TH11 EXPERIMENTAL MANUAL.pdf

8/10/2019 TH11 EXPERIMENTAL MANUAL.pdf

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EXPERIMENTAL MANUAL

MODEL: TH 11

SOLUTION ENGINEERING SDN. BHD.

NO.3, JALAN TPK 2/4, TAMAN PERINDUSTRIAN KINRARA,

47100 PUCHONG, SELANGOR DARUL EHSAN, MALAYSIA.

TEL: 603-80758000 FAX: 603-80755784

E-MAIL: [email protected]: www.solution.com.my

SOLTEQ EQUIPMENT FOR ENGINEERING EDUCATION

029-0210-TH

PERFECT GAS

EXPANSION

APPARATUS

PERFECT GAS

EXPANSION

APPARATUS


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TABLE OF CONTENT

LIST OF FIGURES i

1. INTRODUCTION 1

2. GENERAL DESCRIPTION 22.1 Description 22.2 Experimental Capabilities 32.3 Specifications 32.4 Optional Items 32.5 Requirements 32.6 Overall Dimensions 32.7 Manual 42.8 Assembly view 4

3. SUMMARY OF THEORY 53.1 The Perfect Gas 5

3.1.1 Boyles Law 53.1.2 Charless Law 6

3.2 First Law of Thermodynamics 73.3 Specific Heat 83.4 Internal energy, enthalpy and specific heat of ideal gases 83.5 Specific heat relations of ideal gas 93.6 Determination of the Heat Capacity Ratio 93.7 Determination of Ratio of Volume using an isothermal process 11

4. INSTALLATION AND COMMISSIONING 124.1 Installation Procedures 124.2 Commissioning Procedures 12

5. EXPERIMENTAL PROCEDURES 135.1 General Operating Procedures 13

5.1.1 General Start-up Procedures 135.1.2 General Shut-down Procedures 13

5.2 Experiment 1: Boyles Law Experiment 145.3 Experiment 2: Gay-Lussac Law Experiment 155.4 Experiment 3: Isentropic Expansion Process 165.5

Experiment 4: Stepwise Depressurization 175.6 Experiment 5: Brief Depressurization 185.7 Experiment 6: Determination of ratio of volume 195.8 Experiment 7: Determination of ratio of heat capacity 20

6. REFERENCE 21

APPENDICES


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i

LIST OF FIGURES

Figure 1 Assembly view of TH11 4


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SOLTEQPERFECTGASEXPANSIONAPPARATUS(MODEL:TH11)

1

1.0 INTRODUCTION

The Perfect Gas Expansion Apparatus (Model: TH 11) is a self-sufficient bench top unit designed to

allow students familiarize with several fundamental thermodynamic processes. Demonstration of thethermodynamic processes is performed with air for safe and convenient operation.


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2.0 GENERAL DESCRIPTION

2.1 Description

The Perfect Gas Law Apparatus is customarily designed and developed to provide students acomprehensive understanding of First Law of Thermodynamics, Second Law of Thermodynamicsand relationship between P-V-T. The Perfect Gas Expansion Apparatus enable the students tohave a good understanding in energy conservation law and the direction in which the processesproceed.

The Perfect Gas Expansion Apparatus comes with one pressure vessel and one vacuum vessel.Both vessels are made of glass tube. The vessels are interconnected with a set of piping andvalves. A large diameter pipe provides gradual or instant change. Air pump is provided topressurize or evacuate air inside the vessels with the valves configured appropriately. The

pressure and temperature inside the vessels are monitored with pressure and temperature sensorsand clearly displayed by digital indicator on the control panel. With an optional automatic dataacquisition system, the modern version of a classic Clement and Desormes experiment can beconducted as pressure and temperature changes can be monitored continuously with thecomputer.


