Koya University

Faculty of Engineering,

School of chemical& Petroleum Engineering

Chemical Engineering Department

3rd Stage

( Temperature measurement )

AUTHOR NAME: shwan sarwan

EXPERIMENT CONTACTED ON: oct. 28th-2015

REPORT SUBMIITED ON: nov. 4th-2015INSTRUCTOR: mr. ahmad & mr.ahmadGroup: -B-

HEAT TRANSFER LAB. EXP.NO.1

1

List of content:

Aim………………………………………………………….3Introduction...…………………………….……………..….4Background Theory ……………………………………….5Procedure …………………………………………………..6Equipment and components used........................................7Calculation.............................................................................8Plot………………………………………………………..…9Discussion ………………………………………………….10References ………………………………………………….11

2

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}

3

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 these devices. 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}

4

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

5

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.

6

Equipment and components used:

1-power-regulated socket2-laboratory heater for water and sand3-psychrometer to determine air humidity4-gas pressure thermometer5-bimetal thermometer6-vacuum flask7-mercury thermometer8-digital display, thermocouple type K9-digital display, thermistor (NTC)10-digital display, Pt10011-multimeter

7

{4}calculation:

Table of calculation:

NO NTC NTC Gas P.T B.M.TH Mercury.TH

1 26.5 27 23 18 28

2 37.7 39.2 36 30 40

3 50.8 52.4 44 43 52.3

4 62.5 60.2 51 53 63

5 72.1 65.1 58 62 72.5

8

Plot:

NO NTC NTC Gas P.T B.M.TH Mercury.TH1

26.5 2723

18

28

2

37.7 39.236

30

40

3

50.8 52.4

44 43

52.3

4

62.5 60.2

51 53

63

5

72.1

65.1

5862

72.5

Temperature measurement

NO.1 NO.2 NO.3 NO.4 NO.5

9

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 MeasurementsIn 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 multiplemeasurements.

10

References:

1-http://fetweb.ju.edu.jo/ME/courses/labs/measurements/labsheet/Experiment%20No%207%20RTD.pdf

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

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

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

11