is enough to get some

things wrong) are,incorrect procedures, broken measuring

instruments, and poorly calibrated instruments. The goal of a scientist

is to minimize the possible sources of error in any measurement. The

list of ways to do this is large, but the most common ones used in class

will be by following proper procedures, calibrating instruments,

testing versus known quantities, and making multiple

measurements.

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References:

1- http://fetweb.ju.edu.jo/ME/courses/labs/measurements/l

absheet/Experiment%20No%207%20RTD.pdf

2- http://me.emu.edu.tr/haybar/ME345/Experiment1.pdf

3- http://mechanical.poly.edu/faculty/slee/ME3511/Exp4.p

df

4- http://www.gunt.de/static/s3651_1.php#