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2.2 Experimental Capabilities Demonstration of First Law of Thermodynamics Demonstration of Second Law of Thermodynamics and its corollaries

Observation of P-V-T relationship and use it to determine other thermodynamic properties Observation of responses to different rate of changes in a process

2.3 SpecificationsThe Perfect Gas Expansion Apparatus comes complete with the followings:

Test Section:Pressure vessel: 25 L and made of glassVacuum vessel: 12.37 L and made of glassTemperature sensor with the range of 0-100C mounted on the top of vesselsPressure sensor with the range of 160kPa mounted on the top of vessels

Vacuum/Air pump:Capacity: 1.1 CFM open flowMaximum vacuum: 24 HGMotor specification: 1/8 HP (230/50/1HP)

Instrumentation:Digital indicator with bright LCD display

2.4 Optional Items-DAS

SOLDAS Data Acquisition System

i) A PC with latest Pentium Processorii) An electronic signal conditioning systemiii) Stand alone data acquisition modulesiv) Windows based software

Data Logging Signal Analysis Process Control Real-Time Display Tabulated Results

Graph of Experimental Results

2.5 RequirementsElectrical: 230 VAC/1 phase/ 50 HzBarometer (recommended)

2.6 Overall DimensionHeight: 0.90 mWidth: 0.75 mDepth: 0.60m


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2.7 ManualThe unit is supplied with Operating and Experiment Manuals in English giving full descriptions ofthe unit, summary of theory, experimental procedures and typical experimental results.

2.8 Assembly View

Figure 1: Assembly view of TH11

1 Pressure Transmitter

2 Pressure Relief Valve

3 Temperature Sensor

4 Big glass

5 Small glass

6 Vacuum pump

7 Electrode

1

1

2

3

3

4

5

6

7


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5

3.0 SUMMARY OF THEORY

3.1 The Perfect Gas

Perfect gas is also known as ideal gas. An ideal gas is defined as one in which all collisionsbetween atoms or molecules are perfectly elastic and in which there are no intermolecularattractive forces. An ideal gas is also an imaginary substance that obeys the ideal gas equation ofstate.

In 1662, Robert Boyle, an Englishman, discovered in his experiment that the pressure of gases isinversely proportional to their volume in a vacuum chamber. In 1802, J. Charles and J. Gay-Lussac, Frenchman, determined that at low pressures the volume of a gas is proportional to itstemperature. That is,

)(V

TRP (1)

where the constant of proportionality R is called the gas constant and is different for each gas.Equation (1) is called the ideal gas equation of state. Any gas that obeys this law is called an idealgas. In ideal gas equation of state, P is the absolute pressure, T is the absolute temperature and vis the specific volume. The ideal gas equation of state can be written in other form:V = mv, thusPV = mRT (2)

By writing equation (2) twice for a fixed mass and simplifying, the properties of ideal gas at twodifferent states are related to each other by:

2

22

1

11

T

VP

T

VP (3)

It has been experimentally observed that ideal gas relation closely approximate the P-v-T behaviorof real gases at low density. At low pressure and high temperature, the density of gas decreases,and the gas behaves as an ideal gas under these conditions.

Besides of ideal gas equation of state, the ideal gas also obeys the following law:a. Boyles Law

b.

Charless Lawc. Gay-Lussacs Law

3.1.1 Boyles Law

Boyles law is a special law that describes the inversely proportional relationship betweenthe absolute pressure and volume of a gas, if the temperature is kept constant within aclosed system. The mathematical equation for Boyles law is:PV = k (4)


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Where P = pressure of the systemV = volume of the gask = constant value representative of the pressure and volume of the system

As long as the temperature remains constant at the same value the same amount of energygiven to the system persists throughout its operation and therefore, theoretically, the value ofk will remain constant. By forcing the volume V of the fixed quantity of gas to increase,keeping the gas at the initially measured temperature, the pressure p must decreaseproportionally. On the contrary, reducing the volume of the gas will increase the pressure.

The Boyles law is used to predict the result of introducing a change, in volume and pressureonly, to the initial state of a fixed quantity of gas. The equation below is used to relate thevolumes and pressure of the fixed amount of gas before and after expansion process, wherethe temperature before and after the process are the same.

p1V1= p2V2 (5)

3.1.2 Charless Law

Charless law is a gas law which states that:At constant pressure, the volume of a given mass of an ideal gas increases or decreases bythe same factor as its temperature (in Kelvin) increases or decreases.

The formula for this law is:

kT

V (6)

Where V = volume of the gasT = temperature of the gas (measured in Kelvin)k = constant

To maintain the constant, k, during the heating of gas at fixed pressure, the volume mustincrease. On the other hand, cooling the gas decreases the volume. The exact value of theconstant need not be known to make use of the law in comparison between two volumes ofgas at equal pressure.

2

2

1

1

T

V

T

V (7)

As a conclusion, when the temperature increases, the volume of the gas increase.

3.1.3 Gay-Lussacs Law

Gay-Lussacs law states that the pressure of a fixed quantity of gas at constant temperatureis directly proportional to its temperature in Kelvin.The formula is:

kT

P (8)

Where P = pressure of the gasT = temperature of the gas (measured in Kelvin)k = constant


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The temperature is a measure of the average kinetic energy of a substance; as the kineticenergy of a gas increases, its particle collide with the container walls more rapidly, andtherefore exerting increased pressure. In order to compare the same substance under twodifferent sets of condition, the law can be written as:

2

2

1

1

T

P

T

P (9)

3.2 First Law of Thermodynamics

The first law of thermodynamics, also known as the conservation of energy principle, states thatthe energy can be neither created nor destroyed; it can only change forms. The conservation ofenergy principle may be expressed as follows:

The net change (increase or decrease) in the total energy of the system during a process is equalto the difference between the total energy entering and the total energy leaving the system duringthat process.Ein Eout= Esystem (10)

This relation is often referred to as the energy balance and is applicable to any kind of systemundergoing any kind of process. The determination of the energy change of a system during aprocess involves the evaluation of the energy of the system at the beginning and at the end of theprocess. That is,Energy change = energy at final state energy at initial state

Besides, the energy also can exist in numerous form such as internal (sensible, latent, chemical,and nuclear), kinetic, potential, electrical, and magnetic, and their sum constitutes the total energyof the system. For a simple compressible system, the change in the total energy of a system duringa process is the sum of the changes in its internal, kinetic and potential energy can be expressed inthe following form:

PEKEUE (11)

Where

U = m (u2 u1) (12)

KE = )(2

1 21

2

2 vvm (13)

PE = mg (z2-z1) (14)

Energy can be transferred to or from a system in three forms, which is heat, work and mass flow.Energy interactions are recognized at the boundary of system as they cross it and they representthe energy gained or lost by a system during a process. For a closed system, the energy involvedis heat and work. Heat transfer to a system increases the energy of the molecules and thus theinternal energy of the system, meanwhile the energy transfer from a system decreases it since theenergy transferred out as heat comes from the energy of the molecules of the system. Work is anenergy interaction that is not caused by a temperature difference between a system and its


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surrounding system. The example of work interactions are rising piston and a rotating shaft. Worktransfer to a system increases the energy of the system, and work transfer from a systemdecreases it as the energy transferred out as work comes from the energy contained in the system.The mass flow involved in the open system. When mass enters a system, the energy of the systemincreases because mass carries energy with it. Likewise, when the mass flows out from thesystem, the energy contained within the system decreases because the leaving mass takes outsome energy with it.

From the description above, it is known that the energy can be transferred in the forms of energy,work and mass flow, and the net transfer of a quantity is equal to the difference between theamounts transferred in and out. In conclusion, the energy balance can be written more explicitly as:Ein Eout= (Qin Qout) + (Win Wout) + (Emass,in Emass,out) = Esystem (15)

3.3 Specific Heats

The specific heat is defined as the energy required to raise the temperature of a unit mass of asubstance by one degree. The energy depends on how the process is executed. Normally inthermodynamics, two kinds of specific heats are broadly used, which is specific heat at constantvolume (Cv) and specific heat at constant pressure (Cp). The specific heat capacity at constantvolume is defined as the energy required to raise the temperature of the unit mass of a substanceby one degree as the volume is maintained constant. The specific heat capacity at constantpressure is the energy required to raise the temperature of the unit mass of a substance by onedegree as the pressure is maintained constant. The Cpis always larger than Cvas at constantpressure the system is allowed to expand and the energy for expansion work must be supplied tothe system. The defining equations for Cvand Cpare as follow:

(16)

(17)

From the equation, it shows that the Cv is a measure of the variation of internal energy of asubstance with temperature, and Cpis a measure of the variation of enthalpy of a substance withtemperature.

3.4 Internal energy, enthalpy and specific heats of ideal gases

Joule has demonstrated in his classical experiment that the internal energy is a function of thetemperature only. In his experiment, two tanks connected with a pipe and valve was submerged ina water bath. Initially, one tank contained air at high pressure and the other tank was evacuated.

After thermal equilibrium was attained, he opened the valve to let air pass from one tank to theother until pressure equalized. From the observation, temperature of water bath remains constantand assumed no heat transfer. Since there is also no work done, he concluded that the internalenergy of the air did not change even though the volume and the pressure changed. Internal

v

vT

uC

p

pT

hC


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energy is a function of temperature only. By using the definition of enthalpy and the equation ofstate of an ideal gas,

h = u +PvandPv = RT

By combining both equations,h = u + RT (18)since R is a constant and u= u(T), the enthalpy of an ideal gas is also a function of temperatureonly,h = h (T)Therefore, at a given temperature for an ideal gas, u, h, Cvand Cpwill have fixed values regardlessof the specific volume or pressure. Thus the differential changes in the internal energy and

enthalpy of an ideal gas can be expressed as:du = Cv(T)dT (19)dh = Cp(T)dT (20)

3.5 Specific heat relations of ideal gas

A special relationship between Cp and Cv for ideal gases can be obtained by differentiating therelation h = u +RT, which yields

dh = du + RT (21)

by replacing dh by CPdT and du by CvdT and dividing the resulting expression by dT, the equationbecomesCp= Cv+ R (22)

Another ideal gas property called the specific heat ratio k, defined as

v

p

C

Ck (23)

3.6 Determination of the Heat Capacity Ratio

The heat capacity ratio, k, given by equation (23) can be determined for air near standard pressureand temperature which is determined by a two step process:

1) An adiabatic reversible expansion from initial pressure, Pi, to an intermediate pressure Pm.2) A return of the temperature to its original value, To, at constant volume, attaining a final

pressure, Pf

v

p

C

Ck


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Where Cp is the molar heat capacity at constant pressure and Cv is the molar heat capacity atconstant volume.

For a perfect gas, the following is true:

Cp= Cv+ R

For a non-ideal gas, such as a reversible adiabatic expansion, dq = 0. According to first law ofthermodynamics,dU = dq + dW

During the expansion process:dU = dWdU = -PdV (24)

The heat capacity related the change in temperature to the change in internal energy when thevolume is held constant, shown as follow:dU = CvdTsubstituting CvdT into equation (24) and the equation becomes:CvdT = -PdV (25)

Substituting into the ideal gas law, followed by integration yields equation (26)

i

m

i

m

i

m

vV

VR

V

V

P

PC ln)ln(ln (26)

Rearranging and substituting from equation (22):

i

m

v

p

i

m

VV

CC

PP lnln (27)

During the return of the temperature to its initial value, the following relationship is known:

f

i

i

m

P

P

V

V (28)

Substituting equation (28) into equation (27) and rearranging to obtain a heat capacity ratio (29), acomparison between theoretical and experimental heat capacity ratios can be easily conducted fora diatomic ideal gas.

fi

mi

v

p

PP

PP

C

C

lnln

lnln


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3.7 Determination of Ratio o f volumes using an isothermal process

To determine the ratio of volumes using an isothermal process, one pressurized vessel is allowedto leak slowly into another vessel of different size. At the end of the process, the two vessels areequilibrated and the final pressure is constant in both vessels. The final equilibrium absolutepressure, Pabsf, can be determined using the ideal gas equation:

)(

)(

21

21

VV

RTmmPabsf

(29)

Where the subscript 1 and 2 represent vessels one and two respectively. Since both of the vesselsare at room temperature before the valve is opened, and the entire process is isothermal, then theinitial temperature will be equal to the final temperature. Taking the ideal gas equation intoconsideration, equations (30) and (31) are derived according to the initial mass contained within

each vessel:

RT

PVm

iabs,11

1

(30)

(31)

using equations (30) and (31) and substituting the solutions for m1 and m2 respectively into

equation (29), the equation becomes

21

,22,11)(

VV

RTRT

PV

RT

PV

P

iabsiabs

f

(32)

Cancelling RT and rearranging to provide the ratio of the two volumes,

iPP

PP

V

V

absf

fiabs

,1

,2

2

1

(33)

RT

PVm

iabs ,22

2


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4.0 INSTALLATION AND COMMISSIONING

4.1

Installation Procedures

1. Unpack the unit and place it on a table close to the single phase electrical supply.2. Place the equipment on top of a table and level the equipment with the adjustable feet.3. Inspect the all parts and instruments on the unit and make sure that it is in proper condition.4. Connect the pump to the nearest power supply.

4.2 Commissioning Procedures

1. Install the equipment according to 4.1.2. Make sure that all valves are initially closed.

3.

Fill up the sump tank with clean water until the water level is sufficient to cover the return flowpipe.

4. Then test the pump according to Section 5.1.5. Check that pump, flow meter and the pressure gauges are working properly. Identify any

leakage on the pipe line. Fix the leakage if there is any.6. Turn off the pump after the commissioning.7. The unit is now ready for use.


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5.0 EXPERIMENTAL PROCEDURES

5.1

General Operating Procedures

5.1.1 General Start-up Procedures1. Connect the equipment to single phase power supply and then switch on the unit.2. Fully open all valves and check the pressure reading on the panel. This is to make sure

that the chambers are under atmospheric pressure.3. Then, close all the valves.4. Connect the pipe from compressive port of the pump to pressurized chamber or connect

the pipe from vacuum port of the pump to vacuum chamber.5. Now, the unit is ready for use.

5.1.2

General Shut-down Procedures1. Switch off the pump and remove both pipes from the chambers.2. Fully open the valves to release the air inside the chambers.3. Switch off the main switch and power supply.


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5.2 Experiment 1: Boyles Law Experiment

Objectives:To determine the relationship between pressure and volume of an ideal gasTo compare the experimental results with theoretical results

PRECAUTIONS:When carrying out the experiment, pump pressure level should not exceed 2 bar as excessivepressure may result in glass cylinder breaking.

Experimental Procedures:

1. Perform the general start up procedures in section 5.1. Make sure all valves are fully closed.

2.

Switch on the compressive pump and allow the pressure inside chamber to increase up toabout 150kPa. Then, switch off the pump and remove the hose from the chamber.

3. Monitor the pressure reading inside the chamber until it stabilizes.4. Record the pressure reading for both chambers before expansion.5. Fully open V 02 and allow the pressurized air flows into the atmospheric chamber.6. Record the pressure reading for both chambers after expansion.7. The experimental procedures can be repeated for the following conditions:a) From atmospheric chamber to vacuum chamberb) From pressurized chamber to vacuum chamber8. Calculate the PV value and prove the Boyles Law.


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5.3 Experiment 2: Gay-Lussac Law Experiment

Objectives:To determine the relationship between pressure and temperature of an ideal gas

Experimental procedures:1. Perform the general start up procedures in section 5.1. Make sure all valves are fully closed.2. Connect the hose from compressive pump to pressurized chamber.3. Switch on the compressive pump and records the temperature for every increment of 10kPa

in the chamber. Stop the pump when the pressure PT 1 reaches about 160kPa.4. Then, slightly open valve V 01 and allow the pressurized air to flow out. Records the

temperature reading for every decrement of 10kPa.5. Stop the experiment when the pressure reaches atmospheric pressure.6. The experiment is repeated for three times to get the average value.

7.

Plot graph of pressure versus temperature.


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5.4 Experiment 3: Isentropic Expansion Process

Objectives:To demonstrate the isentropic expansion process

Experimental procedures:

1. Perform the general start up procedures in section 5.1. Make sure all valves are fully closed.2. Connect the hose from compressive pump to pressurized chamber.3. Switch on the compressive pump and allow the pressure inside chamber to increase until

about 160kPa. Then, switch off the pump and remove the hose from the chamber.4. Monitor the pressure reading inside the chamber until it stabilizes. Record the pressure

reading PT 1 and temperature TT 1.5. Then, slightly open valve V 01 and allow the air flow out slowly until it reaches atmospheric

pressure.6. Record the pressure reading and temperature reading after the expansion process.7. Discuss the isentropic expansion process.


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5.5 Experiment 4: Stepwise Depressurization

Objectives:To study the response of the pressurized vessel following stepwise depressurization




reading PT 1.5. Fully open valve V 01 and bring it back to the closed position instantly. Monitor and records

the pressure reading PT 1 until it becomes stable.6. Repeat step 5 for at least four times.7. Display the pressure reading on a graph and discuss about it.


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5.6 Experiment 5: Brief Depressurization

Objectives:To study the response of the pressurized vessel following a brief depressurization




reading PT 1.5. Fully open valve V 01 and bring it back to the closed position after few seconds. Monitor and

records the pressure reading PT 1 until it becomes stable.6. Display the pressure reading on a graph and discuss about it.


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5.7 Experiment 6: Determination of ratio of volume

Objectives:To determine the ratio of volume and compares it to the theoretical value

Experimental Procedures:

1. Perform the general start up procedures in section 5.1. Make sure all valves are fully closed.2. Switch on the compressive pump and allow the pressure inside chamber to increase up to

about 150kPa. Then, switch off the pump and remove the hose from the chamber.3. Monitor the pressure reading inside the chamber until it stabilizes.4. Record the pressure reading for both chambers before expansion.5. Open V 02 and allow the pressurized air flows into the atmospheric chamber slowly.6. Record the pressure reading for both chambers after expansion.

7. The experimental procedures can be repeated for the following conditions:a) From atmospheric chamber to vacuum chamberb) From pressurized chamber to vacuum chamber8. Calculate the ratio of volume and compares it with the theoretical value.


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5.8 Experiment 7: Determination of ratio of heat capacity

Objectives:To determine the ratio of heat capacity




reading PT 1 and temperature TT 1.5. Fully open valve V 01 and bring it back to the closed position after few seconds. Monitor and

records the pressure reading PT 1 and TT1 until it becomes stable.6. Determine the ratio of heat capacity and compare with the theoretical value.


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6.0 REFERENCEShttp://www.chemeng.queensu.ca/courses/CHEE218/projects/GasExpansion/ExpansionProcesses

ofaPerfectGas.php


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APPENDIX A

SAMPLE DATA SHEET


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EXPERIMENT 1: Boyles Law Experiment

Before expansion After expansion

PT 1 (kPa abs)

PT 2 (kPa abs)

EXPERIMENT 2: Gay-Lussac Law Experiment

Trial 1 Trial 2 Trial 3

Pressure

(kPa abs)

Temperature (C) Temperature (C) Temperature (C)

Pressurise

vessel

Depressurise

vessel

Pressurise

vessel

Depressurise

vessel

Pressurise

vessel

Depressurise

vessel

110

120

130

140

150

160

EXPERIMENT 3: Isentropic Expansion Process


PT 1 (kPa abs)

TT 1 (C)


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EXPERIMENT 4: Stepwise Depressurization

PT 1(kPa abs)

initial After first

expansion

After second

expansion

After third

expansion

After fourth

expansion


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EXPERIMENT 5: Brief Depressurization

PT 1(kPa abs)

initial After brief expansion


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EXPERIMENT 6: Determination of ratio of volume

PT 1 (kPa abs) PT 2 (kPa abs)

Before expansion

After expansion

EXPERIMENT 7: Determination of ratio of heat capacity

initial intermediate final

PT 1 (kPa abs)

TT 1 (C)


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APPENDIX B

TYPICAL EXPERIMENTAL RESULT


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EXPERIMENT 1: Boyles Law Experiment

Condition 1: from pressurised vessel to atmospheric vessel


PT 1 (kPa abs) 147.1 131.6

PT 2 (kPa abs) 101.5 131.7

Condition 2: from pressurised vessel to vacuum vessel


PT 1 (kPa abs) 157.1 123.7

PT 2 (kPa abs) 54.2 123.7

Condition 3: from atmospheric vessel to vacuum vessel


PT 1 (kPa abs) 103.9 92.9

PT 2 (kPa abs) 70.3 93.0

Sample calculation:

For condition 1: from pressurised vessel to atmospheric vessel

V1= 0.025m3

V2= 0.01237m3

By using Boyles Law,

P1V1= P2V2

(147.1 x 0.025)+(101.5 x 0.01237) = (131.6 x 0.025)+(131.7x 0.01237)

3.6775 + 1.255555 = 3.29 + 1.629129

4.933055 = 4.919129

The difference is only 0.013926, therefore the Boyles Law is verified.


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EXPERIMENT 2: Gay-Lussac Law Experiment

Trial 1 Trial 2 Trial 3

Pressure

(kPa abs)

Temperature (C) Temperature (C) Temperature (C)

Pressurise

vessel

Depressurise

vessel

Pressurise

vessel

Depressurise

vessel

Pressurise

vessel

Depressurise

vessel

110 28.9 31.2 29.4 29.4 28.8 31.5

120 29.2 32.2 29.4 30.7 29.1 32.5

130 30.0 33.0 30.0 31.8 29.9 33.2

140 31.0 33.6 30.7 32.6 30.9 33.7

150 31.9 34.0 31.5 33.3 31.9 34.0

160 32.8 34.1 32.6 33.8 32.8 34.1

Pressure

(kPa abs)

Average

temperature (C)

110 29.9

120 30.5

130 31.3

140 32.1

150 32.8

160 33.4


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Graph of pressure against temperature

The pressure is directly proportional to temperature. Hence, the Gay Lussac Law is verified.


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EXPERIMENT 3: Isentropic Expansion Process


PT 1 (kPa abs) 157.0 101.4

TT 1 (C) 31.4 28.4

Sample calculation:

For isentropic process,)

1(

1

2

1

2 k

k

P

P

T

T

k = 1.4

(28.4/31.4) = (101.4/157.0)0.2857

0.9045 = 0.8826

The difference is 2.48%. The expansion process is proven as isentropic.


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EXPERIMENT 4: Stepwise Depressurization

Pressure (kPa abs)

initial After first

expansion

After second

expansion

After third

expansion

156.6 123.4 102.6 101.4

123.5 102.7 101.5

123.6 102.8 101.6

123.7 102.9 101.7

123.8 103.0 101.8

123.9 103.1 101.9

124.0 103.2 102.0

124.1 103.3 102.1

124.2 103.4 102.2

124.3 103.5 102.3

124.4 103.6 102.4

124.5 103.7 102.5

124.6 103.8 102.6

124.7 103.9 102.6

124.8 104.0 102.6

124.9 104.1 102.6

125.0 104.2 102.6

125.1 104.3

125.2 104.4

125.3 104.5

125.4 104.6

125.5 104.7

125.5 104.8


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.

104.9

105.0

105.1

105.2

105.3

105.4

105.5

105.6

105.7

105.8

105.9

106.0

106.1

106.1

106.1

106.1


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Graph of response of pressurised vessel following stepwise depressurisation


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EXPERIMENT 5: Brief Depressurization

PT 1(kPa abs)

initial After brief expansion

156.9 103.3

103.4

103.5

103.6

103.7

103.8

103.9

104.0

104.1

104.2

104.3

104.4

104.5

104.6

104.7

104.8

104.9

105.0

105.1

105.2

105.3

105.4

105.5


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105.6

105.7

105.8

105.9

106.0

106.1

106.2

106.3

106.4

106.5

106.6

106.7

106.8

106.9

107.0

107.1

107.2

107.3

107.4

107.5

107.6

107.7

107.8

107.9

108.0

108.1


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108.2

108.3

108.4

Graph of response of pressurised vessel following a brief depressurisation


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EXPERIMENT 6: Determination of ratio of volume

Condition 1: from pressurised vessel to atmospheric vessel


Before expansion 147.1 101.4

After expansion 132.1 132.2

Condition 2: from pressurised vessel to vacuum vessel




Condition 3: from atmospheric vessel to vacuum vessel




sample calculation:

condition 1:

Volume 1/Volume 2= (P2,initial P2,final) / (P1,final P1,initial)

0.025/0.01237 = (101.4-132.2) / (132.1-147.1)

2.02 = 2.05

Difference = 0.03


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EXPERIMENT 7: Determination of heat capacity

initial intermediate final

PT 1 (kPa abs) 191.8 109.8 120.0

TT 1 (C) 31.8 29.0 29.3

fi

mi

v

p

PP

PP

C

C

lnln

lnln

0.120ln8.191ln

8.109ln8.191ln

= 1.189

The ideal k,v

p

C

C= 1.4

deviation = (1.4-1.189) / 1.4 x 100%

deviation = 15%

The deviation is due to the measurement error. Theoretically, the intermediate pressure should be

lower than the measured intermediate pressure. However, due to the heat loss and sensitivity ofpressure sensor, the error occurs.

Note: The intermediate pressure should be taken as the lowest pressure which read at the moment the

valve is closed.


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APPENDIX C

ASSEMBLY OF TH11


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Parts of TH11

Make sure the gasket is placed properly inside the groove. Make sure the gasket is inside the

groove of the PVC valve (V2).


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Place the big glass on the flange on top of the gasket.

Screw in the electrodes into the support of the flange


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Place the flange on top of the big glass and screw the electrode caps with one washer in between. Plug

in the pressure transmitter cap and temperature sensor.

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TH11 EXPERIMENTAL MANUAL.pdf

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